The transcription factor BnHY5-2 is associated with plant stress resistance.In order to reveal the response of Brassica napus L.transcription factor BnHY5-2 to salt alkali stress in B.napus,the response of BnHY5-2 to light and salt and alkali was analyzed by transient overexpression,qRT-PCR analysis and subcellular localization.The results revealed that under light conditions,the expression level of the BnHY5-2 gene in B.napus leaves and stems was 29.22 and 3.15 fold higher,respectively,compared to dark conditions.The higher sensitivity to light in leaves suggested that they were the primary site for light signal response.Under light conditions,the expression of BnHY5-2 in leaves and stems was significantly downregulated by 53.1% and 31.0%,respectively,when B.napus was planted in Dalian coastal saline-alkali soil;after applying saline-alkali treatment under dark conditions,the expression of BnHY5-2 was downregulated by 48.2% in the stem,while the difference in expression in the leaves was not significant,indicating organ differences,indicating that the leaves had stricter requirements for light conditions.In B.napus leaves with transient overexpression of BnHY5-2,two out of six genes related to saline-alkali stress(BnNAC32 and BnGS)showed upregulation by 1.25,3.28 fold,respectively,while the other four genes(Bnamy,BnAsp,BnNHX7,BnTPS)were downregulated by 24.8%,25.4%,71.0%,and 82.0%,respectively.Meanwhile,the content of the resistance substance betaine in B.napus increased from 0.256 to 0.573 mg/g,indicating an enhancement by 1.24 fold,suggesting that the overexpression of BnHY5-2 gene could improve the saline-alkali tolerance of B.napus.Subcellular localization results showed that the transcription factor BnHY5-2 was localized in the nucleus and regulates the expression of functional genes.Therefore,BnHY5-2 is not only related to light signaling but also participates in the saline-alkali resistance of Brassica napus L.

To improve the applicability of biochar in saline-alkali agroecosystem,the effect and microbial mechanism of modified biochar were studied.In a 2-year field experiment,common biochar(4.5 t/ha),nitrogen-rich modified biochar(7.5 t/ha)and phosphorus-rich modified biochar(15.0 t/ha)were added to investigate their impact on crop grain yield,soil physicochemical properties and soil microbial diversity.It had been observed that the addition of biochar enhanced the quality of saline-alkali soil,with nitrogen-rich modified biochar and phosphorus-rich modified biochar demonstrating more notable effects.Biochar could boost crop yield,improve soil structure and reduce soil bulk density in saline-alkali land.The effects of the three biochar types were not consistent.Among them,the application of 15.0 t/ha phosphorus-rich modified biochar showed favorable responses,with grain yield of(8.92±0.12)t/ha,representing a 110% increase compared to the control group.Biochar affected soil microbial diversity.Common biochar increased soil microbial diversity,whereas phosphorus-rich modified biochar decreased it.With the continuous addition of biochar,soil physical and chemical properties could affect the relationship between soil microorganisms and plant structure,weakening their relationships.In this study,the application of 15.0 t/ha phosphorus-rich modified biochar was recommended to improve saline-alkali agroecosystem.

To investigate the effect of exogenous melatonin (MT) on salt tolerance of soybean seedlings,and to screen the appropriate application concentration under different salt stress.The soybean variety Tianyou-2986 was used as the test material,and 3 salt concentrations (low salt S₃:3 g/L,medium salt S₅:5 g/L,high salt S₇:7 g/L ) and 6 MT concentrations were set(M₀:0 μmol/L,M₁:25 μmol/L,M₂:50 μmol/L,M₃:75 μmol/L,M₄:100 μmol/L,M₅:150 μmol/L),the morphological parameters,biomass,antioxidant enzyme activity and osmoregulatory substance content of soybean seedlings were analyzed.With the increase of salt stress,the root morphological parameters,biomass,root-shoot ratio,antioxidant enzyme activity and osmoregulatory substance content of soybean seedlings decreased,while the malondialdehyde content increased.Under low salt (S₃) and medium salt (S₅) stress,The number of total length,lateral roots,SOD and POD of 50 μmol/L MT were increased by 52.30%,19.98%,74.10%,40.03% (low salt) and 68.52%,19.24%,81.72% and 37.42% (medium salt),respectively.Under high stress (S₇),75 μmol/L MT increased by 71.17%,19.11%,80.79% and 27.01%,respectively.Under salt stress,exogenous 25—100 μmol/L MT promoted soybean seedling growth and improved salt tolerance to different degrees.The overall evaluation of the affiliation function showed that 50 μmol/L MT was the most effective in alleviating salt damage under low and medium salt stress,and the suitable concentration of MT was 75 μmol/L under high salt stress,and the main reason for the alleviation of salt damage in soybean seedlings was that MT increased the activities of antioxidant enzymes and osmoregulatory substance content,and reduced the content of malondialdehyde,which could alleviate oxidative and osmotic stresses of soybeans under salt stress.

To investigate the influence of green manure cultivation on the carbon and nitrogen content of saline-alkali soil under freshwater leaching,a field experiment was conducted from October 2021 to May 2022.Three treatments were set up:winter fallow(T1),Dongmu 70 rye(T2),and rape(T3).The spatial distribution of soil organic carbon(SOC),nitrate nitrogen($\mathrm{NO}_{3}{ }^{-}-\mathrm{N}$),and ammonium nitrogen($\mathrm{NH}_{4}^{+}-\mathrm{N}$)in the soil and leachate were measured.The results revealed that in the 0—30 cm soil layer,the soil organic carbon content of T1,T2,and T3 increased from 6.20,6.58,7.24 g/kg before leaching to 6.48,7.39,8.06 g/kg after leaching,representing an increase of 4.41%,12.20%,and 11.23%,respectively.After freshwater leaching,the nitrate nitrogen content in the 0—60 cm soil layer of T1 was significantly higher than that of T2 and T3.In the 0—30 cm soil layer,the respective reductions for each treatment were 42.42%,3.85%,and 10.84%.In the 60—90 cm soil layer,the reductions were 1.38%,7.96% and 18.11%.There were no significant differences in ammonium nitrogen content among the different treatments before leaching,but after leaching,the highest ammonium nitrogen content was observed in T2.In conclusion,after leaching irrigation,the soil organic carbon content in different soil layers increased compared to before leaching,while soil nitrogen showed a significant decrease.Analysis of nitrogen content in the soil and leachate indicated that the main nitrogen loss caused by leaching irrigation was in the form of nitrate nitrogen.Compared to winter fallow farmland,the cultivation of rapeseed green manure had a significant effect on increasing soil nitrogen content,while Dongmu 70 green manure was the the most effective in reducing soil nitrogen loss.

In order to explore the effect of salt stress on the physiological mechanism of cotton,saline-tolerant cotton Zhong J0710 was used as a control,two new cotton distantly hybrid germplasms HL2 and A₂H cultivated in cotton breeding research group were treated with salt solution for 15 d(concentration of 200 mmol/L)at seedling stage,and the relative plant height,relative root length and relative survival rate of the test materials were analyzed,and the salt damage index was calculated.The salt tolerance of the test materials was comprehensively evaluated by combining the measurement results of physiological indicators such as primary light energy conversion efficiency (Fv/Fm),antioxidant enzyme activity,proline content,and soluble sugar of seedlings at different treatment times (0,5,12,24,48 h).The results showed that after 15 d of salt stress,the damage degree of the growth of seedlings of the three test materials was as follows:Zhong J0710<HL2<A₂H,and salt stress significantly inhibited the relative plant height,relative root length and relative survival rate of A₂H,indicating that the salt concentration treatment had less effect on the growth and development of HL2 and Zhong J0710,but had a greater effect on A₂H.Under different treatment times,salt stress had different degrees of influence on the maximum light energy conversion efficiency of the three test materials,and the inhibition degrees from weak to strong compared with before stress were HL2<A₂H<Zhong J0710.Compared with the non-stress period, the peroxidase (POD) activity of the tested materials was increased by salt stress, and the POD activity of HL2 during the stress process was significantly higher than that of A2H and Zhong J0710 in the salt-tolerant control, and reached a very significant level at 12—48 h of stress,and the change law of superoxide dismutase (SOD) activity was not obvious,and the role in salt stress was low.The contents of proline in HL2 and the salt-tolerant control increased with the increase of salt stress time,and the soluble sugars and soluble proteins of germplasm HL2 were significantly higher than those in the salt-tolerant control and A₂H during the entire salt stress period.In summary,in salt adversity,salt-tolerant materials have a more developed root system;higher light energy conversion efficiency,higher reactive oxygen species clearance capacity in cells and higher accumulation of osmoregulatory substances are the physiological basis for strong salt tolerance.

In order to cultivate and screen saline-alkali tolerant peanut varieties and expand the utilization area of saline-alkali soil,50 peanut varieties were used as materials,and four saline-alkali gradients,including 0,0.4%,0.8% and 1.2%,were set by potting to screen saline-alkali tolerant varieties. The results showed that under the saline-alkali stress of 0.8% in the germination stage,the seeds of 50 varieties were significantly differentiated in terms of saline-alkali tolerance,and the germination rate and seedling vigor of 8 varieties remained above 90% and 85%. The evaluation results of various physiological indexes at the seedling stage showed that the root indexes and aerial traits did not change much under low concentration (0.4%)saline-alkali stress,but showed different degrees of decline under medium (0.8%)and high (1.2%)concentration stress,and the reduction range was 22%—54% and 30%—56%,respectively. In addition,chlorophyll indexes showed an upward trend with the increase of saline-alkali concentration,with an increase range of 12%—13%. The comprehensive evaluation results of peanut using the excellent index showed that 23,5 and 0 varieties performed excellently under the saline-alkali stress of 0.4%,0.8% and 1.2%,respectively. Correlation analysis revealed that,there was no significant correlation between saline-alkali tolerance stress at the germination stage and the seedling stage,indicating that there were different mechanisms of saline-alkali tolerance during germination and seedling stages. The above results concluded that under the conditions of pot cultivation,moderate concentration (0.8%)saline-alkali was suitable for the screening of peanut saline-alkali tolerance varieties. According to the comprehensive excellence index,five saline-alkali tolerant peanut varieties were selected,namely Jihua 572,Tang 3432,Jinonghua 31,Yihua 16 and Yuhua 191,which provided a basis and germplasm resources for the promotion and cultivation of salt alkali tolerant peanut varieties.

The cultivation of salt-tolerant varieties is one of the measures to improve the yield reduction caused by secondary salinization. Therefore,the salt-tolerant varieties were screened and their tolerance mechanism were determined.Under control and salt treatment conditions,9 varieties of Brassica Campestris L. were used to compare the differences of salt-tolerance among varieties. Meanwhile,the salt-tolerant varieties and salt-sensitive varieties of Brassica Campestris L. were screened out. The photosynthetic characteristics,MDA content,relative conductivity,histochemical staining,SOD,POD,CAT,APX activity,root activity,nitrate content,and nitrate reductase activity of different varieties were determined under salt stress condition. Finally,the salt tolerance mechanism was preliminarily clarified.The growth indexes of 9 varieties were analyzed,and the salt-tolerant variety Lianzhou F₁ and salt-sensitive variety Jinqiuhong No.2 were selected. Compared with 15 mmol/L Ca(NO₃)₂ treatment (the control),the chlorophyll content,net photosynthetic rate,stomatal conductance,and transpiration rate of Lianzhou F₁ under 80 mmol/L Ca(NO₃)₂ stress were significantly lower than those of Jinqiuhong No.2. The relative conductivity,MDA content,O₂ {\mathrm{ }}^{\frac{-}{·}},and H₂O₂ content of Lianzhou F₁ had a slower degree of increasing than those of Jinqiuhong No.2 under Ca(NO₃)₂ stress,while the scavenging of oxygen free radicals had an opposite trend. Compared with the control,the increase of nitrate content in the shoot and root of Lianzhou F₁ under 80 mmol/L Ca(NO₃)₂ stress was lower than that of Jinqiuhong No.2,while the activity of nitrate reductase showed an opposite trend. Moreover,the root activity of Lianzhou F₁ was less affected by nitrate than Jinqiuhong No.2.Lianzhou F₁ is a salt-tolerant Brassica Campestris L. variety,and Jinqiuhong No.2 is a salt-sensitive variety. Lianzhou F₁ has a low degree of oxidative stress,and a high photosynthetic efficiency and nitrate reducing ability,which can make it have a good growth ability under nitrate stress. Therefore,in the land with high degree of salinization,Lianzhou F₁ was recommended as the main cultivar.

In order to explore the effects of straw and microbial fertilizer on the salt content of soil and crops in saline-alkali soil,the experiment was conducted in Dalat Banner,Inner Mongolia.Four treatments were set up:no straw and no microbial fertilizer(CK),single application of straw(G),single application of microbial fertilizer(F)and combined application of straw and microbial fertilizer(GF).Four crops,oat,sorghum hybrid sudangrass,proso millet and oil sunflower,were planted,respectively.The effects of straw and microbial fertilizer on salt ion concentration and salt content of soil and crops in saline-alkali soil were analyzed.The results showed that compared with CK,straw combined with microbial fertilizer could significantly reduce soil salt content,increase crop biomass and salt ion accumulation in crops,and the soil total salt content in the soil planted with oil sunflower was the lowest at 4 400.41 mg/kg,which was significantly reduced by 13.85% compared with CK.Crop biomass and salt ion accumulation of sorghum hybrid sudangrass treated with straw combined with microbial fertilizer were the largest,and the biomass and salt ion accumulation were increased by 68.32% and 108.28% compared with CK,respectively.In addition,straw combined with microbial fertilizer enhanced the selective absorption ability of each crop for salt ions.Under combined treatment,oat had stronger absorption ability for Mg²⁺,Cl^- and {{\mathrm{SO}}_4}^{2-},which were 50.51%,72.74% and 56.39% higher than CK,respectively.The selective absorption capacity of Ca²⁺ was 76.01% higher than that of CK.Oil sunflower mainly absorbed K⁺,and its content was 12.90% higher than CK.In conclusion,straw combined with microbial fertilizer could significantly improve crop biomass,salt ion accumulation and salt ion selective absorption ability,and could effectively reduce the total salt content of saline-alkali soil.Among the 4 crops,sorghum hybrid sudangrass and oil sunflower perform better.

In order to explore the effects of melatonin on the growth and development of adzuki bean seedlings under salt stress,a phytotron experiment was conducted with Baohong 876 as the material and four treatments:CK(Clear water),S(60 mmol/L NaCl),MT(50 μmol/L melatonin)and S-MT(60 mmol/L NaCl and 50 μmol/L melatonin).The growth indexes,photosynthetic indexes,mineral ion contents and antioxidant enzyme activities of adzuki seedlings were analyzed using classical physicochemical determination.The results showed as follows:under salt stress,compared with CK treatment,the growth of adzuki bean seedlings was significantly inhibited,chlorophyll content,net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductivity(Gs)and intercellular CO₂ concentration(Ci)were significantly decreased;the contents of Na⁺ in leaves,stems were significantly increased.Meantime,the content of Ca²⁺ in leaves was significantly increased while the content of Mg²⁺ was significantly decreased,and the ratio of Na⁺/K⁺ was significantly increased.The contents of MDA and H₂O₂ increased significantly,which damaged the selective permeability of membrane lipid.Compared with S treatment,the plant height,leaf area,biomass,and total root length of adzuki bean seedlings were significantly increased under S-MT condition.Meantime,chlorophyll content,leaf Pn,Tr,and Ci were increased.The contents of Na⁺ and K⁺ in leaves,stems were significantly decreased,the content of Mg²⁺ in leaves was significantly increased and Ca²⁺ was significantly decreased,and the Na⁺/K⁺ ratio was decreased.The contents of MDA, {\mathrm{O}}_2^{-} and H₂O₂ decreased.The levels of SOD,POD and CAT activity in leaves and roots were increased.Under normal conditions,the application of melatonin could promote the growth of adzuki bean seedlings,improve the photosynthetic capacity of seedlings,and increase the content of soluble protein.Spearman correlation analysis was performed on 15 representative indicators,and it was found that total root length,chlorophyll content,net photosynthetic rate,and antioxidant enzyme activities were significantly or extremely significantly negatively correlated with Na⁺/K⁺ ratio and ROS.In summary,under salt stress,melatonin can directly and indirectly reduce H₂O₂ content and maintain the stability of membrane lipid permeability by activating the antioxidant enzyme activity of adzuki bean seedlings,thus maintaining the Na⁺/K⁺ balance in plants.Meanwhile,H₂O₂ and Ca²⁺,as signaling molecules,have a synergistic effect in the regulation process of melatonin regulating intracellular ion balance,thereby improving the salt tolerance of plants.

Based on the long-term improvement experiment of organic fertilizer of soda saline-alkali soil in Songnen Plain,the effects of different improvement years(4,11,15,20 a)on soil colloid components,soil organic carbon components and soil organic-mineral compound degree were studied with no improvement as the control(CK).The results showed that with the increase of improvement years,the colloidal content of soil water dispersive group(G₀)decreased significantly(P<0.05),while that of soil calcium-binding complex(G₁)increased significantly(P<0.05);there were no significant changes in colloid content of soil iron and aluminum oxide binding complex(G₂)and(G₀+G₁+G₂)content of different treatments;the organic carbon content in G₀ group,G₁ group and G₂ group showed an increasing trend.Organic carbon content and heavy fraction organic carbon content of all organic fertilizer treatments were significantly increased compared with CK(P<0.05).In all treatments,organic carbon content in 4 a treatment was the highest,and heavy fraction organic carbon content in 11 a treatment was the highest.The total contribution rate of soil carbon sequestration of the treatments complexes with improved years of 11 a or more was 35.51%—54.64%.Compared with CK,organic-mineral compound degree of soda saline-alkali soil treated with organic fertilizer increased to varying degrees,and the increase was obvious in the treatment of 11 a and above.In conclusion,the long-term application of organic fertilizer promoted the transformation of water dispersive colloid of soda saline-alkali soil to water stable complex,significantly increased the contribution rate of the complex to soil carbon fixation,and significantly improved the degree of organic-mineral composition of the soil.

In order to reduce the nitrate content of Brassica rapa L.ssp. chinensis L.,this study carried out nutrient-breaking treatment before the Brassica rapa L.ssp. chinensis L.was harvested.Physiological analysis of Brassica rapa L.ssp. chinensis L.nutrient-breaking treatment showed that Brassica rapa L.ssp.chinensis L.yield did not decrease significantly at 5 d,but the nitrate content of root,petiole and leaf decreased by 49.77%,23.90% and 33.39% respectively.Transcriptome comparison found that 301,2 270,and 2 271 differentially expressed genes(DEGs)were identified in Brassica rapa L.ssp.chinensis L.root,petiole,and leaf at 5 d,respectively.The Gene Ontology(GO)analysis revealed that these DEGs were mainly enriched in nitrogen(N),carbon(C)and reactive oxygen species(ROS)metabolism.In the process of N metabolism,nitrate uptake transporter NPF7.2 genes were down-regulated expression in root,petiole and leaf.The upstream regulator ERF104 of NPF7.2 were down-regulated expression in petiole and leaf.Nitrate retransporter NPF2.13 and NPF1.1 genes were up-regulated expression in leaf.Nitrate assimilation key enzyme glutamine synthetase(GS)genes were up-regulated expression in root and leaf.In the process of C metabolism,the sucrose phosphate synthase(SPS)genes,a key enzyme for sucrose synthesis in petiole and leaf,were up-regulated expression.In the process of ROS metabolism,superoxide dismutase(SOD)and ascorbate peroxidase(APX)genes were up-regulated expression in root.The expression of cytochrome P450,peroxisome and lipoxygenase genes were down-regulated expression in petiole and leaf.Catalase(CAT)and peroxidase(POD)genes were up-regulated expression in leaf.In summary,the nutrient-breaking treatment 5 d before harvesting can not only ensure that the yield of Brassica rapa L.ssp.chinensis L.was not affected,but also improve the quality of Brassica rapa L.ssp.chinensis L..

In order to analyze the salt tolerance of ScALDH21 transgenic cotton at seedling stage,T₄ transgenic ScALDH21 cotton lines and its recipient Xinnongmian 1 was used as the research material,and the research were executed under field and greenhouse conditions.In field condition,the plant materials were planted with 0.4%,0.5% and 0.6% salt soil in stripe pots,respectively.The growth phenotype,the chlorophyll content and survival rate of each transgenic lines and its recipient under different salt concentrations were observed and monitored,and their net photosynthetic rate,stomatal conductance,transpiration rate and instantaneous water use efficiency were measured.In greenhouse condition,the contents of MDA,POD activity,lignin,Na⁺,K⁺ and Na⁺/K⁺ were determined after 150 mmol/L NaCl and water treatment respectively.Compared with the recipient cotton,the survival rate,chloroplast content,net photosynthetic rate,stomatal conductance,transpiration rate and instantaneous water use efficiency of ScALDH21 transgenic cotton were increased under salt stress.MDA content decreased,POD enzyme activity increased,lignin content increased.From the aspect of morphology and physiological indexes, it was verified that the transgenic ScALDH21 cotton improved the salt tolerance of the plant at the seedling stage.

In order to establish a chlorate-based screening system for barley with different nitrogen use efficiency(NUE),the effects of chlorate treatment on barley seedlings were explored,barley germplasms with different responses to chlorate treatment will be used for molecular mechanism research on NUE and crop breeding with high NUE in barley.Eighteen barley landraces from Shanghai region and three main cultivars in present barley production were used as test materials,and hydroponic experiments were carried out in an artificial climate room,and 2 mmol/L KNO₃(CK)and 2 mmol/L KClO₃ treatments were setrespectively.The traits of seedling height,root length,shoot and root dry masses of barley seedlings were measured after 4 days of treatments,respectively.It was showed that the growth of barley seedlings was obviously inhibited under chlorate treatment,especially the seedling height and dry mass related traits.The ANOVA showed that there were extremely significant differences in all traits under both chlorate treatment and normal condition(the control),and there were also extremely significant interactions between the treatments and varieties.The coefficient of variation analysis showed that the coefficients of variation of root length and dry mass related traits were relatively large in both treatments,while the seedling height was relatively small.Correlation analysis also showed that these indexes were positively correlated under both conditions.The chlorate susceptibility was consistent based on both seedling height and shoot dry mass in general,but there were still some differences.The response of seedling height and shoot dry mass to chlorate could be used as an index for screening barley with different NUE,and B104,B002,B053,B092 and B068 were among the six most sensitive varieties to chlorate based on both seedling height and shoot dry mass,indicating that these five barley cultivars might have higher NUE;while B016,B006 and B008 were among the 6 least sensitive varieties to chlorate,suggesting that the NUE of these three barley varieties might be relatively lower.

NRL(NPH3/RPT2-Like)is a type of light-responsive protein unique to plants and plays a vital role in the phototropic signal pathway. To reveal the NRL gene maize genome's characteristics and expression,we analyzed them using bioinformatics methods combined with qRT-PCR technology. The property,structure,evolution of their encoded proteins,and growth period tissue expression and stress expression were analyzed. 31 ZmNRL genes identified were located in nine maize chromosomes,encoding protein amino acids 464-749 aa,which predicted to have chloroplast,nuclear and cytoplasmic locations. According to protein conservation,ZmNRL family was divided into four categories. Their gene structure also presented certain conservation,the most contained four exons. Analysis of the cis-elements of gene promoters revealed a large number of abscisic acids,jasmonic acid,light response,and anti-oxidation elements,among which G-box and Sp1 were two types of light-related elements. The expression of ZmNRL family genes in tissues during the growth period showed a temporal and spatial specificity,and the majority expression level was not high. Only ZmNRL2,ZmNRL4,ZmNRL24,and ZmNRL29 highly expressed. Furthermore,the characteristic modules were produced based on the data of the tissue co-expression genes. And the GO enrichment analysis of a particular leaf growth module containing six ZmNRL genes,mainly associated with the plastid organization biological processes and rRNA binding molecular functions. The expression of ZmNRL5,ZmNRL7,ZmNRL12,and ZmNRL19 genes were analyzed by qRT-PCR under salt,drought,high temperature,and Rhizoctonia solani inoculation treatments. The results showed that ZmNRL12 was significantly up-regulated in maize seedlings treated with high temperature,while ZmNRL5,ZmNRL7 and ZmNRL19 genes were down-regulated in drought,salt and pathogen treatments. In summary,31 ZmNRL genes were identified in the maize genome. They not only had apparent specific tissue expression but also participated in biotic and abiotic stress responses.

The SiPRR73 gene was cloned from Yangu 11 using RT-PCR technology,and through analyzing tissue-specific expression,responsive features of SiPRR73 to different photoperiods,photo-thermal combinational treatments and five abiotic stress treatments,the regulation mode of photoperiod and temperature on SiPRR73,and the responsive pattern of SiPRR73 to abiotic stresses in foxtail millet were explored. The results showed that totally 2 928 bp cDNA sequence of SiPRR73 was obtained from Yangu 11,which included 2 283 bp CDS region,encoding 760 amino acids. The SiPRR73 proteins of C4 crops including Panicum miliaceum,Panicum hallii,Sorghum bicolor and Zea mays showed relatively close relationship with SiPRR73. The second parietal leaf was the highest expression tissue of SiPRR73,but the expression level at root,stem and panicle tissues was relatively lower. The expression level of SiPRR73 was higher at light period than that at dark period under both short-day and long-day conditions,and during the whole vegetative growth phase,SiPRR73 showed higher expression level under long-day compared to short-day,which indicated that the expression of SiPRR73 was induced by light and controlled by photoperiod. The temperature determined expression peak number of SiPRR73 and the photoperiod determined occurrence time of expression peaks,so temperature and photoperiod participated in regulating of SiPRR73 expression mutually. PEG and low temperature stresses induced SiPRR73 expression totally,NaCl induced SiPRR73 expression at early stress stage,but inhibited it at later stress stage. Fe stress inhibited SiPRR73 expression at early stage,but induced it at later stage. ABA stress caused the close responsive feature of SiPRR73 to NaCl. This study indicated that SiPRR73 showed light-dependent expression feature,and photoperiod and temperature regulated SiPRR73 by interaction pattern,suggesting that SiPRR73 participated in adaptability regulation process to different photo-thermal conditions and might play a certain role in coping with drought,low temperature,ABA,NaCl and Fe stresses in foxtail millet.

To investigate the function of soybean GmPP2C89 gene in plant abiotic stress response and adaptation. The expression patterns of GmPP2C89 under NaCl,PEG and mannitol treatments were detected by transcriptome data and Real-time quantitative PCR. Then,the cis-acting elements on the promoter of GmPP2C89 in response to abiotic stress were analyzed,and promoters of different lengths were cloned according to the distribution of cis-elements to construct fusion GUS vectors to obtain the corresponding transgenic Arabidopsis. The response of the promoters to NaCl,PEG and mannitol was analyzed by GUS staining. Transgenic Arabidopsis overexpressing the GmPP2C89 was constructed,and the root length,leaf MDA content and electrolytic leakage,and the expression of salt stress-related genes(SOD,POD,CAT,RD26,RD29A,and RD29B)were measured under normal and NaCl treatment conditions. The results showed that NaCl,PEG and mannitol treatments all led to a significant increase in the expression level of soybean GmPP2C89;the promoter region contained many cis-acting elements such as ABRE,DRE,G-box,MBS,MYB,MYC and TC-rich repeats which were involved in abiotic stress response,and this promoter was more responsive to NaCl treatment. In addition,under the salt treatment,the root length of transgenic Arabidopsis GmPP2C89-OX was significantly greater than that of WT,while the MDA content and electrolytic leakage were significantly lower than those of WT,and the salt tolerance was significantly enhanced;the expression of antioxidant enzyme genes(SOD and POD)and ABA pathway key gene RD29B in GmPP2C89-OX was significantly higher than that in WT. These results indicated that soybean GmPP2C89 was induced by NaCl,PEG and mannitol,and GmPP2C89 overexpression could enhance the salt tolerance of transgenic Arabidopsis by activating antioxidant and ABA pathways.

In order to explore the molecular mechanism of Zoysia grass in resistance to abiotic stresses,in the present study we reported the function of a cold responding gene from Zoysia matrella designated as ZmCOR410. The sequence information of the gene was obtained on the base of transcriptome and genomic data. The expression profile of ZmCOR410 in response to low temperature was detected by qRT-PCR,and the functions of the gene under abiotic stresses were estimated in Arabidopsis and yeast by genetic transformation.The results showed that the CDS of the gene was 927 bp in length,encoding an acid dehydrin that contains 308 amino acids. In the polygenetic tree of COR410 homologues from gramineous grasses,ZmCOR410 had a close relationship with the homologues of Cleistogenes songorica and Eragrostis curvula,two species that were high tolerant to drought stress. In the genomic DNA,there were four copies of core sequence of DRE-cis element in the 1 700 bp region upstream of the CDS of ZmCOR410,and its mRNA was accumulated in leaves exposed to cold. Compared to WT plants,Arabidopsis plants over expressing ZmCOR410 showed reduced injury in leaves after a freezing-temperature exposure,and showed higher survival rates under drought and high temperature stresses. Yeast cells harboring ZmCOR410 were also more tolerant to high temperature stress than the control cells. The results indicated that the product of ZmCOR410 could enhance cells resistance to freezing cold,high temperature and drought stresses,which would help Zoysia matrella going through adverse environments.

To provide a solid foundation for studying the biological function of WRKY family members in kenaf in response to salt stress,all members of WRKY family were identified and their expression patterns were analyzed.Physical and chemical properties,phylogeny and conserved functional domains of WRKY gene family members were analyzed by bioinformatics method.The expression characteristics of WRKY gene family members under salt stress were analyzed by RT-PCR.The results showed that a total of 33 WRKY family members were identified,which were unevenly distributed on 12 chromosomes.There were certain differences in the physical and chemical properties of each member,such as amino acid number,molecular weight and theoretical isoelectric point.The conserved sequence WRKYGQK of each member did not change.Phylogenetic tree analysis showed that 33 WRKY family members were divided into 3 groups,GroupⅠ,GroupⅡ,Group Ⅲ,of which Group Ⅲ contained 5 subgroups.The real-time fluorescence quantitative RT-PCR results showed that there were 26 WRKY family members induced by salt stress,of which 23 had positive regulation and 3 had negative regulation.A total of 33 WRKY family members of kenaf were identified,of which 26 WRKY family members were involved in the salt stress response of kenaf.

In order to explore the effects of saline-alkali stress on the physiological and molecular mechanism of Brassica napus L.,using Huayouza 62 as experimental material.The seedlings of Brassica napus L.were treated with different concentrations of compound salt,compound alkali and compound saline-alkali solution.Physiological indexes such as seed germination rate,chlorophyll content,proline content,soluble sugar content and antioxidant enzyme activity in Brassica napus L.leaves were determined.The accumulation of betaine in rape leaves was determined by high performance liquid chromatography(HPLC).The key enzyme gene choline monooxygenase gene(CMO)in betaine synthesis pathway was analyzed by qRT-PCR technique.The results showed that the degree of damage to seed germination in artificially simulated saline-alkali solution of different concentrations was compound saline-alkali>alkali>salt.Low concentration saline-alkali solution promoted chlorophyll formation in rape leaves,while high concentration saline-alkali solution inhibited chlorophyll formation,saline-alkali stress significantly increased the contents of proline and soluble sugar,and the contents of proline and soluble sugar in high saline-alkali solution(YJ75,saline-alkali 75 mmol/L)for 21 d were 65.99 and 5.21 times higher than those in the control group,respectively,and the content of malondialdehyde was increased by saline-alkali stress.Saline-alkali stress significantly increased the activity of peroxidase(POD).Compared with the control group,the content of POD in high saline-alkali solution(YJ75)increased by 2.26 times after 21 d,and the content of POD reached the highest value on the 14th day after treatment with compound salt and compound alkali,however, the activity changes of superoxide dismutase (SOD) and catalase (CAT) were not obvious, and the role of species in the process of saline-alkali stress was low.Saline-alkali stress significantly increased the expression of key enzyme gene CMO,thus regulating the accumulation of betaine.In summary,the damage degree of saline-alkali stress to Brassica napus L. was compound saline-alkali > alkali > salt.Under high saline-alkali stress,Brassica napus would accumulate a large amount of betaine to reduce the damage.

Application of some hormonal signaling compounds,as brassinolides and their derivatives,could significantly improve the salt stress resistance in plants.The purpose of present work was to test whether the over-expressing of Methylsterol monooxygenase gene(SMO),a key gene coding a bio-synthesizing enzyme of sterol in plants,could promote the salt-stress tolerance of target plants.PnSMO1.1,gene encoding of methylsterol monooxygenase in the plant species of Pharbitis nil was firstly cloned and then used as target gene for following genetic transformation process,while wild-type Pharbitis nil seedlings were used as the receptor plants for constructing of the transgenic lines which over-expressed PnSMO1.1 genes.In this work,the PnSMO1.1 gene transformed Pharbitis nil lines were constructed via an ovary injection transformation method.Plantlets from individual PCR identified transgenic plant lines were used as materials to detect vegetative growth figures and some pivotal physiological indicators,for instance,contents of malondialdehyde (MDA),relative conductivity,as well as castasterone and 6-deoxo-castasterone contents in cells under stresses with gradient NaCl conditions varied from 0—200 mmol/L.The results showed that the over-expression PnSMO1.1 significantly improved the relative growth of roots and hypocotyls in transformants than in wild-type (WT) or vacant plasmid transformed control (BL) plants under 100—250 mmol/L NaCl stresses.Compared to WT and BL seedlings,significantly higher accumulation of 6-deoxo-castasterone,but lower relative conductivity (rEC) values,castasterone accumulation or MDA contents were found in transgenic lines under various NaCl stresses.Stresses such as salinity,drought and freezing temperatures,had severely suppressed the vegetative growth of plants,as well as their yields.These results highlighted that over-expression of the PnSMO1.1 gene could significantly improve the salinity-stress resistance of transgenic plants by delicately adjusting the dynamic homeostasis of brassinolides in cells,and protecting the structural integrity of plasma membrane.

In order to explore the effects of cattle manure on soil salinity and sodicity on the sodic soil in long-term experiments,the experiments were performed in a randomized complete block design with four treatments;soils that received manure applications for 8,12,18 years were used as the experimental treatments,and soil that did not receive cattle manure application was used as the control treatment(CK).The results showed that the application of cattle manure to saline-sodic soil resulted in a reduction in the bicarbonate ion(HCO₃^-)contents,the elimination of carbonate ions(CO₃^2-),the decrease in soil bulk density(ρ_b),the increases in soil porosity(f_t)and soil organic matter(SOM),the decreases in the exchangeable and soluble sodium ion (Na⁺)contents associated with increases in the exchangeable calcium ion(Ca²⁺),soluble potassium ion(K⁺),and magnesium ion(Mg²⁺)contents compared to those in untreated soil.The soil exchangeable sodium percentage(ESP)and pH were both significantly and positively correlated with the exchangeable Na⁺ and HCO₃^-,and CO₃^2- contents,and soil pH was significantly and negatively correlated with SOM.Regression analysis showed that the dominant factors affecting the sodium absorption ratio(SAR)were the soluble Mg²⁺ and Na⁺ contents in the soil.Pearson correlation analysis showed that there were significantly negative correlation between the accumulated amount of cattle manure among the indicators of soil salinization degree,such as pH,EC,ESP and SAR.It was concluded that long-term manure application significantly decreased the soil pH,ESP,electrical conductivity(EC)and SAR due to the replacement of soil colloidal Na⁺ with Ca²⁺,the leaching of soil soluble salts from the topsoil and changes in the soil soluble salt ion composition.These outcomes were likely due to the decrease of ρ_b associated with increase of f_t and Ca²⁺ and Mg²⁺ contents caused by annual manure application.

Screening salt-tolerant yardlong bean is very important for developing salt resistant cultivars. This work was performed on 12 varieties of yardlong bean that have been cultivated across large areas in Jiangsu Province. Vermiculite was used as a cultivation matrix. During the cotyledon expansion stage, 50, 100, 150, 200, 250 mmol/L of NaCl solution was added to 1/2 Hoagland nutrient solution for treatment and the 1/2 Hoagland nutrient solution served as a control. After 4 weeks of treatment, the effects of eight indicators including salt tolerance rating(STR), chlorophyll content(SPAD), plant height(PH), root length(RL), aerial biomass fresh weight(AFW), aerial biomass dry weight(ADW), root fresh weight(RFW), and root dry weight(RDW)of yardlong beans under different concentration of salt stresses during the seedling stage were studied. The salt tolerance of 12 varieties was evaluated by membership function value(F_i), and the evaluation method of tolerance to salt in yardlong bean was determined. Based on the above method, we also assessed salt-tolerance germplasm resources in 84 representative yardlong bean accessions at the seedling stage. It was found that the STR value of 12 varieties increased with the increase of salt concentration, and the coefficient of variation was the highest under 150 mmol/L NaCl stress. Thus, we choose it as the optimum concentration for evaluating the salt tolerance of 12 yardlong bean varieties by membership function value(F_i). Suzi 41 and Lüling 4 were selected as salt-tolerant varieties(F_i>0.60), and Sujiang 1419 as salt-sensitive variety(F_i<0.30). The evaluation method of tolerance to salt was established in yardlong bean seedling stage, using the seedlings grown in vermiculite with 150 mmol/L NaCl treatment for about four weeks. There was a large variation of 84 yardlon bean germplasm accessions in F_i, 0.06-0.88, and Suzijing 1 and Zijinroudoujiao etc. as the 8 salt-tolerance accessions were selected. In this study, 10 salt-tolerant germplasm accessions screened will provide gene resources for the breeding of salt-tolerant yardlong bean.

The aim of this study was to explore the effect of applying microbial fertilizer on salt reduction and the response of cotton growth in coastal saline cotton field. The mild and moderate saline cotton fields in the coastal area of the Yellow River Delta were selected. Cotton field experiments were conducted with different kinds of biological products and different amounts of microbial fertilizer. Soil salinity, cotton plant height, SPAD value, canopy NDVI and other data were collected. The effect of microbial fertilizer on reducing salt in saline cotton field and its response to cotton growth were systematically analyzed. The results showed that different kinds of biological products had a certain effect on salt reduction, and the salt content in surface and underlayer, rhizosphere and between ridges decreased. In mildly saline cotton field, soil salt content decreased between 7.03% and 35.06%, plant height increased by 9.76% to 15.40%, SPAD value increased by 12.97% to 22.64%, and NDVI value increased by 12.58% to 19.85%. Microbial fertilizer treatment had the best effect. Soil salt content decreased by 6.18% -31.85%, plant height increased by 10.02% -17.12%, SPAD value increased by 13.67% -15.55%, and NDVI value increased by 9.22% -18.69% in moderate salinized cotton fields. The effect of microbial fertilizer on reducing salt was the most obvious. In general, the salt reduction and growth promotion effects of the application of microbial fertilizer were better than that of organic matter+beneficial microbial treatment, and better than that of commercial organic fertilizer treatment. The recommended application amount of microbial fertilizer was 1 500 kg/ha. This study proved that the application of microbial fertilizer in coastal saline cotton field had an obvious effect of reducing salt, and had a positive effect on the growth of cotton. The results provided a reference for the biological improvement of coastal saline farmland.

To explore the effects of Trichoderma fertilizer on wheat growth, disease resistance, yield and soil enzyme activities under salt stress.Plant height, root length, root number, physiological and biochemical indexs, diseased ears rate, disease index, control efficiency, thousand seeds weight and soil enzyme activity of Xinong 979 were measured under salt stress by using Trichoderma Fertilizer instead of 30% chemical fertilizer and using 100% chemical fertilizer.The results showed that compared with chemical fertilizer, the application of Trichoderma fertilizer significantly increased plant height, root length and root number of wheat by 10.91%, 43.45% and 42.86% under salt stress, respectively.Secondly, under salt stress, the activity of phenylalanine ammonia-lyase (PAL) and content of chlorophyll in wheat leaves increased significantly after Trichoderma fertilizer application, while the contents of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) in wheat leaves were significantly lower than that of chemical fertilizer.Moreover, the incidence rate of Fusarium head blight in wheat after Trichoderma fertilizer application was significantly lower than that in wheat applied with chemical fertilizer, with the control efficiency of 88.36% to Fusarium head blight.The thousand grains weight of wheat grain increased by 9.5% after Trichoderma fertilizer application compared to control.In addition, the activities of soil enzymes including urease, sucrase, dehydrogenase, catalase, peroxidase and polyphenol oxidase in wheat rhizosphere and non-rhizosphere were much higher after Trichoderma fertilizer application.In sum, under salt stress, Trichoderma fertilizer enhanced the disease resistance of wheat by increasing activities of antioxidant enzymes and chlorophyll content as well as improving the ecological environment of soil, subsequently increasing yield and improving quality of wheat grains.

In order to determine the optimum range of salinity, alkalinity and pH value of sperm motility and fertilization rate of Amur ide. Different NaCl salinity(1‰, 2‰, 3‰, 4‰, 5‰, 6‰, 7‰, 8‰), NaHCO₃ alkalinity(10, 20, 30, 40, 50, 60, 70 mmol/L)and pH value(5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0)were set to stimulate the sperm motility of the Darinor Lake Amur ide.The sperm status of different treatment groups was observed, and the intense movement time, fast movement time and life span of the sperm were measured. Meanwhile, the fertilization rate in different salinity, alkalinity and pH solutions was determined.The results showed as follows. When the salinity ranged from 0 to 4‰, the sperm intense movement, fast movement time and life span increased gradually, and reached the maximum at 4. When the alkalinity was 0-50 mmol/L, the sperm intense movement, fast movement time and life span were prolonged with the increase of alkalinity, and reached the maximum at 50 mmol/L. In the pH value 5.0-7.0, the sperm intense movement, fast movement time and life span increased with the increase of pH, pH value 7.0 reached the maximum. The fertilization rates reached the highest when the salinity was 4‰, the basicity was 30 mmol/L and the pH value was 6.5, respectively. The fertilization rates in different salinity and alkalinity groups were significantly lower than those in the control group. In conclusion, based on the analysis results of different salinity, alkalinity and pH on sperm motility and fertilization rate of Amur ide, it was suggested to select saline-alkali water or fresh water with salinity of 0-4‰, alkalinity of 0-30 mmol/L and pH of 6.0-7.0 in the process of total artificial reproduction and cross breeding of Amur ide. It can obtain higher fertilization rate and seedling survival rate.

The effect of different concentrations salt stress on seedling growth and expression of related genes were explored in this study. Firstly, salt tolerant variety Yura Hama Daikon and susceptible variety Wujinhong were selected according to germination under salt stress conditions among 11 cultivars.And then the seedling height(SH) and the leaf scorch index(LSI) of Yura Hama Daikon and Wujinhong were investigated under salt stress treatment.The results showed that SH decreased and LSI increased under salt stress in both varieties.Compared with the salt-sensitive variety Wujinhong,the salt-tolerant variety Yura Hama Daikon had a smaller decrease in SH and lower LSI.Under 200 mmol/L salt stress,SH and LSI of salt-tolerant Yura Hama Daikon were 46.18% and 20.56,respectively,while those of salt-sensitive Wujinhong were 75.25% and 56.11.The transcription of RsCAT and RsSOD genes was studied in salt-tolerant and susceptible varieties under different salt concentrations by qPCR.The expression of RsCAT gene was first increased and then decreased under low salt concentration treatment,and reached the maximum at 7 day.When treated with high salt concentration,the transcription of RsCAT in Wujinhong was the highest at 48 h,while the expression level in salt-tolerant varieties increased gradually and maintained for a longer time,reaching the highest at 7 day.After high salt concentration treatment,the transcription of RsSOD gene reached the highest expression level at 24 hours,and then maintained a higher level in salt-tolerant variety.In salt-sensitive varieties,the maximum expression level of RsSOD appeared at 14 day.The above results will lay foundation for revealing the mechanism of salt stress in radish and provide technical support for radish salt-tolerant breeding.

In order to further reveal the role of kidney common bean NAC gene in regulating plant growth and development and in response to abiotic stress, this research was used the salt-tolerant common bean variety HYD as the test material and used the Illumina HiSeq technology, the transcriptome of common bean leaf tissue under the NaHCO₃ and NaCl treatments was constructed. A total of 8 saline-alkaline related NAC transcription factors were screened from the transcriptomic data, and carried out analysis of physicochemical property, systematic evolution, phosphorylation site prediction, protein secondary structure prediction, promoter element analysis, gene structure analysis, chromosomal location analysis and expression analysis. The result showed:The molecular weight of 8 common bean saline-alkaline response NAC genes was 23 676.36-44 354.33 ku, and the protein codes were 203-394 amino acids. The isoelectric point was between 4.74 and 8.86, of which 3 genes encoded acidic proteins, and 8 genes were divided into 4 subfamilies (a-d), positioning in 8 chromosomes, including 3 membrane-bound proteins, the number of serine was the largest in 8 proteins, there were 10-22, and the random coil structure accounts for the largest proportion, 68.0% to 84.5%. All 8 proteins were located in the nucleus. Under NaHCO₃ treatment, 4 genes were up-regulated expression (log₂FC>2), 2 genes were down-regulated expression (log₂FC<-2), Under NaCl treatment, 1 gene was up-regulated expression (log₂FC>2), 4 genes were down-regulated expression (log₂FC<-2), 3 genes respond to both NaHCO₃ and NaCl. A total of 10 promoter elements were found in 8 gene promoters, and each gene contained 3-7 elements. It indicated that these genes might be involved in the stress response of common beans.

To assess the peanut rhizosphere bacteria community structure in response to salt stress at different development stages, the peanut variety Huayu 25 was used as experimental material, and a pot experiment was set with three salt concentrations to study the effect of salt stress on peanut yield and analyze the changes of microbial community structure of peanut rhizosphere at flowering and harvest stage under salt stress by high-throughput sequencing technology. The results showed that the rhizosphere microbial composition of peanut were basically similar under different salt stress treatments, but the diversity and richness significantly varied between flowering and harvest stage. Under higher salt stress, the diversity and richness of rhizosphere bacterial community were increased at the flowering and needling stage but decreased at the harvest stage. The dominant bacteria phyla of all soil groups were Proteobacteria, Actinobacteria, Chloroflexi, Acidobacteria, Verrucomicrobia, Bacteroidetes, and Patescibacteria. The relative abundance of Cyanobacteria, Gammaproteobacteria, Verrucomicrobiae and Bacteroides significantly increased under salt stress, especially at the flowering and needling stage. Hierarchical clustering revealed that the microbial community diversity was markedly altered by the salt concentrations and growth stages, samples of the same growth period were clustered into one group under salt stress. KEGG functional prediction analysis indicated that sequences related to carbohydrate metabolism, amino acid metabolism, energy metabolism, and metabolism of cofactors and vitamins were enriched, whereas that of signal transduction mechanisms, lipid metabolism, replication and repair, xenobiotics biodegradation and metabolism, metabolism of other amino acids, and folding, sorting and degradation were decreased. Among them, salt stress increased the abundance of functional groups involved in substance and energy metabolism, membrane transport, translation, replication and repair, and signal transduction, but decreased the 100 fruit weight and 100 kernel weight of peanut resulted in the decrease of peanut yield. Therefore, salt stress had a great impact on the peanut rhizosphere bacterial community structure and peanut yield. The salt tolerance of peanut could be enhanced by improving soil microbial environment. The results provided a theoretical basis for the development of peanut production in saline-alkali areas.

To explore the effects of spraying CaCl₂ at different concentrations on physiological characteristics of apple seedlings under salt stress, two-year-old T337 seedlings were used as test materials, and the pot experiment was used to set 100 mmol/L NaCl(T1) and 100 mmol/L NaCl + four different concentrations of CaCl₂ (5.0(T2), 7.5(T3), 10.0(T4), 12.5 mmol/L(T5)) treatment, watering with deionized water was used as the control(CK).Determine the chlorophyll content, photosynthetic and fluorescence parameters, antioxidant enzyme activity and osmotic adjustment substance content of each treatment group, and carry out correlation and principal component analysis. The results showed that with prolonged stress time, the catalase(CAT), peroxidase(POD), superoxide dismutase(SOD) of T337 leaves first increased and then decreased, malondialdehyde(MDA), intercellular CO₂ concentration(Ci), proline(Pro) and relative conductivity(REC) showed a rising trend, initial fluorescence(F0), PSⅡ maximum light energy conversion rate(Fv/Fm) stomatal conductance(Gs) and the transpiration rate(Tr) showed a downward trend;compared with CK and T1, the variation amplitudes of T337 leaves after treatment with exogenous CaCl₂ were all reduced, and there was a significant concentration effect. Among them, the relative chlorophyll content(SPAD), Pn, Tr, POD, F0 and SOD decreased the least under T4(10mmol/L) treatment, which was significantly higher than other treatment groups;MDA, REC and Ci increased the least, which was significantly higher than CK and lower than others processing group. Correlation analysis of 14 indicators showed that Pn was positively correlated with CAT, Tr, Gs, F0, Fv/Fm, ETR, SPAD, SOD and POD, and negatively correlated with Pro, MDA, Ci, and REC. Principal component analysis was performed on 14 related indicators after salt stress treatment, and 2 principal components with eigenvalues greater than 1 were extracted, and their eigenvalues were 11.190, 2.295, respectively;The first and second principal component variance contribution rates were 79.930%, 16.394%, respectively, the cumulative variance contribution rate reached 96.324%, which meets the analysis requirements. According to the ranking of principal component scores, the mitigation ability of exogenous CaCl₂ to T337 salt stress was T4>T3>T2>T5 from high to low. Therefore, 10 mmol/L CaCl₂ could improve the photosynthetic fluorescence characteristics of T337 rootstock leaves under salt stress, improve the antioxidant enzyme system and osmotic adjustment ability, and enhance the stability and permeability of biofilms to alleviate salt stress.

In order to study the tolerance of heterologously overexpressed Atvip1 gene in sorghum to defense saline-alkali stress and the corresponding growth, NaHCO₃:Na₂CO₃ of 5:1 solution with 75 mmol/L and pH 9.63 was used in sorghum at the stage of three leaves and one heart. The root growth index, chlorophyll content, antioxidant enzyme activity and MDA content were measured at 0, 4, 12, 24, 72, and 120 h of stress. The results indicated that the heterologous overexpression of Atvip1 gene could alleviate the damage of saline-alkali stress on the growth of sorghum seedlings, increase the root surface area and root volume, the number of root tips and branches, and also cause the browning of sorghum main roots to appear later and mild symphonys, and the earlier and more lateral roots occurrence. The new leaves could still be normally extended at 72 h and present little effect on the growth of aboveground. Overexpression of Atvip1 gene could increase the activity of O₂^-· resistance, decrease the content of MDA and enhance the activities of antioxidant enzymes in transgenic sorghum roots. SOD, CAT and GR had obvious effects at 4-12 h during the early stage of stress, respectively. All enzymes played roles during the middle of stress at 24-72 h. CAT and GSH-PX played important roles at the later stage of stress at 120 h. On the base of differential transcriptome analysis of saline-alkali stress, COG analysis of differentially expressed genes(DEGs) showed that defense mechanisms accounted for a relatively large proportion during various periods, and 42 DEGs related to antioxidant enzymes were obtained. Heterologous overexpression of Atvip1 gene can improve the resistance of transgenic sorghum to saline-alkali stress by alleviating the effects on photosynthesis, growth and development, reducing the damages of reactive oxygen species and membrane damage.

In order to clarify whether existed autophagy phenomenon in sugar beet under salt stress and its relationship with plant salt-resistant physiological characteristics, the self-phage occurrence, reactive oxygen species content, osmosis regulating substance content and their relationship under different salt gradients were studied with salt-resistant sugar beet variety LS2004 and salt-sensitive sugar beet variety KWS7125 as experimental materials. The results showed that salt stress could induce autophagy in sugar beet seedlings. Autophagy was involved in the defense process of sugar beet seedlings against salt stress. The specific manifestation was that autophagy increased with the increase of salt concentration. Under the salt stress condition of 300 mmol/L, LS2004 had the strongest autophagy and the largest number of autophagosomes, which was 1.22 times that of KWS7125. The hydrogen peroxide content of KWS7125 and LS2004 reached the peak under the treatment of 200 mmol/L, which were increased by 40.06% and 41.54% respectively compared with that of the control. Under each treatment, the superoxide anion content and relative electrical conductivity of KWS7125 were higher than those of LS2004. The soluble protein content, proline content and total soluble sugar content of LS2004 firstly increased and then decreased with the increase of salt concentration, but there were differences in change rules with KWS7125. In summary, autophagy existed in sugar beet seedlings under salt stress, and the comprehensive effect of autophagy, alleviating oxidative damage, and osmotic adjustment substance content could be used by sugar beet seedlings to improve the salt tolerance of sugar beet.

To explore the effects of different exogenous melatonin concentrations on the growth of cucumber seedlings in a saline environment, in the experiment, cucumber Xintai Mici was used as the test material, and the method of foliar spraying was used to study the effect of different exogenous melatonin concentrations (0, 50, 100, 150, 200 μmol/L) in a moderately saline environment on cucumber seedling growth indicators, osmotic adjustment substances, antioxidant enzyme activity, photosynthetic pigment content, leaf enzyme activity and relative conductivity. The results showed that the treatment with an exogenous melatonin concentration of 100 μmol/L could significantly improve the resistance of cucumber seedlings to stress in a saline environment, and the plant height, stem thickness, leaf length and leaf width of the seedlings was better than the treatments with the melatonin concentrations of 150, 200 μmol/L, and increased by 21.0%, 6.0%, 5.8% and 6.0%, respectively, compared with the control, which promoted plant growth. The SOD, POD and root activity of cucumber seedlings increased by 95.8%, 3.6% and 39.2%, compared with the control, the MDA content and the relative conductivity of the leaves reduced by 23.7% and 8 percentage point, respectively, compared with the control, indicating that the melatonin treatment improved the ability to remove active oxygen and reduced the damage of membrane lipid peroxidation to cucumber seedling cells. Its chlorophyll a content increased by 37%, compared with the control. After 15 d of treatment, the initial fluorescence value (Fo) and maximum fluorescence value (Fm) of M2 seedlings were significantly higher than those of the control. There was no difference between the value of light energy conversion rate (Fv/Fm) and the control. The contents of osmotic regulator soluble protein, proline and soluble sugar significantly increased by 13.8%, 37.5% and 3.6%, respectively, compared with the control. Therefore, when cucumber seedlings are treated with exogenous melatonin at a concentration of 100 μmol/L, it not only promotes the growth of cucumber seedlings, but also improves the stress resistance of cucumber seedlings in a saline environment.

Nitrate transporter (NRT) in plants can effectively regulate and transport NO₃^- and improve nitrogen utilization efficiency. In order to investigate the relationship between Poa pratensis L. NRT2.4 and nitrogen stress, Poa pratensis L. was selected as the material for the cloning and bioinformatics analysis of NRT2.4 gene, and the regulation of this gene expression was observed under treatment by nitrogen nutrient solution. The cloned NRT2.4 gene of Poa pratensis L.belonged to the Nitrate/nitrite transporter NarK superfamily, and was highly homologous to that of Brachypodium distachyon (L.) Beauv. and Aegilops tauschii Coss. Between the 6th and 7th transmembrane domain (TMD), there was a sequence with signature of G-X3-D-X2-G-X-R unique to the MFS family. The 4th TMD had a typical NO₃^-/NO₂^- transporter signature sequence of A-G-W-G/A-N-M-G. There was a conservative protein kinase C motif (S/T-X-R/K):SKR after the 8th TMD.The expression level of Poa pratensis L.NRT2.4 gene was tissue-specific, with the most expressed in leaves. Nitrate nitrogen was conducive to the expression of NRT2.4 gene, both nitrogen starvation and the treatment by nitrogen nutrient solution with a high NaNO₃ were beneficial to the expression of NRT2.4 gene. The results above have provided a theoretical bad for the application of Poa pratensis L.NRT2.4 in stress-tolerance gene engineering in turfgrass.

In order to investigate the function of StTCP13 in salt stress and lay the foundation for the functional study of StTCP13 in response to abiotic stress of potato. The coding sequence of StTCP13 was obtained by homologous cloning. The protein domain and phylogenetic tree were analyzed by bioinformatics.The results showed that the StTCP13 gene was cloned from the potato variety Favorita.The coding sequence length of StTCP13 was 669 bp, encoding a protein composed of 222 amino acid residues.The results of prokaryotic expression suggested that the molecular weight of fusion protein was 51 ku.Protein domain analysis suggested that the protein contained a conserved TCP domain.The results of phylogenetic tree revealed that the protein had a high homology with the TCP13 in Solanum pennellii and Capsicum annuum.Expression pattern of StTCP13 was analyzed by qRT-PCR.Expression analysis showed that the StTCP13 exhibited different expression levels in root, stem, leaf, bud and bud eye in potato. The StTCP13 had high expression level in root, low expression level in bud eye, in addition,the FPKM of StTCP13 in Spud DB showed that the expression of StTCP13 was induced by high-salinity, drought and ABA treatments.The StTCP13-pGEX6P1 prokaryotic expression vector was constructed by double enzyme digestion. Prokaryotic expression results showed that the StTCP13-GST tag fusion protein was successfully expressed in Escherichia coli BL21 . Salt stress phenotype analysis suggested that StTCP13 could improve the tolerance to salt stress in E.coli BL21 . Above all, the StTCP13 might play a role in response to salt stress in potato.

Abiotic stress environment severely restricted tomato production, so it is particularly important to find genes related to abiotic stress tolerance in tomato.In the early stage of this study, UDP-glycyltransferase gene screened by high-throughput sequencing was able to participate in the response to cadmium stress in tomatoes. Therefore, this study took tomatoes as the test material to further study the anti-resistance function of this gene.First, the full length UDP cDNA sequence was obtained by homologous cloning method, and the sequence was analyzed by bioinformatics.Phylogenetic tree was used to analyze the phylogenetic relationship between the protein and plants.Secondly, Real-time fluorescence quantitative PCR was used to analyze the tissue expression characteristics of the gene and its expression patterns under three different abiotic stress conditions (Cd, PEG-6000, NaCl).The stress phenotype of transgenic yeast was further analyzed.The sequencing results showed that the cDNA of this gene was 1 486 bp in length, containing a 1 452 bp open reading frame (ORF), encoding 483 amino acids, and was named SlUDP.Phylogenetic tree analysis showed that the protein was most closely related to potato.The results of Real-time fluorescence quantitative PCR showed that the expression of this gene was different in different tissues of tomato, and the expression level was the highest in leaves, and the expression level in each part was root > fruit > lateral stem > main stem > flower.The stress phenotype analysis results of transgenic yeast showed that SlUDP gene improved the yeast's tolerance to Cd and drought.According to the above results, SlUDP may play a certain role in tomato response to abiotic stresses such as heavy metals cadmium, high salt and drought.

In order to breeding salt tolerant rice varieties, a target was designed to simultaneously knockout OsEIL1 and OsEIL2 genes in rice variety Dongnong 427 by using CRISPR/Cas9 technology. Five mutant plants were obtained in T₀ via PCR and sequencing method, one of them was double genes mutant plant. In the T₁ mutant lines of this plant, four double gene homozygous mutant plants without T-DNA element were obtained. Salt tolerance experiment in seedling stage and agronomic trait analysis at maturity were carried out in T₂. The results indicated that after 200 mmol/L NaCl solution treatment for 5 days, the fresh weight and the dry weight of mutant plants were significantly higher than wild type plants, the Na⁺ content in shoot and root were significantly lower than wild type plants, however, the K⁺ content was no difference with wild type plants. After recovered for 7 days, the seedling survival rate of mutant plants(75.0%) was significantly higher than wild type plants(8.3%). The main agronomic traits didn't change significantly at maturity. In summary, this study improved the salt tolerance of rice variety Dongnong 427 by using CRISPR/Cas9 technology, and provided a theoretical and material basis for the cultivation of salt tolerant rice variety.

To study the effects of salt stress on growth and physiological characteristics of sorghum at different growth stages(elongation, flowering, and maturity), two sorghum varieties with different salt tolerances, Gaoliangzhe(salt tolerance) and Henong No.16(salt sensitive), were planted at four salt treatment levels(CK:0 g/kg, S3:3 g/kg, S5:5 g/kg, S7:7 g/kg). Moreover, the two varieties were compared under different salt treatment levels, plant morphology, root morphology, leaf photosynthetic characteristics and antioxidant enzyme activities at different growth stages. The results showed that with increasing salt treatment concentration, the antioxidant enzyme activity and relative chlorophyll content(SPAD) of the two varieties increased first and then decreased. The antioxidant enzyme activity reached the maximum value under S3 or S5 treatment, and there were significant differences between the maximum and CK. With the increase of salt treatment concentration, the malondialdehyde(MDA) of the two sorghum varieties increased significantly, which S7 treatment was significantly higher than CK. Under the same treatment, the antioxidant enzyme activity of salt-tolerant varieties(Gaoliangzhe) was higher than that of salt-sensitive varieties(Henong No.16), but the content of MDA was lower than that of salt-sensitive varieties. The photosynthetic capacity of the two varieties was significantly affected by salt stress. In elengation, S7 treatment significantly reduced the Pn of Gaoliangzhe, and Ci of the two varieties under S7 treatment was higher than that of CK. Under salt stress, the growth of the sorghum aerial portion and underground portion of sorghum were affected. The basal stem diameter, total length of root, root surface area, number of root tips, and number of root branches for two varieties reached the maximum under S3 treatment. And basal internode length, plant height, total length of root and root volume reached the lowest value under S7 treatment. In addition, grain fat content and grain starch content in two sorghum varieties decreased under salt stress.The grain tannin content was significantly higher than CK in low-salt (S3, 3 g/kg). In general, low-salt can promote the growth of sorghum, while medium-salt (S5, 5 g/kg) and high-salt (S7, 7 g/kg) conditions have a significant inhibitory effect on sorghum growth. And Gaoliangzhe is more salt-tolerant than Henong No.16.

To explore the physiological mechanism of exogenous brassinosteroids (BRs) regulating salt tolerance of alfalfa seedling, the seedlings of M. sativa cv. Zhongmu No.3 and M. sativa cv. Longzhong were selected as the experimental materials, water culture with nutrient solution was used, under 150 mmol/L NaCl stress, the leaves were sprayed with 0.1 μmol/L exogenous 2,4-epibrassinolide (EBR), the effects of exogenous EBR on plant height, aboveground biomass, osmoregulation and antioxidant capacity of alfalfa seedlings under NaCl stress were studied. The results showed that:under 150 mmol/L NaCl stress, the seedling height and aboveground biomass of Zhongmu No.3 and Longzhong decreased significantly, the content of soluble protein and CAT activity in leaves decreased significantly, active oxygen (O₂^-·, OH^·, H₂O₂) accumulated in large quantities, MDA content of membrane lipid peroxidation products increased significantly. Under 150 mmol/L NaCl stress, after spraying 0.1 μmol/L exogenous EBR, the seedling plant height of Longzhong and the seedling aboveground biomass of Zhongmu No.3 increased significantly,the content of soluble protein in the leaves of Longzhong alfalfa and Zhongmu No.3 alfalfa seedlings increased significantly, the content of soluble protein in leaves increased significantly, the activities of SOD, GPX, APX, GR, CAT and GSH, AsA increased significantly, the production of active oxygen (O₂^-·, OH^·, H₂O₂) decreased significantly, and the degree of membrane lipid peroxidation decreased significantly. The results showed that under NaCl stress, the application of exogenous EBR could enhance the osmotic regulation ability of alfalfa seedlings, increased the activities of enzymatic antioxidant system and non enzymatic antioxidant system of alfalfa seedlings, and inhibit the accumulation of active oxygen in alfalfa seedlings. All above resulted in the reduction of osmotic stress and oxidative damage caused by NaCl stress on alfalfa seedlings, and the significant promotion of alfalfa seedlings growth, which having a positive effect on improving salt resistance of alfalfa seedling.

In order to verify the mechanism of hydrogen sulfide to regulate the plant response to salt stress, cucumber seedlings were used as materials and treated with Hoagland(CK), 200 mmol/L NaCl(T) and 200 mmol/L NaCl+15 mmol/L NaHS (the donor of H₂S, S). The expression of transcriptome genes of cucumber roots were studied by using Illumina HiSeq high-throughput sequencing technology. A total of 365.35 Mb of Clean reads were obtained from 9 samples. Mapped reads was 315.74 Mb, and the percentage was 86.27%-88.64%. Analysis of differentially expressed genes revealed that T group had 1 168 genes up-regulated and 1 076 genes down-regulated compared with CK group, and S group had 435 genes up-regulated and 218 genes down-regulated compared with T group. The Gene Ontology (GO) enrichment analysis revealed that the differentially expressed genes were mainly concentrated in binding and catalytic activity in molecular functional classes; in biological process classes, they were mainly enriched in metabolic processes and cellular processes and single-organism process; Among cell components, the membrane and membrane part classes were mainly concentrated. KEGG enrichment analysis of the differentially expressed genes could be divided into 139, 75 and 127 pathway of 3 comparison groups, respectively. The differentially expressed genes in S group compared to the T group were mainly abundant during plant hormone signal transduction, protein processing in endoplasmic reticulum and photosynthesis pathway. Screening of 10 genes that might be related to H₂S regulating cucumber response to salt stress:CSC1-like protein ERD4, nitrate reductase (NADH)-like, protein TIFY 10B-like, allene oxide cyclase, BTB/POZ and TAZ domain-containing protein 1-like, tricalbin-3-like, mitogen-activated protein kinase kinase 3-like, transcription factor bHLH18-like, IAA-amino acid hydrolase ILR1-like 4 and potassium channel AKT1. Studying the mechanism of H₂S regulating cucumber response to salt stress provides theoretical data and reference basis for improving plant salt tolerance.

In order to study the role of RcCNGC2 in the salt tolerance of castor,we cloned and obtained the CDS of RcCNGC2,which was a cyclic nucleotide gated ion channel,from the leaves of Tongbi 5. The CDS of RcCNGC2 was analyzed by bioinformatics,and a multiple expression vector was constructed. The results showed that the CDS length of RcCNGC2 was 2 148 bp,encoding 715 amino acids;the molecular weight of the protein was 34.15 ku; the isoelectric point was 9.96; and there were five transmembrane domains. Amino acid sequence analysis showed that RcCNGC2 had the highest homology with Hevea,up to 89.15%. The results of qRT-PCR showed that the expression of RcCNGC2 was significant difference up-regulated in roots(P<0.05),but decreased significantly in the stem and leaf with the increase of NaCl treatment time. Comprehensively, RcCNGC2 played an important signal transduction role in castor under salt stress.

To study the function of maize small G protein in salt stress, the ZmRab7 was identified and its role was characterized in tolerance to salt stress. Multiple sequence alignment showed that ZmRab7 encoded 206 amino acids, including conserved G1-G5 motifs and C-terminal Cys site. Phylogenetic analysis indicated that the amino acid sequence of ZmRab7 was highly homologous to SbRab7 in Sorghum bicolor. There were four α-helixes, several β-sheets and random coils in the predicted secondary and tertiary structure of ZmRab7, which was similar to the spatial structure of AtRab7. Furthermore, in the promoter region of ZmRab7, there were four GT1GMSCAM4 and two DRECRTCOREAT cis-acting elements to respond to salt stress. ZmRab7 was mainly expressed in the maize root and young embryo, and slightly repressed by high salt treatment. Additionally, heterologous expression of ZmRab7 in yeast remarkably reduced yeast cell tolerance to salt stress. Taken together, these results suggested that ZmRab7 might act as a negative regulator involved in the salt stress response.

QTL sites controlling the concentrations of Na⁺ and K⁺ in the upper ground of rice seedlings were detected under salt and alkaline stress conditions to provide a theoretical basis for further research on salt tolerance, alkaline tolerance genetic mechanism and molecular marker assisted breeding of rice. A group of 200 recombinant autogenous lines was derived from Xiaobaijingzi/Kongyu 131 and its genetic linkage map containing 142 SSR marks to analyze the QTL of score of salt and alkali toxicity, Na⁺ concentration, K⁺ concentration and Na⁺/ K⁺ in rice seedling stage under salt and alkaline stress. A total of 15 QTLs were detected under two conditions, seven and eight QTLs were detected under salt and alkaline stress, distributed on chromosomes 2, 3, 5, 7, 8, 9, 11 and 12, LOD values range from 2.52 to 6.59, and phenotype contribution rate ranges from 6.10% to 28.00%. Among them, qSSNC3 associated with Na⁺ concentration under salt stress and qASNK3 associated with Na⁺/ K⁺ under alkaline stress were located in adjacent intervals; qSSNK2 associated with Na⁺/K⁺ under salt stress and qASKC2 associated with K⁺ concentration under alkaline stress were located in the same interval; qSAT8 and qASNC8 related to Na⁺ concentration and qASKC8 related to K⁺ concentration were located in the same or adjacent interval under alkaline stress. The results showed that Na⁺ and K⁺ concentrations had some genetic overlap under two stress conditions. The results of this study were compared with those of previous studies by the same marker or comparative map,13 QTLs were found to be known as QTLs, while qSAT8 and qASNC8, located between RM547-RM22750, were the new QTL sites.

The identification of salt tolerant genetic loci in rice can provide study basis for the molecular mechanism of salt tolerance and gene resources for improving salt tolerant cultivars. Recombinant inbred lines (RILs) derived from Zhaxima, a landrace indica variety from Yunnan Province and Nanjing 46, an elite japonica varirty with superior grain quality from Jiangsu Province were used. The salt tolerance at seedling stage of the RIL population were investigated as the phenotypic value. Combined with the linkage map, a total of 4 QTLs were detected: qSST-1，qSST-3，qSST-5 and qSST-11 ，located in rice chromosome 1, 3, 5 and 11, respectively. All positive alleles were from the parent Nanjing 46. These QTLs were not included in the same chromosome interval as the cloned rice salt tolerance genes, and thus were described as new candidate gene loci associated with seedling stage salt tolerance. The results supplies important information for further exploration and utilization of new salt tolerant QTLs in rice.

In order to clarify the effects of nitrogen fertilizer applications on key enzyme activities of nitrogen metabolism and protein concent of rice in saline-alkali land, five kinds of nitrogen fertilizer operations were set up in the field experiment using japonica rice variety Kenjing 8 as material. Namely no nitrogen fertilizer(N0),farmers' conventional nitrogen application(N1,the total amount of pure N was 150 kg/ha,base fertilizer：tillering fertilizer：panicle fertilizer=6：3：1),balanced nitrogen application(N2,the total amount of pure N was 150 kg/ha,base fertilizer：tillering fertilizer：panicle fertilizer=4：3：3),balanced nitrogen reduction and fertilization(N3,the total amount of pure N was 135 kg/ha,base fertilizer：tillering fertilizer：panicle fertilizer=4：3：3),and nitrogen fertilizer advancement(N4,the total amount of pure N was 150 kg/ha,base fertilizer：tillering fertilizer：panicle fertilizer=5：3：2). Among them,N1 was used as a control. To analyze the activities of nitrate reductase(NR), glutamine synthetase(GS) and glutamate synthase(GOGAT) in flag leaves and grains at the heading stage of rice in saline-alkali land, as well as protein content and protein components in grains, the effect of amino acid content. Results showed that,compared with N1, N2, N3 and N4 increased the activity of NR, GS and GOGAT in the flag leaves of rice at the heading stage, especially the activities of NR, GS and GOGAT of N2 and N3 were significantly increased by 74.21%, 63.22%, 45.46% and 28.95%, 34.28%, 27.27%; The activities of NR, GS and GOGAT in the grain after heading decreased with the advancement of the filling process, and the trend of each period was consistent with the flag leaf at the heading stage. The albumin, globulin and gluten content of N2 and N3 were significantly increased by 28.30%, 14.29%, 10.32% and 20.76%, 9.89% and 8.70%, respectively. The prolamin was significantly reduced by 7.55% and 9.43%, respectively. The total protein content increased by 9.59% and 7.26%, respectively. The protein content of N4 and its components were improved, and gluten was significantly increased by 7.08%. The contents of total amino acids, essential amino acids and non-essential amino acids in the grains treated with N2 and N3 were significantly increased by 29.78%, 31.14%, 29.09% and 19.11%, 17.96%, 19.39%, respectively. N4 significantly increased the total amino acid and non-essential amino acid content. In summary, balanced nitrogen application and balanced nitrogen reduction are beneficial to maintain high levels of NR, GS and GOGAT activities during flag leaf and grain filling, and regulate protein content, its components and amino acid content, and effectively improve the nutritional quality of rice.

In order to find a variety of switchgrass varieties suitable for planting in the Yinbei saline-alkali area of Ningxia, this study analyzed and compared the biomass yield and nitrogen uptake and utilization of 11 different species of switch grass varieties through field experiments. The results showed that among the 11 switchgrass varieties, the yield of Alamo was the highest, which was 20.47 t/ha, which was significantly higher than that of other varieties (P <0.05). The nitrogen uptake efficiency decreased firstly during the whole growth period. The general trend of rising and then decreasing, and the absorption efficiency of Cave-in-Rock nitrogen was higher in the flowering and filling stages, which was significantly higher than that in other varieties (P <0.05). Black Well nitrogen utilization efficiency was the highest. Up to 69.26 kg/kg, it can be known from the clustering results that it is divided into four categories. Among them, the Alamo variety of switchgrass in the second category had the highest biological yield, and the nitrogen use efficiency was second only to Black Well, which was 67.66 kg/kg. There was no significant difference between the two (P >0.05). The comprehensive analysis showed that planting Alamo variety switchgrass in this area can not only obtain higher biological yield, but also avoid a series of environmental pollution problems caused by excessive application of nitrogen fertilizer, and provide a theoretical basis for its cultivation and management in saline-alkali soil.

In order to excavate the role of exogenous silicon(Si) in salt stress response and explore the regulation mechanism of salt stress response, the cotton variety Xinluzao 45 was used as test material, and was treated with 3 levels of salt(NaCl:0, 100, 200 mmol/L) and 2 levels of silicon(K₂SiO₃:0, 262.3 mg/L). The changes of seedling growth, osmotic regulation, reactive oxygen, malondialdehyde(MDA) content and electrolyte leakage rate were measured after the treatment of exogenous Si, and the effect of silicon in relieving the inhibitory effect of NaCl on cotton seedlings were studied. The results showed that, compared to CK, the fresh leaf weight, dry leaf weight, stem fresh weight, stem dry weight, root dry weight, root cap ratio, root activity, malic acid and citric acid of cotton seedlings all showed a downward trend along with the increase of NaCl levels, while the contents of free proline(Pro), hydrogen peroxide(H₂O₂) and malondialdehyde, the rate of electrolyte leakage and the oxygen free radical(O₂^·) production presented a upward trend, and SS and free amino acid contents increased first and then decreased. The biomass and osmotic regulator of cotton seedlings increased obviously in the same salt treatment after application of exogenous silicon, while the rate of O₂^· production, electrolyte leakage rate, the contents of hydrogen peroxide and malondialdehyde in cotton seedlings decreased obviously. Comprehensive analysis showed that the salt stress could inhibit the growth of cotton seedlings, and with the increase of salt concentration, the inhibition effect and osmotic stress degree aggravated. The exogenous silicon increased the accumulation of osmotic regulation substances and reduced the accumulation of active oxygen in cotton seedlings, so it could alleviate the inhibiting effect of salt stress on cotton seedling growth and improve the salt resistance of cotton seedlings.

A pot experiment was conducted to study the effects of salinity-alkalinity stress on rhizosphere microecological environment of two common bean varieties, HYD and JW. Two kinds of alkaline salts(Na₂CO₃, NaHCO₃) were mixed together in the proportion of 1:9. According to the percentage of soil mass after mixing, four treatments of 0(S0), 0.4%(S1), 0.8%(S2)and 1.2%(S3)were set to investigate the effects of different treatments on rhizosphere soil microbial quantity and enzyme activity. The results showed that under salt-alkali stress, HYD was better than JW in plant height, root length, shoot biomass and root biomass. There was a significant difference in the number of bacteria, fungi and actinomycetes in rhizosphere soil under saline-alkali stress treatments, and the number of bacteria was higher than those of fungi and actinomycetes. The soil urease, phosphatase, catalase activity and soil microbial quantity in rhizosphere of two common bean cultivars were the maximum in S1 treatment, reaching to a significant difference. Under the same treatment, the growth characteristics of plant height, root length,shoot biomass and root biomass of HYD were significantly higher than those of JW. The number of microorganisms and enzyme activity in the rhizosphere soil of HYD were significantly higher than those of JW. Correlation analysis showed that urease activity had significantly or extremely significantly positive correlation with the numbers of bacteria, fungi and actinomycetes, and total amount of microorganisms, while there was significantly positive correlation between phosphatase activity and the number of actinomycetes and between catalase activity and the number of fungi. Under salinity-alkalinity stress, the soil pH rose and microbial population changed, which led to changes in enzyme activity and indirected changes in rhizosphere soil microenvironment. A certain amount of salinity-alkalinity stress is beneficial to the improvement of soil microorganism and enzyme activity in common bean rhizosphere. A certain amount of saline-alkali stress promotes the growth of common bean.

To study the effects of carbonaceous materials on soil improvement and crop growth, the field experiment was conducted on representative soda saline soil in Northern Shanxi. It studied the effects of weathered coal, biochar, cattle manure and corn stalk on soil physical properties,soil salinity, soil nutrient and spring maize growth. The results showed that all carbonaceous materials reduced soil bulk density and improved soil porosity. Soil bulk density followed a trend of weathered coal < cattle manure < corn stalk < biochar < CK. Compared with CK, soil bulk density of weathered coal and cattle manure treatments decreased by 4.73%,7.05% and 5.75%,3.91% for 0-10 cm,10-20 cm soil layers.Carbonaceous materials increased soil organic matter content. Compared with CK,soil organic matter content significantly increased by 54.78%,36.62% for 0-10 cm soil layer and 37.40%,32.95% for 10-20 cm soil layer after applying weathered coal and cattle manure.In addition, the soil pH and total salinity of the 0-20 cm soil layer were significantly reduced by carbonaceous materials.The effects of weathered coal and cattle manure were better than biochar and corn stalk. Compared with CK,soil pH of weathered coal and cattle manure treatments were significantly reduced by 0.59, 0.55 and 0.53, 0.53, while total salinity decreased by 13.49%, 14.27% and 8.10%, 7.35% for 0-10 cm, 10-20 cm soil layers, respectively. Further, carbonaceous materials could reduce the content of water-soluble sodium ions, carbonate ions and bicarbonate ions and the effects of cattle manure and weathered coal treatments were better. The application of carbonaceous materials increased the soil nutrients content, the cattle manure and weathered coal treatments had a great influence on the content of total nitrogen and available phosphorus, and corn stalk treatment had a great influence on the content of available potassium. Carbonaceous materials promoted the growth and yield of spring maize. Plant height, dry matter and yield all followed the trend of weathered coal and cattle manure > corn stalk and biocha > CK.Compared with CK, the spring maize yield of weathered coal and cattle manure treatments significantly increased by 31.81%, 37.72% and 28.58%, 22.99% for 2016 and 2017, respectively. In conclusion,carbonaceous materials had positive influences on the improvement and utilization of soda saline soil, the effects of weathered coal and cattle manure were better than biochar and corn stalk. The study results will provide reference for the application of weathered coal and cattle manure.

The salinization of land in China is becoming more and more serious, and the sustainable development of agriculture is seriously hindered.Taking corn Xianyu 335 as the research object in this experiment, the effects of different combinations of acetylated glucose, urea, phosphate fertilizer and organic fertilizer on soil character improvement effect and effects of maize growth and development were investigated under the saline and alkaline land conditions in Xugou Town, Qingxu County, Shanxi Province. The results showed that the combination of acetylated glucose, urea, phosphate fertilizer and organic fertilizer had the most significant effect on the improvement of saline-alkali land. The pH of the soil was 0.32 lower than that of the control (without any treatment). The SPAD value of maize leaves increased by 50.834 and the net photosynthetic rate increased by 21.8 μmol/(m² · s). The plant height and stem diameter of maize at seedling uprooting stage and harvest stage increased by 45.99, 0.36 cm and 77.13,0.50 cm, respectively. The ear length, ear weight, 100-grain weight and grain number per ear of maize increased by 5.06 cm, 118.216 g, 11.123 g and 271.8 grains, respectively. The combination of acetylated glucose and fertilizer can promote crop growth and improve soil properties, which can be used as one of the important measures to improve saline-alkali land in the future.

In order to investigate the effect of salt stress on starch synthesis and accumulation of Japonica rice in cold-region and enrich the physiological basis of salt tolerance research.The paper used pot experiment to study the influence of different concentrations of salt stress on the key enzymes activities related to starch of Japonica rice in cold-region and the relationships between the changes rule in key enzymes activities and starch content, revealed the response mechanism of Japonica rice in cold-region kernel starch anabolism under salt stress,studied the effect of yield and yield components of Japonica rice in cold-region under salt stress, as well as the effect of yield formation mechanism of Japonica rice in cold-region under salt stress. The results showed that compared with the control, the activities of soluble starch synthase (SSS),ADPG pyrophosphorylase and starch branching enzyme(Q enzyme) in grain of Japonica rice in cold-region decreased under salt stress, and the contents of total starch and amylopectin in grain decreased, while the amylose content in grain increased. Meanwhile,with the increased of salt concentration, the indicators of yield components gradually declined, salt stress mainly affected the grain number per panicle and seed setting rate of MDJ30 and thus affected the yield, while LD5 was the effective panicle number and seed setting rate. When soil salt content was more than 0.075%, the theoretical yield was greatly affected. In terms of variety, compared with MDJ30, the salt-tolerance variety LD5 had relatively high starch synthase activity, which results in a higher content of starch and its components.This was beneficial to grain dry matter accumulation and ensure that its yield could still be maintained at relatively high levels under salt stress. Thus, the key enzyme activite of starch synthesis in kernel is different product of different salt-tolerant varieties responding to salt stress, the change rule and the level of its activity can be used as an indicator for salt tolerance identification.