In order to explore the photosynthetic physiological response mechanisms of three summer maize varieties (Xundan 20, Jinbei 288 and Dika 667) which were commonly cultivated in arid and semi-arid areas to drought stress, these three varieties were treated under different drought stresses (including non-drought treatment (CK), light drought (LD) and heavy drought (HD)). Responses of net photosynthetic rate to light intensity (Pn-PAR) and net photosynthetic rate to intercellular CO₂ concentration (A-Ci) were estimated by the portable photosynthesis system Li-6400, and responses of chlorophyll fluorescence parameters to light intensity were measured by portable modulation chlorophyll fluorescence meter MINI-PAM, respectively. The results were as follows. As for all these three varieties, the response modes of Pn and stomatal conductance (Gs) to PAR were similar among these three maize varieties, and the responses of Pn to Gs shifted to left along the drought stress gradient. The initial chemical efficiency (CE) and photosynthetic capacity (Amax) were significantly lower under heavy drought treatment than under the other two treatments for each of the three varieties. Compared with the results under CK treatment, the non-photochemical quenching coefficient (qN) and the quantum yield of the regulatory energy dissipation (Y (NPQ)) were lower and the quantum yield of non-regulated energy dissipation (Y(NO)) was higher under LD or HD treatment for the two varieties of Jundan 20 and Dika 667; and the photochemical quenching coefficient (qP) was lower under HD treatment for the variety of Jinbei 288. Compared with the results under CK treatment, the maximum net photosynthetic rate (Pmax) and initial quantum efficiency (AQY) were a little higher under LD treatment for the variety of Jinbei 288. Compared with the other two varieties, the Pmax and AQY showed higher tolerance to drought stress by keeping relatively lower qQ and lower Y(NO) for the variety of Jinbei 288, and these results not only showed the greater tolerance of Jinbei288 to drought stress, but also provided reference for the screening of crop varieties for drought tolerance.

In order to study the effect of drought stress on physiological characteristics of grafting flue-cured tobacco,using KRK26 as scion, KRK26,K326 and Anyan 2 as rootstock,analysing and discussing root morphology, plant morphology and physiological indexes of resistance in pot culture under different treatment. The results indicated that under drought stress conditions at early period, the relative content of chlorophyll (SPAD readings) decreased, while the content of proline, superoxide dismutase (SOD) activities, catalase (CAT) activities and peroxidase (POD) activities in flue-cured tobacco demonstrated an increasing trend. The root length,surface area,plant height,stem girth, node spacing and LAI of the grafted tobacco plants showed a decreasing trend,the content of proline continued to increase in both grafted seedlings and non-grafted seedlings with the aggravation of drought stress when tobacco leaves were turning to mature, whereas, the SPAD readings, SOD activities, CAT activities and POD activities all demonstrated a decreasing trend. The speed of decreasing in different root grafted was slower than that in own root grafted. Compared with KRK26/K326 and KRK26/KRK26, KRK26/Anyan 2 had greater parameters under drought stress, but the SPAD readings did not have significant difference. All the results showed that less damage was made to KRK26/Anyan 2 than KRK26/K326 and KRK26/KRK26 under drought stress, and KRK26/KRK26 suffered the most serious damage. According to correlation analysis, there was a certain correlation between morphological indexes and resistance indexes of grafting flue-cured tobacco. In conclusion, there were obvious differences among grafted tobacco in physiological characteristics, and there response to soil drought. The order of drought resistance was KRK26/Anyan 2, KRK26/K326 and KRK26/KRK26 in turn from strong to weak, based on the main root morphology,plant morphology,physiological characteristics under drought stress.

In order to explore the effects of growth and aging characteristics of peanut under drought and salt stress,using Huayu 25 as material,potted experiment was carried out to study the change of peanut growth and aging characteristics due to the stress of drought and salt at flowering stage.The results showed that drought treatment (D),salt stress treatment (S),drought and salt stress (DS) increased the content of soluble protein,soluble sugar,free amino acid,proline,O₂^· and MDA. S treatment and DS treatment reduced the activity of SOD,POD and CAT in the leaves,which continued to decrease as time prolonged. But D treatment enhanced SOD and CAT activity in the leaves. After 10 days of rehydration,the content of soluble sugar,soluble protein,free amino acid,proline,O₂^· and MDA of D treatment reduced compared with the numerical values which detected before rehydration.D treatment had no significant difference with CK,including activity of SOD and POD and content of O₂^·,MDA,soluble sugar,free amino acid,proline. However,the difference of the activity of SOD,POD,CAT of DS treatment was significant compared with S treatment,so did the content of O₂^· and MDA.In the harvest time,single plant yield and the kernel rate of D treatment had no significant difference with CK,but DS treatment had significant difference with S treatment. Data from DAT9 showed that drought and salt stress had no significant interaction with soluble sugar,soluble protein,free amino acid and proline content in leaves. However,there was significant interaction of SOD,POD,CAT activity and O₂^·,MDA content between drought stress and salt stress. The interaction between drought stress and salt stress inhibited the activity of SOD,POD and CAT and exacerbated the peroxidation of plant cell membranes. Eventually it decreased the single plant yield and the kernel rate. Therefore,peanuts planting under salt stress should avoid the drought at flowering stage to reduce the harm of salt stress,drought stress and the interaction between salt stress and drought stress.

In order to clarify the effects of drought stress on the photosynthetic characteristics in flag leaf in the afternoon during grain filling stage and grain yield of winter wheat with different drought resistance,an experiment with two winter wheat cultivars and four water levels was conducted under the condition of rainproof pond cultivation in 2018—2019 and 2019—2020.The two winter wheat cultivars were Jinmai 47(JM47,strong drought resistance)and Yanzhan 4110(YZ4110,weak drought resistance).The four water treatments included severe drought(W1:65% MFC(maximum field water capacity)before sowing + 45%—55% MFC after jointing),moderate drought(W2:75% MFC before sowing + 55%—65% MFC after jointing),mild drought(W3:75% MFC before sowing+65%—75% MFC after jointing),suitable water supply(W4:75%MFC before sowing+75%—85% MFC after jointing).The net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO₂ concentration(Ci),transpiration rate(Tr),instantaneous water use efficiency(IWUE),maximum photochemical efficiency of PS Ⅱ (Fv/Fm)and actual photochemical efficiency of PS Ⅱ(ΦPS Ⅱ)in flag leaf from 14:00 to 16:00 during the early,medium and medium-late grain filling stage and the grain yield and its components at maturity were investigated.The results showed that both water and cultivars had significant effects on the photosynthetic and fluorescence characteristics in flag leaf in the afternoon during the grain filling stage and the grain yield at maturity of winter wheat.From the two-year average,compared with W4,the Pn,Gs and ΦPSⅡ in flag leaf in the afternoon during the grain filling stage under drought stress(W1,W2 and W3)respectively decreased by 2.07%—68.92%,-3.23%—50.00% and -1.89%—30.19% in JM47,and decreased by 7.71%—80.19%,11.11%—59.26% and 0—73.47% in YZ4110;the flag leaf Tr values in the afternoon during the medium grain filling stage in JM47 and YZ4110 respectively decreased by 6.30%—32.87% and 6.49%—41.74%,and the flag leaf Fv/Fm values in the afternoon during the medium-late grain filling stage decreased by 1.20%—18.52% and 2.50%—30.00%.In general,for all the above indexes,the decreasing amplitude for the same index was JM47<YZ4110.Compared with YZ4110,the Pn,Gs,ΦPSⅡ and Fv/Fm in flag leaf in the afternoon during the grain filling stage under drought stress(W1,W2 and W3)of JM47 respectively increased by 0.86%—64.89%,8.33%—36.36%,1.96%—184.62% and 1.25%—17.86%,and the grain yields of JM47 were respectively increased by 28.91%,8.06% and 5.40%.Except for IWUE,the flag leaf photosynthetic parameters in the afternoon during the grain filling stage were significantly and extremely significant correlated with grain yield,but the correlation indexes varied with variety and grain filling stage.For JM47,the correlation indexes between the grain yield and flag leaf photosynthetic parameters were highest for Pn,Gs and Fv/Fm during the medium-late grain filling stage,for ΦPSⅡ during the medium grain filling stage,and for Tr during the early grain filling stage.For YZ4110,the correlation indexes were highest for Pn,Gs and Tr during the early grain filling stage,for ΦPSⅡ during the medium grain filling stage and for Fv/Fm during the medium-late grain filling stage.In summary,drought stress decreased the photosynthetic function of flag leaf in the afternoon during grain filling stage and thus decreased the grain yield of winter wheat,the strong drought resistance variety could maintain better flag leaf photosynthetic characteristics in the afternoon during the grain the filling stage under drought stress condition,and significantly improved the ΦPSⅡ of flag leaf in the afternoon during the medium grain filling stage and the Pn,Gs and Fv/Fm of flag leaf in the afternoon during the medium-late grain filling stage,thereby increasing the grain yield.

In order to study the effects of continuous drought treatment in whole growth period on cotton growing development and final yield,in this experiment,pot-culture method was taken and Xinluzao 19hao,Xinluzao 27hao and Xinluzao 54hao as materials,the treatments were light and moderate drought stress,then measured morphological indexes,physiological indexes and photosynthetic parameters at seedling stage,bud stage,blooming stage and boll opening stage,and investigated yield components at harvest time.Results showed:cotton height and stem diameter decreased with the strengthen of drought stress; The content of reactive oxygen species and antioxidant enzyme activities were great difference at different growth stage,correlation analysis showed that there were significant or extremely significant correlation between active oxygen content and antioxidant enzyme activity,indicted that antioxidant enzymes activity changed regularly with the content of reactive oxygen species,so as to eliminate the excessive oxygen species in vivo and prevent the damage of reactive oxygen species; The photosynthesis of cotton at bud stage decreased with the strengthen of drought stress,but increased at boll opening stage,except Xinluzao 27hao which possibly due to persistent drought treatment caused the different developmental stage of cotton at later growth stage; Drought stress reduced the yield per plant and fiber length of Xinluzao 27hao and Xinluzao 54hao,light drought stress had little effect on single boll weight,even played a role in promoting; There were four indexes of cotton at blooming stage had significant correlation with yield per plant,indicted that cotton blooming stage might be the key period which easy to be affected by environment and determined the final yield.

Drought stress has a serious effect on the growth and development of maize,which leads to a decrease of maize yield.Purple acid phosphatase is a phospholipase protein involved in many physiological and biochemical functions of plants.In order to further study the role of purple acid phosphatase family genes in the process of stress resistance of maize,this paper explored the response mode of ZmPAP26b gene under drought stress,and Real-time fluorescence Quantitavive analysis was used to analyze the relative gene expression in different maize inbreeding lines under simulated drought conditions;ZmPAP26b(GenBank:NC_050104.1)was cloned from maize,and PAP genes in Zea mays,Arabidopsis thaliana,Oryza sativa L.,Triticum aestivum L.,Sorghum bicolor and Brachypodium distachyon were identified and bioinformatic analysis was performed.Meanwhile,prokaryotic overexpression strains were constructed for functional verification.The results showed that the expression of this gene decreased in drought tolerant materials and increased in drought sensitive materials under drought stress.The CDS length of this gene was 1 431 bp,encoding 476 amino acids.A total of 228 PAP genes were found in six species,divided into 4 subfamilies by phylogenetic analysis.The 19 PAP genes in maize were distributed on 9 chromosomes and had similar conserved domains.Analysis of promoter cis-acting elements showed that they contained elements responding to drought and hormones.Prokaryotic expression experiments showed that the growth of strains containing the recombinant plasmid pET28a-ZmPAP26b was inhibited compared with non-loaded strains under 10% PEG-6000 and 15%PEG-6000 simulated drought stress.In summary,it is speculated that ZmPAP26b is negatively regulated under drought stress.

To study the physiological effects of different degrees of drought on soybean cultivars in different development periods. Two soybean cultivars with different drought resistances were taken as the experiment materials to study the effects of drought stress on the resistance index and physiological characteristics of soybean in different growth periods, and to explore the physiological mechanism of soybean response to different drought intensities at different developing stages in pot culture. Four treatments were set up:continuous mild drought stress (T1), continuous moderate drought stress(T2), drought stress in full seed stage (T3) and without drought stress(CK). The results showed that under drought stress, the chlorophyll contents of both soybean cultivars increased, and Jindazaochun 2 was more obvious at early stage, but it was less than that of Jinda 74 at grain-filling stage. Under continuous mild drought stress and continuous moderate drought stress, the MDA content of Jindazaochun 2 at different growth stages significantly increased, while the POD and MDA contents of Jinda 74 significantly increased under continuous moderate drought stress. At the branching stage, the content of reducing sugar in Jinda 74 decreased significantly during moderate drought. In the Granulation stage, the reducing sugar content of soybean leaves in Jindazaochun 2 was significantly increased, Jinda 74 was only reduced under drought treatment in the Granulation stage. At flowering stage, reducing sugar content reduced in Jindazaochun 2, but increased significantly in Jinda 74. It was found that drought had a great influence on reducing the plant height, node number, stem diameter of both cultivars. The decrease in plant height and stem diameter of Jinda 74 was more obvious. The resistance of Jinda 74 to drought was higher than that of Jindazaochun 2, which was related to the reduction of plant height and water consumption under continuous drought conditions. The results will provide a basis for comprehensive understanding of the soybean resistance to drought stress.

In order to explore a fast and efficient way to screen drought-resistant varieties of winter wheat, and to select drought-resistant winter wheat varieties. Six winter wheat varieties, Yannong 999, Taimai 1918, Jimai 22, Jimai 23, Taishan 27 and Shiluan 02-1 were used in this study. Normal water treatment(75% relative soil water content), mild drought treatment(55% relative soil water content) and moderate drought treatment(40% relative soil water content) were arranged to explore the chlorophyll fluorescence parameters, biomass, root-shoot ratio, SPAD, superoxide dismutase(SOD) activity, malondialdehyde(MDA) content and their correlations. Results showed that, compared with other varieties, under drought stress, Taimai 1918 obtained the highest drought resistance coefficient(DTC). The smallest reduction of root to shoot ratio, SPAD value, photosystem Ⅱ maximum photosynthetic efficiency(Fv/Fm), photosystem Ⅱ actual photosynthesis efficiency(φPSⅡ), relative electron transfer rate(ETR), SOD, and the largest increasing in non-photochemical quenching(NPQ) and minimal increasing in MDA content were observed in Taimai 1918. The order of drought resistance of 6 winter wheat varieties was Taimai 1918 > Yannong 999 > Jimai 22 > Jimai 23 > Taishan 27 > Shiluan 02-1. The chlorophyll fluorescence parameters were significantly correlated with drought resistance coefficient, SOD activity and MDA content. Sum up, the drought resistance in Taimai 1918 was strongest, and chlorophyll fluorescence parameters can be used for screening drought-resistant winter wheat varieties at seedling stage.

In order to understand the dynamic rules of sugars, starch, protein and trace elements of different types of wheat during grain filling stage under drought stress, and to identify the difference of nutriment between drought and irrigation in the process of grain-filling by high-yield wheat, high-quality wheat and water-saving wheat, the wheat varieties of Jimai 325, Jimai 418 and Jimai 323 in the North of Huang-Huai Region were used as experimental materials. The plants heading and flowering on the same day were selected for marking, and the grains of each variety were taken every 6 days after 7-31 days after anthesis. The effects of drought during grain filling on the contents of total soluble sugar, sucrose, glucose, fructose, protein, Fe, Zn, Mn, Cu, amylose and amylopectin accumulation, starch accumulation rate and the activities of key enzymes in starch synthesis were studied. The results showed that the content of sucrose and glucose in wheat grains was significantly decreased under drought stress, and the effect on fructose content was relatively small, and the sucrose and fructose of high-yielding variety Jimai 325 were less affected by drought in the filling process. Drought stress decreased the content of amylopectin and total starch in wheat grains, but had relatively little effect on the content of amylose. The effect of drought stress on starch content of high-yield and high-quality varieties was significantly greater than that of drought-tolerant variety Jimai 418. The activity of starch synthase was increased in the early and middle stages of filling stage under drought stress, and decreased rapidly in the middle and late stages compared with irrigation control. The content and accumulation of four mineral elements in wheat grains were Mg>Fe>Zn>Mn. With the progress of grain filling, the content of trace elements showed a downward trend. The accumulation of Fe, Zn and Mg in grains of Jimai 325 was higher. The difference of nutrient accumulation in grain filling process of different types of wheat under drought conditions were studied to provide theoretical data and reference basis for optimizing cultivation measures and realizing high quality, high yield and water saving of special wheat.

In order to clarify the drought resistance and drought resistance mechanism of Allium polyrhizum in Inner Mongolia grassland,potted water control method was adopted.Two gradients were set,75% of the maximum field water capacity as the control(CK),and 25% of the soil relative water content under 30 days of drought stress.The root morphology,physiological characteristics and leaf photosynthetic characteristics of Allium polyrhizum from different sources were analyzed under drought stress. The result showed that Allium polyrhizum in Siziwang Banner compared with the Chifeng and Ordos was remaining relatively high root surface area,root volume and root length 0-0.5 mm in diameter. Allium polyrhizum root growth was relatively less affected by drought stress,chloroplasts were relatively stable and strong drought resistance in Siziwang Banner. Drought stress significantly decreased the above ground biomass,below ground biomass and total biomass of Allium polyrhizum in Chifeng and Ordos,but had no significant effects on Siziwang Banner(P>0.05). The Pn,Tr,Gs,Ci and leaves relative water content of Allium polyrhizum seedlings were significantly decreased and the relative permeability of cytoplasmic membrane was markedly increased under the whole drought stress treatment. Drought stress induced stomatal closure of Allium polyrhizum leaves and reduced transpiration to decrease water loss.The root characteristics,relative water content,chlorophyll and photosynthetic characteristics of Allium polyrhizum in different sources were certain differences under the same treatment. In general,the effect of drought stress on Allium polyrhizum in Siziwang Banner was relatively weak,it was indicating stronger drought tolerance.

A Receptor-like kinase(RLK)gene, OsSIK1,plays important roles in drought stress-tolerance in rice,through the activation of the antioxidative system.To make maize plants have much more drought resistance genes and further to obtain drought tolerance maize germplasm.In this study, OsSIK1 gene of rice was transformated into maize inbred Zheng 58 plants by pollen-mediated method.First,transgenic plants in T₁,T₂ and T₃ were detected by Kanamycin resistance screening,PCR and Southern Blotting,transgenic plants were obtained from T₁ and pure transgenic lines was obtained from T₃.Next,drought resistance analysis to transgenic maize plants and non-transformation control plants were conducted under the condition of 16.1% PEG drought stress.The results showed that compared with non-transgenic plants,the seedling leaf relative water content,chlorophyll content and SOD activity of transgenic plants were increased by 7.4%-19.8%,11.3%-106.9% and 45.8%-93.4%,respectively;furthermore,the relative conductivity and MDA content were decreased by 35.4%-58.1%,and 25.7%-50.4%,respectively.All the physiological indexes under the drought stress proved that transgenic OsSIK1 gene improved the drought resistance of transgenic maize plants,further analysis found that there were significant differences on drought tolerance between 5 transformed lines and their control groups,and their performance of field were superior to that of non-transgenic maize seedlings.At last,5 transgenic maize inbred lines were obtained,which suggested that genetically modified maize has improved the drought resistance by introducing foreign OsSIK1 gene of rice.

In order to explore the effect of grain size and sowing depth on emergence and seedling growth,determining suitable grain size and sowing depth in mechanization of summer maize production of Southwest Hilly Area.In the split-plot design,using Zhenghong 505 as the test material,3 kinds of grain size was assigned to the main plot,and 3 sowing depth(2,6,10 cm) to the subplot,emergence rate of maize,seedling quality,yield and yield components have been investigated in drought condition.The results showed that compared with small grain,large grain had higher emergence rate,the seedling was more haleness and grew better in drought,and there was a certain effect of increasing yield ultimately;Shallow sowing(2 cm) was conducive to the emergence,and the growth vigor of the seedlings of 6 cm sowing depth was best just when emerging,then the 10 cm depth of the seedling grew gradually strong,and obviously better at the 5 leaf period(large and medium grain)-7 leaf period(small grain) than shallow sowing treatment,which also showed a certain increase in yield.Therefore,in the dry land or dry season,choosing large grain and suitable sowing depth in maize production can effectively better sthong seedlings,improve the resistance of drought,and achieve the purpose of producing income insurance.

Calcium-dependent protein kinases (CDPKs) function as Ca²⁺ sensor in various plant physiological processes.CPK10 was one member of CDPK family.In order to investigate the molecular mechanisms of CPK10 and it's high homology CPK30 in response to stress,cpk10×cpk30 double mutant was firstly constructed.The phenotypes in response to various stress were detected,and the RT-PCR method was used to analyzed the two genes expression.The results showed that there was no difference in the seed germination stage between double mutant and wild-type plants in the treatment of drought,salt and ABA.In the mature stage,double mutant exhibited no difference to drought stress compared with wild-type and single mutant.Nevertheless,the expression levels of RD29A was decreased in the double mutant and showed opposite trend in wild-type and single mutant during drought stress.The expression of ABA-responsive gene OST1 was enhanced obviously in double mutant after drought stress 0.5 h.The cpk10×cpk30 double mutant was successfully obtained.Our data indicated that CPK10 and CPK30 might be involved in ABA-dependent signal transduction pathway,and showed redundant functions.

This study provides a good foundation for further elucidating the function and mechanism of AhPLDα1 and AhPLDα2 in responding to drought stress in peanut.The full-length CDS sequences of AhPLDα1 and AhPLDα2 were cloned from Jihua 4 peanut leaf with ABA treatment using RT-PCR.The AhPLDα1 and AhPLDα2 gene fragments were inserted into the expression vector pBar-F3 by forward ways.These constructs were transformed into Agrobacterium tumefaciens GV3101 by freeze-thawing method and then introduced into wild-type Arabidopsis thaliana using modified floral-dip method.Under the condition of drought,the authors observed phenotypic changes of wild type and transgenic plants.Colony PCR and enzyme digestion results showed that,the plant overexpressing recombinant plasmid pBar-AhPLDα driven by CaMV35S promoter was successfully constructed.Glyphosate resistance screening,PCR detection and gene expression analysis showed that the positive transgenic plants were obtained.Under water deprivation,overexpression of AhPLDα1 and AhPLDα2 in transgenic Arabidopsis plants resulted in significantly enhanced tolerance to drought stress.In conclusion, AhPLDα1 and AhPLDα2 have a certain relation with drought stress signal transduction in transgenic Arabidopsis plants,and are potential candidate genes on the way to modified crop drought resistance.

The purpose of this study was to explore the effects of different drought stress levels on maize growth traits and yield in the semi-arid region of Northeast China, and to lay a theoretical foundation for further research on the physiological mechanism of maize drought resistance.Three kinds of maize varieties with different drought tolerance were selected and five water gradients of normal water supply(CK), light drought(LS), moderate drought(MS), severe drought(SS)and lethal(S)were set at maize jointing, tasselling and filling stages, respectively. The effects of different drought stress on the growth traits and yield related indexes of three maize varieties were comprehensively analyzed. The plant height, ear position and dry matter weight of maize decreased with the increasing of drought degree, but the stem diameter had no significant difference with the increasing of drought degree. The plant height, ear position and dry matter accumulation of maize variety Jinqing 707 was the highest, followed by Nendan 19 and Fudan 16. During tasselling stage, the spike characters of maize changed most obviously under drought stress, and the maize yield was the lowest under severe drought, and no yield under continuous drought.Under the same drought degree, the worse the drought tolerance of maize varieties, the greater the yield reduction. The specific performance of maize yield is Jinqing 707 > Nendan 19 > Fudan 16.A comprehensive analysis of multiple indicators shows that tasselling stage is the key period of water requirement of maize, which is easily affected by drought stress. At the same time, it is pointed out that drought stress or serious degree of drought stress in tasselling stage is the main factor leading to the decrease of maize yield.

bZIP transcription factors are widely found in plants and play an important role in regulating plant growth and development and abiotic stress response.In order to explore the functional role of bZIP transcription factor in maize drought stress response,transcriptome sequencing technology was used to analyze the expression changes of transcription factors in maize seedlings treated with drought stress for 5 days and rehydration for 3 days,and a bZIP transcription factor(ZmbZIP26)was screened from transcriptome data in response to drought and rewatering treatment.Co-expression network analysis revealed that ZmbZIP26 was at the core node of network regulation.The gene contained a 558 bp open reading frame encoding 185 amino acids,which was a hydrophilic protein.Phylogenetic tree and conserved sequence analysis showed that ZmbZIP26 protein had high homology with homologous proteins of sorghum and Miscanthus,and also had the same conserved motifs at the same amino acid positions.Cis-element analysis showed that the upstream 2 000 bp region of the ATG site contained drought response elements,hormone response elements and light response elements.qRT-PCR analysis showed that ZmbZIP26 was a constitutively expressed gene,which was highly expressed in young stems,female panicles and roots.ZmbZIP26 positively responded to drought,high temperature,high salt and nitrogen stress and the process of restoring,which might play an important role in the process of plant resistance.Subcellular localization analysis revealed that ZmbZIP26 was a nuclear protein localized in the nucleus.Protein interaction prediction showed that ZmbZIP26 might interact with zinc finger protein,serine protein,Ca-dependent protein and glutathione transfer protein to construct a regulatory network,which cooperatively regulated maize growth and development and stress response process.

To reveal the mechanism of drought resistance of different resistant rice during germination period,Rice drought-sensitive materials(Calrose,Jingning 10,Shanxing 86)and drought resistance materials(Farry,Songjing 3,Ningjing 36)were studied on the effects of simulated drought stress(15% PEG-6000)on the growth index,physiological indexes and corresponding gene expression of different rice seeds.The results showed that under normal conditions,there were no significant differences in the expression levels of growth indicators and stress-related genes between drought-sensitive and drought-resistant cultivars.However,changes in physiological indicators were shown that there were no significant differences in the activities of superoxide dismutase(SOD) and peroxidase(POD),the contents of soluble sugar(SS) and hydrogen peroxide(H₂O₂) among different genotypes.The contents of malondialdehyde(MDA) and superoxide anion($\mathrm{O}_{2}^{\bar{.}}$) in the drought-sensitive cultivar Shanxing 86 were significantly higher than those in other materials,and the contents of catalase(CAT),proline(Pro) and soluble protein(SP) of drought resistant Ningjing 36 were significantly higher than those of other materials as well.Under drought stress,the relative germination potential(RGP),relative bud length(RSL),germination drought resistance index(GDRI)and vitality index(VI)of germinating seeds increased by 0.03—0.07 percentage,0.32—0.39 percentage,0.12—0.18 percentage and 92.41%—108.39%,respectively;MDA and reactive oxygen species($\mathrm{O}_{2}^{\bar{.}}$,H₂O₂) contents in germinating seeds of drought-resistant cultivars decreased by 2.54%—61.64%,19.60%—46.30% and 35.61%—62.02% respectively compared with drought-sensitive cultivars.The contents of osmotic regulating substances(Pro,SS,SP) increased by 5.93%—18.29%,1.08%—7.97% and 3.47%—6.03% respectively.The activities of antioxidant enzymes(SOD,POD, CAT) were increased by 17.29%—33.12%,15.24%—76.06% and 14.68%—18.61% respectively.The relative expression levels of OsP5CS,antioxidant enzyme synthesis genes (OsALM1, OsPOX1, OsCATC) were up-regulated by 2.66%—182.31% and 57.14%—513.27%,0.38%—109.06% and 63.39%—184.25% respectively.Comprehensive analysis showed that drought stress inhibited the germination of rice seeds and affected the physiological characteristics of seeds and the expression of corresponding genes during germination.Under drought stress,vigor index(VI),peroxidase(POD)and peroxidase synthesis gene(OsPOX1)are the key indicators affecting rice seed germination,whether it is drought-resistant or drought-sensitive materials.In addition to the above indicators,soluble protein(SP),proline synthesis gene(OsP5CS)and catalase gene(OsCATC)are other key indicators affecting drought-resistant materials.Relative shoot length(RSL),hydrogen peroxide(H₂O₂)and superoxide dismutase gene(OsALM1)are other key indicators affecting drought-sensitive materials.

To identify the miRNAs and their response regular patterns to salt stress and drought stress,rice seedlings at three leaves stage were used to quantify the expression of miRNAs and their targets when treated with salt and drought stresses at 0,3,6,12,24,48 h by qRT-PCR. The results demonstrated that expression patterns of miRNAs were affected by space-time and tissues under salt and drought treatments. Further analysis indicated that the expressions of miR156,miR164,miR167,miR169, and miR171 upregulated in roots with time and expressions of miR159,miR160,miR319,miR398, and miR1848 downregulated at 3 h and then upregulated when treated with salt(NaCl). And the 10 miRNAs were performed their lowest expressions in shoots at 3 or 6 h under NaCl treatment. On the other hand,the expressions of the most of the 10 miRNAs downregulated in roots generally and expressions of miR156,miR159 and miR160 downregulated in shoots and the expression patterns of miR167,miR169,miR319,miR398, and miR1848 down regulated first and then upregulated when treated with drought(PEG). Furthermore,expression patterns of targets were also affected by space-time and tissues. And only few expression patterns of the 10 miRNAs negatively correlated with its target,which implied the complexity of the regulation network of miRNA and its target in response to stresses.

To provide one elite drought-resistance gene resource for maize breeding program,a trehalose-6-phosphate synthase(TPS) gene sequence was obtained from Gossypium arboretum by bioinformatics analysis and molecular experimental operation. The gene was optimized and synthesized based on maize preferred codons. Afterwards,the gene was cloned into expression plasmids by multiple DNA restriction enzyme digestion and molecular ligation operations,and further transformed into E.coli and yeast cells to identify its expression status. Finally,the new TPS gene was cloned into plant expression vector. The results showed that the new synthesized gene had 2 586 bp in length,it contained a whole open reading frame and encoded 861 amino acids;constructed prokaryotic and eukaryotic expression plasmids can agree with our predicted results,this suggested that the gene could be used for cell transformation experiment;the synthesized TPS gene could effectively express trehalose-6-phosphate synthase in E.coli and yeast cells;the TPS gene was successfully ligated into plant expression vector pCAMBIA-2300,and further transformed into engineering strain LBA4404 of Agrobacterium. Comprehensively,it was concluded that a new TPS gene was obtained in this experiment,which could express trehalose-6-phosphate synthase in prokaryotic and eukaryotic cells. Therefore,the constructed plant expression plasmid can be directly applied in maize drought-resistance breeding program.

In order to explore the effect of plastic film mulching on the growth and yield of millet, clarify the mechanism of plastic film increase production, and provides theoretical basis for the whole film dibbling technology in the summer crops, a study on influence mechanism of film mulching on growth development and yield had been conducted. The test using spit plot experiment design was executed in Shijiazhuang luancheng Qiema experimental station, 2015. The main plot had two treatments, respectively is plastic mulch and no plastic mulch. The split plot had three varieties, respectively is Jigu 19, 36 and 38. Under the condition of plastic mulch and no plastic mulch, the morphological characteristics, yield and its traits, flag leaf SPAD values and flag leaf net photosynthetic at heading stage millet rate were studied. Results show that:compared with no plastic mulch, the sum area of top three leaves increased 12.83-26.36 cm², chlorophyll SPAD value increased 8.2%-17.1%, net photosynthetic rate increased 34.9%-34.9%, and yield increased 7.3%-10.8%. Yield performance of Jigu 36 was better than Jigu 19 and Jigu 38, and yields of three varieties (especially Jigu 38) were improved by film mulching. Yield had a significantly positive correlation with 2nd top leaf area, net photosynthetic rate, leaf area and the top three leaves area. Flag leaf area was positively correlated with grain weight per ear and ear length. Therefore, the growth and developing physiological stage of top leaves (especially 1st top leaf), film mulching affected the growth of ear and increased millet yield eventually.

To study the expression of grape stress tolerance gene (CAN70200.1),a 1 354 bp promoter fragment (named as P_CAN) upstream of the gene CAN70200.1 was isolated by using PCR technology.Promoter sequence was analyzed by the database of PlantCARE and PLACE.The result showed that the P_CAN sequence contained basic elements CAAT-box,TATA-box and some cis-acting elements that response to abiotic stresses,light and plant hormones.To verify the expression pattern of the promoter,the P_CAN fragment was fused with GUS reporter gene located on pCAMBIA1391Z to construct a plant expression vector p1391Z-CAN,followed by transformation into tobacco by Agrobacterium-meditated method.The expression activity of P_CAN promoter reached highest at 120 min after drought stress treatment or at 30-60 min under 4℃ cold treatment condition,indicated that the P_CAN promoter could express under the condition of treatments with cold and drought.

Aquaporins are channel proteins, which located in biological membranes including plasma membrane and tonoplast.It can highly facilitate water transportation across biological membranes.To investigate molecular mechanism of water regulation during seed germination, a tonoplast intrinsic proteins(TIPs)gene fragment TIP4;1 was isolated from Brassica napus seed by RT-PCR.The expression ofTIP4;1 gene during seed germination and stresses treatment was analyzed by quantitative Real-time PCR(qRT-PCR).The transcription levels of TIP4;1 was analyzed during germination, and these results showed TIP4;1 expression levels was scarcely detected in dry seed, but was up-regulated during germination as well as early young seedlings.In addition, expression of TIP4;1 in response to abiotic stress was investigated, and results showed that TIP4;1 gene expression was upregulated under drought, cold and salt stress, suggesting that TIP4;1 may be involved in Brassica napus seed germination and stress response process.Aquaporin regulation mechanism would be further revealed in future, which had realistic significance for solving drought and salt stress problems.

The yield formation and the water consumption characteristics of winter wheat under micro-irrigation were studied with flooding irrigation as control in combined irrigation area of well and canal. The purpose is to provide technical support for the application of water saving technology in this area. 4 micro-irrigation treatment(the water amount were 90,135,180,225 mm respectively) and 1 flood irrigation control treatment were set. The result showed that the highest grain yield and spike number was get when the irrigation amount was 180 mm,and grain number per spike and grain weight were also higher in this irrigation amount. The irrigation amount was maximum for flood irrigation treatment,but the yield had no advantage. The water consumption amount increased with the increasing of irrigation amount,especially when the irrigation amount more than 135 mm the water consumption amount increased rapidly,while the water use efficiency decreased obviously when the irrigation amount more than 180 mm. The higher leaf area index could be obtained when the irrigation amount was 180 mm,and the crop growth rate was faster and the dry matter accumulation was higher in this irrigation amount. Higher leaf SPAD value was not get under less or more irrigation amount,while the keeping green time for leaf was longer when irrigation amount in the range of 135 mm to 180 mm. So the micro-irrigation amount should be controlled in less than 180 mm in this year type. Compared with the flood control,the grain yield was higher,and irrigation water amount and water consumption amount were decreased by 148 mm and 123 mm,respectively,and WUE increased substantially within the 180 mm irrigation amount.

In order to reveal the protective mechanism of exogenous Brassinolide on the photosynthesis of maize seedlings under drought stress,this experiment used the Zhuyu 309 as test materials and adopted the solution culture method,studying the changes of growth parameters,chlorophyll content,photosynthetic parameters,chlorophyll fluorescence parameters and D1 protein content of maize seedlings that used 20% PEG-6000 to simulate drought stress after exogenous Brassinolide (BR) pretreatment. Compared with that of drought stress,the results of corn seedling which after the BR pretreatment showed that its height increased by 45.87%,the root length increased by 20.56%,the total dry matter accumulation increased by 8.01%,the relative water content increased by 4.50%,chlorophyll a content increased by 26.32%,and photosynthetic parameters (Pn,Gs,Ci,Tr) increased by 9.57%,38.23%,30.19% and 28.12% respectively,the activity of photosynthetic system Ⅱ (Φ_PSⅡ) increased by 20.48%,and the maximum photochemical efficiency increased by 0.66%. Photosynthetic system Ⅱ absolute electron transport rate (ETR (Ⅱ) and the relative electron transport rate of photosynthetic system Ⅱ(rETR(Ⅱ)) were increased by 20.40% and 31.02% respectively. The content of D1 protein increased by 37.34% (P <0.05). The results showed that BR treatment under drought stress condition could improve the growth and development of maize seedlings,alleviate the damage of photosynthesis system,promote the stability of D1 protein and improve the adaptability of maize seedling to drought stress.

WRKY transcription factor plays an important role in plant response to abiotic stress and regulation of resistance gene expression. In order to reveal the role of a soybean transcription factor GmWRKY58 in response to abiotic stresses.The full length of GmWRKY58 cDNA was cloned from soybean,and the amino acid sequence,physiological and biochemical characteristics and evolutionary relationship were deduced. Subcellular localization and the changes of gene expression under different tissues and abiotic stress were studied. The results showed that GmWRKY58 had a 954 bp length open reading frame and encoded a total of 317 amino acids. Subcellular localization results showed that GFP signals combined GmWRKY58 was only detected in the nucleus. Real-time RT-PCR analysis showed that GmWRKY58 was expressed in soybean roots,stems,leave,flowers and pods,and the expression in each tissue of roots,stems and leave was significantly higher than flowers and pods. In soybean roots, GmWRKY58 gene can be significantly induced by abiotic stress factors such as high salinity,drought,low nitrogen and iron deficiency.Under high salt stress, GmWRKY58 gene expression was increased by more than 187.4 times. Moreover,this gene just slightly induced by other abiotic stresses shch as SA,low temperature,low phosphorus and low potassium. The results indicate that GmWRKY58 plays an important regulatory role in abiotic stress process of salt,drought,low nitrogen and iron deficiency in soybean.

Eleven representative wheat varieties from 1960s to now were selected to explore the evolution of wheat varieties of Henan Province under drought stress.At two-leaf stage,the drought stress was carried out by 20%-PEG6000(m/V) for 48,120 h,and the physiological drought resistance of different cultivars at seedling stage was analyzed by fuzzy subordinate function of each index.The results indicated that drought stress presented an increasing trend in the nine times of wheat variety upgrading in Henan Province.Under drought stress,relative water content and chlorophyll were reduced,while SOD and POD activity kept rising.Clustering analysis indicated that the 11 cultivars could be classified as four types:highly resistant type (Luohan 2 and Luohan 12);drought resistant type (Zhengmai 9023,Yumai 21,Yumai 49-198 and Zhoumai 18),weakly resistant type (Yumai 18,Zhengmai 366 and Fengchan 3) and highly sensitive type (Bainong 3217 and Zhengyin 1).The performance of drought resistance in 11 wheat varieties was Luohan 2 > Luohan 12 > Zhengmai 9023 > Yumai 21 > Yumai 49-198 > Zhoumai 18 > Yumai 18 > Zhengmai 366 > Fengchan 3 > Bainong 3217 > Zhengyin 1.

To explore more drought-related transcription factors genes in early growth and development of tassels, two drought-tolerant (DT) Tie 7922, X178 and two sensitive maize inbred lines (DS) Ji 81162, Dan 340 were used. The potted planting method was used to cultivate the seedlings, and the materials were treated by artificial simulated field drought stress and normal irrigation under the same and suitable water conditions. RNA-Seq technique was used to detect the changes in transcriptional level of the gene in drought related transcription factor family in the early stage of maize ear development compared with the normal irrigation treatment. The results showed that 287 genes were differently expressed under drought stress, and 34 of them are related to drought tolerance regulation revealed by GO enrichment and annotation, including 6 commons in two drought-tolerant line, 3 commons in two sensitive line, and all with uniform expression pattern, and 1 detected in four inbreds. The results provided the basic knowledge for drought tolerant gene identifition and molecular breeding of maize.

In order to relieve the crisis of water resource scarcity in the low plain area,study was conducted in 2012-2013 and 2013-2014 wheat growing seasons in different rainfall years. A split block design was used with 5 different irrigation regimes(1,2,3,4 times irrigation,no irrigation as control,represented by W1,W2,W3,W4 and W0 respectively,and W0 as control) as the main treatments and 3 different types of winter wheat varieties(Hengguan 35,Heng 4399,Shi 4185) as the sub-treatments. The yield,components of water consumption,stage water consumption,water use efficiency(WUE) and irrigation water use efficiency(IWUE) of wheat were analyzed,so as to provide basis for high efficient utilization of water resources.The results showed that the yield increased nonlinearly with the increase of irrigation amount,the highest yields were with 3 irrigations model in 2012-2013(less rainfall) and 4 irrigations model in 2013-2014(more rainfall) respectively,but not significantly different from the yield of 2 irrigation model in 2012-2013,and they were affected by amount and distribution of rainfall.As far as variety was concerned,water response characteristics of different varieties were different. Shi 4185 was comparatively more sensitive to irrigation and Hengguan 35 and Heng 4399 were more tolerant to drought with higher yield at a same irrigation model. As to water use efficiency,they were first increased and then decreased with the amount of irrigation increments,but IWUE always decreased. WUEs of different cultivars were different in two years. WUE of Henguan 35 were highest with 2 irrigation mode,Shi 4185 with 3 irrigation mode and Heng 4399 with 3 irrigation in 2012-2013 and 1 irrigation mode in 2013-2014. The water consumption and water consumption components were affected by irrigation amount and distribution of rainfall,the greater the amount of irrigation,the less proportion of soil water consumed. Stage water consumption varied with rainfall distribution,it was higher in 2012-2013 than 2013-2014 at the jointing to early filling stage and the water consumption component was mainly soil water(2012-2013) and rainfall(2013-2014) respectively.In the low plain area,selecting the irrigation regimes of 2 irrigations was able to take the advantage of both variety yield potential and a higher WUE.

In order to understand developmental behavior of four protective enzymes (SOD,POD,CAT,GSHR) in Barley.Experimental data based on 196 genetic populations were used for the additive-dominant-maternal-paternal(ADMP) model with genotype×environment interaction and multivariable conditional analysis.The results showed that the genetic effects of 4 protective enzymes were not the same in different developmental stages.In the emergence to jointing stage,the dominant effect of SOD was the most strongest and the maternal effect of GSHR had the maximum value;from jointing to flowering,the SOD and POD had a relatively large additive effect,but GSHR had the maximum value of paternal effect;from the flowering to grain filling,the value of additive genetic was greater than the dominant effect on SOD and POD,the larger maternal effect of SOD and CAT had been detected,Meanwhile,the maximal value of paternal effect was detected on GSHR.In different growth stage,the drought-resistant identification indexes could be used:From emergence to jointing stage,the identification indexes was GSHR for the inbred line or parents,and SOD was suitable indexes for F₁ or F₂ of filial generation.From jointing to flowering stage,SOD and POD could be used as identification indexs for the inbred line or parents,meanwhile,POD could also be used to identify for F₁ or F₂ of filial generation.Flowing to grain filling stage,4 enzymes could be used as identification index for the inbred line or parents,but for F₁ or F₂ generation,only POD was suitable index.

To provide theoretical help and scientific basis for sustainably increasing wheat yield and production efficiency with high water use efficiency,an experiment was conducted in an artificial glass rainproof shed to study the effects of 9 irrigation methods(different irrigation combination of irrigation stages and amount) on roots,photosynthesis,quality and yield of wheat.The results indicated that the total root length,total volume,total surface area,average diameter and total root tips of W1(adequate water was supplied during the whole growth period) were the highest,irrigation at jointing stage and heading stage could obtain equivalent root traits to W1 treatment.W2 (jointing stage 45 mm) and W3(heading stage 45 mm) treatments had the highest values of wheat canopy chlorophyll density under the condition of irrigation one times,and W5 (jointing stage 22.5 mm+heading stage 22.5 mm) had the highest values of wheat canopy chlorophyll density under the condition of irrigation two times.Under the same amount of irrigation water,the wheat photosynthesis was not obviously affected by the increasing of irrigation times,the combination of irrigation at jointing and heading stages was the best irrigation combination when irrigation two times during the whole growth period of wheat.Irrigation at heading stage can help to enhance protein content when compared to other irrigation treatments,the W1 treatment had the highest values of starch content,wet gluten content and sedimentation value,and followed by W2,and the difference between W1 and W2 was insignificant.The W1 treatment had the highest values of spike number grains per spike,1000-grain weight and yield,and followed by W2,when compared to W0(no irrigation during the whole growth period of wheat) they were significantly increased by 3.2%,5.4%,6.1%,15.3%and 2.1%,4.3%,5.6%,10.9%,and if the irrigation amount was the same,the effects of irrigation one time on increasing yield could be better than or equivalent to irrigation two and three times.Correlation analysis showed that the total root volume, total surface area,average diameter,total root tips were all positively correlated to photosynthetic rate,canopy chlorophyll density,1000-grain weight and yield.All the findings indicated that irrigation at jointing stage and heading stage was the best for improving root traits,photosynthesis,quality and yield,and the effects of the increasing of irrigation times was not obvious under the same irrigation amount.

The objective of this experiment is to study the production of transgenic maize with the resistance of drought stress.In this study,an expression vector containing drought resistance gene AtHDG11 was used to transform to maize elite inbred line Chang 7-2 by ultrasonic assisted Agrobacterium mediated pollen transformation method,and produced transgenic maize plants.Based on herbicid resistance,PCR analysis and transcriptional analysis,five transgenic maize lines were selected from a large number of transgenic lines.Subsequently,the inbred line Chang 7-2 was used as the nontransgenic control to analyze the drought resistance of transgenic plants.Physiological active substances and photosynthetic parameters were measured on plants at the seedling stage and 10-leaf stage in a drought stress treatment.The results showed that Pro content of transgenic maize was higher than that of the CK plants under drought stress conditions,while MDA content was lower.Both normal conditions and drought condition,photosynthetic rate and water use efficiency of transgenic lines were significantly higher than that of CK plants.And transpiration rate and stomatal conductance of transgenic lines were significantly lower than the control plants.Therefore,ultrasonic assisted Agrobacterium mediated pollen transformation method is feasible in the maize. AtHDG11 is a strong biotechnological candidate for use in efforts to produce a drought-resistance maize.This study will provide new germplasm resources and new transgenic method.