This study revealed the changes of bacterial community structure and diversity in facility cucumber rhizosphere soil affected by different reactors,aiming at providing theoretical basis and practical basis for cucumber rhizosphere soil improvement and sustainable utilization of protected soil.This experiment was based on the V3-V4 region of the 16S rRNA gene,seven treatments namely,original greenhouse soil(CK),untreated cucumber rhizosphere soil for 100 days(CK1) and 200 days(CK2),corn straw bioreactor-treated cucumber rhizosphere soil for 100 days(S1)and 200 days (S2),and sheep manure bioreactor-treated cucumber rhizosphere soil for 100 days(M1)and 200 days(M2).High-throughput sequencing technology using Illumina Miseq was used to analyze the diversity,structure,and physical and chemical properties of the bacterial communities in the rhizosphere soils of different bioreactor treatments on facility cucumber.The results showed that 6 344 OTUs were obtained from soil samples after sequencing,which mainly belonged to 39 phyla,315 orders and 980 genera.M2 treatment could improve the bacterial richness in cucumber rhizosphere soil and significantly increase the diversity of bacterial community.At the phylum level,the dominant population structure of bacterial phylum in soil treated by corn straw bioreactor and sheep manure bioreactor was similar,among which Actinobacteriota and Proteobacteria were the dominant phylum.At the genus level,norank_f_JG30-KF-CM,Arthrobacter,norank_f_norank_o_Gaiellales,norank_f_67-14,Blastococcus,Gaiella and Marmoricola were significantly different among different treatments.According to the composition of bacterial community abundance,M2 and S2 treatments increased the relative abundance of some beneficial bacterial groups in cucumber rhizosphere to some extent.RDA analysis showed that the soil bacterial community was significantly affected by soil environmental factors,and the contents of ammonium nitrogen(P=0.015),total potassium(P=0.002)and available potassium(P=0.005)had significant effects on the bacterial community.Therefore,M2 treatment can improve the bacterial richness in facility cucumber rhizosphere soil,increase the diversity of bacterial community and change the bacterial community structure,which is beneficial to the improvement of facility cucumber rhizosphere soil.

GDSL is an important gene affecting the development of cuticle.This study cloned cucumber GDSL lipase gene and analyzed its expression pattern,in order to lay a foundation for the study of cuticle development and the glassiness of cucumber.The gene sequence was cloned to clarify its role in cucumbers with different glossiness by using six cultivars with different glossiness as materials.The promoter of CsGDSL lipase gene was cloned to analyze its functional elements.According to the reference sequence in cucumber genome database,we cloned the GDSL lipase gene of cucumber and analyzed by bio-informatics.The expression of the gene in different tissue parts of cucumber was confirmed by qRT-PCR technique.The CDS of CsGDSL length 1 059 bp which encoded 352 amino acids,and the secondary structure was mainly random curl(45.45%)and α-helix(33.24%).This gene was conservative in the process of evolution and was most closely related to CmGDSL.The expression level was the highest in the male flower of cucumber on the flowering day,and the expression level in the ovary at 3 days after flowering was higher than that at 0 days after flowering.The CDS sequence of CsGDSL gene was conservative in six cultivars. CsGDSL gene was responsive to stress,hormone and light.We obtained the CsGDSL lipase gene in this study,and identified its expression in different tissue parts of cucumber,the gene is relatively conserved in different cultivars,suggesting that CsGDSL may affect cucumber glossiness.

To reveal the effect process and mechanism of nitrogen application level on the chlorophyll fluorescence characteristics of cucumber in fruit stage under high-temperature stress,the Jinyou 101 cucumber was used as the tested material,the air temperatures were set at 35 ℃/25 ℃,38 ℃/28 ℃,41 ℃/31 ℃,in the same time the 28 ℃(daily maximum temperature)/18 ℃(daily minimum temperature)was as the control(CK);the nitrogen(N)application level was set at 0(N0),160(N1),240(N2),320 kg/ha(N3);total 16 treatments and three duplicates.The dynamic parameters of chlorophyll fluorescence of cucumber functional leaves were measured systematically after 9-days high-temperature stress in fruit stage,the differences between in various treatments were also discussed.The PSⅡ reaction centre of cucumber leaves were significantly damaged and the maximum fluorescence(Fm),maximum photochemical quantum yield(Fv/Fm),photosynthetic performance index(PIabs),area enclosed by Fm and fluorescence curve(Area)were significantly decreased after high-temperature stress in fruit stage.Under the 35 ℃ high-temperature stress,the values of ΔW_O-J and ΔW_O-K were negative in treatment N1—N3,and the oxygen evolution complex(OEC)was not inactivated.At the same time,the energy transfer between PSⅡ central thylakoids was unhindered.However,the ΔW_O-J of leaves was positive in treatment N1 under 38 ℃ and treatment N2 under 41 ℃,which means the OEC was inactivated.Therefore,the energy transfer between PSⅡ central thylakoids was blocked due to the positive ΔW_O-K in treatment N1—N3 under the 38,41 ℃.Under the high-temperature stress,the nitrogen application significantly increased the chlorophyll content,Fm,Fv/Fm,PIabs,PItotal,Area and Sm of cucumber leaves,and enhanced the OEC activity and smooth the energy transfer between the PSⅡ central thylakoids;the ABS/RC,TRo/RC and DIo/RC of cucumber leaves also decreased with the increase of nitrogen application level while the electron transfer energy(ETo/RC)increased.Nitrogen application rate and temperature had significant interactive effects on the fluorescence characteristics and yield of cucumber leaves.Under the 35,38,41 ℃high-temperature stress in fruit stage,when the nitrogen application rates were 236,283,177 kg/ha respectively,the photosynthesis of cucumber leaves was stronger and higher yield could be obtained.Therefore,the reasonable nitrogen application could improve the OEC activity of PSⅡ,promote energy transfer,and slow down the inhibition of electron receptor pool on the side of PSⅠ receptor of cucumber leaves under the high-temperature stress in fruit stage,and also improve the orderly progress of photosynthesis.

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.

Transcriptome analysis was conducted on cucumber short fruit mutants by EMS in the previous experiment,a differentially expressed gene up-regulated in short-fruit mutants was obtained, CsIAA29 (Csa2G381840),log₂FC=2.09. This gene belonged to Aux/IAA family and is involved in auxin response in early plant growth and development. In order to study the role of CsIAA29 gene in the growth and development of cucumber,the CDS sequence of CsIAA29 gene was cloned from cucumber 649 by PCR. Expasy and other online software were used for the physicochemical analysis of CsIAA29 protein. The results showed that CsIAA29 protein encoded 207 amino acids,the molecular formula was C₁₀₆₂H₁₆₃₄N₃₀₂O₃₁₃S₇,the fat coefficient was 71.16,and the total average hydrophilicity was-0.831. Protein structure prediction found four CsIAA29 structure domains,conform to the domain of Aux/IAA family structure characteristics,a preliminary estimate the function of the four structural domain and Aux/IAA family Ⅰ,Ⅱ,Ⅲ and Ⅳ was consistent. Evolutionary analysis showed that CsIAA29 of cucumber was closely related to IAA29 of pumpkin and melon. The results of qRT-PCR showed that the expression of CsIAA29 gene was the highest in cucumber ovary,while the expression of CsIAA29 gene in male flowers and leaves was relatively low. The CsIAA29 gene promoter component was analyzed using the online software PLANTCAT,the results of promoter element analysis showed that the CsIAA29 gene promoter contained several regulatory elements related to the regulation of endogenous growth hormone transport in plants,which were involved in photosynthesis and auxin polarity transport in cucumber. The above experimental results proved that CsIAA29 might affect the growth and development of cucumber fruits by regulating endogenous growth hormone.

Drought stress is one of the most serious threats to cucumber quality and yield. In order to better understand the molecular mechanism of cucumber's response to water stress,this experiment obtained a differentially expressed gene CsaV3_3G039670 (log₂FC=1.10) related to drought and significantly up-regulated expression from the previous work. Its homologous gene AtMYB94 was passed in Arabidopsis regulating the epidermal wax content of the plant to improve drought resistance,it was named CsMYB94. The CDS sequence of CsMYB94 gene was 885 bp in length and encoded 294 amino acids. By analyzing the protein domain,the CDS sequence contained two DNA-binding domains,which were R2R3 type MYB transcription factors. Protein analysis found that the molecular formula of CsMYB94 protein was C₁₄₂₆H₂₂₄₂N₄₀₄O₄₅₄S₁₁; the expected molecular weight was 3.27 ku; the theoretical isoelectric point was 6.53; it was a hydrophobic protein and an unstable protein. Analysis by subcellular localization software revealed that CsMYB94 protein was localized in the nucleus. The phylogenetic tree analysis showed that CsMYB94 in cucumber had the closest relationship with MYB94 in white algae and closer to MYB94 in pumpkin,bitter gourd and melon. The results of qRT-PCR analysis showed that CsMYB94 had the highest expression in cucumber leaves,but relatively low expression in male flowers,tendrils and stems. Therefore,it is speculated that CsMYB94 also responds to drought stress by regulating the wax content of cucumber,and the specific regulation path needs further study.

During 2018 to 2019,pepper plants showed typical symptoms of dwarf,yellowing,curling,chlorosis and rolling up of leaves were found in Kashgar,Xinjiang Uygur Autonomous region. To identify the virus that causing pepper virus disease,total RNA was isolated from the diseased tissues with typical virus symptoms,and reverse transcription(RT)-PCR assays were performed with specific primers for Cucumber mosaic virus (CMV)and Pepper mild mottle virus (PMMoV). The expected 735 bp CMV and 472 bp PMMoV fragments were amplified from diseased pepper tissue samples,respectively. Sequence analysis showed 95%,99% similarity with that of CMV(South Korea,GU327368.1)and PMMoV(Japan,AB276030.1),respectively. The results showed that pepper plants were co-infected by CMV and PMMoV in Kashgar,Xinjiang region.

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.

To improve soil ecological environment of greenhouse vegetables and promote the implementation of Zero Increment Plan for Chemical Fertilizer. Three fertilization treatments including chemical fertilizer(WSF),Cai-18 microbial fermentation liquid(Cai-18) and no-fertilizer (CK) were chosen in green house fertile soil with the content of available N 283.55 mg/kg,P 574.05 mg/kg,K 1 161.3 mg/kg and organic matter 54.9 g/kg. Rhizosphere soil micro-flora,soil nutrient content,quality and yield of cucumber grown on fertile soil with the above three fertilization treatments in greenhouse were tested by using Miseq high-throughput technique,GC-MS determination,HS-SPME-GCMS analysis,as well as other general testing methods. The results showed that there was no significant difference in cucumber yield between WSF and Cai-18 treatments whose consumption in N,P,K was reduced by 93.48%,95.44% and 98.63% compared with the former,while the cucumber yield was 6.21% and 6.59% higher than that of CK(P <0.05),respectively. These two treatments had no difference in the fruit texture and content of soluble sugar,while the contents of soluble sugar were significantly higher than that of CK. Comparably,more species and higher relative contents of esters could be produced by using Cai-18 microbe fermentation liquid with a result of facilitating fruit favor. The indexes of OTU,Chao 1 and Shannon in bacterial flora of rhizosphere soil treated by Cai-18 microbial fermentation liquid were higher than those treated by WSF and CK,but Chao 1 and Shannon indexes were lower in fungi flora.Cai-18 treatment improved quantity homogeneity of bacterial and fungi flora in rhizosphere soil,while CK treatment ameliorated fungi flora homogeneity. The content of available K in Cai-18 treatment,was 140.85 mg/kg lower than that of WSF treatment in soil after harvest (P <0.05),while there was no significant difference in the content of available P between these two treatments. As compared with CK,the treatments of Cai-18 and WSF gained significantly higher content of available K and P. It could be concluded that as compared with chemical fertilizer,Cai-18 microbe fermentation liquid on fertile soil could improve quality of product and balance structure of micro-flora and nutrition in soil with no-reducing cucumber yield.

Continuous cropping obstacles caused by long-term intensive cultivation has become an important bottleneck restricting the sustainable development of greenhouse vegetable industry. Increasing the knowledge available regarding the soil mechanisms behind continuous cropping obstacles is beneficial to develop the effective approaches to overcome this difficult problem present in intensive greenhouse vegetable production. Here,based on a continuous greenhouse cucumber cropping system located at North Henan Province of China,we evaluated the changes in soil fungal abundance and community structure with increasing cucumber cultivation history(the duration from 1 to 20 years with the interval of 5 years per treatment)through Real-time PCR and high-throughput sequencing. Continuous cropping of greenhouse cucumber significantly altered soil fungal abundance. In brief,fungal abundance initially increased and then decreased as increasing greenhouse cultivation history,and the peak occurred at the tenth year after continuous cropping of greenhouse cucumber. The tendency of the ratio of soil fungal to bacterial abundance with increasing greenhouse cultivation history was in line with soil fungal abundance. High-throughput sequencing revealed that the β diversity rather than α diversity of soil fungal community was obviously altered by continuous cropping of greenhouse cucumber. Increasing greenhouse cucumber cultivation history lowered the numbers of unique OTU in fungal community. At phylum level,Ascomycota dominated soil fungal community,and its average relative abundance was insensitive to continuous cropping of greenhouse cucumber. At order level,Microascales,Pezizales,Norank_p_Ascomycota and Sordariales together dominated fungal community. At genus level, Pseudallescheria, Lasiobolidium, Ochroconis and Chaetomium were the predominant members in fungal community. Continuous cropping of greenhouse cucumber significantly changed average relative abundances of these dominant community members. Meanwhile,most of these dominant community members significantly correlated to soil physicochemical variables. RDA analysis indicated that soil nitrate and available potassium and organic mater contents were the most important contributors to the alteration of soil fungal community structure. In conclusion,the results demonstrated soil fungal abundance and community structure as affected by continuous cropping of greenhouse cucumber.

Differentially expressed genes of cucumber in vitro gynogenesis in the early stage were analyzed by comparing the transcriptome of early cultured ovaries from both high and low regeneration frequency genotypes with the method of gene chips and qPCR technology. The results showed that 8 differentially expressed genes we selected, which appeared high level expressions in high regeneration frequency genotype, but low level expressions or overall decline in the low regeneration frequency genotype from 0th to 6th day of culture. 3 genes were found to be associated with hormonal stimulation response:respectively response to salicylic acid and jasmonic acid defense system, abscisic acid stimulation, auxin-induced binding protein and CTK expression in the Zeatin biosynthesis. 2 genes were found to be involved in the expression of POD activity which played an important role in the progress of biological oxidation. The remaining 3 genes were related to STK activity, aquaporin, mechanosensitive ion channel protein and separately participated in response to environmental stress, response to borates, arsenites and other boron, arsenic materials, transmit signals inside and outside cells and other biological processes.It is preliminarily believed that the 8 genes were important during the early stage of cucumber in vitro gynogenesis.

In order to invest the dynamic effects of fertilization on the chemical properties of cucumber soils, and provide theoretical support for fertilization in greenhouse, two vegetable greenhouses were set up as research objects, which were located in Jingmen City, Hubei Province. In the experiment, different kinds of fertilizers were used to study the changes of soil chemical properties within 14 days after fertilization and profile soil. The results showed that soil surface acidification was significant in the greenhouse, and the nutrient content gradually decreased with the increase of soil depth in the range of 0-100 cm. Soil microbial biomass carbon(SMB-C), Ammonium nitrogen and Soil microbial biomass nitrogen(SMB-N) showed the same trend in the observation period of shed A and B. And they all reached the first peak at the 2nd day after fertilization(SMB-C in B greenhouses reached the first peak at the 3rd day after fertilization). The content of ammonium nitrogen were the highest after two days of fertilization in the two greenhouses, and the content of ammonium nitrogen and nitrate nitrogen increased first and then decreased during the whole observation period. It could be seen that the fertilizer effect was the most significant on the 2nd day after fertilization by observing the changes of soil chemical properties. There was a dynamic relationship between the change of soil alkaline nitrogen content and fertilizer application for a period of time, but with the increase of fertilization time, it would return to the state of non-fertilization. It was found that the chemical properties were gradually recovered to the level of non-fertilization by observing the monitoring results for 14 days. Therefore, the next monitoring period could be lengthened to provide a theoretical basis for the rational formulation of the fertilization cycle.

In order to screen the suitable concentration of nutrient solution for enclosed circulation trough of Cucumis sativus L., taking advantages of the characteristics of nutrient solution recycling in enclosed circulation trough, the effect of different concentrations of nutrient solution on the growth, quality, yield, photosynthetic capacity and microstructure of leaves were studied. Using Zhongnong 26 as experimental material, the basic EC value of nutrient solution was 2.7 mS/cm, the five treatments were T1, T2 (CK), T3, T4 and T5 (EC value 2.3, 2.7, 3.1, 3.5, 3.9 mS/cm respectively) and the growth status, photosynthetic capacity of leaves, fruit quality and yield were screened. The results showed that with the increase of EC value, the content of soluble sugar increased and VC, free amino acid and soluble protein of cucumber first increased and then decreased. Compared with T2, T3 had a better blade structure with closely arranged palisade tissue and relatively loose sponge tissue, and the qP,ΦPSⅡ and ETR values were higher than those of other treatments, which the open degree of PSⅡ reaction center, the efficiency of the original photochemical reaction and the electron transfer of the PSⅡ was significantly improved.And the light energy was mainly distributed to the photochemical reaction P and the antenna heat dissipation D, and reduced the part of non-photochemical dissipation Ex. The value of β/α-1 for T3 was the lowest and qP was the highest, the PSⅠ and PSⅡ were relatively balanced, the light energy utilization efficiency was higher, and the photosynthesis of leaves was enhanced, which was also the material basis for improving fruit quality and yield. Therefore, T3 treatment was more suitable for cucumber growth and development. The content of soluble sugar and soluble solids of T4 was higher than T2, there was no significant difference with T3 yet. The net photosynthetic rate and the photosynthetic pigment content in T4 leaves were the highest, Pn was increased by 58.85% compared with T2.In addition, the T3 and T4 treatments were lower in Fo and the Fv/Fm was higher than the T2 treatment, the PSⅡ reaction center activity of both were higher. Under the condition of closed trough culture, the photosynthetic electron transfer efficiency of cucumber leaves with EC value of 3.1 and 3.5 mS/cm was higher, and the photosynthetic capacity was enhanced, which improved the yield and quality of cucumber.

In order to deeply understand the effect of CsamiR399b on cucumber fruit expansion, the bioinformatics analysis of CsamiR399b and its target gene CsUBC24 were carried out, and the expression characteristics of CsamiR399b was analyzed using qRT-PCR. The results showed that the CsamiR399b precursor sequence contained the complete stem-loop. CsamiR399b showed higher expression level in expanding fruit than in ovary(0 d)and unexpanding ovary, which proved that CsamiR399b involved in fruit expansion of cucumber. Bioinformatics analysis showed that the secondary structure of CsUBC24 protein was mainly composed of random curl and α-helix. CsUBC24 protein was a soluble protein without signal peptide and transmembrane structure, which might be located in the nucleus. Phylogenetic tree indicated that cucumber CsUBC24 shared highly similarity with UBC24 from melon, pumpkin and balsam pear. The sequence and functional domain of UBC24 protein among differential species were highly conserved based on the analysis of sequence alignment and conserved domain, which indicated the conserved function among differential species. The results suggested that CsamiR399b involved in fruit expansion of cucumber by regulating the expression of CsUBC24, which would provide a basis for further studying the function of CsamiR399b and its target gene CsUBC24 in cucumber fruit expansion.

To reveal the role of chloroplast in the PCD of cucumber induced by salicylic acid (SA),10 mmol/L salicylic acid was added to the leaves of cucumber seedlings at the four-leaf period,and the samples were collected at the location where SA was added. ROS in situ detection,Trypan blue staining,PI and FDA staining,and TUNEL detection were performed. These results showed that SA could induce PCD process in cucumber. According to the results of high-throughput sequencing,15 genes annotated with chloroplast were screened out among 1 759 differentially expressed genes. These genes were expressed in cucumber leaves treated with SA was confirmed by RT-PCR. It was preliminarily identified that these genes were involved in the PCD process induced by SA in cucumber. According to the expression of qRT-PCR,the 15 genes played a role of positive regulation or negative regulation in PCD induced SA in cucumber,upon regulating characteristics five kinds of genes were raised:Probable thylakoidal processing peptidase 1 gene, 6-phosphogluconate dehydrogenase gene, Probable fructose-bisphosphate aldolase 3 gene, Alpha-glucan water dikinase 1 gene and Allene oxide cyclase 4 gene, down-regulated expression of 10 genes were:Betaine aldehyde dehydrogenase 1 gene, Calcium sensing receptor gene, Pheophorbide a oxygenase gene, Probable chlorophyll(ide) b reductase1 gene, Sigma factor binding protein 1 gene, NADPH-protochlorophyllide oxidoreductase gene, 2-succinylbenzoate-CoA ligase gene, ATP-dependent zinc metallopro-tease FtsH1 gene, Nicotinamide adenine dinucleotide transporter 1 gene and CBS domain-containing protein1 gene. It lays a foundation for further revealing the role of chloroplast in cucumber PCD induced by SA.

In order to explore the intrinsic mechanism of exogenous carbon monoxide (CO) improving the germination and growth of cucumber seedlings under drought stress. Cucumber Xinjinyan 4 seeds were pretreated with the CO donor,hematin (0.01 mol/L),and their germination,nutrient absorption ability,plasma membrane stability,osmotic adjustment substance content,hydrolase activities and isoenzyme expression under drought stress simulated by 10% polyethylene glycol 6000 were investigated. The results showed that,under PEG stress,exogenous CO improved the germination potential,germination rate,root length,hypocotyl length and fresh weight of cucumber seeds,promoted imbibition of cucumber seeds,enhanced root activity,significantly decreased plasma membrane permeability and malondialdehyde (MDA) content,and increased the contents of soluble protein and soluble sugar. Meanwhile,the results also demonstrated that exogenous CO apparently up-regulated the activities of amylase and esterase and their isozyme expression. Compared with the PEG treatment,the root activity,soluble protein and soluble sugar content,amylase and esterase activity of PEG+CO treatment increased by 12.57%,5.84%,32.56%,9.87% and 48.87%,respectively,MDA content decreased by 25.81%. These results suggested that exogenous CO could improve the adaptability of cucumber seeds to drought stress by enhancing the nutrient absorption ability of cucumber seeds,protecting the stability of cell membrane system,improving osmotic adjustment ability,enhancing the hydrolase activities and their isozyme expression,and consequently induce the germination and growth of cucumber seeds under drought stress.

To explore the control mechanism of fermentation broth of Stremptomyces roseoflavus Men-myco-93-63 on cucumber powdery by means of electronic microscopy as well as cytochemical technology, then, Ultrastructure changing of the host cell wall and Sphaerotheca fuliginea(Schlecht.) Poll. was studied. Scanning electron microscopy was employed to investigate the spore germination, growth of mycelium, sporulation time treated by fermentation broth of Men-myco-93-63.The results showed that by means of TEM, being treated with fermentation liquid of Men-myco-93-63 against cucumber powdery mildew, the host cells produced defense structures and material related to infection, it showed that the host cell wall was thickened and deeply stained, solidity of papilla structure produced under the cell wall, dark material deposited between the cell wall and plasmalemma. The number of haustellum of Sphaerotheca fuiginea was reduced obviously, haustoria became malformed and haustorial wall thickened, organelles disintegrated, haustoria necrotizcd finally, the haustoria can't absorb favourably nutrition from the host. By means of scanning electron microscopy which employed hat the fermentation broth of Men-myco-93-63 reduced sphaerotheca fuiginea(Schlecht.) Poll germination 31.51%.The amount of hypha were restrained a certain extent after treatment by the fermentation broth of Men-myco-93-63. The hypha on the host surface had taken place a series of change, such as hypha distortion, clone sparsing and decreesinsing,and which delayed come into being sporule about two days. The control effect on powdery mildew was confirmed by observation with scanning electron microscopy.

The effect applications of the soluble fertilizer with dicyandiamide(DCD) or nitrapyrin on yield and quality of cucumber in greenhouse were studied.The results showed that,compared with the fertilization treatment(FP),the applications of DCD and nitrapyrin treatments of In-1 and In-2 could increase the yield of cucumber by 5.57% and 18.67%.Applications of the soluble fertilizer with DCD and nitrapyrin could improve the quality of cucumber obviously except amino acids,reduced the content of nitrate significantly by 21.59%,34.85% in cucumber respectively,and increased the content of VC and soluble sugar.With the addition of DCD and nitrapyrin treatments,content of Σ16 kinds amino acids were 14.86×10^-2,18.34×10^-2 mg/g respectively,were significantly lower than fertilization treatment by 39.15% and 24.98%,especially aspartic acid,glutamic acid and serine.Applications of the soluble fertilizer with DCD also decreased the content of glycine in cucumber.Compared with application of DCD,the nitrapyrin application was better for increasing the yield and improving the quality of cucumber in greenhouse.

In order to studied the effects of different nitrogen application on yield and quality of cucumber and provide the theoretical basis for reasonable fertilization of cucumber in greenhouse,there are five nitrogen fertilizer pretreatment treatment,CK,60%CF,80%CF,CF,120%CF,to determine the effect of different treatments on cucumber yield,quality,fruit morphology.The result shows that,on the basis of conventional fertilization,appropriate reduction of nitrogen fertilizer can improve the yield and quality of cucumber,application of nitrogen can increase the yield of cucumber compared with CK,80%CF treatment of which the highest yield,was 122 366 kg/ha. But with the increasing in fertilizer,yield showed a downward trend;The content of soluble sugar,Vc and soluble solids in cucumber fruits increased first and then decreased with the increasing of nitrogen application rate,80%CF treatment was highest;With the increasing of nitrogen uptake,the nitrogen content of cucumber fruits and plants increased compared with CK,80%CF was most significant (P < 0.05).But the 120%CF treatment nitrogen content was lower than that of CF;There was no significant difference in P and K contents between treatments(P > 0.05).Considering the yield and quality,the recommended use of nitrogen was 393.96 kg/ha under the condition of soil organic nitrogen content of 139.30 mg/kg.

Skp1 is a key protein of ubiquitin E3 ligase SCF complex. In order to further identify Skp1 function, the open reading frame of Skpl gene which is composed of 468 nucleotide in length encoding 155 amino acids was amplified by PCR using PGADT7-Skp1 as template, and cloned into expression vector pET-28a to generate recombinant plasmid pET Skp1. After verification by colony PCR and sequencing, the recombinant plasmid was transformed into Escherichia coli strain BL21 for protein expression. SDS-PAGE analyses showed that under the condition of 37℃, Skp1 protein was efficiently expressed after IPTG treatment for 3, 6, and 9 h respectively. Treatment for 6,9 h showed no significant impact on the expression of Skp1, thereby treatment of 3 h could be used for further protein expression. The expressed Skp1 protein was purified and used for producing the antiserum in rabbit. After collecting the fifth anti-serum the sensitivity of the anti-serum was analyzed using ELISA assay and showed the sensitivity between 1:128 000-512 000. Western Blot analysis was further used to detect Skp1 protein using total protein extracted from cucumber leafs, and a specific band at 20 kDa was detected which was corresponding to the expected size of Skp1.

In order to investigate the nutrient available of manure under different soil temperature condition and nutrient uptake ability of plants, a field experiment was carried out to study the effects of soil temperature and different fertilizer treatments on physico-chemical properties and urease activities in the soil as well as cucumber growth. Two levels of soil temperature (no heating as control (10±2)℃ and heating at (20±2)℃) and three levels of fertilizer treatments (no manure + urea (CK), chicken manure + urea (CMC), swine manure + urea (SMC)) were designed in the experiment. The results showed that applying chicken and swine manure could resist low soil temperature negative effect on cucumber growth and ensure the normal blossom and fruiting, and soil heating enhanced this promoted action. Compared with CK, heating soil improved cucumber yield by 44.33% in chicken manure and 31.08% in swine manure. In addition, heating simultaneously improved fruit soluble protein and pericarp chlorophyll contents, and also decreased nitrate accumulation in fruits. Elevating soil temperature increased cucumber root dry quality, root surface area, root length and root tip numbers. It indicated higher intercepted areas could make the plant absorbing more nutrients. Root at low soil temperatures showed adaptability action to enhance root average diameters and roots thickness. Furthermore, elevating soil temperature improved soil urease activities and facilitated available nutrients transformation. So, in winter out of season cultivation, application of manure and elevating soil temperature could ensure cucumber efficient production and increased fertilizer utilization efficiency.

In order to explore the effect of CO₂ on SOD, POD and CAT activity and their gene expressions under high temperature, the grafting cucumber in greenhouse was used as material, trying to study the changes of cucumber leaf SOD, POD and CAT activity and gene expression under high temperature after treating with CO₂.The results showed SOD,POD and CAT activity in cucumber leaf were increased after treating with CO₂ under high temperature. Comparing with room temperature treatment,the max difference of cucumber SOD,POD and CAT activity were at 42,28 and 21 days after treating with CO₂ and high temperature,and increased by 19.1%,50.4% and 45.0% respectively. Using Real-time PCR analysis cucumber SOD, POD and CAT gene expression were all increased after treating with CO₂ under high temperature. The max difference of cucumber SOD, POD and CAT gene expression level were at 28,28 and 21 days after treating with CO₂ and high temperature,and with 60.7%,70.3% and 44.9% higher than room temperature treatment respectively. In conclusion,after treating with CO₂,the cucumber SOD,POD and CAT activity and their gene expression level were both increased under high temperature.

The changes of leaf area increase,photosynthetic rate,SPAD values of cucumber leaves and contents of starch,carbohydrate and MDA between functional leaves and old leaves were studied in greenhouse under high temperature and elevated CO₂ coupling. The purpose of research was to investigate the effect of high temperature and elevated CO₂ coupling on photosynthesis and leaf senescence of cucumber in greenhouse. Main results were as follows:Both the net photosynthetic rate and SPAD values increased markedly under high temperature and elevated CO₂ coupling. But the values under high temperature with high concentration of CO₂ reached at the peak level after treatment of 13 days; the values under high temperature with medium concentration of CO₂ were significantly higher than control,high temperature with low concentration CO₂ and high temperature treatments during 10-19 days. Comparing with the functional leaves,contents of starch went up and contents of carbohydrate declined remarkably in old leaves under high temperature with high concentration of CO₂; while there was no significant change in contents of starch and carbohydrate under high temperature with medium and low concentration of CO₂. The content of MDA in old leaves under high temperature with high concentration of CO₂ grew significantly,and it was higher than those in other treatments except in high temperature treatment. The result above illustrated that under high temperature photosynthesis of cucumber would be increased quickly,but the speed of leaf senescence would also grew up with high concentration of CO₂; while photosynthesis of cucumber would be increased continually,and the speed of leaf senescence would be decreased with medium concentration of CO₂.

Irrigation scheduling of greenhouse vegetable has a strong regional suitability,in order to obtain appropriate drip irrigation scheduling of cucumber under solar greenhouse in coastal area of Tianjin,an experiment of six combinations of irrigation rate one time and irrigation interval was carried out in spring season,particularly including T1(6 mm+3 d),T2(12 mm+3 d),T3(18 mm+3 d),T4(12 mm+6 d),T5(18 mm+6 d)and T6(24 mm+6 d). It was showed that the yields under six treatments were respectively 75 056,79 352,80 042,73 023,76 398,78 891 kg/ha,correspondingly,the values of irrigation water efficiencies were 397,257,187,386,307,255 kg/mm. Generally,greater irrigation water rate or lower irrigation interval was beneficial to obtain higher production of cucumber,however,there were down trends of quality and irrigation water efficiency of cucumber with adding irrigation water rate. Therefore,it is recommended that the T2 treatment,12 mm of irrigation rate one time and 3d of irrigation interval,is suited for the cultivation of cucumber under solar greenhouse in spring,comprehensively considering factors of yield,quality and water-saving of cucumber.

In order to determine the optimum furrow depth of the double border deep furrow ridge for cucumber cultivation in green house by furrow irrigation under the membrane,different irrigation furrow depth,15,11,8 cm corresponding to the irrigation of 300,225,and 150 m³/ha were tested,and with the conventional furrow ridge and the irrigation of 450 m³/ha as control.The experiment investigated the yield and quality of cucumber plants Dongli 519(rootstocks:pumpkin Gaoyouliang),soil quality,and water use efficiency under the three irrigation furrow depth.The results showed that compared to the conventional irrigation,all the 3 deep furrow ridge irrigation could meet the demand of cucumber normal growth,and had no significant effect on the fruit production and quality,no obstacles on the root nutrient absorption and utilization,no influence of soil environment.In additionly,all the three irrigations significantly increased the water use efficiency.In autumn and winter crop,water-saving rates were 27.03%,40.54%,54.05% respectively;and in winter and spring crop,water-saving rates were 30.20%,45.30%,60.40% respectively.Considering yield and irrigation water use efficiency,the optimum and recommended furrow depth in deep furrow ridge mode for cucumber cultivation was 8 cm,corresponding to the irrigation of 150 m³/ha, which meet the water needs of grafting cucumber production.

For the purpose of exploring the colonization on the cucumber,the Bacillus subtilis BSD-2 had remarkable control effect on the Botrytis cinerea. In this study,the plasmid of pGFP4412 that contains green fluorescent protein gene(GFP) was transformed into the Bacillus subtilis BSD-2 by modified electroporation.The plasmid stability,growth curve and the inhibition activity of GFP-labeled strains were measured.The results showed that the GFP-tagged strain could emit green fluorescence successfully.The tagged strain nearly had the same trend with the wild type strain in growth.The stability of GFP-marked in engineering B.subtilis BSD-2 strain was 86% after transference of culture 56 hours continuously without selective pressure.Inhibition activity showed that the GFP-marked strain exhibited the comparable ability as the wild type strain to inhibit Fusarium oxysporum and Botrytis cinerea.Observation by fluorescence microscope indicated that the GFP-tagged BSD-2 could colonize on the root tissue after inoculated 24 hours.It could be seen on the leaf veins after five days.It still could be observed on the leaf veins after 50 days.All of these data indicated that the GFP-marked strain could colonize on the cucumber so properly that stopped pathogens to invade the plant.

In order to probe into variation characteristics of leaching of potassium from soil,a study was conducted in cucumber greenhouse in Yongqing of Hebei Province to investigate dynamics of potassium concentrations in soil solution and leaching of potassium from soils during the whole cucumber growth period by the different fertilizer application.The results showed that dynamics of potassium concentrations in soil solution collected in the depths at 35-40 cm and 95-100 cm soil layers.Potassium concentration (47.7-114.0 mg/L) for all the treatments increased at first,decreased subsequently and then increased again in soil solution at 35-40 cm for greenhouse.Meanwhile potassium concentrations in soil solution at 95-100 cm (40.3-105.0 mg/L) kept the similar dynamic trend to that at 95-100 cm for conventional potassium rate treatment.However,potassium concentrations in soil solution of CK (49.6-66.5 mg/L) and the treatment of recommended potassium rate (30.6-42.8 mg/L) kept stable during different periods at 95-100 cm.Potassium levels of leaching solution increased with increase of potassium application rate and ranged at 27.9-65.1 mg/L for the cucumber greenhouse.Total amounts of potassium leaching from soil layer (0-100 cm) of the greenhouse was 154 kg/ha.Therefore,the application rates at 600 kg/ha could not only keep the high yields of cucumber and reduce soil potassium leaching loss,but also increase the economic benefit and environment benefit effectively.

In order to detect and identify the viral causing agent that infecting cucurbit vegetable plants in Shandong, 867 cucurbit plant samples of suspected viral diseases from 11 vegetable planting areas in Shandong were collected during July to August, 2014.9 primer pairs specific to Cucumber mosaic virus (CMV), Cucumber green mottle mosaic virus (CGMMV), Watermelon mosaic virus (WMV), Tobacco mosaic virus (TMV), Zucchini yellow mosaic virus (ZYMV), Squash mosaic virus (SqMV), Melon yellow spot virus (MYSV), Cucurbit chlorotic yellows virus (CCYV), Prunus necrotic ringspot ilarvirus (PNRSV) and Melon necrotic spot virus (MNSV) were used respectively to perform PCR detection.The results showed that viruses carried rate was 34.8%, 10.4%, 20.0%, 41.7%, 27.0%, 7.8%, 2.6%, 1.7%, 0 and 0.9% respectively.The natural infection of these viral diseases except PNRSV in Shandong was confirmed, and the incidence of CMV and TMV were higher than others.Two or more than two viruses mixed infections were also very common in field.At the same time, those CMV positive samples from 11 regions were selected for subgroup classification.Coat protein(CP) gene and the whole RNA3 nucleotide sequences were determined.Sequence alignment and phylogenetic analyses were performed.The results showed that the CMV isolates of cucurbit vegetables in Shandong area were all members of CMV subgroup IB with the highest similarity to a South Korea isolate As(AF013291), no other strains were found.