Calmodulin is an important Ca²⁺ receptor protein in plants,which plays an important role in calcium signaling pathway and stress resistance.It is of great significance to study the mechanism of CaM protein in tomato under low temperature stress for cold tolerance breeding of tomato.Tomato calmodulin genes SlCaM3, SlCaM4 and SlCaM5 were cloned from tomato varieties Heinz1706,LA3969,Jifen 2,Jifen 3 and Nongbofenba 15,and their sequences and protein sequences were analyzed by bioinformatics;the cis acting elements in the promoter regions of SlCaM3,SlCaM4 and SlCaM5 were analyzed by plantcare;Quantitative Real-time PCR was used to analyze the expression patterns of SlCaM3,SlCaM4 and SlCaM5 under 15,5 ℃ temperature stress in different tomato varieties,and the specific expression of SlCaM3,SlCaM4 and SlCaM5 in different tissues was analyzed in combination with RNA-seq data.The results showed that the coding sequence of SlCaM3,SlCaM4 and SlCaM5 were 450 bp,and their similarity was 93.63%;the encoded amino acid sequences were identical,belonging to acidic stable hydrophilic protein with typical conservative domain of cam protein.The analysis of cis acting elements showed that the promoter regions of the three genes contained not only the necessary core elements,but also a variety of biotic and abiotic stress response elements,and showed a complementary pattern.The analysis of the expression patterns of different degrees of low temperature stress showed that the expression patterns of SlCaM3,SlCaM4 and SlCaM5 in five tomato materials showed a trend of first decreasing and then increasing at 15 ℃,and the expression of SlCaM5 increased more significantly.At 5 ℃,SlCaM3 and SlCaM4 did not change significantly,but the expression level of SlCaM5 gene increased significantly in the later stage of treatment.The high expression of SlCaM5 gene in the process of tomato resistance to low temperature indicated that it maintained the translation level of cam protein under low temperature and ensured that the function of CaM protein was not affected.The analysis of SlCaM3,SlCaM4 and SlCaM5 specific expression in different tissues of Heinz1706 showed that SlCaM3 and SlCaM4 were highly expressed in meristem,while the expression of SlCaM5 different tissues was not significantly different.

In order to identify the pathogenic fungi which causing tomato bacterial wilt in Fengnan District of Hebei Province.This study proved the disease as Bipolaris sorokiniana by pathogen isolation,pathogenicity test,morphological observation,and rDNA-ITS gene sequence analyses was caused by Fusarium oxysporum f.sp.radicis-lycopersici(Forl).The result showed that the mortality and morbidity of stem based inoculation were higher than root soaking inoculation.So,the disease with stem based inoculation developed faster.The study provided theoretical basis for the breeding of disease resistance and the screening of the fungicides.

It is necessary for us to clone some endogenous promoters with high transcription activity in tomato leaves and construct CRISPR/Cas9 system, which could provide an effective technology for the research of molecular design breeding in tomato. Six different truncated tomato U3 promoters had cloned by two rounds of PCR amplification from tomato variety Zhongshu 4. Six GUS fusion expression vectors were constructed and transformed into tomato leaves by the agroinfiltration. After right sequencing of the transfer PCR products, the necessary element for transcriptional function of six kinds of SlU3 promoter was analyzed using DNAMAN software. The different truncated SlU3-1P,SlU3-3P and SlU3-4P promoters from tomato variety Zhongshu 4 were performed to clone by two rounds of PCR amplification, altogether there were six different promoters. Lengths were 489,318,450,248,457,248 bp respectively. Six GUS fusion expression vectors were constructed and transformed into tomato leaves.The promoter sequence alignment analysis revealed that the tomato U3 promoter, like the Arabidopsis U3 promoter, also contained two more conserved elements, the USE and TATA boxes, and the positions between the two elements were relatively fixed.Transfected tomato leaves by agroinfiltration transformation method. The results showed that the six truncated U3 promoters could drive GUS expression in tomato leaves and tomato leaves could be stained blue and the shorter promoters also had stronger transcription activity as original promoters.Six different tomato U3 promoters had cloned with high-level transcription in tomato leaves, which could provide ideal endogenetic promoters for the construction of CRISPR/Cas9 system for tomato functional genomics research.

The effect of soil amendments on soil microbial communities,quality and yield of tomato in protected house were investigated for providing a scientific basis for reasonable use of soil amendments.A field experiment was initiated in a planting tomato greenhouse with different kinds of soil amendments(lime nitrogen,fosthiazate,abamectin and substrate).Changes of bacteria,fungi,quality,yield were monitored.Results showed that four different types of soil amendments could significantly increased the number of soil bacteria,fungi,actinomycetes and antagonists,while the numbers of bacteria and fungi in the later growing period of tomato compared with the middle growing period were decreased;the contents of lycopene and Vc reached the highest under substrate treatment for 8.75 mg/100g,78.60 mg/kg,respectively;the soluble sugar content ranged from 2.85% FW to 3.29% FW;compared with other treatments,the sugar acid ratio of CK,substrate and abamectin were 7.57,6.91 and 7.70,respectively,taste the best;under substrate treatment,the yield of tomato was the highest for 139 059.30 kg/ha,which was increased by 21.18% compared with CK.Considering the taste quality and yield,substrate could be used as a preliminary reference for tomatoes production.

The effect of SA on physiological indexes and gene expression were studied in tomato seedlings under low potassium stress in order to provide an important theoretical basis for the relationship between SA and low potassium stress. In this study,the different concentrations of salicylic acid (SA) (0.10,0.25,0.50,1.00 mmol/L) affect antioxidant enzyme activities and gene expression in tomato seedlings under low-potassium stress were investigated.The results showed that the chlorophyll (Chl) and proline (Pro) contents,as well as catalase (CAT),ascorbate peroxidase (APX),peroxidase (POD) and superoxide dismutase (SOD) activities,were significantly increased,and malondialdehyde (MDA) concentration decreased under 0.25 mmol/L SA treatment compared with that in the control.Meanwhile,the gene expression levels of APX,CAT,POD,and SOD in tomato leaves were analyzed through quantitative Real-time PCR.Four gene expression levels of antioxidant enzymes were considerably increased after 48,96 h treatment.These results suggested that SA promoted the gene expression levels of APX,CAT,POD,and SOD to alleviate the damage of low potassium stress,and decreased the accumulation of ROS and enhanced resistance in tomato seedlings under low-potassium stress.

This experiment consists of eight varieties of tomato were collected from home and abroad,the indexes of physiological and biochemical characteristics,field resistance,yield and quality were determined after the haze.The results showed that:during the weather of low temperature and haze,solar greenhouse's own environmental conditions far could not meet the requirements of the temperature,light and humidity of tomato.Under stress conditions,the varieties with stronger resistance were Jinpeng No.8 and Fenyan No.1,their fruit drop rates were 2.5%,3.7%,dead rates of plant were 38.8% and 25.0%,the diseases incidence rates were 35.5% and 35.0% respectively,These indicators were in the lower level than other varieties.And Jinpeng No.8 had the highest yield,54 300 kg/hm²,followed by Fenyan No.1and T1701,which production were more than 50 000 kg/hm². Fruit quality,the maximum of sugar acid ratio was Jinpeng No.8,and the taste was best;The minimum of the nitrate content was Fenyan No.1.The whole fog and haze,the smallest decrease amplitude of chlorophyll was Jinpeng No.8,Fenyan No.1 wasthe second.Physiological and biochemical indexes,the varieties of accumulated more contents of soluble sugar and proline were Jinpeng No.8,Fenyan NO.1,the value of SOD and POD were also higher,The content of MDA didn't have obvious differences between species in this experiment.Therefore,under low temperature and weak light,the varieties with self-regulation,strong adaptability were Jinpeng No.8,Fenyan NO.1,which results of physiological indexes were consistent with the results of field experiments.

In order to prepare the special antiserum of Tomato chlorosis virus (ToCV),the total RNA of tomato leaves infected with ToCV were extracted.According to the coat protein gene of ToCV,specific primers were designed to amplify the coding region of coat protein by RT-PCR,the prokaryotic expression vector pET32a-ToCVCP was constructed and the recombinant protein was expressed in E.coli Rosetta (DE3).The results showed that the ToCVCP gene(NCBI:KT809400)owned 774 bp nucleotides,encoding 257 amino acids.The similarity of nucleotide and predicted protein were 97.2%-99.6% and 97.3%-100.0%,respectively,compared with the CP gene of other ToCV isolates registered in GenBank.The nucleotide sequence of conserved sites accounted for 91.3% of all loci,the amino acid sequence conserved sites accounted for 88.3% of all loci,indicated that the geographical origin of different ToCV CP gene had a relative higher conservative property.The ToCV CP gene was subcloned into the expression vector pET-32a(+) and the fusion protein was expressed in vitro.SDS-PAGE analysis showed that a specific recombinant protein of approximately 33 kDa was produced in the Rosetta (DE3) with the prokaryotic expression vector pET32a-ToCVCP in 37℃ with 1.0 mmol/L IPTG for 6 hours.

To clarify the suitable application rate of the soluble ammonium polyphosphate fertilizer for tomato,the phosphorous rates of soluble ammonium polyphosphate fertilizer on yield,quality,phosphorous uptake of autumn-winter tomato were studied in a plastic greenhouse.The results showed that the yield of tomato and the fruit weight were highest at the 29 kg/ha,however,when continue to increase the amount of phosphorus,the yield and fruit weight will be lower.The most appropriate phosphorus rate for tomato quality was 29 kg/ha.As the phosphorus uptake of tomato roots,the difference between treatments was not significant; After fitting,the most appropriate phosphorus rate for tomato fruit and whole-plant were 21.17 kg/ha and 25.79 kg/ha respectively.The phosphorous utilization efficiency (PUE) was higher than other treatments at 29 kg/ha.In summary,the most appropriate phosphorous rate for a higher autumn-winter tomato yield was 29 kg/ha under this soil fertility.

In order to optimize Cd low accumulation or Cd high resistant tomato varieties,in this paper,4 tomato varieties(Provence,Ruitina,Kate 2 and 908) were selected as the research objects,and the differences of growth index and resistance index of tomato seedlings under cadmium stress were compared in detail by hydroponics experiment. The results showed that 908 had the highest natural characteristics in plant height,root length,total biomass,MDA and chlorophyll content under the condition of nutrient solution without Cd;Provence showed the most prominent in CAT activity;Ruitina showed the highest activity on POD. Under the condition of Cd stress,low Cd content promoted the growth of root system of Provence,which was 24.72% higher than that of CK,other varieties did not change much;the plant height of Ruitina was most sensitive to the stress of middle and high Cd content,other varieties had no obvious change. CAT of four tomato varieties under low and medium Cd stress has increased 12.58%-84.91%;the activity of CAT decreased sharply and the resistance function was seriously weakened under high Cd stress. The resistance of POD in 908 to medium and high Cd stress was increased,and the enzyme activity was enhanced by 76.07% and 72.65%;the activity of POD in Ruitina decreased sharply and the resistance was seriously affected. The contents of Cd in shoots and roots of 908 were the highest among the four varieties,3-12 times of other varieties,Provence was the lowest,and the transport coefficient of four varieties were all<1. Under the same Cd stress,the high Cd concentration absorbed by the 908 plants induced a high increase in the activity of antioxidant enzymes,reflected that the scavenging ability of 908 plants to reactive oxygen species was stronger than that of the other three varieties. In conclusion,under the medium and high Cd stress,Provence was selected as Cd low accumulation tomato variety,908 had the strongest resistance and higher Cd content,belonging to the high Cd resistant varieties.

There exists the compound infection of Tomato chlorosis virus (ToCV) and Tomato yellow leaf curl virus (TYLCV), and the incidence of the two diseases presents a tread of increase in recent years, which becomes a new threat to tomato farming. In order to study the interaction and variation of the two virus genes after single and mixed infection, the molecular identification and sequence analysis of the CP gene and the HSP gene of ToCV and the gene of TYLCV occurred in Tianjin were carried out. The results showed that, compared with the single infection samples, 6 base mutations of TYLCV were found in mixed infection samples, i.e. 73rd A→C, 92nd A→G, 347th C→T, 1 209th C→T, 1 618th A→G and 2 107th A→T, among which the 73rd and 92nd mutations were not in the coding region and the other four were located in the ORF box with 3 missense mutations and one samesense mutation(1 209th). There was also one samesense mutation in the CP gene of ToCV. There were 4 base mutations in HSP gene of ToCV, among which the 826th T→C and 1 166th G→A were samesense mutations, while the 1 395th A→G and 1 630th A→G were missense mutations. The accumulation amount of TYLCV and ToCV in tomato samples after single infection and mixed infection were analyzed by RT-qPCR. The results showed that the accumulations of TYLCV and ToCV had no significant difference between single infection and mixed infection. In the mixed infection samples, the copy of TYLCV was about 262-436 times that of ToCV.

In order to study the function and molecular mechanism of SlYAB2a in growth and development of tomato.The cDNA sequence of SlYAB2a was cloned from tomato by RT-PCR.Bioinformatics analysis showed that SlYAB2a encodes a putative polypeptide of 192 amino acids with a calculated molecular mass of 21.35 kDa,a theoretical pI of 8.79,and a grand average of hydropathy value of-0.487.SlYAB2a protein was predicted to possess a Pfam:YABBY domain architecture at position 6-165,a C₂C₂ zinc finger-like domain at position 20-47,and a helix-loop-helix domain at position 122-181.Secondary structure analysis revealed that SlYAB2a protein contains 19.79% α-helical domains,14.06% β-sheet domains,and 66.15% random coil.The analysis of protein multiple sequence alignments showed that the percent identity of the SlYAB2a with members of group YABBY2 from Solanum tuberosum,Nicotiana sylvestris,Vitis vinifera,Glycine max,Arabidopsis thaliana,Brassica napus,Oryza brachyantha,Zea mays and Triticum aestivum were 98%,78%,71%,65%,64%,64%,58%,57% and 57%,respectively;which suggested the percent identity of the SlYAB2a with other members of group YABBY2 from dicotyledon was higher than that from monocotyledon.The analysis of phylogenetic relationship showed that YABBY2 was easily separated into two distinct subgroups,that was dicotyledon subgroup and monocotyledon subgroup.SlYAB2a belonged to dicotyledon subgroup and was most closely related to members of group YABBY2 from Solanum tuberosum,Solanum pennellii,Nicotiana tomentosiformis and Nicotiana sylvestris. The expression of SlYAB2a was determined by Real-time quantitative RT-PCR.The result showed that the SlYAB2a gene was transcribed in different tissue organ.The expression level of SlYAB2a in flowers and mature green fruits was much higher than that in any other analyzed tissue organs.These results suggested that SlYAB2a might be involved in flower and fruit development.Following transient expression of SlYAB2a in onion epidermal cells,SlYAB2a was found to be localized in the nucleus.

The effects of exogenous H₂S and H₂O₂ physiological regulation on the processing tomato seedlings under NaCl stress were investigated,KT-32 with weak salt tolerance and KT-7 with strong salt tolerance as the materia. Research of 50 μmol/L H₂S and H₂O₂ were determined by pot culture under the conditions of 0.5,1.5,3.0 mmol/L. Effects of cotreatment on the growth,osmoregulation,material accumulation and reactive oxygen metabolism of seedlings of processed tomato under 250 mmol/L NaCl stress.The results showed that the cotreatment of exogenous H₂S and H₂O₂ alleviated the inhibitory effect of NaCl stress on the growth of seedlings of processed tomato seedlings,and maintained a strong photosynthetic pigment content,relatived water content and root activity in processed tomato seedlings.And decreased the electrolyte leakage rate,the content of MDA,the content of H₂O₂ and the production rate of O₂^· free radical and enhanced the activities of antioxidant enzymes SOD,POD and CAT activity. Among the two strains,soluble sugar increased 24.0% and 29.4% by compared with 50 μmol/L H₂S treatment alone at 50 μmol/L H₂S and 1.5 mmol/L H₂O₂ ,proline content increased by 25.8% and 21.3%,respectively,and the effect of salt stress alleviation was the most significant.In summary,there were a certain degree of synergy between exogenous H₂S and H₂O₂,which could enhance the osmotic regulatory capacity of plants under enhanced NaCl stress in tomato seedling plants to enhance the removal of reactive oxygen species H₂S and H₂O₂ in the tomato seedlings,and then weakened the injury of reactive oxygen species on the plasma membrane in processed tomato cells and then increased the adaptability of tomato seedlings to salt stress. The synergistic effect of the two signaling molecules will provide the theoretical basis for alleviating the physiological mechanism of salt stress in tomato seedlings.

Using single factor randomized block experiment,make saline water (EC=3 mS/cm)irrigation directly as control,to study effect on contents of mineral elements of tomato plants'roots,stems,leaves at fruit-set period,the early stage of full bearing period,later stage of full bearing period and different growing periods fruits of different irrigation methods of saline water.Results showed that:①These ten kinds of mineral elements in tomato roots,stems,leaves and fruits all showed regular changes.Six kinds of mineral elements contents in roots,stems,leaves were N,K,Ca greater than P,Mg,Na,in four kinds of microelements,the Fe,Mn was higher,next was Zn,Cu was the lowest;Except K,young fruits had the highest contents of five kinds of macroelement,the content of K was the highest in mature fruits.Microelements' content in fruits were Fe,Zn was higher,Cu,Mn was lower.In fruits,K was positive correlation with the other nine kinds of mineral elements.Na,Mg,Mn was antagonism with Zn,Cu,P. ② Saline water irrigation increased Na content of tomato root, stem, leaf and fruit in quality formation period, direct irrigation with saline water increased the maximum. Compared with freshwater irrigation, the total N content of all parts of tomato plant is also improved under saline water irrigation directly, but it was not conducive to the absorption and accumulation of N, P and 4 kinds trace elements of tomato fruit. Fresh water irrigation is beneficial to improve the content of P, K and Zn in each part of the plant, and promote the uptake and accumulation of N, P, K and Fe, Zn of tomato fruit. The content of Ca, Mg and Fe in each part of the plant can be improved when use saline water and fresh water rotation irrigation according to plant growth periods, Ca and Mg content of tomato at young fruit period and mature period are also higher under saline water freshwater irrigation in sequence and rotation irrigation according to plant growth periods. The contents of Cu and Mn in each part of plant are higher when use mixed water irrigation and saline water fresh water irrigation in sequence, so the content of Cu under mixed water irrigation and the content of Mn under saline water fresh water irrigation in sequence in the fruit are also higher at fruit quality formation period. So,using saline water irrigation in a short time or decreased the EC of saline water (rotation irrigation,mixing water irrigation)could avoid the negative influence of saline water and supplement the necessary elements of plants,they were N,Ca,Mg and Fe,Mn,Cu and so on.

In order to identify the function of SlETR6 gene in tomato under different abiotic stresses, the SlETR6 gene was cloned by RT-PCR from Solanum lycopersicum, and the phylogenetic tree was clustered based on its amino acids by MEGA 5.0 soft. The temporal and spatial (included root, leaf, flower, and fruit in different stage) expression patterns of SlETR6 were analyzed by Real-time quantitative PCR (qPCR), and the relative expression level of SlETR6 gene was analyzed by qPCR under high salt stress, high temperature, low temperature and drought stress during tomato seedling development. The results showed that SlETR6 contained 2 265 bp ORFs, encoded 754 amino acid residues. The protein SlETR6 with a molecular mass of 80.05 ku and isoelectric point of 7.28, and had a closer relationship with Solanum tuberosum ETR2-like. Promoter analysis revealed that SlETR6 contained several stress-responsive elements involved in heat, drought, anaerobic, light, ethylene, salicylic acid, and gibberellin signaling. qPCR analysis showed that the SlETR6 was constitutively expressed in all examined tissues, including seed, root, flower, leaf and fruit,and it showed a higher level in flower and breaker fruit. SlETR6 was up-regulated under high salt stress 6 h compare to control, and the expression level was the highest at 12 h under stress, then return to the normal. The transcription level of SlETR6 was up-regulated significantly under high-temperature stress. Drought stress could significantly up-regulated the expression of SlETR6 in the early stage, and the expression level was the highest at 1 h under stress. These results suggested that SlETR6 might function as an stress-responsive gene under high salt stress, high temperature and drought stress during tomato development. This study provided a potential novel candidate for abiotic research in tomato.

WRKY transcription factor is a family of transcription factors unique to plants.Studies have demonstrated that WRKY transcription factor played an important role in plant growth and development and in plant response to biological and abiotic stress.In order to reveal the function of tomato WRKY gene,two inbred lines of tomato with high resistance to bacterial wilt Hm 2-2(R)and high susceptibility to bacterial wilt BY 1-2(S)were used as experimental materials based on the preliminary transcriptome data,and a WRKY transcription factor SlWRKY75 gene(Solyc05g015850.3)was cloned.The structure,expression pattern and function of the gene and its encoded protein were analyzed by bioinformatics analysis,multiple alignment of amino acid sequences,phylogenetic tree construction,Real-time Quantitative PCR(qRT-PCR)and virus induced gene silencing(VIGS).The results showed that the full length of the cDNA of this gene was 653 bp,its maximum open reading frame was 519 bp,encoding 172 amino acids,the relative molecular weight of the protein was 19.878 51 ku,the theoretical isoelectric point was 9.32.The protein belonged to the hydrophilic non-secreted protein,and there was no transmembrane structure.Meanwhile,the protein had a highly conserved WRKY domain and a CX₄CX₂₃HXH zinc finger motif,which belonged to the Class Ⅱ family.Phylogenetic tree analysis showed that SlWRKY75 was closely related to Solanum pennellii SpWRKY75 and clustered into a group with other Solanaceae,while it was far related to Hevea brasiliensis HbWRKY75 and Gossypium hirsutum GhWRKY75 and was in different branches in the phylogenetic tree.The results of qRT-PCR analysis showed that the expression of SlWRKY75 gene were tissue-specific and could be induced by Ralstonia solanacearum,salicylic acid and jasmonic acid.VIGS result showed that silencing SlWRKY75 reduced plant resistance to bacterial wilt,indicating that SlWRKY75 positively regulated tomato resistance to bacterial wilt.These results suggested that SlWRKY75 gene played an important role in regulating tomato resistance to bacterial wilt.

To investigate the effects of organic and inorganic fertilizers on the yield and quality of pepper and tomato.Under the greenhouse cultivation condition,the pepper and tomato of field experiments were conducted to study the effect of yield and quality when reduced organic and inorganic fertilizers and combined the both application.The treatments were set up as no fertilizer,100% organic fertilizer,75% organic fertilizer,50% organic fertilizer,50% chemical fertilizer+50% organic manure fertilizer,75% chemical fertilizer,50% chemical fertilizer.The results showed that reduction and combined application of chemical and organic fertilizer had no significant effect on the yield of pepper, the effect of soluble solids content, soluble sugar content and soluble protein content was relatively small.The treatment that combined application of chemical and organic fertilizer and the quality of pepper which the content of nitrate was the lowest and the content of vitamin C was highest.While reduced the fertilizer application would lead to a different degree of yield increase for tomato, and compared with other treatments,treatment of 50% chemical fertilizer+50% organic manure fertilizer reached the highest yield and the best quality which the nitrate content of tomato was the lowest, and the content of vitamin C and amino acid were the highest, and the difference of soluble solids content and sugar acid ratio was relatively small.

The purpose of this study was to determine whether the tomato plants in Tianjin was infected by Tomato chlorotic virus (ToCV) and whether variation had occurred in the important genes of ToCV.ToCV isolated in Tianjin was diagnosis at molecular level.The genome sequence of coat protein and heat shock protein had been cloned and analyzed.The results showed that the homology of the CP isolate in Tianjin was 97.3% or more with the representative isolates of different countries and regions.The homology of the Hsp70h isolate in Tianjin was 97.2% or more with the representative isolates of different countries and regions.It is proved that Hsp70h and CP protein are the most conserved proteins.This is the first report of Tomato chlorosis virus occurrence in Tianjin.

To figure out the physiological regulation mechanism of tomato cold resistance,we used two type tomatoes which one is cold resistance wild tomato LA1777 and the other is low temperature sensitive cultivated tomatoes LA2706 as our test materials to study the influence of low temperature on antioxidant metabolism and carbon assimilation. Results showed that under the stress of low temperature,the contents of superoxide-anion radical (O₂^·),hydrogen peroxide(H₂O₂),malondialdehyde(MDA),dehydroascorbic acid(DHA)increased,and it that in LA2706 was about 0.3%-21.0%,1.2%-17.3%,13.4%-36.9%,and 13.3%-21.0% higher than LA1777,that speeded up the process of membrane lipid peroxidation. The contents of reduced ascorbic acid(AsA)had a slight upward trend with cryogenic processing time extended;the activity of superoxide dismutase(SOD)decreased by 55.3% and 28.2% 7 d after treatment in LA2706 and LA1777,LA2706 fell obviously than LA1777;the peak of ascorbic acid catalase(APX)in LA1777 was significantly higher than LA2706,and about is 1.7 and 4.0 times that of LA2706 in 1 and 7 d after treatment. With the extension of low temperature processing time,the total sugar content,acid invertase activity,neutral invertase activity and sucrose phosphate synthase all raised,LA2706 had a significantly higher increment than LA1777,and about was 5.8,4.8,10.2 and 1.7 times in 7 d that of 0 d after treatment.Low temperature made LA2706 to have a large number of decomposition starch into sugar,to alleviate the stress of low temperature environmental damage.