Abstract:Phosphorus is a limited natural resource， but the utilization rate of phosphorus fertilizer in the current season is low， and excessive application of phosphorus increases the risk of agricultural non-point source pollution. It is an important way to save phosphorus resources and protect the ecological environment to excavate the genetic characteristics of phosphorus efficiency and cultivate low phosphorus tolerance varieties in potato. The establishment of an evaluation system of low phosphorus tolerance of potato varieties （lines） based on photosynthetic phenotypic parameters can achieve rapid， non-destructive and efficient identification and selection of low phosphorus tolerance potato germplasm. A total of 20 potato varieties （lines） were cultured in normal phosphorus nutrient solution pool （1.70 mmol/L NaH2PO4） and low phosphorus nutrient solution pool （0.17 mmol/L NaH2PO4）， and the biomass， yield and photosynthetic phenotype of each cultivar were measured. The low P stress tolerance index of each index was calculated. Using the comprehensive membership function method， principal component analysis and regression analysis， the low phosphorus tolerance of each potato variety（lines） was divided， and the low phosphorus tolerance of each potato variety（lines） was comprehensively evaluated. Compared with normal P stress， the average value of yield， plant dry weight and root dry weight of potato varieties under low P stress decreased greatly， with the coefficient of variation of each index ranging from 3.24% to 132.99%. The photosynthetic parameters， such as non-photochemical quenching coefficient （qN）， open ratio of PSⅡ reaction center （qL）， and quantum yield of non-regulatory energy dissipation（?no）， were increased. The cumulative variance contribution rate of five principal components was 86.32%. The membership function method was used to calculate the comprehensive evaluation value of low phosphorus tolerance （D）， and the D value ranged from 0.3258 to 0.7702. Using multiple regression analysis method， the D value regression equation was established to predict potato low phosphorus tolerance. Five identification indexes of low phosphorus tolerance were determined by multiple regression analysis and systematic clustering was carried out. The 20 potato varieties （lines） were divided into three types： low phosphorus tolerance type， intermediate type， and low phosphorus sensitive type. Red rose， 6-1， Dianshu 1520， Lishu 6， 27-1 and Dianshu 1208 were selected as low P tolerant varieties， while 86-2 and 54-2 were poor in low P tolerance and were P sensitive varieties.

Abstract:The okra fruit is easily lignified， whereas the fruit lignification would decrease the commercial value. In order to explore the aging mechanism of okra fruit， two cultivars， Z06 （easy to age）， and Suyoukui 3 （not easy to age）， were used for physiological indicators quantification and transcriptome sequencing at three developmental stages. The differences in fruit texture between cultivars or at different developmental stages was mainly caused by the accumulation of lignin， while cellulose and protopectin were also found with positive effects. The differentially expressed genes （DEGs） of the same cultivar at different fruit development stages were significantly enriched in the phenylpropane biosynthesis and secondary metabolite biosynthesis pathways. While the DEGs between the cultivars were found with enrichments in the phenylpropane biosynthesis pathway， the photosynthesis and photosynthesis antenna protein pathways. During the hardening stage of okra fruit， the gene PAL was found as key regulator that affected lignin accumulation. The SUS3 gene contributed predominantly to the accumulation of cellulose， and the down-regulated expression of the BGLU gene was also an important factor in promoting the accumulation of cellulose. Two genes GAUT6 and SUS6 largely contributed to the accumulation of protopectin， but most of the PME and PG genes had a negative contribution to the accumulation of protopectin. Lignin synthesis-related genes PAL6， PAL5， PAL1， CCR2， CYP84A1， CYP73A12， and photosynthetic pathway-related genes PSBP2 and CAB1R were important genes that affected the texture differences of two cultivars.

Abstract:Abstract: in this study,we studied the effects of the aging condition of high temperature and humidity(40℃、100%HR) on four kinds of Elymus sibiricus L. seeds vigor and physiological and biochemical characteristics. The results were as follows: we found that vigor index of Elymus sibiricus L. seeds had a degressive tendency with prolonging of the aging to deal with Elymus sibiricus L. seeds. The conductivity and soluble suger content of Elymus sibiricus L. seeds had been increased after decreased in a short period of time as the aging gradient extension. The MDA increased with the longer aging. The study showed that ,with exacerbation of artificial aging, POD activity had been no rule changes, SOD activity had been increased and then reduced in the later stage, and CAT activity was weaken after aging. These conclusions will play a very important role to the future research of Elymus sibiricus L. germplasm and provide the basis theoretical.

Abstract:Seed aging is a complex biological progress from quantitative change to qualitative change. Seed aging is closely related to the dysfunction of mitochondria. In the view of the “mitochondria aging theory”, the excessive accumulation of ROS in mitochondria is the main reason of seed aging. Understanding the changes takes place in mitochondria during seed aging is important to reveal the mechanism of seed aging and ensure safe conservation of seeds. In this paper, the current process of mitochondrial structure, respiration and antioxidant systems during seed aging were reviewed. Moreover, problems in the study of seed aging and mitochondria were discussed.

Abstract:The difference of aging tolerance and the heatstable proteins were among 10 kenaf(Hibiscus cannabinus L.)cultivars,though aging treatment of kenaf.The results indicated that,(1)Seed gemmation and vigor index of 10 kenaf varieties reduced with the extent time in the process of aging,while there were notable difference in 10 kenaf varieties;(2)The content of heatstable protein gradually increased with aging treatment deepening,SDS-PAGE eletrophoresis showed that a 62.8kD heatstable protein appeared only in liao 55 in 140h aging treatment，there were no differences in others.Liao 55 was the most antiaging variety during aging treatment in 10 kenaf varieties,these results suggested that the special heatstable proteins might be related to aging tolerance.

Abstract:In this study soybean cultivar Zhong Huang 18 was used as materials, and the genetic integrity of population with different germination percentage and their descendant population was investigated by 60 core SSR primers. The result showed that there was no significant difference in the allelic frequencies and the effective number of alleles of the aged population and their descendant population compared with the control population. It indicated that the allelic frequencies of the aged population and their descendant population changed slightly. There was no significant difference in the number of alleles, the index of genetic diversity, Shannon’s information index and the number of rare alleles between the control population with the germination percentage of 98% and its first and second descendant population, and the value of genetic identity was relatively high. The number of alleles, the index of genetic diversity, Shannon’s information index and the number of rare alleles of the aged population (G0-3 and G0-4) with the germination percentage below 85% and their first and second descendant population were significantly reduced compared with the control, and the value of genetic identity was relatively high.Therefore, seed aging maybe had a greater impact on the genetic composition of the soybean population than regeneration times.

Abstract:对玉米自交系Mo17种子分别进行58℃热水和45℃恒温老化处理并对种子老化过程中种子发芽率、EST同工酶酶谱变化与染色体畸变规律进行了研究。结果显示：Mo17玉米种子萌发一天的种子胚EST酶谱共表现为14条清晰条带，58℃热水处理30min后，有四条酶带(Rf值为0．44、0．47、0．77、0．80)消失，酶带号为1、2、6、7、9的五条酶带着色变浅。由一、二级酶带变为二、三级酶带。45℃恒温老化处理60d后，Mo17种子EST酶谱中编号为2和5的两条酶带(Rf值为0．33、0．39)消失。处理70d后，种子发芽率降至39％，醇带号为11、12、13、14的四条酶带消失。随着老化时间延长。老化程度不断加重，发芽率低的玉米种子其根尖染色体畸变率相对较高，单桥、双桥、断片、落后及其它染色体畸变类型均被观察到。58℃热水老化其发芽率降至5％时，染色体畸变率上升为12．22％。