干旱-盐胁迫对西瓜幼苗可溶性蛋白质及可溶性糖的影响

为探讨西瓜抗逆性及其丰产人工栽培技术,通过PEG 6000和0.1mol·L-1 Nacl处理分别模拟干旱和盐胁迫,并测定其可溶性蛋白质和可溶性糖的含量变化来对西瓜幼苗在干旱、盐逆境交叉适应的反应机制进行研究。结果表明:西瓜在经过单一盐胁迫后,其可溶性蛋白质含量明显下降,可溶性糖的含量明显增加;并且在干旱-盐交叉逆境中可溶性蛋白质含量下降幅度有所减小,可溶性糖的含量增加幅度有所提高。因此,可以初步断定,干旱预处理可以提高西瓜幼苗的耐盐性。

Analysis on Maize EST Database under the Co-stress of Drought,Salt and Alkali

[Objective] The research aimed to construct maize cDNA library under the co-stress of drought,salt and alkali,and initially analyze the expression of gene which related to the cellular function.[Method] The total RNA of mixed tissue（leaf,stem and blossom bud） of maize YQ7-96 in the male and female differentiation period（12-leaf age） was extracted.By using SMART technology,cDNA library of pDNR-LIB vector was constructed.BlastX contrast and MIPS classification analysis of EST sequence were carried out by randomly picking the clone.[Result] 3 027 cDNA clones were picked out to sequence.The length of 94.45% EST was bigger than 400 bp,and 1 861 single gene clusters were obtained.The gene which maintained the normal physiological activity occupied 65.36%.The genes which involved in the intracellular transportation,signal transduction,cell defense and cycle,DNA metabolic process were respectively 9.26%,6.58%,2.63% and 3.16%.[Conclusion] Based on the successful construction of maize cDNA library under the co-stress of drought,salt and alkali,EST was sequenced,analyzed and classified.EST which related to the cellular function was screened.It laid the foundation for the following research.

Stability of Cereal Crops to Drought and Saline Stress in Vivo and in Vitro

Complex research is devoted to basic non-specific stress-reactions caused by abiotic factors such as drought and salinity in vivo and in vitro. A comparative physiological, biochemical and cytogenetic analysis was performed and showed the peculiarities of growth and viability on various （cellular, tissular, organismic） levels of plants structural arrangement at stress conditions. Determined the parameters of the growth, ion balance, the content of free proline, superoxide dismutase activity and conducted the cytological studies. The commonness of cytological reactions of plant cells to abiotic stress was revealed. The considerable positive correlation relationships between growth of callus biomass and increases of primary roots number under abiotic stressess, between growth of callus biomass and capacity for survival of seedlings under osmotic stress were registered. Such correlation tells about comparability of stress tolerance valuation at different levels of plants structural arrangement. The considerable negative correlation between K~/Na~ ions relations and percent increase of free proline in calluses were showed. Physiological and biochemical indicators of abiotic stresses impact on plants cells and tissues, such as SOD activity and K^＋/Na^＋ ions correlation were noted. These indicators are effective as metabolic markers in the course of testing and selection of stress-resistant cereals in vivo and in vitro.

Species-specific responses to drought,salinity and their interactions in Populus euphratica and P.pruinosa seedlings

Aims Drought and salinity are severe abiotic stress factors,which limit plant growth and productivity,particularly in desert regions.In this study,we employed two desert poplars,Populus euphratica Oliver and Populus pruinosa Schrenk seedlings,to compare their tolerance to drought,salinity and combined stress.Methods We investigated species-specific responses of P.euphratica and P.pruinosa in growth,photosynthetic capacity and pigment contents,nonstructural carbohydrate concentrations,Cl−allocation,osmotic regulation and the accumulation of reactive oxygen species(ROS)under drought,salinity and the combined stress.Important Findings Populus pruinosa exhibited greater growth inhibitory effects,photosynthesis decline,stomatal closure and ROS accumulation,and lower antioxidant enzyme activities and osmotic regulation compared with P.euphratica under drought,salinity and especially under their combined stress.On the other hand,salt-stressed P.euphratica plants restricted salt transportation from roots to leaves,and allocated more Cl−to coarse roots and less to leaves,whereas salt-stressed P.pruinosa allocated more Cl−to leaves.It was shown that there is species-specific variation in these two desert poplars,and P.pruinosa suffers greater negative effects compared with P.euphratica under drought,salinity and especially under the combined stress.Therefore,in ecological restoration and afforestation efforts,species-specific responses and tolerances of these two poplar species to drought and salinity should be considered under climate change with increasing drought and soil salinity developing.

ISSR markers based on GA and AG repeats reveal genetic relationship among rice varieties tolerant to drought,flood,or salinity

Drought, flood, salinity, or a combination of these limits rice production. Several rice varieties are well known for their tolerance to specific abiotic stresses. We determined genetic relationship among 12 rice varieties including 9 tolerant to drought, flood, or salinity using inter-simple sequence repeat （ISSR） markers. Based on all markers, the nine tolerant varieties formed one cluster distinct from the cluster of three control varieties. The salt-tolerant varieties were closest to two flood-tolerant varieties, and together they were distinct from the drought-tolerant varieties. （GA）8YG was the most informative primer, showing the highest polymorphic information content （PIC） and resolving power （Rp）. The drought-, flood-, and salt-tolerant varieties grouped in three distinct clusters within the group of tolerant varieties, when （GA）8YG was used. Sabita was the only exception. The two aus varieties, Nagina22 and FR13A, were separated and grouped with the drought- and flood-tolerant varieties, respectively, hut they were together in dendrograms based on other primers. The results show that ISSR markers associated with （GA）sYG delineated the three groups of stress-tolerant varieties from each other and can be used to identify genes/new alleles associated with the three abiotic stresses in rice germplasm.