Identification Of Drought Resistance And Research Of Leaf Drought Resistant Mechanisms In Peanut Vaireties

Twelve peanut genotypes that had different drought resistance were tested in this study.The experiment settled drought stress at the seedling stage and at the pod fruiting stage,respectively. Relationship between drought resistance of peanut varieties and morphologicaland physiological leaf traits were studied. Drought resistance and leaf drought resistant traitsof the forty germplasm were identified and evaluated. Main results were as follows.1Drought resistance of peanut varietiesThis research adopted drought coefficient as indicator to evaluate drought resistance ofpeanut varieties. During ten days drought stress at seedling stage and tweenty days droughtstress at podding stage, respectively, we graded the tested varities according to the values ofdrought reisistance of biomass at seedling stage and of yield at podding stage. The resultsshowed that the fortissimo drought-resistant varieties consisted of Shanhua11, RugaoXiyangsheng and A596. Shanhua9, Haihua1,79266and Hua17had high drought resistance.Moderate drought tolerant genotypes of peanut included Baisha1016and ICG6848. Nongda818and Huayu20had high drought resistance at seedling stage, while fortissimo droughtresistance at podding stage. Penglai Yiwohou had moderate drought resistance at seedlingstage, while high drought resistance at poddling stage.2Responses of leaf morphological and physiological traits of peanut species on droughtUnder severe drought stress condition at the seedling period of peanut varieties, thedrought relevant traits of peanut species were as follows: Shanhua11had photosynthetic rate、transpiration rate、water potential、rate of leaf water loss and Pn/E; Ruogao xiyangsheng andA596had the same drought-resistant traits consisted of photosynthetic rate、transpiration rate、PSII、rate of leaf water loss and Pn/E; Shanhua9had photosynthetic rate、PSII、rate of leafwater loss and Pn/E; Nongda818had PSII and rate of leaf water loss; Haihua1had waterpotential、rate of leaf water loss、bound water content、bound water/free water and Pn/E; Huayu20had bound water content and bound water/free water;79266had Chl(a+b) and Pn/E;Hua17had transpiration rate; Penglai yiwohou had Chl(a+b) and PSII; Baisha1016hadtranspiration rate and PSII; ICG6848had leaf water potential.Depending on the moderate drought circumstance at the pod bearing period of peanutgenotypes, the drought-resistant traits of peanut species were as follows: Shanhua11hadPSII、Fv/Fm、Chl(a+b)、water potential and Pn/E; ICG6848had Chl(a+b) and rate of leafwater loss; Nongda818had transpiration rate、PSII、Fv/Fm、water potential、bound watercontent、bound water/free water; Hua17had Chl(a+b); Haihua1had photosynthetic rate、PSII、Chl(a+b)、water potential and rate of leaf water loss; Penglai yiwohou had Chl(a+b)、bound water content and bound water/free water; Ruogao xiyangsheng had photosyntheticrate、Fv/Fm、PSII、transpiration rate、specific leaf weight、water potential and Pn/E; A596had PSII、photosynthetic rate、Fv/Fm and transpiration rate; Baisha1016had photosyntheticrate and rate of water loss; Huayu20had photosynthetic rate、transpiration rate、specific leafweight、bound water content and bound water/free water;79266had photosynthetic rate、bound water content and bound water/free water; Shanhua9had photosynthetic rate、transpiration rate、Fv/Fm、specific leaf weight、rate of leaf water loss and bound water content.3Leaf drought-resistant mechanisms of peanut speciesThe drought-resistant mechanisms of peanut species were closely related to leaf traits,therefore we can discuss drought-resistant mechanisms of peanut species according to themetabolic laws of all the leaf traits under water stress. Shanhua11had drought tolerance andwater consumption drought resistance; Haihua1had better drought tolerance and droughtresistance; A596and Hua17equally showed water-saving drought resistant mechanism; bothof Huayu20and79266put up drought avoidance and water consumption mechanism; Baisha1016showed up drought resistance; Rugao Xiyangsheng and Nongda818evenly had betterdrought resistance and drought avoidance; Shanhua9belonged to water consumption droughtresistance at seedling stage and drought avoidance and drought tolerance at pod bearing stage;Penglai Yiwohou showed up drought resistance at the seedling stage and drought avoidance atthe pod bearing stage; ICG6848didn’t have obvious advantages on the above traits.4Identification method and evaluation indicator of drought resistance and droughtrelevant traits of peanut speciesThis research adopted drought coefficient as indicator of drought resistance identificationand employed drought-resistance index as standard of drought resistant identification as leaf traits. After ten days of severe drought stress at the seedling stage, we adopted droughtcoefficient of single plant biomass to evaluate peanut drought resistance and used ratio ofpalisade and spongy tissue thickness, stomatal aperture, photosynthetic rate and Pn/E asidentification traits of drought resistance; when moderate drought stress was settled at the podbearing period tweenty days later, we employed drought coefficient of yield to evaluatedrought resistance of peanut varieties, meanwhile, we used ratio of palisade and spongy tissuethickness, stomatal aperture, photosynthetic rate and Pn/E as identification traits of droughtresistance.