Studies On Physiological Indexes Of Drought Resistance In Wheat

In this work, the influence of drought stress on physiological indexes in differentstages of wheat varieties Yannong21, Lumai21, Jimai22and Yannong0428wasinvestigated. To elucidate the trend of physiological index changes under differentdrought stress in wheat, three PEG-6000concentration were used as drought stress atgermination and seedling stage. Changes of agronomic traits under drought stresswere recorded during the growth period using “off season” technique, with droughttreatment and control groups. The relationship between these physiological indicatorsand drought resistance was evaluated based on the yield related traits.The effects of drought stress on wheat germination: Light drought stress couldpromote the growth of wheat while severe drought stress inhibited it; Germinationrate, germination potential and length of main radicals were highly correlated withdrought resistance, and coleoptile length was positively correlated with droughtresistance.The effects of drought stress on wheat seedling: Physiological indicators betweencontrol group and treatment group had no significant difference (P＞0.05) at lowPEG-6000concentrition, and this difference was significant at high PEG-6000concentration (P＜0.01). As changes of physiological indexes in leaf can be easilymeasured and were more regular than those in root, leaf was preferred tissue type forevaluating the drought resistance. Soluble protein content, MDA content, APXactivity, soluble sugar content and relative electric conductivity in leaves were highlycorrelated with drought resistant. POD activity was significantly correlated withdrought resistance. CAT activity and SOD activity were positively correlated withdrought resistance.Result of native polyacrylamide gel electrophoresis (PAGE) showed that droughtstress under high level PEG-6000could induce the expression increase of antioxidantsystem of isozyme. The expression levels of the same enzyme between leaves androot was obviously different, expression level in leaves was greater than that in root.CAT isozyme in root was not detected in this study.Grown using “off season” technique, the wheat plants showed strong springness, with typical performance of non-tillering. There were significant differences betweenCK and DT group in agronomic traits. Number of grains per spike and flag leaf areawere highly correlated with drought resistance.1000-grain weight was significantlycorrelated with drought resistance. The number of total spikelets and effectivecorrelated with drought resistance.Production index evaluated based on drought resistance: Yannong0428＞Lumai21＞Yannong21＞Jimai22. Comprehensive analysis showed that the droughtresistance ofYannong0428was the best among the four varieties tested in this work.