Effect Of Drought Stress With Rewatering On The Growth And Endogenous Hormones Content Of Pea Root

Pot experiment was conducted to study the root growth,physiological characteristic and the content of endogenous hormones of Pisum sativum L.(Yinwan NO.1) at different stage,severity and duration after drought stress and rewatering. The main results were as following:1.At seedling stage,the length of root under lighter drought stress was higher than that of control and severe stress,but reduced with severity and duration at flowering and seed filling stage.After rewatering,all treatments showed compensation effect,short-time severe stress at seedling stage was notable,increased 41.72% of control and showed over-compensation.The diameter of main root was also reduced with severity and duration and short-term severe stress at seedling stage achieved high significant difference as compared with control.After rewatering,the diameter of main root of all treatments increased,expect that long-term severe stress at seed filling stage decreased.The compensation effect at seedling stage was best,but did not exceed the control,about 98.51% as compared with control.2.The development of root and shoot were depressed under drought stress.The dry weight decreased,at the same time,the R/S increased.It showed that inhibition of drought stress was more notable at shoot than at root.After rewatering,the treatments showed compensation effect at seedling and flowering stage,but long-term severe stress at seed filling stage showed compensation at early rewatering stage only.Short-term severe stress at seedling stage showed over-compensation, increased 0.58% after 10 days of rewatering as compared with control.The number of effective nodule at seed filling stage decreased because of root aging,others increased after rewatering when compared with at the end of stress.The compensation effect of and long-term light stress at flowering stage was best, about 84.34% after 10 days of rewatering as compared with control.3.The root activity was decreased during stress and the tendncy enhanced with the increasing of drought stress degree and duration.After rewatering,the root activity was decreased yet at seed filling stage.At seedling and flowering stage,the compensation effect of short-term stress was more notable, respectively about 110.11%,96.02% after 10 days of rewatering as compared with control.The root activity of long-term severe stress was lower than that of control after rewatering.4.After drought stress,the content of GA and ZT decreased,the content of ABA and IAA increased and the IAA/ABA also increased.After rewatering,all treatments showed compensation,but the degree of compensation effect depended on stress stage,severity and the period of rewater.At seedling and flowering stage,the compensation of rewatering after short-term severe stress was better than that after long-term light stress.At seed filling stage,the content of hormones showed compensation at early rewatering stage only.To sum up,at seedling stage,the compensation effect on root was best and the short-term severe stress was approprite.The plant should avoid drought stress at flowering and seed filling stage.