Growth Responses Of Rice To Drought Stress

Drought,with no-efficient water,is one of the most serious problems confronted with in the word agriculture,especially in our country.It is estimated that the loss in world agriculture caused by drought is nearly same as that by theother stresses.Therefore,it is increasingly interested in the physiological response and adaptation of plants to drought stress,and,the studies of watersaving planting methods are necessary.Through the method of planting rice in pot,applying different organic fertilizers,and the growth and physiological characters of three rice varities were studied under three water management conditions(flooded,wet and drought stress condition).The results are as follows:The growth and physiological characters of three rice varities,Y6,H3 and L4,were changed under different water management conditions;the rice height,tillering number, chlorophyll content and activities of antioxidases(SOD,CAT and POD) of rice decreased. The rice height and tillering number of Y6 and L4 under flooded and wet conditions were significantly higher than those under drought stress condition,while those of H3 were not significantly different under three water management conditions,but had lilltle same numeric differences.The activities of antioxidases(SOD,CAT and POD) in three rice varieties under flooded condition were not significantly different between those under wet condition,but only the activities of antioxidases in L4 were significantly differences beween drought condition and flooded/wet condition.The differences of activities of POD in Y6 and L4 between under drought stress condition and flooded/wet condition were significantly higher than those in H3.We have already known that H3 is a varity which have stronger ablity to adapt to drought,thus the stronger of anti-drought ability of rice,the less of differences of these indexes between drought condition and flooded or wet condition.The study of Y4 in different water management conditions indicated that inputing different organic matter in different way,the rice height and tillering number were decreased,and taproot length,root surface area,root volume and rootlet number were increased under drought stress;the drought resistant indexes(content of chlorophyll and activities of antioxidases SOD,CAT and POD) of rice were decreased significantly under drought stress,and straw mulched on surface soil and pig manure mixed in soil could abate the changes caused by drought depress and protect rice from damnification,while straw mixed in soil and pig manure added in surface soil could not.