The Study On Influence Of Drought Stress And Rehydration For China Aster Growth And Development

This paper chose Callistephus chinensis(L.)Nees cv. Jinongda Blue as experiment material under drought stress and rehydration by the way of weighting with water content controlled.Drought stress set five different treatments which soil relative water content of maximum capacity of soil moisture at CK(80%～90%), T1(65%～75%), T2(50%～60%),T3(35%～45%) and T4(20%～30%).Studied the effects of growth and development of China aster under different drought stress and rehydration treatments. The results were as follows:1.Under drought stress,every growth indexes of China aster were depressed.With the stress time prolonged,the plant’s height and diameter rose.But the more stressed degree,the slower of the growth speeder.The leaves area were risen firstly and then reduced,and the soil relative water content of maximum capacity of soil moisture at20%-30%showed that leaves area had no clearly change which was the supreme stress treatment.Relative water content and retaining capacity and chlorophyll content of leaves were reduced with stress time prolonged and stress level deeped.The activity of SOD,POD and root system rose firstly and then reduced,soluble protein and cell membrane permeability vice versa.However,the content of soluble sugar and Pro and MDA content had positive correlation with stress level.Under water stress,net photosynthetic rate and transpiration rate and stomatal conductance were reduced with stress level deepen,and rose firstly then reduced with stress time prolonged.2.After water regain,plant height, diameter and leaves area were risen and the risen speed under the soil relative water content of maximum capacity of soil moisture at65%～75%and50%～60%was risen slower than35%～45%and20%～30%,except the soil relative water content of maximum capacity of soil moisture at65%～75%resumed to control level.The water content in leaves of other treatments showed increase trend.Only the soil relative water content of maximum capacity of soil moisture at65%～75%resumed to control level others had not resumed at the same time.Activity of SOD and POD,chlorophyll content and root activity rose firstly and then reduced,failed to resume to control level.Soluble sugar content and soluble protein content reduced with water regain time prolonged but still higher than CK.Cell membrane permeability and MDA content reduced firstly and then rose later.The mild stress could be resumed to control level only,physical and biochemistry characteristics improved but didn’t resume to control level.3.After drought stress and rehydration,flower bud appeared postpone than control level,bud diameter and flower number reduced.Flower period was shorter than CK and the more severe stress,the smaller the flower diameter was.In conclusion,water stress made serious hurt for plants growth though water regain showed some compensation effects.Severe stress made plant bud,flower number and period,bud diameter and flower diameter lower than CK,life history early completed.As a result,watch value declined..