Responses Of Three Kinds Of Jasminum Sambac To Drought Stress

Under drought stress,the difference of physiological characteristics,photosynthesis and cellular ultra microstructure of 3 Cultivars of Jasmine were studied comparatively.The results showed that under the same stress degree and time,the difference of electrolyte leakage,content of MDA and Chl,activity of CAT,POD and SOD were obvious.Activity of them decreased with the increase of degree and time of drought stress.Compared with Jasminum sambac(single petal) and J sambac (multiple petal),the content of MDA in J sambac (double petal) increased no significantly.Activity of CAT,POD and SOD were high and the decreasing range were light,the WUE and content of Chl were high.It was supposed that the free radical scavenging capacity of double petal was stronger than single petal and multiple petal and the injury was also lighter.Pn,Tr,WUE,Gs in leaf of Jasmine decreased under drought stress,difference between varieties reached significant level,p<0.001.Under mild drought stress,Gs in single petal and multiple petal began to decrease,the diffusion rate of CO2 was slower,Pn,Tr,WUE,Gs,Ci decreased simultaneously.Assimilation capacity and photosynthetic apparatus in mesophyll cell hadn't been destroyed. Under moderate drought stress,Pn,Tr,Gs continued decreased,Ci increased inversely. Assimilation capacity and photosynthetic apparatus in mesophyll cell were destroyed,such as plasmolysis,some matrix digestion,deformation deformation,and so on.Under severe drought stress, Assimilation capacity in mesophyll cell of single petal and multiple petal decreased which led to light excess and photo inhibition,chloroplast lamellar space increased,severely distorted.The toleration to drought stress of 3 cultivars of Jasmine were:double petal>single petal>multiple petal.