Studies On Physiological And Biochmical Mechanisms Of Heat-Resistance In Zizyphus Jujuba

Experimental material is Zizyphus jujube. Heat stress has been of the limited environmental factors in distribution of Prunus pseudocerasus. Physiological and biochemical methods have been carried out to study the mechanism of heat-resistences on Zizyphus jujuba under high temperatures.The main results obtained in this paper were as follows:(1) Different temperatures and duration time caused the different damage levels ofleaves.The damage levels were more seriously with the increasing of temperature and thdprolonged stress time.In general,the effects of relative high temperatures and short duaration time were identical with that of relative low temperatures and long duaration time.(2)At35℃and36hours, the relative electrolyte rate began to increase obviously.lt showed that when temperature higher than350C the heat stress accelerated the degree of membrane-lipid peroxidation in short time. With the increasing of temperature and the prolonged stress time, the content of MDA tended to rise.lt showed that high temperature stress accelerated the degree of membrane-lipid peroxidation.(3)The activity of SOD and POD rose first, and then dropped with the increase of temperature and duration time.(4)Under high temperature stress, the content of soluble sugar and proline were tended to rise with the increasing of temperature and thd prolonged stress time.The content of soluble protein dropped all the time. And the average content of protein were lower than control treatment in heat stress. These results indicated that the soluble probein suffered with bad breakage and the soluble sugar and proline may strengthen heat-resistance Zizyphus jujuba of leaves in heat stress.