The Physiological And Biochemical Effect On Leaves Under The High Temperature Stress

Torreya grandis'Merrillii', a kind of plant that belongs to the genus of Torreya, is rare species in China, fruit nourishment and expensive. The distributing areas of Torreya grandis are much narrower and limited output, whose demand exceeds supply up to now.The temperature is a very important fact which determine the natural distribution of Torreya grandis'Merrillii'. This thesis Analysis of the impact of high temperature on the law of Torreya grandis leaves, Torreya grandis to proven high temperature stress on the mechanism of harm,Torreya grandis for the development of scientific and rational cultivation and management technologies, Torreya grandis planting to improve the management and the cultivation efficiency, To expand the cultivation area and also to provide the theoretical basis of Torreya grandis.Three experiments show that: From 27℃to 36℃, Torreya grandis leaves the relative membrane permeability, MDA content, SOD, POD, CAT activity, proline content and soluble sugar content increases as the temperature rises, Chlorophyll content decreases with the increasing temperature; when the temperature exceeds 36℃, relative membrane permeability, MDA content, CAT activity, proline content and soluble sugar content significantly increases the speed was faster, chlorophyll content decreased rapidly.Is a critical temperature of 36℃section, stress temperature exceeds 36℃, stress effects become apparent, the damage becomes severe Torreya grandis.When the temperature reaches 42℃, cell membrane was severely damaged in a short time, the relative membrane permeability and MDA content rapidly approaching peak; protective enzyme system in a short time after the destruction of stress, activity decreased; soluble sugar content also reduced after a period of time. Torreya grandis was 42℃stress, leaves the target in the recovery after the test is very difficult to restore.In the high temperature below 36℃, the Torreya is not subject to the stress level, the physiological and biochemical indicators of slow change, increase or decrease in volume are not many; temperature higher than 36℃, stress became apparent, the index changes become severe , increase or decrease in volume gets larger, then began to truly reflect the high temperature stress; when the temperature reaches 42℃, in a short period of treatment, Torreya grandis will be subjected to severe heat stress, membrane systems and enzymatic defense system damage to the hard recovery level, chlorophyll content decreased to a promotion, a long time photosynthesis was inhibited, the degradation of soluble sugar to normal levels eventually.