Study On The Physiological And Biochemical Characters Of Rice [Oryza Sativa L.] Under High Temperature Stress

The paddy rice is the important grain crops.And the Yangtze valley area planter is particularly widespread in the south of our country. But its characters, output and quality are easily infected by environmental condition. Especially the temperature of the time in the milk is the biggest factor to decide its quality. According to the research the difference of paddy rice quality caused by seedtime adjustment, height above sea level, region characteristics, and so on.It has direct relation with which caused by the temperature change.In recent years, with the global climate warmed up gradually, our country Yangtze valley's paddy rice production area presented high temperature requently in summer. For example the Chongqing area, the temperature in the feeding time is frequently above 37℃. This article has studied ordinary rice variety named K30, whose physiological biochemistry character under the high temperature stress, inquired its anti-high temperature mechanism to provide the theory basis about the rice anti-high temperature. In the agricultural production, it can provide the reference to prevent the rice from hot stress and enhance the output.The rice sample grows rice seedlings with conventional method. Treating the experimental materials to the booting stage, then select the materials whose growth advancement and trend in the basic consistent situation. Each material has 90-120 plants.And moved into the earthen bowl, each has three or four, continue to raise for several days. In the day of rice growing to the consistent degree, transfers to the earthen bowl in the different temperature processing climate box. Then take the sample (function leaf) every six days. The liquid nitrogen or the refrig will freeze the preserved sample, after treating the rice mature, the unification will carry on the related test analysis.Through comparing the physiological and biochemistry characters between under the high temperature and the suitable temperature we have the experimental result is below.1. The flag leaf rice conductivity average compared with the control group increased by 35%, reflecting the high-temperature rice cell membrane permeability to a certain extent of the injury, which is to increase the permeability of cell membranes under high temperature stress.2. Membrane lipid peroxidation named MDA has a marked increase, compared to the periods which as control. The difference between them reached significant levels under high temperature stress.Especialiy from the first 12 days to 30 days, during the same period when the differences to achieve a significant level.3. The photosynthesis and transpiration rate, the flag leaf stomatal conductance, total chlorophyll content, intercellular CO₂ content dropped. One important indicator of photosynthetic system is the photosynthetic.And it fell to merely 72.9% of the control. And the transpiration rate compared with the control group, which has a decrease of 16%.The impact of high temperatures, physical activities have effect on rice under high temperature stress.4. The flag leaf soluble sugar content in the lower average compared with the control, which has a decrease of 58%.This rate may be related to light chlorophyll and decline under high temperature stress. The correlation analysis showed that the material content of soluble and membrane between the degree of injury was a negative correlation.5. The soluble protein content has increased, compared with the control average increase of 17 %, the biggest difference in the period, even higher than 27 %under high temperature stress.6. The SOD, POD and other antioxidant enzyme activity is decreased significantly after high temperature.The hydrogen peroxide, superoxide as the oxygen of the indicators of activity have increased significantly. Between the two types of indicators is a negative correlation. It indicated that under the high temperature treatment rice leaves reactive oxygen species in the accumulation of reactive oxygen species due to removal of the main activity of the suppression of active oxygen content increased. That is high temperatures damaged the plants to maintain active oxygen production and remove the dynamic balance, so that timely removal of plants in the accumulation of reactive oxygen species decline.The results indicated that the plants infiltration of regulation is decreased, the antioxidant activity is also decreased.Through reducing the cell's ability to eliminate active oxygen, it caused hazards to the cells after the high temperature treatment. In addition the photosynthetic rate lower leads to the plant yield and quality of significant decline.