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Plants in the process of growth and development are often subjected to the stress of light, temperature, low temperature, drought and waterlogging stress, thus affecting the normal physiological and biochemical metabolic processes in the plant. Temperature limit plant growth, development and yield of important environmental factors, especially in recent years, with the industrial development, a large number of emission the CO 2 the the atmospheric CO 2 concentration continuously increased, the formation of the \Biofilm on a variety of lipid saturation level and plant response to the temperature adversity has a close relationship. Glycerol-3 - phosphate acyltransferase (GPAT: EC2.3.1.15) as of the first enzyme in the biosynthesis of glycerides of different substrate selectivity differences affect the thylakoid membrane lipid saturation level, so GPAT play an important role in the response process on the temperature in the plant membrane system. In this paper, to turn just sweet pepper glycerol -3 - phosphate acyltransferase transgenic tobacco and wild-type tobacco (CaGPAT) as experimental materials to study the changes in the composition of the transgenic tobacco thylakoid membrane lipid under high temperature stress in transgenic tobacco PSII light absorption, electron transport capacity and photochemical activity, provide a theoretical reference for the new varieties of GM crops, improve stress resistance. The main results are as follows: 1, turn sweet pepper GPAT transgenic tobacco thylakoid membrane lipids little change in the relative content of PG content increased slightly. However, the thylakoid the membrane lipid monogalactosyldiacylglycerols two grease (MGDG), double galactose diglycerides of fat (DGDG), isothiocyanate rhamnose the diglycerides fat (SQDG) and phosphatidylglycerol (PG) degree of saturation are increased by the MGDG saturation level increased by 16.2%, the most significant increase. 2, the with stress temperature rises, turn transgenic tobacco plants and wild-type plants Pn, Fv / Fm, ΦPS II, Fv '/ Fm', QP continue to reduce both the same trend, when no significant difference in 35 ° C, 40 the decrease of ~ 48 ° C between transgenic plants was significantly less than the wild-type, 48 ° C stress difference is most significant. As the the stress temperature rises, the transgenic tobacco plants Fo NPQ rise by less than the wild-type plants, transgenic tobacco plants PS Ⅱ at high temperatures can be maintained higher photochemical activity, to a certain extent to maintain a high photosynthetic rate, transgenic tobacco temperature capability. 3 in 35 4 4 ° C temperature range, transgenic tobacco and wild-type tobacco the Q A the degree of reduction and the reduction rate of increase show that Q A Q B of electron transfer is inhibited. The transgenic tobacco electron transfer by the degree of inhibition, indicating that the transgenic plants significantly improve the ability to change the membrane lipid composition of PS Ⅱ electron acceptor high temperature. High temperature injury electron transfer body, resulting in receptor weakened the ability to accept electrons, electron acceptor library thus smaller, the Q A redox also decreases the number of wild-type tobacco PS II electron acceptor library the ability to withstand high temperatures of less than transgenic tobacco. 4,48 ° C high temperature stress, turn just bell pepper the GPAT gene tobacco membrane system by damage to a lesser extent, F K / the F J , Ψo and Fv '/ Fm' The smaller changes, Fv / Fm, ΦPSII maintained at a relatively high level. This shows that transgenic tobacco PS II donor side of the oxygen-evolving complex and the acceptor side electron transfer and light-harvesting complex less affected by high temperature, so to maintain a relatively high photochemical efficiency at high temperatures.
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