高温胁迫下烟草对波动光强的光合生理响应

	高温胁迫下烟草对波动光强的光合生理响应; Photosynthetic Response to the Combination of Moderate Heat Stress and Fluctuating Light in Tobacco
	谭顺玲
导师	黄伟
摘要	Photosynthesis is one of the most important chemical reactions on Earth, closely linked to global challenges such as increasing food production, global warming and renewable resources. Under natural conditions, leaves usually undergo the changes in light intensities, which is called fluctuating light. When the light intensity decreases instantly, the photosynthetic rate will decrease rapidly, while the photosynthetic apparatus will generally not be damaged. When leaves are suddenly exposed to high light, the light absorption by photosystem (PSII) antennas immediately increases, easily causing damage to PSI and PSII. This damage, in turn, will affect photosynthesis rate and the growth of plants. Paying attention to photosynthetic responses under fluctuating light is of great significance for understanding the ecological adaptation of plants and improving crop yields. In summer, moderate heat stress is usually accompanied with fluctuating light. However, no study has examined the photosynthetic responses to the combined stresses of moderate heat and fluctuating light. And it is unclear whether moderate heat stress aggravates photoinhibition of PSI under fluctuating light. In this thesis, we used an important economic crop and model plant tobacco (Nicotiana tabacum L. cv. Sumsan) as the research material. The mature and immature leaves of tobacco were subjected to the same degree of fluctuating light intensity at 25°C and 42°C, respectively. The main results are as follows: 1. The moderate heat stress did not significantly exacerbate the photoinhibition of PSI and PSII under fluctuating light in tobacco mature leaves. In general, moderate heat stress may cause reversibly increase in the proton conductance, which impedes the establishment of the proton gradient across the thylakoid membranes(ΔpH). And then the insufficient ΔpH will raise the risk of PSI photoinhibition under fluctuating light. Our present study showed that the photorespiration consumed a significant fraction of reducing power to protect PSⅠ when the light intensity suddenly increased. Simultaneously, the stimulation of cyclic electron flow (CEF) by heat provided additional ATP to support the energy demand from photorespiration. Therefore, the coordination between CEF and photorespiration is crucial in photosynthetic acclimation to combination of moderate heat stress and fluctuating light in tobacco mature leaves. 2. The moderate heat stress significantly accelerated PSI photoinhibition under fluctuating light in tobacco young leaves. Within the first 10 s after a sudden transition from low to high light, moderate heat stress delayed the activation of CEF, thus making photorespiration to be limited by the lack of ATP. During every cycle of the fluctuating light treatment, the over-reduction of PSI at 42°C was always in higher level than that at 25°C. Therefore, PSI in tobacco young leaves was more sensitive to the combined stresses of moderate heat and fluctuating light. For PSⅡ, mode
	2021-05
文献类型	学位论文
条目标识符	http://ir.kib.ac.cn/handle/151853/74533
专题	昆明植物所硕博研究生毕业学位论文
推荐引用方式 GB/T 7714	谭顺玲. 高温胁迫下烟草对波动光强的光合生理响应, Photosynthetic Response to the Combination of Moderate Heat Stress and Fluctuating Light in Tobacco[D],2021.

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