墨兰（Cymbidium sinense）对氮供应量的生理及生长响应

	墨兰（Cymbidium sinense）对氮供应量的生理及生长响应; The response of physiology and growth of Cymbidium sinense to nitrogen concentration
	李志雄
导师	张石宝
摘要	Cymbidium sinense is a traditional ornamental orchid in China with a long cultivation history. Due to illegal collection and habitat destruction, the wild populations and individuals of C. sinense have been severely threatened. This species has been listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and is also a first-class key protected plant species in China. C. sinense is a terrestrial species growing under the forest with slow growth rate. It is of great significance to explore the response mechanism of this species to environmental stress for the conservation and utilization of species resources. Nitrogen is the key factor affecting plant growth and development, but it is still unclear how the physiology and growth of C. sinense respond to nitrogen stress and the combined stress of nitrogen and fluctuating light. The present thesis, by using controlled experiment, investigated the photosynthesis, and growth of C. sinense under different nitrogen gradients and fluctuating light intensities to understand its demand for nitrogen nutrition and adaptation strategy to nitrogen availability. The main results are as follows. (1) Under the nitrogen concentrations of 0 mM and 10 mM, the growth of C. sinense was inhibited, while the nitrogen concentrations of 1.25 mM and 5 mM were more suitable for its growth. Nitrogen supply significantly affected the growth of new ramets, especially the flowering performance. C. sinense could adapt to nitrogen stress by adjusting biomass allocation. Under the nitrogen concentration of 0 mM, the ratio of root to shoot, mass fraction and specific leaf area of C. sinense increased, while the leaf mass fraction and stem mass fraction decreased significantly. When the nitrogen supply concentration increased, the ratio of root to shoot, mass fraction and specific leaf area of C. sinense decreased, while the leaf mass fraction and stem mass fraction increased significantly. At the same time, the contents of carbon, nitrogen and phosphorus of C. sinense were significantly affected when it was subjected to low nitrogen supply. These indicated that nitrogen had a significant effect on the growth and biomass distribution of C. sinense. (2) Under the nitrogen concentration of 0 mM, the contents of total chlorophyll, chlorophyll a, chlorophyll b and carotenoid of C. sinense decreased significantly, and The contents of these components in the new ramet were significantly lower than those in the old ramet. The activities of Photosystem II and photosystem I also decreased, which led to a decrease in light energy utilization and affected light energy distribution in photosystem II. Both high and low concentrations of nitrogen affected the electron transfer rate of C. sinense, but the electron transfer rate of photosystem II and photosystem I was the lowest under 0 mM nitrogen treatment.
	2021-11
文献类型	学位论文
条目标识符	http://ir.kib.ac.cn/handle/151853/74568
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	李志雄. 墨兰（Cymbidium sinense）对氮供应量的生理及生长响应, The response of physiology and growth of Cymbidium sinense to nitrogen concentration[D],2021.

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