兰科植物根的功能性状及其对水分变化的适应研究

	兰科植物根的功能性状及其对水分变化的适应研究; Functional trais of root and its adaptation to water availability in Orchidaceae
	齐颖
导师	张石宝
摘要	Water plays a vital role in plant life, and is a key abiotic factor affecting the physiological metabolism, growth and development, productivity and geographical distribution of plants. As the main absorbing organ for water and nutrients, root morphology and anatomy affect the water absorption and utilization of plants, and can be plastic regulated in different water availabilities. Many studies have focused on the response of leaf to water availabilities. However, owing to the restriction of research methods, studies on root traits and function are far less than those on aboveground organs. Thus, root is labelled “the hidden half”. Members of the family Orchidaceae have high economic value because of high ornamental and medicinal value. The Orchidacea also have diverse ecological adaptation characteristics, which make them good materials for studying the response of different ecotypes to the environment. Because of the significant differences in water availability, light environment and nutrients experienced by the roots of epiphytic and terrestrial orchids, we speculated that the structure and function of roots may be significantly different among different life forms of orchids. However, little is known about the differences in root morphological and anatomical traits between epiphytic and terrestrial orchids and how they respond to water availability. In the present thesis, 83 orchids from different habitats were used to investigate the difference in root traits of epiphytic and terrestrial life types. Secondly, the root and leaf traits and their relationships with altitude were studied in 21 Dendrobium species, and the correlated evolution between root and leaf traits was analyzed. Finally, the morphological and anatomical traits, biosynthesis and accumulation of ABA, and composition of metabolites in roots of Dendrobium species were studied by controlled experiments. The main purpose of the present study was to systematically explore the role of root traits in water adaptation of orchids with different life forms through multidisciplinary research. The main results were as follows. 1. The study on root traits of 83 species from different habitats found that the main differences in root traits between epiphytic and terrestrial orchids was root radius, and the ratio of velamen thickness to root radius. Compared with epiphytic species, terrestrial species had thicker roots and larger number of exodermis cells. However, epiphytic orchids had higher ratio of velamen thickness to radius. Epiphytic orchids constructed a high proportion of velamen under the condition of limited carbon resource, which implied that velamen had an important role in adaptation of epiphytic orchids to their habitat. In addition, the altitude range of terrestrial orchids was larger than that of epiphytic orchids, indicating that epiphytic orchids had more stringent environmental requirements. 2. The study on 22 root traits and 14 leaf traits of 21 Dendrobium species foun
	2020-11
文献类型	学位论文
条目标识符	http://ir.kib.ac.cn/handle/151853/74239
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	齐颖. 兰科植物根的功能性状及其对水分变化的适应研究, Functional trais of root and its adaptation to water availability in Orchidaceae[D],2020.

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