Physiological diversity of orchids.

	Physiological diversity of orchids.
	Zhang, Shibao; Yang, Yingjie; Li, Jiawei; Qin, Jiao; Zhang, Wei; Huang, Wei; Hu, Hong
刊名	Plant diversity
	2018
卷号	40 期号:4 页码:196-208
ISSN号	2468-2659
英文摘要	The Orchidaceae is a diverse and wide spread family of flowering plants that are of great value in ornamental, medical, conservation, and evolutionary research. The broad diversity in morphology, growth form, life history, and habitat mean that the members of Orchidaceae exhibit various physiological properties. Epiphytic orchids are often characterized by succulent leaves with thick cell walls, cuticles, and sunken stomata, whereas terrestrial orchids possess rhizomes, corms, or tubers. Most orchids have a long juvenile period, slow growth rate, and low photosynthetic capacity. This reduced photosynthetic potential can be largely explained by CO2 diffusional conductance and leaf internal structure. The amount of light required for plant survival depends upon nutritional mode, growth form, and habitat. Most orchids can adapt to their light environments through morphological and physiological adjustments but are sensitive to sudden changes in irradiance. Orchids that originate from warm regions are susceptible to chilling temperatures, whereas alpine members are vulnerable to high temperatures. For epiphytic orchids, rapid water uptake by the velamen radicum, water storage in their pseudobulbs and leaves, slow water loss, and Crassulacean Acid Metabolism contribute to plant-water balance and tolerance to drought stress. The presence of the velamen radicum and mycorrhizal fungi may compensate for the lack of root hairs, helping with quick absorbance of nutrients from the atmosphere. Under cultivation conditions, the form and concentration of nitrogen affect orchid growth and flowering. However, the limitations of nitrogen and phosphorous on epiphytic orchids in the wild, which require these plants to depend on mycorrhizal fungi for nutrients throughout the entire life cycle, are not clearly understood. Because they lack endosperm, seed germination depends upon obtaining nutrients via mycorrhizal fungi. Adult plants of some autotrophic orchids also gain carbon, nitrogen, phosphorus, and other elements from their mycorrhizal partners. Future studies should examine the mechanisms that determine slow growth and flower induction, the physiological causes of variations in flowering behavior and floral lifespan, the effects of nutrients and atmospheric-nitrogen deposition, and practical applications of mycorrhizal fungi in orchid cultivation.
语种	英语
内容类型	期刊论文
源URL	[http://ir.kib.ac.cn/handle/151853/64796]
专题	中国科学院昆明植物研究所
推荐引用方式 GB/T 7714	Zhang, Shibao,Yang, Yingjie,Li, Jiawei,et al. Physiological diversity of orchids.[J]. Plant diversity,2018,40(4):196-208.
APA	Zhang, Shibao.,Yang, Yingjie.,Li, Jiawei.,Qin, Jiao.,Zhang, Wei.,...&Hu, Hong.(2018).Physiological diversity of orchids..Plant diversity,40(4),196-208.
MLA	Zhang, Shibao,et al."Physiological diversity of orchids.".Plant diversity 40.4(2018):196-208.