Plant Diversity ›› 2015, Vol. 37 ›› Issue (01): 55-62.DOI: 10.7677/ynzwyj201514046

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Physiological Response to High Light in Cymbidium tracyanum and C.sinense

 匡美龄1、2, 张石宝1、3   

  1. 1 Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming
    650223, China; 2 University of Chinese Academy of Sciences, Beijing 100049, China; 3 Key Laboratory of Economic
    Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
  • Received:2014-03-18 Online:2015-01-25 Published:2014-06-09
  • Supported by:

    国家自然科学基金项目 (31170315, 31370362), 云南省应用基础研究计划重点项目 (2013FA044)


The members of the genus Cymbidium are important ornamental flowers. Most species of this genus prefer to grow on the shady places of the forest floor, while epiphytic Ctracyanum can grow well in the presence of direct sunlight. To explore the physiological mechanism underlying the adaptation of Ctracyanum to high light, we used terrestrial Csinense as the control, and measured the chlorophyll fluorescence and P700 redox state in those two species grown at two different light regimes. Our results showed that the activities of photosystem I and II in Csinense under high light decreased more strongly than those in Ctracyanum. The activation of cyclic electron flow (CEF) in Ctracyanum under high light could serve as a main mechanism of photoprotection. However, the weak of CEF in Csinense limited its adaptation to high light. Since epiphytic habitats may suffer more intermittent direct sunlight than understory, the strong adaptability of Ctracyanum to high light may contribute to its utilization of light energy in epiphytic habitats.

Key words: Cymbidium, Photosynthetic characteristics, Cyclic electron flow, Chlorophyll fluorescence, Light intensity

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