Vegetative anatomy and photosynthetic performance of the only known winter-greenCypripediumspecies: implications for divergent and convergent evolution of slipper orchids
Open Access
- 22 May 2021
- journal article
- research article
- Published by Oxford University Press (OUP) in Botanical Journal of the Linnean Society
- Vol. 197 (4), 527-540
- https://doi.org/10.1093/botlinnean/boab033
Abstract
Cypripedium subtropicum is the only known winter-green species in the genus Cypripedium, whereas the other nearly 50 species keep their leaves for less than half the year. Life form has an important effect on carbon acquisition and adaptation of plants. However, the physiological mechanism behind it remains unclear. In this study, we investigated vegetative anatomy and photosynthetic performance of C. subtropicum across with its leaf ages. These anatomical and photosynthetic traits were also compared with typical Cypripedium spp. and other members of subfamily Cypripedioideae. The obtained results confirmed that this species exhibited many characters of shade plants, such as thin leaves, extremely low photosynthetic rate and light saturation point and high chlorophyll content. Unlike the strategy adopted by typical Cypripedium spp. that quickly achieve annual carbon gain with a high assimilation rate in a short growing season, C. subtropicum obtains its carbon through a low assimilation rate but a much longer leaf lifespan. The local climate and favourable light condition guaranteed the comparable carbon income in winter to compensate for its low photosynthetic capacity. The long-lived, thin leaves of C. subtropicum, differing from the long-lived, thick leathery leaves in conduplicate-leaved genera, represent a distinct adaptive strategy in subfamily Cypripedioideae. Our findings shed light on the divergent and convergent evolution in slipper orchids, and we hope these findings will contribute to the conservation of such an endangered orchid.Keywords
Funding Information
- Applied Basic Research Plan of Yunnan Province (2018FA016)
- Science and Technology Plan of Yunnan (2018BB010)
- Construction of International Flower Technology Innovation Center and Achievement Industrialization (2019ZG006)
- National Wild Plant Germplasm Resource Center (ZWGX1907)
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