The study of a determinate growth orchid highlights the role of new leaf production in photosynthetic light acclimation
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Plants usually respond to the changes of growth irradiance by a combination of the physiological modifications in their preexisting leaves and the production of new leaves. However, those with a determinate growth habit produce certain number of leaves in a growing season and cannot produce new leaves when light condition changes. We used an epiphytic orchid with only one leaf produced every growing season to examine whether and how determinate growth species adapt to changing environments after their preexisting leaves mature. Leaf photosynthesis and anatomy of Pleione aurita were investigated at full expansion and at 40 days after the fully expanded leaves were transferred from high to low light or from low to high light. Leaves show large physiological and morphological plasticity to light gradients at full expansion and the transferred leaves exhibited multiple physiological modifications, including reallocation of nitrogen between light harvesting and carbon fixation, and enhancement of thermal dissipation in their new environments, to optimize carbon assimilation and avoid photoinhibition. Irrespective of the various changes either to shade or sun, the sole preexisting leaf could not fully acclimate to new light environments due to the mesophyll thickness constraint. This leads to the consequence that only plants exposed to high light throughout the experiment had a positive annual biomass gain. Our results highlighted the importance of new leaf production in the carbon accumulation during photosynthetic light acclimation, and contribute new insights of epiphytes physiological responses to their highly dynamic arboreal habitat.
KeywordsCarbon starvation Carry-over effect Epiphytic plant Leaf anatomy Leaf production Light acclimation
This work was financially supported by the National Natural Science Foundation of China (31670342, 31370362, 31170315), the Natural Science Foundation of Yunnan Province (2013FA044), and the National Key Project of the Ministry of Science and Technology of China (2015BAD10B03).
- Chen X, Cribb PJ, Gale SW (2009) Pleione D. Don. In: Wu ZY, Raven PH, Hong DY (eds) Flora of China, vol 25. Missouri Botanical Garden Press, St.Louis, pp 325–333Google Scholar
- Cribb P, Butterfield I (1999) The Genus Pleione, 2nd edn. Royal Botanic Gardens, Kew, RichmondGoogle Scholar
- Einzmann HJR, Beyschlag J, Hofhansl F, Wanek W, Zotz G (2015) Host tree phenology affects vascular epiphytes at the physiological, demographic and community level. Aob Plants 7. doi: 10.1093/aobpla/plu073
- Mondragón D, Valverde T, Hernández-Apolinar M (2015) Population ecology of epiphytic angiosperms: a review. Trop Ecol 56:1–39Google Scholar
- Niinemets U, Cescatti A, Rodeghiero M, Tosens T (2006) Complex adjustments of photosynthetic potentials and internal diffusion conductance to current and previous light availabilities and leaf age in Mediterranean evergreen species Quercus ilex. Plant Cell Environ 29:1159–1178. doi: 10.1111/j.1365-3040.2006.01499.x CrossRefPubMedGoogle Scholar