期刊
ENVIRONMENTAL AND EXPERIMENTAL BOTANY
卷 58, 期 1-3, 页码 261-268出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.envexpbot.2005.09.007
关键词
elm; leaf growth; JIP-test; thermostability of photosystem II
Experiments were conducted to investigate the photosynthetic activity and thermostability of photosystem 11 (PSII) in elm seedling (Ulmus pumila) leaves from initiation to full expansion. During leaf development, photosynthesis, measured as CO2 fixation, increased gradually and reached a maximum value when leaves were fully developed. In parallel with the increase of carbon assimilation, chlorophyll content increased. The chlorophyll a fluorescence measurements showed that the maximum quantum yield of PSII primary photochemistry (phi(po)), the efficiency with which the energy of trapped excitons is converted into the electron transport beyond Q(A) (phi(Eo)) and the quantum yield of electron transport beyond Q(A) (phi(Eo)) increased gradually. The low light experiments confirmed these results independently. When subjected to heat stress, young leaves exhibited progressively lower phi(po) and maximal fluorescence (F-m) values with considerably higher minimal fluorescence (F-o) than mature leaves, demonstrating that PSII in newly initiating leaves is more sensitive to heat stress. Further analysis revealed that PSII structure in newly initiating leaves showed a robust alteration under heat stress, which was reflected by the clear K phase in the OJIP curves. Therefore, we suggest that the enhanced thermostability of PSII in the case of leaf growth might be associated with an improvement of the stability of the oxygen-evolving complex (OEC) to heat stress during leaf development. (c) 2006 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据