《植物生理学报》 2013, 49(6): 551-560

利用快速荧光、延迟荧光和820 nm光反射同步测量技术探讨干旱对平邑 甜茶叶片光合机构的伤害机制

张菂, 陈昌盛, 李鹏民^∗, 马锋旺

旱区作物逆境生物学国家重点实验室, 西北农林科技大学园艺学院, 陕西杨凌712100

通信作者：李鹏民；E-mail: Lipm@nwsuaf.edu.cn；Tel: 029-87082648

摘　要：

本文以苹果砧木平邑甜茶为实验材料, 利用快速叶绿素荧光、延迟荧光及820 nm光反射同步测量技术, 研究了干旱胁迫对平邑甜茶叶片光合机构的光系统I (PSI)、光系统II (PSII)以及整个光合电子传递链的伤害机制。实验结果表明: 干旱胁迫下平邑甜茶叶片的整个光合电子传递链都受到不同程度的影响。干旱2 d, PSII反应中心捕获的光能用于还原QA的能力低于电子从QA-向下游传递的能力, 电子从QA-向下游传递给QB和PQ库等中间电子传递体的能力小于电子从QB和PQ库向PSI受体侧传递的能力, 但干旱5 d上述变化则相反, 且更加显著。由此可以得出, 严重干旱胁迫下, 沿着从PSII到PSI受体侧的光合电子传递链, 电子传递的能力越来越低。此外, 随着干旱胁迫, PSII和PSI反应中心色素的降解速率快于天线色素,且PSII的捕光效率和PSI反应中心的含量逐渐降低。快速荧光、延迟荧光及820 nm光反射同步测量结果互相印证了上述结论。我们推测, 这可能是平邑甜茶叶片对干旱的一种适应机制。

关键词：平邑甜茶; 快速荧光; 延迟荧光; 820 nm光反射; 干旱

收稿：2013-03-25   修定：2013-05-03

资助：国家自然科学基金项目(31000890和31171915)和西北农林科技大学国际科技合作交流项目(A213021202)。

Effects of Drought on the Photosynthetic Apparatus in Malus hupehensis Leaves Explored by Simultaneous Measurement of Prompt Fluorescence, De-layed Fluorescence and Modulated Light Reflection at 820 nm

ZHANG Di, CHEN Chang-Sheng, LI Peng-Min*, MA Feng-Wang

State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China

Corresponding author: LI Peng-Min; E-mail: Lipm@nwsuaf.edu.cn; Tel: 029-87082648

Abstract:

In this study, prompt fluorescence, delayed fluorescence and modulated light reflection at 820 nm were measured simultaneously to explore the effect of drought on PSI and PSII as well as the whole photosyn-thetic electron transport chain in Malus hupehensis leaves. The results showed that the whole electron transport chain including the two photosystems was differently affected by drought. At day 2 of drought stress, the capac-ity of QA reduction by the trapping light in PSII reaction centers was lower than that of electron transfer from QA- to the downstream electron carriers, and the capacity of electron transfer from QA- to the downstream intermediate carries such as QB and PQ was also lower than that from QB and PQ to PSI acceptor side. Never-theless, at day 5 of drought stress, the above electron transfer capacities changed contrary with the changes be-ing more significantly, compared with that at day 2. In general, along the photosynthetic electron transport chain from PSII to PSI acceptor side, the electron transport capacity decreased gradually under severe drought stress. The results also exhibited that during drought stress, the degradation of PSII and PSI reaction centers was faster than that of their antenna pigments. The trapping efficiency of PSII and the content of PSI reaction center also decreased. The simultaneously measuring results of prompt fluorescence, delayed fluorescence and modulated light reflection at 820 nm supported the above conclusions, and corroborated each other. We speculate that this might be an adaption mechanism of Malus hupehensis leaves to drought stress.

Key words: Malus hupehensis Rehd; prompt fluorescence; delayed fluorescence; modulated light reflection at 820 nm; drought