《植物生理学报》 2016, 52(9): 1413-1420

干旱复水激发玉米叶片光系统II性能的生理补偿机制

高杰^1,2, 李青风², 薛吉全^1,*, 张仁和¹

¹西北农林科技大学农学院/农业部西北旱区玉米生物学与遗传育种国家重点实验室, 陕西杨凌712100; ²贵州省旱粮研究所, 贵阳550006

通信作者：薛吉全；E-mail: xjq2934@163.com

摘　要：

以‘陕单609’为材料, 采用盆栽控水试验, 在干旱及复水条件下, 利用快速叶绿素荧光动力学分析了苗期玉米叶片光系统II对干旱胁迫的响应以及复水条件下的生理补偿效应, 结果表明: 干旱胁迫条件下, 叶绿素荧光诱导动力学曲线出现K相和L相, 表明PSII供体侧的放氧复合体受到了损伤, PSII复合体的稳定性下降。随着胁迫时间的延长, V_j、M_o上升, Ψ_o下降表明QA处于高度的还原态, QA-下游的电子传递受到抑制(ET_o/ABS的下降幅度要大于TR_o/ABS的下降幅度)。RC/CS_o和PI_ABS下降显著表明PSII反应中心的失活和整体性能的下降; 复水条件下, 在复水6 d时, DS4和DS6处理下的K带的下凹, 表明放氧复合体的恢复, DS6处理下的V_j显著地低于对照、M_o恢复到对照水平和Ψ_o显著地高于对照, 表明PSII反应中心受体侧电子传递的受阻得以解除, TR_o/ABS高于对照则说明PSII捕光色素复合体功能恢复正常, RC/CS_o和PI_ABS恢复到对照水平并超越对照, 表明PSII整体性能的恢复, 同时出现了补偿效应。干旱处理6 d (DS6)时复水补偿效应最大, 其主要生理机制可能是PSII供受体侧协调性的迅速恢复并超越对照, 以及单位面积内有活性反应中心数目的超补偿增加所致。苗期干旱锻炼能够激发PSII性能的提升, 增强玉米的抗旱能力, 有利于适应水分亏缺的环境, 实现节水高产。

关键词：玉米; 干旱胁迫; 光系统II; 补偿效应; 快速叶绿素荧光动力学

收稿：2016-06-24   修定：2016-08-09

资助：国家公益性行业(农业)科研专项(201203031-07)、陕西省科技计划农业攻关项目(2014K01-02-03)和陕西省农业科技创新转化项目(NYKJ-2015-16)。

Physiological compensation mechanism of photosystem II in maize leaves induced by drought stress and re-watering condition

GAO Jie^1,2, LI Qing-Feng², XUE Ji-Quan^1,*, ZHANG Ren-He¹

¹College of Agronomy, Northwest A&F University, Key Laboratory of Biology and Genetic Improvement of Maize in Arid Area of Northwest Region, Ministry of Agriculture, Yangling, Shaanxi 712100, China; ²Guizhou Institute of Upland Crops, Guiyang 550006, China

Corresponding author: XUE Ji-Quan; E-mail: xjq2934@163.com

Abstract:

Maize cultivar ‘Shandan609’ was used to analyzing the response and compensation effect of photosystem II to drought stress and re-watering condition by chlorophyll a fluorescence (O-J-I-P) transient at seedling stage in pot experiment. The results showed that Chlorophyll a fluorescence (O-J-I-P) transient curve presented K-band and L-band in drought stress, which indicated oxygen evolving complex damaged severely and PSII units less grouped. The increasing of V_j, M_o and decreasing of Ψ_o with the extension of drought stress time indicated QA was in a higher degree of reduction and electron transport of QA- downstream was inhibited. Significant decreasing of RC/CS_o and PI_ABS showed that reaction center of PSII inactivated and performance of PSII descended. After 6 days re-watering, K-band of DS4 and DS6 were less than zero, which showed oxygen evolving complex recovered; V_j of DS6 significantly lower than the control, M_o of DS6 returned to control level and Ψ_o of DS6 significantly higher than the control indicated that the disruption of electron transfer of PSII acceptor side reaction center was relieved, TR_o/ABS higher than the control indicated the function of PSII light harvesting pigment complex recovered, RC/CS_o and PI_ABS were higher than the control, which showed that performance of PSII recovered, and appeared a compensative effect. The compensative effect represented maximum in re-watering condition after 6 days drought stress, the main physiological mechanism of which can be accounted by the rapid recovery of coordination between donor side and receptor side of PSII and super compensation increasing number of PSII reaction center. Seedling drought exercise can stimulate the performance of PSII, enhance the ability of maize drought resistance, which is conductive to adapt to the environment of water deficit, achieve the water-saving and high yield.

Key words: maize; drought stress; photosystem II; compensation effect; chlorophyll a fluorescence (O-J-I-P) transient