STRESS TOLERANCE OF PHOTOSYSTEM-II INVIVO - ANTAGONISTIC EFFECTS OF WATER, HEAT, AND PHOTOINHIBITION STRESSES
STRESS TOLERANCE OF PHOTOSYSTEM-II INVIVO - ANTAGONISTIC EFFECTS OF WATER, HEAT, AND PHOTOINHIBITION STRESSES
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DOI：
10.1104/pp.100.1.424
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发表时间：
1992-09-01
期刊：
影响因子：
7.4
通讯作者：
HAVAUX, M
中科院分区：
文献类型：
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作者：
HAVAUX, M
光系统11的体内光化学活性由几种植物物种（Lycopersicon esculentum Mill.，马铃薯、龙葵（Solanum nigrum L.）暴露于单独或组合施加的各种环境胁迫（干旱、热、强光）。光系统II被证明具有高度抗旱性：即使离体叶样本在空气中剧烈干燥，对光系统II中光化学的量子产率也只有轻微影响。然而，水分胁迫显着修改的光系统II叠加的限制的反应。光系统II对热的稳定性被观察到在暴露于水分胁迫条件下的叶片中强烈增加：热处理（例如，在黑暗中42 ℃），其引起充分浇水（番茄）叶片中光系统II的完全和不可逆的抑制，导致干旱胁迫叶片中光系统II的光化学效率的小的和完全可逆的降低。在体内光声数据表明，光系统I是高度耐热和水的压力。当叶片在25 ℃下用强烈的白色光照射时，光系统II的光抑制损伤在水分胁迫的叶片中比在未干燥的对照中更明显。然而，在非脱水的叶片中，光系统II的光抑制强烈地依赖于温度，在高于38至40摄氏度的高温下被强烈地刺激。因此，当暴露于强光在高温下，光系统II的光化学显着抑制脱水叶片比对照水分充足的叶片。我们的研究结果表明，物理化学应力之间存在显着的拮抗作用，水分胁迫增强光系统II的阻力的限制（热，强光在高温下），通常与干旱在该领域。
The in vivo photochemical activity of photosystem 11 was inferred from modulated chlorophyll fluorescence and photoacoustic measurements in intact leaves of several plant species (Lycopersicon esculentum Mill., Solanum tuberosum L., Solanum nigrum L.) exposed to various environmental stresses (drought, heat, strong light) applied separately or in combination. Photosystem II was shown to be highly drought-resistant: even a drastic desiccation in air of detached leaf samples only marginally affected the quantum yield for photochemistry in photosystem II. However, water stress markedly modified the responses of photosystem II to superimposed constraints. The stability of photosystem II to heat was observed to increase strongly in leaves exposed to water stress conditions: heat treatments (e.g. 42-degrees-C in the dark), which caused a complete and irreversible inhibition of photosystem II in well-watered (tomato) leaves, resulted in a small and fully reversible reduction of the photochemical efficiency of photosystem II in drought-stressed leaves. In vivo photoacoustic data indicated that photosystem I was highly resistant to both heat and water stresses. When leaves were illuminated with intense white light at 25-degrees-C, photoinhibition damage of photosystem II was more pronounced in water-stressed leaves than in undesiccated controls. However, in nondehydrated leaves, photoinhibition of photosystem II was strongly temperature dependent, being drastically stimulated at high temperatures above 38 to 40-degrees-C. As a consequence, when exposed to strong light at high temperature, photosystem II photochemistry was significantly less inhibited in dehydrated leaves than in control well-hydrated leaves. Our results demonstrate the existence of a marked antagonism between physicochemical stresses, with water stress enhancing the resistance of photosystem II to constraints (heat, strong light at high temperature) that are usually associated with drought in the field.