田间大豆叶片光合作用与活性氧清除酶的日变化  

DIURNAL CHANGES OF PHOTOSYNTHESIS AND ACTIVE OXYGEN SCAVENGING ENZYMES IN SOYBEAN LEAVES UNDER FIELD CONDITIONS

作　　者：许长成[1] 樊继莲[1] 孟庆伟[1] 赵世杰[1] 邹琦[1] 

机构地区：[1]山东农业大学植物生理生化研究室,泰安271018

出　　处：《西北植物学报》1997年第3期292-297,共6页Acta Botanica Boreali-Occidentalia Sinica

基　　金：国家自然科学基金

摘　　要：开花期大豆叶片光合速率（Pn）在晴天中午伴随气孔导度（Gs）下降而降低，而叶温（TL）、光呼吸速率（Pr）以及Pr／Pn比值在中午前后明显上升。胞间CO2浓度（Ci）在上午下降，之后则逐渐增加。在最高光量子通量密度（PFD）低于1．2mmol·m-2·s-1的多云天气，大豆叶片Pn与Pr的日变化依赖于PFD、Ci与Pr／Pn比值在一天中基本恒定。晴天与多云天气大豆叶片细胞活性氧清除系统的超氧物歧化酶（SOD）、过氧化氨酶（CAT）、谷胱甘肽还原酶（GR）与抗坏血酸过氧化物酶（ASA－POD）活性均出现明显的日变化，中午前后酶活性明显增加。文中讨论了大豆叶片细胞活性氧清除酶系统日变化的适应性意义。The diurnal variations of photosynthesis and active oxygen scavenging enzyme sys-tem were inverstigated in leaves of well-watered soybean plants under field condltions. Amidday depression in net photosynthetic rate (Pn) and in stomatal conductance was ob-served on a summer sunny day, being accompanied by an increase in leaf temperature andin photorespiratory rate (Pr) as well as in Pr/Pn ratio. Intercellular CO2 concentrationdecreased before noon and increased in the afternoon. On a cloudy day with maximum photon flux density below 1200 μmol· m-2· s-1,Pn and Pr were dependent uponlight intensity and Pr/Pn ratlo remalned constant over the day. The activit1es of superox-ide dismutase,catalase,glutathione reductase and ascorbate peroxidase in soybean leavesincreased during midday,showing a marked diurnal variations.The roles of active oxy-gen scavenging system and photorespiration in the protection of higher plants from thedamaging effects of excesslve light energy were discussed.

关 键 词：大豆 光合作用 活性氧清除酶 日变化 

分 类 号：S565.101[农业科学—作物学]