光强对木本植物叶绿体中活性氧产生的调控作用

THE REGULATION OF LIGHT INTENSITY IN ACTIVE OXYGEN PRODUCTION OF CHLOROPLASTS IN WOODY PLANTS

摘要:

将亚热带自然林的乔木荷树、黧蒴和灌木九节、罗伞幼苗栽种于3种不同光强下分析叶片中的LOX、XOD、MAO活性和分离叶绿体中和活性氧O₂^-.、OH·和H₂O₂的产生速率差别的结果表明:全自然光下生长的叶片中LOX和XOD活性最高,降低光强则2个酶的活性下降。叶绿体中的3种活性氧的产生随光强变化的趋势与LOX及XOD活性变化相似。这反映高的LOX和XOD活性是高光强下叶片中出现较高活性氧水平的原因之一。供试灌木的LOX和XOD活性低于乔木,但其活性及活性氧形成速率对光强变化的敏感性高于乔木。

Abstract:

The seedlings of two tree species (Schima superba and Castanopsis fissa )and two shrub species (Psychotrla rubra and A rdisia quinquegona) from a subtropical natural forest were grown in pots under 100％，36％ and 16％ natural light． The difference in activities of lipoxygenase (LOX)， xanthine oxidase (XOD) and monoamine oxidase (MAO) in leaves and the production rates of three active oxygen species (O₂^-., OH·, H₂O₂) in chloroplasts were c0mpared．Leaves grown under 100％ sun light showed highest activities of LOX and XOD．The changing trends ofO₂^-., OH· and H₂O₂ in chloroplasts responding to light intensity were significant and similar to that of LOX and XOD activities．High activities of LOX and XOD might be one of the causes of high active oxygen level in leaves that were adapted to high light intensity．The tested understory shrub plants showed lower LOX and XOD activities than the canopy tree species， but the response of enzyme activity and active oxygen production to the change of light intensity was more sensitive than tree species.