菠萝叶片PEP羧激酶活性及草酰乙酸与腺苷酸库的昼夜变化  

Diurnal Changes of Phosphoenolpyruvate Carboxykinase Activity,Oxalacetate Content and Adenosine Pool in Pineapple Leaves

作　　者：林植芳[1] 彭长连[1] 林桂珠[1] 李双顺[1] 

机构地区：[1]中国科学院华南植物研究所

出　　处：《植物生理学报（0257-4829)》1994年第4期353-359,共7页Acta Phytophysiologica Sinica

基　　金：国家自然科学基金

摘　　要：自然条件下生长的菠萝植株，其叶片的ＰＥＰ羧激酶的脱羧与可逆羧化活性于中午１２时达最大值。脱羧／羧化比值在上午明显高于下午和晚上。脱羧反应底物ＯＡＡ含量于夜间增高，至次日早晨６时最高，随后下降。白天的ＯＡＡ／Ｍａｌ值高于夜间。参与Ｍａｌ及ＯＡＡ形成转化的ＰＥＰＣ和ＭＤＨ活性的昼夜变化与ＰＥＰ羧激酶（ＰＥＰＣＫ）活性的图式相似。ＰＥＰ羧激酶脱羧反应的另一底物ＡＴＰ在夜间０～６时内处于低水平，白天９～１５时内则显著增高。The day/night cycles of decarboxylation and carboxylation of phosphoenolpyruvate carboxykinasePEPCK) and the levels of its substrate oxalacetate, ATP and ADP fromgreenhouse--grown pineapple leaves were studied by sampling every three hours. The diurnal change in both forward and reverse activities of PEPCK showed a two--peak pattern with a maximum at noon (12 h) and another smaller one at midnight (21 h). The average decarboxylation / carboxylation ratio in the morning was higher than those in the afternoon and night time.The contents of malate and oxalacetute increased at night and reached their maxima in the morning (6 h-- 9h) and then declined. OAA/malate ratio was higher in day time than at night. The day/night cycles of the activities of PEP carboxylase and malate dehydrogenase were coincident with that of PEPCK activity. ATP and ADP contents increased progressively from 9 h to 15 h and then decreased. It was almost undetectacble through 24 h to 6 h. The ratio of ATP/ADP showed pronounced diurnal fluctuation. The results suggested that the substrate level was the important factor regulating PEPCK activity and its catulytic direction, and the activity of PEPCK was related with the activties of PEP carboxylase and malate dehydrogenase.

关 键 词：草酰乙酸 腺苷酸 菠萝 羧基裂解酶 昼夜变化 

分 类 号：S667.801[农业科学—果树学]