【摘要】 专─ＣＡＭ植物瓦松（Ｏｒｏｓｔａｃｈｙｓｆｉｍｂｒｉａｔｕｓ）．兼性ＣＡＭ植物长药景天（Ｓｅｄｕｍｓｐｅｃｔａｂｉｌｅ、露花（Ｍｅｓｅｍｂｒｙａｎｔｈｅｍｕｍｃｏｒｄｉｆｏｌｉｕｍ）的ＮＡＤＰ─苹果酸酶活性在２５─５５℃的温度范围内，随着温度的升高而增强，高于５５℃后，活性下降；在ｐＨ６─９的范围内，反应系统ｐＨ７．５时，表现出最大活性。苹果酸是该酶反应底物，苹果酸浓度在１─５μｍｏｌ／Ｌ范围内，随着苹果酸浓度增加，酶活性上升，浓度高于５μｍｏｌ／Ｌ，对ＮＡＤＰ─苹果酸酶有抑制作用。光对该酶活性影响不大，在１３５０μｍｏｌ／ｍ２ｓ光照和黑暗条件下，处理４ｈ后，光下酶活性比黑暗下略有提高。看来，ＮＡＤＰ─苹果酸酶活性昼高夜低的变化规律并不是光／暗变化所致。更多还原

【Abstract】 The activity of NADP─malic enzyme increased with temperature increasing from 25 -55℃,decrcased above 55℃,in the obligate CAM-plant Orostachys fimbriatus and facultative CAM-plants Sedum spectabile and Mesembryanthemum cordifolium; the optimum pH of the enzynie is 7.5 within pH 6─9; the malate is substrate of the enzyme, the activity increased with raising concentration of malate within 1─5 μmol/L. and was inhibited gradually above 5μmol/L; The effect of light on the enzyme activity wasn’t evident.The reason that the enzyme activity was higher markedly during the daytime than that at night, wasn’t caused by light.更多还原