光、暗处理对蚕豆茎内皮层形成的影响 Ⅱ.与栓化作用有关的酶及抗氧化剂的关系

Effect of light on the formation of endodermis in stem of broad bean seedling Ⅱ.Relation with enzymes and endogenous antioxidants

以蚕豆（ＶｉｃｉａｆａｂａＬ．）幼苗为材料，结合不同的光强及黑暗对茎中内皮层形成的影响，对参与栓化作用有关的酶活性及内源抗氧化物质的含量进行了测定，并讨论了光对内皮层形成的调节机制。实验结果表明，高光强抑制茎中内皮层形成，而低光强和黑暗诱导茎中形成内皮层。在低光强和暗中，脂肪氧化酶在内皮层栓化前期活性显著增加，可能与栓化作用的启动有关，而高光强下ＬＯＸ始终处在较低水平。ＰＡＬ活性为光所诱导，与内皮层的栓化没有直接的相关性。在高光强条件下生长的幼苗茎中抗坏血酸和谷胱甘肽含量比低光强和暗中的高。外源施用抗坏血酸，可抑制低光强下茎内皮层的栓化，而对暗中茎内皮层的栓化无影响。推测高强度光对栓化作用的抑制原因可能是高光强下植物体内有高含量的抗氧化物质，并具备更有利的活性氧清除途径。

Effect of light on formation of endodermis in stem of broad bean seedling was studied by measuring the levels of endogenous antioxidants and certain key enzymes postulated to be involved in suberization.Formation of endodermis was inhibited in stem grown under high intensity light and induced under low intensity light and in the dark.That lipoxygenase activity markedly increased during the aerly phase of endodermal suberization was associated with triggering of suberization.PAL activity,which was induced by light,was not directly correlated with suberization of endodermis.The stem grown under high intensity light had a higher amount of endogenous antioxidants (ascorbate and glutathione) than under low intensity light and in the dark.