外源精胺对小麦幼苗抗氧化酶活性的促进作用

外源精胺（Spm）降低了离体小麦叶片衰老时MDA的含量，且降低程度与精胺的浓度成正比。0.2mmol/L的精胺提高了小麦幼苗体内的超氧化物歧化酶（SOD），过氧化氢酶（CAT），过氧化物酶（POD）及抗坏血酸过氧化物酶（ASP）的活性。体内及体外试验表明精胺既可诱导SOD与POD的合成，又可直接作用于酶分子上以提高酶的活性；精胺对CAT合成仅能诱导，对已有酶活性无调节作用；精胺对ASP的合成无影响，却能促进已有酶的活性。

Promoting Effect of Exogenous Spermine on Anti-oxidative Enzyme Activity in Wheat Seedlings

The MDA content in detached wheat leaves was decreased by Spm, in a dose dependent manner (Fig.1). The activities of SOD,CAT,POD and ASP in wheat seedlings were increased by Spm 0.2 mmol/L. The results of test in vivo and in vitro showed that exogenous Spm not only stimulated the enzyme synthesis of SOD and POD, but also promoted the activity of the existing enzyme (Figs.2,3); exogenous Spm stimulated the synthesis of CAT, but had no effect on the activity of the existing enzyme (Fig.4); exogenous Spm had no effect on the synthesis of ASP, but promoted the activity of the existing enzyme (Fig.5). It indicated that the ways through which Spm increases the activity of SOD, CAT, POD and ASP in wheat seedlings were different.