低氧胁迫下黄瓜根系细胞壁结合态多胺氧化酶活性变化及测定方法的确立

提出了细胞壁上PAO检测方法，并对低氧胁迫下黄瓜根系细胞壁结合态PAO的灵敏性、pH值范围、底物依赖性以及取样部位进行了测定。结果表明，检测时取根中部或基部为好，提取液pH值为6．5，启动底物为Spm或Put Spd Spm。低氧处理后PAO活性一开始下降，在第3天时处于上升趋势，第8天达最大值，此后虽下降，但一直高于对照，与游离态PAO活性变化趋势一致，但活性要高10倍以上，表明PAO活性绝大部分定位于细胞壁上。

Change and Determination of Binding Polyamine Oxidase Activity on Cell Wall of Cucumber Roots under Hypoxia stress

An advanced determination of cell wall-localized PAO activities was suggested in this study.And the advanced determination of cell wall-localized PAO activities of cucumber roots under hypoxia stress was analyzed in terms of its sensitivity,its applicable pH range,its dependence on different reactants and its distribution in different parts of cucumber roots.The result showed that the middle or base of roots was more suitable to be determined.For cell wall-localized PAO activities,the most suitable pH in extracted solution was 6.5 and the reactant suitable to activate was Spm or Put+Spd+Spm.When cucumber was treated by root-zone hypoxia stress,cell wall-localized PAO activities decreased at first,began to increase three days later and peaked on the 8th day,then reduced but were still higher than that in control plants.The changing trend of cell wall-localized PAO activities was correspond to that of free PAO activities in cucumber roots under hypoxia stress.But the PAO activities in cell wall were 10 times as high as that of the free form.So PAO was mostly localized in cell wall in cucumber.