【作者】 陈阳；

【导师】 胡恒觉；

【作者基本信息】 甘肃农业大学 ， 作物栽培学与耕作学， 2002， 博士

【摘要】 本文以单子叶植物水稻和双子叶植物黄瓜为材料，对硅元素的分布及相应的POD酶活性进行定位，定量分析，结果显示加硅培养的植物叶片硅含量及过氧化物酶含量均高于不加硅处理，并且硅含量与过氧化物酶随着叶龄增加而增加。在两种植物中，水稻表现出老叶硅分布比嫩叶密集，从叶尖-叶中部-叶基部表现出硅分布密集程度逐渐降低的趋势；加硅处理的黄瓜老叶硅的分布较明显，但嫩叶和未加硅处理的叶片未见明显的硅的染色。通过扫描电镜及硅的x能谱分析显示，水稻硅呈纺锤体及扇形硅质体。黄瓜叶片有明显的表皮毛分布，茎中也有类似于叶片的表皮毛分布。表皮毛可检测到微量的硅元素分布。硅的定位结果显示水稻叶片切面有清晰的扇形体，柱形体；在此POD活性定位结果与硅分布一致。黄瓜表皮毛基部细胞因叶龄不同发育程度不—，即叶龄长，硅分布高，其表皮毛细胞组成数量多，在此硅的分布与表皮毛的位置一致，而同时POD活性与硅分布图吻合。体外模拟结果显示POD是硅沉积的一个必需的催化物质，而硅酸在0mM 0.5mM,2mM,浓度下，对POD活性无明显影响；但在5，10mM浓度下，抑制POD活性。因此尽管黄瓜与水稻硅的形态不同，但硅元素的分布与POD活性定位和定量结果有着很好一致性，说明POD在某种程度上影响了硅的沉积数量，部位及形态。更多还原

【Abstract】 The content and distribution of silica .activity and location of POD on the leaves of rice and cucumber were studied by means of localization and quantitlive analysis.The content of Si and activity of POD were higher from +Si leaves than that from -Si leaves in these plants.and that in creased with the ages of leaves. In rices Si were observed distributed densely on the older leaves.from the base to the top of blades,the denity of Si increased. In cucumber, there were obviously Si depoist on the older leaves from +Si plant, Si can’t be observed on the younger leaves from + Si plant.There were no silicon distribtion on the -Si leaves .by analzing EDX map of silicon ,it was showed that,in the leaf blades of rices ,Si exsisted in the form,of fan-shaped and dumbbell-shaped .There were many trichomes which contained Si on the surfaces of leave and stems on cucumber. The results of cytochemical localization of silicon demonstrated that there were fan-shaped silica bodies and cyliner shape silica deposit ,and high activity of POD were observed in fan-shaped silica bodies. The base of trichomes consisted of large quantity of cells.. The number of cell increased with the age of leaves. The silicon and POD accumulated on the base of trichomes .The results of externalexperiment demonstrated that POD is essential for Silica deposit, Addition of Omm,0.5mM and 2mM HsSiO4 to reaction systems had no effect on the activity of POD. But activity of POD was inhibited by 5mm and 10mm HsSiOi .Therefore, though the shape and location of Si on the leaves of rice and cucumber were so different. There were correlation between the position of Si and POD. It was suggest that the amount,location and shape of silicon desopit may be affected by the activity of POD.更多还原