【作者】 肖细元；

【导师】 张杨珠； 陈同斌；

【作者基本信息】 湖南农业大学 ， 土壤学， 2003， 硕士

【摘要】 蜈蚣草是世界上首次报道的一种砷超富集植物，同时也是钙质土壤的指示植物。它具有明显的耐高砷特征及需钙特性。通过砂培盆栽试验，本论文从砷和钙的作用对蜈蚣草生长和累积砷的影响及砷、钙与其他必需金属元素的关系等方面研究了蜈蚣草的营养特性，从砷、钙、磷的亚细胞定位探讨了蜈蚣草对砷的解毒机理及钙的作用机制。所得结果如下： 砂培条件下，蜈蚣草具有明显的耐高砷特征。当介质中砷高达0.2mmol／L时，蜈蚣草的生长正常，与对照比较，其生物量没有显著差异。然而，介质中高浓度的钙表现出明显的抑制蜈蚣草生长作用，特别在5.0mmol／L Ca处理下，生物量极显著减少，而低钙(0.03mmol／L Ca)水平处理有利于蜈蚣草的生长，生物量较大。 砷和钙处理浓度对蜈蚣草植株砷浓度均有显著影响。随着添加砷浓度的提高，蜈蚣草各部位的砷浓度都显著增加，其羽叶／根的富集系数也逐渐提高。提高溶液中钙浓度，根部砷浓度不受影响，但叶柄中的砷浓度增加，羽叶中砷浓度有明显下降，即钙明显抑制蜈蚣草羽叶中砷的吸收。添加砷促进蜈蚣草根部及羽叶对钙的吸收。与低钙处理比较，提高钙水平，蜈蚣草体内钙浓度明显增加，但除叶柄外，中钙和高钙处理间其他部位的钙浓度差别不明显。添加砷抑制蜈蚣草根部磷的吸收，但对地上部磷浓度无明显影响。钙对蜈蚣草根部及叶柄中磷浓度有显著影响。 砷、钙对蜈蚣草羽叶累积砷有显著的交互效应。提高溶液中砷浓度，蜈蚣草对砷的累积量明显增加，而钙处理却极显著抑制蜈蚣草对砷的累积，即低水平钙处理有利于蜈蚣草累积砷。 除Fe和Zn外，添加砷对蜈蚣草羽叶中各金属元素浓度均无显著影响，表明高砷条件下，蜈蚣草中金属元素营养状况正常，可维持良好的生理活动。提高介质中钙浓度对蜈蚣草吸收Pe、Cu和Zn无显著影响，但对K、Mg和Mn的吸收转运均有显著拮抗作用。从根部到羽叶中，各金属元素之间的相互作用逐渐加强，尤其是植株中的Ca作用更明显。在根部中Ca与各种金属元素都无显著的相关性；叶柄中Ca与Fe浓度呈极显著正相关；在羽叶内，Ca浓度的增加明显降低K、Mg、Mn和Zn浓度。 在无砷处理下，蜈蚣草植株体内的砷主要分布在细胞壁，且其根部细胞壁中钙的比重较高，有抑制砷进入蜈蚣草细胞内的趋势。随着砷处理浓度的提高，砷主要位于胞质中，从根部到地上部，砷在胞质中的分布比例逐渐升高，钙在胞质中分布比例与砷相似，呈现从地下部到地上部逐渐增加的规律。更多还原

【Abstract】 Pteris vittata L., an indicator plant for calcareous soils, is an As-hyperaccumulator newlydiscovered by Chen et al. in China. This finding may bring a hope to phytoremediate As-contaminated soils. The effects of As and Ca on the growth of P. vittata L. and As uptake by P. vittata L. were studied under sand culture condition. The interaction of As and Ca on concentration and distribution of metals including K, Mg, Mn, Fe, Zn and Cu in it were also investigated. In addition, the As, P, Ca subcellular distribution in it were elucidated. The results are as follows:P. vittata L. has a strong tolerant capability to high As concentration in the medium. There was no significant difference in biomass between adding As and CK treatments. But the dry matter production decreased markedly with increasing Ca concentration. Especially P. vittata L. grew much badly under the condition treated with 5.0 mmol/L Ca.The effects of As and Ca concentration in culture solution on As content in P. vittata L. were much significant. As uptake by each part of P. vittata L increased obviously with elevating As level and the ratio of pinna As concetration to root As concentration increased gradually. As concentration in root was not affected markedly by Ca levels, while that of petiole increased and that of pinna decreased significantly. Adding As was benefit to take up Ca by P. vittata L. in the roots and pinnae. Ca concentration in the plant strongly increased followed by enhancing Ca level in solution compared to 0.03 mmol/L Ca treatment. But the obvious difference about Ca content in P. vittata L. between middle and high Ca level treatments was not found except that in the petiole. Applying As reduced P concentration in the root, but that in the frond was not affected significantly. The Ca levels had a great influence on P concentration in the root and petiole.It is shown that the concentrations of K, Mn, Fe and Cu in the pinnae were not influenced by enhancing the As in addition to Fe and Zn. When treated with high As level, Pteris vittata L. could maintain its normal nutrition metabolism. The results showed that the accumulations of Fe, Zn and Cu were not significantly affected by Ca levels, but the concentration and translocation of K, Mg and Mn were depressed by Ca. The interaction of metals wasenhanced gradually from the roots to leaves, and the effect of the Ca level on other metal elements was very obvious. There was no significant relationship between the Ca concentration and other metals concentrations in the roots. But the positive correlation between Ca and Fe concentrations hi petioles was very significantly. The K, Mg, Mn and Zn concentrations in pinnae decreased as the Ca concentration increased.The results showed that As distributed mostly in cell walls in the case of 0 mmol/L As, moreover the percentage of Ca content in cell walls was higher, which might inhibit As influxing cell. As concentration mostly existed in cytoplasmic supernatant when applying As in the medium. And the distribution percentage of As in cytoplasmic supernatant increased gradually from root to frond. The Ca percentage in cytoplasmic supernatant followed the same trend as As.更多还原