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作 者 ：李影,褚磊

期 刊 ：生态学报 2008年 28卷 4期 页码：1565~1572

关键词：节节草(Hippochaete ramosissimum)；铜；积累；吸收；化学形态；

Keywords:Hippochaete ramosissimum, Cu, accumulation, uptake, chemical forma,

摘 要 ：通过野外样品分析和室内栽培实验，研究了Cu在节节草（Hippochaete ramosissimum）体内和根细胞内的积累、分布及赋存形态。结果表明，铜尾矿区和室内盆栽的节节草对铜均以根系积累为主，根系中Cu含量最高分别可达1309，1339.75 mg•kg-1；滞留率平均分别为8498%，97.30%。节节草根细胞各组分中，仅细胞壁（F1）和含核糖核蛋白体的细胞溶质（F4）中的铜含量与Cu处理浓度呈极显著正相关（rF1＝0.98，rF4＝0.98，p<0.01）；且细胞壁中的铜占大多数，为总量的45%～70%。此外节节草根、茎中Cu赋存形态存在差异，在其根部主要以醋酸提取态和盐酸提取态形式存在，占总量的60%～80%，且两形态的Cu含量均与土壤Cu浓度呈极显著的正相关（rHAC=0.99，rHCl=0.98，p<0.01）；而茎部铜均以NaCl提取态为主；水溶态铜含量在其根部和茎部所占比例均相对较低。节节草可能通过根部截留和细胞壁沉积的方式，以及使体内的Cu2+形成难溶性、活性低的化合物来降低过量的Cu对其的毒害。节节草对Cu具有较强的耐性和较高的积累能力，在Cu污染土壤修复上有着广阔的应用前景。

Abstract:The accumulation of Cu in different parts of H. ramosissimum, distribution of Cu in root subcellulars and chemical forma of Cu in its body were studied by means of analysis of field samples and greenhouse cultivation. The results showed that most of the Cu of H. ramosissimum growing on the Cu mining spoils and greenhouse cultivation were deposited in the root with the largest content of 1309 mg•kg-1 and 1339.75 mg•kg-1.The average retention rate was 84.98% and 973%, respectively. Moreover, more Cu deposited in the cell wall than that of the other fractions which accounted for 45%-70% in the root subcelluar of H. ramosissimum. The Cu content distributed in the cell wall (F1 ) and plasma part with ribosome (F4) has a marked correlation with Cu concentration of the soil, respectively (rF1＝0.98，rF4＝0.98，p<001). Under Cu stress of different levels, the chemical forma of Cu in the plant was different. The content of Cu forma extracted by HAC and HCl in the root was the greatest with the rate of 60%-80%, which was significantly and positively related to Cu concentration of the soil, respectively (rHAC=0.997，rHCl=0.98，p<0.01) . Meanwhile, NaCl in the shoot was dominant, while that extracted by water was the lowest in both the root and the shoot. The accumulation character and detoxification mechanism in which the mass of Cu were intercepted at the root accumulated in cytoderms and formed certain low dissolvable Cu-compounds, possibly contributing to the reduction of the Cu toxic effect on H. ramosissimum. It was suggested that H. ramosissimum had a remarkable tolerance to Cu and a potential capacity of Cu accumulation could be used widely in phytoremediation of Cu-polluted soils.

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