摘要
研究了芦苇幼苗体内 Cd的积累、亚细胞微区分布、存在形态和其诱导蛋白以及植物络合素合成抑制剂 (BSO)对芦苇光合作用和生长的影响。在 Cd污染条件下 ,芦苇幼苗植株和根皮层细胞中可积累大量的Cd,但 Cd在芦苇各器官和根皮层细胞亚细胞结构中的分布显著不均 ;Cd在芦苇幼苗体内的分配为 :根 >叶片 >茎 >地下茎 ,在根皮层细胞中的分布为 :细胞间隙 >细胞壁 >液泡 >细胞质。受 Cd污染的芦苇幼苗体内的 Cd以不同化学形态存在 ,其中 Na Cl提取态的 Cd在根和叶片中占的比例均为最大 ,其次为根内的醋酸提取态 ;在叶片中以水提取态为主 ,其它形态的含量相对较低。层析结果表明 ,根和叶片中各存在一种Cd结合蛋白 ,其中根内的 Cd结合蛋白可能是一种植物络合素聚合体。受 Cd诱导 ,芦苇幼苗根中还新合成了一种小分子蛋白或多肽 ,但另有一种蛋白因 Cd影响而消失。此外 ,BSO实验证明了植物络合素对 Cd的解毒作用。可见 ,芦苇的抗 Cd机理与以下几个方面有关 :根部截留 ,细胞间隙积累 ,细胞壁沉淀 ,液泡区域化 ,形成活性较低的难溶化合物 ,形成
The influence of Cadmium (Cd) on physiolgical and biochemical growth parameters was studied to elucidate the mechanism of cadmium resistance in Phragmites australis. Cd levels in roots, rhizomes, stems and leaves increased with Cd pollution. The levels in roots were the highest, while that in leaves were the lowest. Using X-ray microanalysis revealed that Cd accumulated markedly in cell wall, cytoplasm, vacuole and intercellular space. A gradient of Cd levels occurred in different parts of root cortex cell with the sequence: intercellular > cell wall > vacuole > cytoplasm. Sequential extraction revealed that the ratio of Cd extracted from different extraction media was markedly different, of which NaCl extractable-Cd was dominant in both roots and leaves of P. australis. Cd-binding proteins were found in both; root and leaf after gel filtration chromatograph. The Cd-binding protein in root might be a polymer of phytochelatins. In addition, a new polypeptides was found under Cd pollution, and at the same time the other protein disappeared. And the experiments of BSO also proved the detoxification of Cd by phytochelatins. All the above results suggested that detoxification of Cd in P. australis may involve different strategies: retention in root, accumulation in intercellular, deposition on cell wall, compartmentalization in vacuole, insoluble Cd-binding components and Cd-binding protein.
出处
《生态学报》
CAS
CSCD
北大核心
2003年第5期856-862,共7页
Acta Ecologica Sinica
基金
国家重点基础发展规划资助项目 (G1 9990 1 1 70 0 )~~
关键词
芦苇
抗镉污染
机理
积累
亚细胞分布
化学形态
诱导蛋白
镉
Pragmites australis
Cd
accumulation
subcellular distribution
chemical forms
Cd-inducing proteins
