红树植物无瓣海桑中重金属元素的分布与富集特征

Distribution and enrichment characteristics of heavy metal elements in mangrove plant:Sonneratia apetala

通过测定江门市新会区银湖湾红树林沉积物及红树植物无瓣海桑中不同部位重金属元素的质量浓度,分析其在沉积物及植株内部的富集和转移能力。结果表明:研究区域的红树林沉积物易于富集铅、铜、镉、铬、锌、砷等重金属元素,已受到重金属元素污染。无瓣海桑对重金属元素有一定的耐性,细根作为植株吸收水分和养分的主要器官,能大量富集重金属元素,凯氏带限制了非必需重金属元素在植株内部的运输;枝、叶生长初期和生殖器官形成时能加大对必需元素的选择性吸收。无瓣海桑主根迁移不同重金属元素至主茎的能力存在差异,材部的综合转移能力高于皮部。无瓣海桑不符合超富集植物的概念,但其生长优势明显且对各种重金属元素都有一定程度的耐性,可用于构建红树林人工湿地重金属污水处理系统。

The concentration of heavy metal elements in different parts of mangrove sediments and Sonneratia apetala in the Yinhu Bay of Jiangmen City were measured,and their accumulation and transfer ability in sediments and plants were analyzed.The results show that the mangrove sediments in the study area incline to accumulate heavy metals such as lead,copper,cadmium,chromium,zinc and arsenic.The area thus had been polluted by heavy metals.Sonneratia apetala has certain tolerance to heavy metals.As the main organ of plant absorbing water and nutrients,the fine root could enrich a lot of heavy metals.The transport of unessential heavy metals in the plant were limited by casparian strip.The selective absorption of essential elements could be increased in the early growth of branches and leaves and in the formation of reproductive organs.The ability of transferring different heavy metals from the main root to the main stem was different,and the comprehensive transfer ability of the wood was higher than that of the skin.Sonneratia apetala doesn't belong to the family of hyperaccumulator,but its growth advantage was obvious,and it had a certain degree of tolerance to heavy metal elements.It could be used for heavy metal wastewater treatment system of artificial cultured mangrove wetland.