冶铅区植被变化及残留植物耐铅性特征研究

对江西莲花县冶铅区的植被变化和残留植物中耐铅性较高的植物的耐铅性特征研究表明:(1)耐铅性较强的植物是:夹竹桃、大青、商陆;(2)木本植物茎的韧皮部富铅最高,草本植物的叶和茎次之.不同器官富集铅的能力是:大青为茎韧皮部＞根＞叶＞茎木质部;夹竹桃为茎韧皮部＞根＞茎木质部＞叶.这两个树种的茎木质部和根的富铅性差异明显.夹竹桃的富铅速率在生长期前4个月最快. (3)冶铅区的铅污染主要分布在0～10 cm土层,很容易通过地表径流扩大污染范围,因此,在冶铅区污染严重的地段进行植被恢复时,应辅以工程措施,防止水土流失;同时采用须根系植物或扦插苗造林(侧根多,吸收面积增大),适当配置草本植物,这样有利于提高植被恢复和污染治理的效率.

A Study on Changes of Vegeta tion and Tolerance of Alive Plantto Pb Pollution in the Area around a Lead Smeltery

Because of Pb pollution , the vegetation changed greatly and a large number of p lants died excep t a fewspecies that showed higher tolerance to Pb around a lead smeltery located in Lian-Hua County of J iangxi Province ,China. With investigation and analysis of these changes , some results were obtained as follows: (1) The specieswith higher Pb toleration was in the order of N erium indicum > Clerodend rum cy rtophyllum > Phy tolacca acinosa;(2) Experiments of p lant tolerance to Pb indicated that the stem phloem ofwoody p lantwas the highest one to accumulate Pb from soil , followed by the stalk of herb p lant. In addition, various organs and tissues of p lant showeddifferences in accumulation of Pb. In this paper it was described that the order of up take of Pb was stem phloem >root > leaf > stem xylem in Clerodendrum cyrtophy llum , and N erium ind icum had another order of up take of Pbwhich was stem phloem > root > stem xylem > leaf . These two species had differences of accumulation of Pb between their stem xylems and between their roots. The rate of up take of Pb of N erium ind icum was the highest at thefirst fourmonths during its growing. (3) Because Pb wasmainly distributed within the dep th of 0210 cm of soil andthe way to lead extensiveness of Pb pollution was that Pb followed water to enter streams , rivers and so on , therefore it is necessary to take the measures of construction engineering for revegetation in the district of heavy Pb pollution and at the same time , seedings of fibrous root and seedings of cuttage and seedings of herb p lant are very im2portant to make more effective revegetation and control of Pb pollution.