3种植物对铀尾渣的耐受性研究

Study on tolerance of three plant species to uranium mining tailings

铀尾渣营养贫乏、重金属含量高,其堆存区植被缺乏,污染物移迁扩散严重.在铀尾渣堆存区域重建植被可防止污染物扩散.针对铀尾渣堆积区的植被重建,选用美洲商陆(Phytolacca americana)、羽叶鬼针草(Bidens maximowicziana)和东方蓼(Polygonum orien-tale)3种植物,将铀尾渣与土壤按不同比例混合改良,用作栽培基质,进行盆栽试验,研究这3种植物对铀尾渣的耐受性以及基质改良对植物生长的影响.分析株高、生物量和叶绿素含量变化,发现羽叶鬼针草对铀尾渣的耐受性强于另外两种植物.铀尾渣中加入土壤有利于3种植物生长.在T60(铀尾渣比例为60%)改良方式中,这3种植物生长最好.利用这3种植物进行植被重建时,建议采用T60方式改良铀尾渣.

Mining tailing sites are damaged and absence of vegetation. Restoration of a vegetation can fulfill the objectives of stabilization, which may help to avoid dispersion of contaminants through wind erosion and by reducing the volume of water percolating through the soil. Revegetation in these sites requires the use of metal-tolerant and metal-accumulating plants to provide the vegetation. Pot experiments were conducted to investigate the tolerance of three plant species to uramium mining railings diluted with red soil amendment. Seedlings of Phytolacca americana, Bidens maximowicziana and Polygonum orientale were planted in pots. Tolerance of these species to uranium mining tailings were studied by measuring different parameters, such as seedling height, biomass, mot length, root tolerance index, chlorophyll content, and so on. The seedling height, biomass and chlorophyll content for P. americana, P orientale in T100 treatment were significantly lower than controls, respectively. But, for B. maximowicziana, the seedling height, biomass and chlorophyll content in T100 treatment were more than its control. The results showed that, among the three species, the tolerance of B. maximowicziana to uramium mining tailings was the best. When uranium mining tailings were diluted with red soil, the substrates were more friendly to seedlings of these plants. In T60 treatments, the seedling height, biomass and chlorophyll content for P. americana, B. maximowicziana and P. orientale were the most high than that in other treatments. The T60 amendment approach, in which the percentage of dry weight of uranium mining tailings in substrate was 60%, is more reasonable for the reclamation of uranium mining tailings.