西南山地小径竹的重金属富集能力

Heavy Metals Bioaccumulation Capacity of Dwarf Bamboo in Southwest Mountain

西南山地小径竹的种类多、分布广、生长快、生物量高,且对土壤重金属具有一定的耐受性,在土壤重金属修复方面具有潜在优势。目前对于西南山地竹区的小径竹在土壤重金属修复方面的研究和应用鲜有报道。以西南山地的林下优势层片缺苞箭竹(Fargesia denudate)和拐棍竹(F.robusta)为研究对象,通过测定分析其茎、叶、笋及根际土壤的重金属Cu、Zn、Pb、Cd、Cr含量,比较不同小径竹地上各部位的富集系数,并与常见的超积累植物相比,探讨小径竹的重金属富集潜力。结果表明:(1)缺苞箭竹和拐棍竹叶的Cu、Zn、Pb、Cd、Cr含量和富集系数均显著大于茎和笋(P=0.001);(2)缺苞箭竹地上各部位对Cu的富集系数大于Zn、Pb、Cd、Cr,而拐棍竹对Cu的富集系数较小;(3)缺苞箭竹地上部的Cu富集系数(2.16)、Zn富集系数(1.27)显著大于拐棍竹(0.17、0.93,P=0.001),而Pb富集系数(0.09)、Cd富集系数(0.34)、Cr富集系数(0.82)显著小于拐棍竹(0.87、0.49、1.03,P=0.002、0.049、0.001);(4)与生长在未被污染土壤中的超积累植物相比,缺苞箭竹具有更大的Cu、Cr富集潜力,拐棍竹对Pb、Cr具有更大的富集潜力。西南山地小径竹在土壤污染修复方面具有较高的生态、经济和景观效益,有发展成为生态-经济型土壤重金属修复植物的潜力。

Numerous dwarf bamboo species, due to rapid growth ability and high biomass capacity, are widely distributed in the Southwest Mountainous area of China. Among these, some species show a strong potential tolerance to the heavy metals in soil. Thus, some of them can be used as bio?remediation of soil contaminated by heavy metals. Up to date, some researches have shown that the absorption and transformation of heavy metals in the bamboo as well as the physiological and ecological responses of bamboo plants under the stress of heavy metals. However, most of these studies focused on bamboo species in the Yangtze River and Nanling Mountains, there were few studies and applications on remediating heavy metals in the dwarf bamboo in the southwest mountainous region. In this paper, the Cu, Zn, Pb, Cd and Cr contents in stems, leaves and shoots and rhizosphere soils in Fargesia denudate and F. robusta, the undergrowth dominant layers in Southwest Mountainous China, were measured over its growing season. The bioaccumulation factors of above?ground parts of different dwarf bamboos were compared accordingly. The results showed, firstly, the contents and bioaccumulation factors of Cu, Zn, Pb, Cd and Cr in leaves were significantly higher than the stems and shoots (P=0.001). Secondly, the bioaccumulation factors of Cu in stems, leaves and shoots of F.denudate were higher than that of Zn, Pb, Cd and Cr, while the bioaccumulation factors of Cu in stems, leaves and shoots of F. robusta were lower than that of Zn, Pb, Cd and Cr. Thirdly, the bioaccumulation factors of Cu (2.16) and Zn (1.27) in stems, leaves and shoots of F. denudate were significantly higher than that of F. robusta (0.17, 0.93, P=0.001), while the bioaccumulation factors of Pb (0.09), Cd (0.34) and Cr (0.82) in stems, leaves and shoots of F. denudate were lower significantly (0.87, 0.49, 1.03, P=0.002, 0.049 and 0.001). Fourthly, compared with common hyperaccumulation plants, F. denudate showed the potential ability on Cu and Cr enrichment, and F. robusta on Pb and Cr. This study indicates that dwarf bamboos probably can be used on the ecosystem service with their higher economic benefits and landscape value in the remediation of soil with heavy metals pollutions.