碱蓬幼苗对Pb、Cd、Cu、Zn耐受性及富集能力

Tolerance and Accumulation of Pb,Cd, Cu, Zn by Suaeda Salsa Seedlings

通过为期4周的水培试验初步研究了碱蓬（Suaeda salsa）幼苗对Pb、Cd、Cu、Zn的耐受性和富集能力。结果表明，碱蓬幼苗对四种重金属的转移系数（TF）均〈1，因而不属于重金属超累积植物。碱蓬幼苗可在水淹条件下生长，并对Pb、Zn具有较强的耐受性，当暴露于浓度0．10mg／L的Pb以及浓度1．00mg／L、5．00mg／L的Zn时，供试植物没有出现毒害症状，生物量也无明显降低；同时，幼茁对两者表现出较强的富集和转移能力，在0．10mg／LPb处理中，地上部和根部的生物浓缩系数（BCF）分别为12和57，转移系数达到0．219；在1．00mg／L和5．00mg／LZn处理中，地上部BCF分别达到50、28，根部BCF分别达到89、90；TF分别达到0．555、0．311。相反，碱蓬幼苗对Cd、Cu的敏感性较大，浓度分别为0.01mg／L和1．00mg／L时即可造成生物量显著降低，根部对Cd、Cu的生物浓缩系数较高可能是由于毒性抑制而使生物量减小所致。从重金属的耐受性和积累能力两方面考虑，碱蓬较适于污水中Zn、Pb的生物净化。

The tolerance and uptake of four heavy metals （Pb, Cd, Cu and Zn） in Suaeda Salsa seedlings were studied with pot-culture experiments for 4 weeks. Results showed that Suaeda Salsa was not a kind of hyperaccumulator because the translocation factor（TF） for all four metals was 〈1.0. Suaeda Salsa seedlings could grow at water-logging condition and appeared higher tolerance to Pb and Zn. Plants accumulated heavy metals in their body without any visible toxic symptoms and significant reduction in biomass when exposed to Pb of 0. 10 mg/L and Zn of 1.00mg/L and 5.00mg/L. At the same time, the seedlings exhibited greater bioaccumulation and translocation efficiency to these two metals. At 0. 10mg/L Pb solution, the bioconeentration factor （BCF） in shoot and root reached 12 and 57 respectively. While, when plants were grown at the Zn levels of 1.00mg/L and 5.00mg/L, the BCF were, respectively, 50 and 28 in shoot and 89 and 90 in root. The value of TF was found to be 0. 219 for Pb and 0. 555, 0. 311 for Zn. However, the seedlings were more sensitive to Cd and Cu exposure. The biomass decreased significantly compared with control even when exposed to CA of 0.01mg/L and Cu of 1. 00mg/L,and the higher BCF value in root may result from biomass reduction caused by toxic inhibition. Considering the tolerance and accumulation, Suaeda Salsa was recommended for the removal of Pb and Zn from wastewater.