不同镉污染土壤下水稻镉富集与转运效率

Cadmium accumulation and translocation efficiency of rice under different cadmium-polluted soils

选取适合湖南种植的48个水稻品种(系)在中轻度和重度镉污染土壤上进行盆栽试验,通过分析水稻籽粒产量、各器官富集系数、转运系数及植株净化效率,探明不同镉污染土壤对水稻镉富集、转运及净化效率的影响。结果表明:中轻度和重度镉污染土壤下糙米Cd含量、籽粒产量分别为0.010~0.048 mg·kg^(-1)、96.63~152.55 g·盆^(-1)和0.105~0.476mg·kg^(-1)、101.10~165.12 g·盆^(-1),重度镉污染土壤明显促进糙米镉含量增加,但对籽粒产量影响不大;中轻度和重度镉污染土壤下糙米镉富集效率和产量均不存在显著相关性;依据产量和糙米镉富集效率进行聚类分析,将所有品种在中轻度镉污染土壤下分为低镉低产组、低镉高产组;重度镉污染土壤分为高镉低产组、高镉高产组;两种镉污染土壤水稻各器官镉富集大小顺序均为糙米<叶<茎秆<根系,转运效率则为土-根>茎-叶>茎-糙米>根-茎,土壤镉主要转运至根部并富集于根部;水稻镉富集及转运效率受产量因素影响较小,但受土壤镉浓度影响较大;重度镉污染土壤明显增强水稻各器官镉富集和根-糙米各环节镉转运效率,较中轻度镉污染土壤增幅显著;水稻根部的净化效率远高于地上部分。

A pot experiment was carried out in mildly and severely cadmiumpolluted soil with 48 rice varieties suitable for planting in Hunan. Based on the analysis of grain yield, the enrichment coefficient of each organ, the transfer coefficient and purification ability of plants, the effects of different cadmium pollution levels on the cadmium accumulation, translocation and purification efficiency of rice were studied. The results showed that the cadmium content and grain yield of brown rice were 0.010-0.048 mg·kg-1 and 96.63-152.55 g·pot-1 for mildly cadmium-polluted soil, and 0.105-0.476 mg·kg-1 and 101.10-165.12 g·pot-1 for severely cadmium-polluted soil, respectively. Severely cadmiumpolluted soil significantly increased cadmium content in brown rice, but had little effect on grain yield. There was no significant correlation between yield and cadmium enrichment efficiency of brown rice in mildly and severely cadmium polluted soil. Based on the analysis of the yield and the concentration of cadmium in brown rice, all the varieties were divided into low cadmium-low yield group and low cadmium-high yield group under mildly cadmium-polluted soil, and high cadmium low yield group and high cadmium high yield group in severely cadmium polluted soil. The cadmium accumulation and translocation efficiency in organs of rice were in the order of brown rice〈leaf〈stem〈root and soil-root〉stem-leaf〉stem-brown rice〉root-stem, respectively. Soil cadmium was transported to roots and enriched in roots. The cadmium accumulation and translocation efficiency of rice were less affected by yield factors, but greatly affected by soil cadmium enrichment. Severely cadmium polluted soil significantly enhanced the cadmium enrichment of each organ and the translocation efficiency of root brown rice, compared to mildly cadmium polluted soil. The purification efficiency of rice roots was much higher than that of the aboveground parts.