稀土微肥对水稻镉胁迫的缓解效应研究

Mitigation Effects of Rare Earth Micro-Fertilizer on Rice Cadmium Stresses

采用添加外源有效态镉的土壤盆栽试验方法,研究了稀土微肥对镉胁迫下水稻的生长发育及其对矿质养分吸收的影响,并比较了水稻植株不同部位的镉含量。结果表明,在添加1.0 mg/kg外源有效态镉的土壤条件下,施用0.2-0.6 g/kg稀土微肥可促进水稻的生长发育,提高稻谷产量、千粒重和谷草比;当稀土微肥施用量为0.4 g/kg时,稻谷产量、千粒重、根系干质量和谷草比最高,分别较对照提高14.6%、6.3%、22.7%和46.7%;稀土微肥促进水稻对P、K、Mg、Zn、Cu的吸收,抑制水稻对Ca的吸收。供试土壤条件下,施用0.2-0.6 g/kg稀土微肥并未抑制水稻对镉的吸收,相反有促进水稻吸镉并使其向地上部转移的趋势。这与稀土微肥促进了水稻根系的生长发育,增强了水稻的吸收作用有关。从水稻经济性状和生产效益分析,稀土微肥的施用量以0.4 g/kg（相当于900 kg/hm^2）为宜。

The effects of rare earth micro-fertilizer on rice growth and mineral nutrients absorption under cadmium stresses were studied by adding exogenous cadmium in soil pots, and cadmium contents of different parts of rice plants were compared in the research. The results showed that in the condition of adding 1.0 mg/kg exogenous cadmium, the application of 0.2-0.6 g/kg rare earth micro-fertilizer could promote the growth of rice and increase the rice yield, 1000-grain weight, and grain/straw ratio. When the application rate of rare earth micro-fertilizer was 0.4 g/kg, the rice yield, 1000-grain weight, dry weight of roots and grain/straw ratio were the highest, which increased by 14.6%, 6.3%, 22.7% and 46.7% than those of the control, respectively. Rare earth micro-fertilizer could stimulate rice to uptake P, K, Mg, Zn and Cu and inhibit the absorption of Ca. The application rate of 0.2 -0.6 g/kg rare earth micro-fertilizer did not inhibit the cadmium absorption of rice in the experimental soil condition; on the contrary there was a tendency to promote rice to uptake cadmium and transport it towards aerial part, which might be associated with the fact that rare earth micro-fertilizer promoted the growth and development of rice root system, and enhanced its ability of absorption. Based on the analysis of economic characters of rice and production efficiency, the application rate of rare earth micro-fertilizer should be 0.4 g/kg（the equivalent of 900 kg/hm^2）.