重金属汞镉污染对水稻生长发育的影响

Effects of Mercury and Cadmium Pollution on Rice Growth and Development

汞(Hg)和镉(Cd)都是农田土壤的污染物质,随着工业的发展,汞和镉污染日趋严重,对人类健康和农业生产构成了严重威胁。试验以水稻为对象,采用水培法进行,研究了不同生长时期,不同外源汞、镉的施用量对水稻所受的污染,重金属在水稻内的迁移和积累的影响。结果表明,随着汞、镉施入量逐渐的增加,水稻对汞镉的吸收增加。在水稻的不同生长期,营养液中的汞镉与水稻根、茎及叶吸收之间的汞镉呈正相关。随着汞镉含量的增加,汞镉对水稻生长的抑制作用加强,从而降低水稻对重金属的吸收,其中生育期短的水稻最为明显。相关分析表明,相同实验条件下,汞、镉的用量越大,其对水稻的生长影响越大;生育期短的水稻,受汞、镉影响越大。通过测定收获后水稻的根茎部分与营养液中汞镉含量可以得出如下结论:随着施用汞、镉量的增加,水稻根茎中的积累也在增加,但达到一定程度时,水稻根茎中的汞、镉含量增加幅度降低,且营养液中的汞积累大于水稻根茎中积累的部分。图4,表4,参22。

Mercury(Hg) and cadmium(Cd) are pollutants in farmland soils. Their pollution has grown with the development of industry,which has threatened human health and agricultural production. Current study took rice as the object,the influence of different Hg and Cd concentrations on the rice growth,as well as the transport and the accumulation of metals in rice were studied by water culture experiment. The results showed that,the absorption amount of Hg and Cd in rice increased with the increasing Hg and Cd application rate. In different growth period of rice,positive correlation was found between Hg and Cd concentrations in nutrient solution and their contents in root,stem and leaf of rice. The inhibition of Hg and Cd to rice strengthened with the increasing Hg and Cd concentrations. Therefore,the absorption ability of rice to Hg and Cd decreased,especially for the rice species with shorter growth duration. The correlation analysis showed that,under the current experiment condition,the influence of Hg and Cd on rice increased with the increasing Hg and Cd rate,and for the rice with shorter growth duration,the influence was bigger. Based on the results of Hg and Cd in root and stem of rice and their concentrations in nutrient solution,it can be concluded as follows:The accumulation of Hg and Cd in root and stem of rice increased with the increasing Hg and Cd application amount,however,when the accumulation reached to a certain level,the increasing amplitude decreased,and the accumulation of Hg in nutrient solution was greater than that in root and stem of rice.