地质因素影响下的硒在土壤-水稻系统中的迁移转化

硒在土壤—水稻系统中的迁移转化,受其在水稻土中的形态分布、土壤理化性质和微量或大量元素的交互作用影响.硒在水稻植株中的分布、迁移和总量传输,是一个动态过程.从土壤和根部传输上来的硒会逐渐在各器官内积累,表现出w_根(Se)＞w_叶(Se)＞w_茎(Se)＞w_穗(Se)的特点.水稻地以上部分的硒量仅占植株总硒量的42%～50%.进入稻穗中的硒量仅为水稻植株总硒量的2.31%～4.31%,且w_稻谷(Se)＞w_糙米(Se)＞w_精米(Se).高硒区土壤总硒与土壤有机态硒和残渣态硒有关,与离子交换态、碳酸盐态和铁锰氧化态硒关系不大.

THE TRANSPORT AND TRANSFORMATION OF SELENIUM IN THE SOIL-PADDY PLANT SYSTEM AFFECTED BY GEOLOGICAL FACTORS

The root system selenium has relationship not only with the amount of selenium, but also with the acidity and alkalinity of soil. The amount of selenium in surface paddy is lower than that in the root system. The amount of selenium in leaves is lower than that in root but higher than in trunk, with the fringe part having the lowest selenium. 42% - 50% of selenium in the plant at surface earth is in the fringe, and only 2.31% -4.31% of selenium is in the plant. Moreover, the amount of selenium in unpolished rice is lower than that in paddy but higher than that in rice. There is a direct proportion between the amount of selenium in paddy and the acidity and alkalinity of soil, which means the stronger the alkali in soil is, the higher the amount of selenium in paddy becomes. The amount of selenium in the body of paddy has something to do with that in the paddy soil, which means that there exists a direct proportion between the amount of selenium in soil and that in paddy.