水稻对天然富硒土壤硒的吸收及转运

Selenium uptake and transport of rice under different Se-enriched natural soils

以杂交晚稻＂皖稻205＂为试验材料,采用盆栽试验方法,研究了不同硒含量（0.5、1.0、1.5 mg·kg^-1）土壤对水稻产量、硒的吸收、转运和分配的影响.结果表明：土壤硒含量≤1.5 mg·kg^-1对水稻产量无明显影响;水稻根系、茎叶和籽粒中的硒含量均随着土壤硒含量增加而增加,并呈现根系〉茎叶〉籽粒的特点,籽粒各组成部分的硒含量呈现米糠〉精米〉稻壳的特点;水稻根系能从富硒土壤中富集硒,根系硒的吸收系数达1.86,而硒向籽粒的转运和积累则相对恒定,转运系数为0.53-0.59;土壤硒含量为0.5-1.0 mg·kg^-1所产的富硒大米（0.15-0.20 mg Se·kg^-1）,可满足人体60-80μg·d-1硒的需要量,而土壤硒含量≥1.5mg·kg^-1所产大米硒含量达到0.319 mg·kg^-1,超出粮食硒含量安全标准.综合产量和籽粒硒含量的表现,在富硒土壤（0.5-1.0 mg·kg^-1）上直接生产富硒大米,而不需要添加外源硒,既降低了生产成本,又避免了可能造成的水土污染.

In this study,a pot experiment was conducted with ＂Wandao 205＂as test materials to investigate Se uptake and translocation in rice under different Se concentrations（ 0.5,1.0,and 1.5mg·kg^-1）. Results showed that there was no significant change in rice yield when Se concentration in soil was lower than 1.5 mg·kg^-1. Significant linear correlations existed between Se concentration in soil and different rice plant tissues. Se concentration in rice plant followed the order of root straw grain. Se concentration in different rice grain fractions followed the order of bran polished rice hull. The root absorption index of Se was more than 1.86,suggest that the rice could absorpt Se from soil effectively. However,the transport and accumulation of Se in seeds from Se-enriched soil was relatively constant. The Se transport index in seeds was between 0.53 and 0.59. Soil Se concentration within the range of 0.5 to 1.0 mg·kg^-1could produce Se-enriched rice,which might be enough for human requirement of 60-80 μg·d-1Se. However,polished rice at high-Se treatment（ 1.5 mg·kg^-1） exceeded the maximum standard limit of Se（ 0.3 mg·kg^-1） for cereals in China.These results suggested that we could produce Se-enriched rice under soil Se concentration in the range of 0.5 to 1.0 mg·kg^-1without spraying Se fertilizer,thus reducing the cost and avoiding soil and water pollution caused by exogenous Se.