不同供硒水平对水稻硒的吸收和累积特性研究

Effect of Se Supplying Levels on Se Absorption and Accumulation in Rice

以“南粳9108”为材料,在巢湖流域研究田间条件下不同供硒水平(Se 0、20、40和60 g/hm^(2))以及等量硒肥二次施用对水稻产量和硒吸收、累积、转运及分配的影响。结果表明:一次性施用不同浓度硒肥对水稻有增产作用,但是增产效果甚微;施用硒肥能够显著促进水稻茎、叶和穗的硒含量,但随着时间的推移,茎、叶和穗的含硒量均出现上升再下降趋势;稻谷、糙米及精米中的硒含量与硒肥施用量呈显著正相关,硒肥处理平均硒含量依次为0.279、0.150、0.055 mg/kg,分别较对照不施硒肥高309%、142%和333%;地上部硒累积量与施硒水平呈极显著的正相关,随着施硒量的增加,尽管硒的表观利用率是增加的,但硒转运系数和硒的收获指数显著下降。等量硒肥二次分施较一次性施用对产量有较为显著的促进作用,该处理下水稻产量较对照增加15%;等量硒肥二次施用增加了稻壳和米糠中的硒含量,精米中的硒没有增加;较一次施用,等量硒肥二次施用肥料表观利用率较高,硒肥的收获指数和转运系数显著下降,地上部累积更多的硒在稻草中。综上所述,外源硒的添加确实能增加大米硒含量,使其达到国家富硒大米硒含量标准范围;但结果同时显示水稻中的硒相当大的一部分累积在谷壳、谷糠及稻草中,可考虑充分利用。

In this study,a field experiment was conducted in Chaohu Lake Basin with rice variety“Nangjing 9108”as the test material to investigate rice yield and selenium(Se)uptake,accumulation,translocation and distribution in rice under different Se supplying levels(0,20,40 and 60 g/hm^(2))with single and two-time fertilization.The results showed that under single Se fertilization,there was no significant increase in rice yield between different Se supplying levels.Se supplying significantly increased Se contents in stems,leaves and panicles of rice,but they also showed the trend of increasing and decreasing with time.Se contents in rice,brown rice and milled rice were positively correlated with Se supplying levels,and the average Se contents in rice,brown rice and milled rice with Se supplying were 0.279,0.150 and 0.055 mg/kg,respectively,which was 309%,142%and 333%higher than that of CK(no Se fertilizer).Se accumulation in rice shoots was positively correlated with Se supplying level,and Se transport coefficient and harvest index decreased significantly,although Se apparent utilization rate was increased with the increase of Se supplying levels.Two-time fertilization significantly increased rice yield than single fertilization,and rice yield increased by 15%compared with CK.Compared with single fertilization,two-time fertilization increased Se contents in rice husk and rice bran while not in milled rice.The harvest index and transporting coefficient of Se fertilizer significantly decreased with higher apparent utilization rate of Se fertilizer,which indicated more Se accumulated in straws.In conclusion,exogenous Se can increase Se content in rice and makes it meet the national standard of selenium-rich rice,however,a significant amount of Se is accumulated in hull,chaff and straw,which is need to be used fully.