不同硒水平下两种大豆对土壤中硒吸收积累的生育期动态

采用盆栽实验研究了不同硒水平两大豆品种对土壤中硒吸收累积的生育期动态。结果表明，大豆植株硒累积量与干物质累积量是同步的。大豆植株硒含量在生育早期高于生育后期。植株硒含量主要受土壤硒水平影响，品种间差异不明显。低硒水平下土壤硒的吸收利用程度较高，而高硒水平下植株吸收的土壤硒向生殖器官的迁移程度较高。因此，土壤硒对于大豆的生物有效性与植株硒水平是土壤—作物相互作用的结果。在大豆营养生长时期，根吸收的硒向地上部转移后仍主要分布在叶片中；而生殖生长时期则不同，在高硒水平下植株硒主要向子粒富集，低硒土壤中则主要集中于营养体。不过，以同一硒水平土壤的大豆根的吸收能力和硒的累积量没有差异，但子粒总硒累积量来说，两种大豆在低硒土壤中差异明显，而高硒土壤中没有差异，这可能涉及不同品种硒转运机制的差异。

DYNAMICS OF Se UPTAKE AND ACCUMULATION IN GROWTH PERIOD BY TWO SOYBEAN CULTIVARS UNDER DIFFERENT Se-LEVELS OF SOIL

Pot experiment of two soybean cultivars in 2 soils with different total Se level was conducted to study the dynamics of Se uptake and accumulation in different soybeans planted in different Se-level soils during growth period. Se uptake and accumulation in plant was found generally synchronic to buildup of dry matter, although shoot Se concentration higher at early growth stages than in the ripening stage. Significant difference of Se accumulation in plant was found not between the two cultivars but between in the two soils. Bigger portion of soil Se was uptaken in the low-Se soil while bigger portion of Se uptaken by the roots was translocated to above ground organs in the high-Se soil. Thus, the bioavailability of soil and, in turn, the plant Se level Se was subject to soil-plant interaction. The Se translocated from root to shoot was observed to concentrate in the leaves before flowering. However, bigger portion of translocated Se was in the grains under high soil Se condition. Nevertheless, the fact that there was significant difference in total grain Se accumulation between the two cultivars in low Se soil but not in high Se may indicate the difference of the Se transporter protein of the two studied soybean cultivars.