不同形态硒对韭菜吸收富集及土壤累积硒的影响

采用塑料大棚试验,研究了施用硒酸钠和亚硒酸钠对韭菜富集硒以及土壤累积硒的影响,旨在为富硒蔬菜的生产提供理论依据。本试验结果表明,在韭菜出苗前向土壤中分别施加亚硒酸钠为Se100、200和400 g·hm~(-2)时,韭菜可食部位硒含量为0.008~0.128 mg·kg~(-1) FW;分别施加硒酸钠为Se 100和200 g·hm~(-2)时,韭菜可食部位硒含量为0.067~0.441 mg·kg-1 FW。按照陕西富硒食品标准(DB61/T556-2012)中新鲜蔬菜硒的含量指标(0.02~0.1 mg·kg~(-1)),亚硒酸钠施用量为Se 200 g·hm~(-2)或硒酸钠施用量为Se 100 g·hm~(-2)时可满足韭菜1个生产季的富硒生产需求。施入土壤中的硒酸钠通过韭菜吸收的回收率约为10%,而亚硒酸钠的吸收回收率不足3%。对韭菜施用硒酸钠的富硒效果比亚硒酸钠的好,亚硒酸钠在土壤中的移动性较差,绝大部分残留于较浅的表层土壤中,而硒酸钠移动性较强,更容易在土壤中发生迁移。

Effects of Soil-applied Selenite and Selenate on Accumulation in Chinese Leek and Retention in Soil of Selenium

A greenhouse experiment of Chinese leek was conducted to study the effects of selenium application (selenate and selenite) to soil on Se accumulation in the edible part of the vegetable and its fate in soil.Selenite and selenate were top-applied between sowing and germination.The edible part of Chinese leek would accumulate 0.008-0.128 mg · kg-1 FW of Se,as affected by selenite of 100,200 and 400 g · hm-2,and 0.067-0.441 mg · kg-1 FW of Se for that affected by 100 and 200 g · hm-2 of selenate.Se content in the edible part of Chinese leek affected by selenite of 200 g · hm-2 or selenate of 100 g · hm-2 could meet the standard for Se-enriched food products proposed by Shaanxi Province (0.02-0.1 mg · kg-1) for a single farming season.The recovery of selenate (the amount of Se accumulated in the vegetable against that added to soil) was about 10％ while that of selenite was below 3％.Selenate was more effective in enhancing Se accumulation in Chinese leek than selenite,because selenite was less mobile and could not move as deeply as selenate,which made selenite retained in the surface of soil as selenate could move down and be taken up by the vegetable.