摘要
在温室中用砂培和水培方法种植紫花苜蓿和大麦,以此来研究SO_4^(2-)和SE(Ⅵ)对作物吸收Se的影响以及SO_4^(2-)和Se(Ⅵ)之间的相互作用。试验结果证明,紫花苜蓿和大麦体内都能累积Se(Ⅵ)并达到危害人类和动物健康的水平。Se(Ⅵ)对紫花苜蓿和大麦的干物质量都有不利的影响。当溶液含Se(Ⅵ)量超过0.1mg L^(-1)时,两者的干物质量减少25％—35％,含Se(Ⅵ)量超过lmg L^(-1)时,作物减产50％以上。SO_4^(2-)对植物吸收Se(Ⅵ)有明显的拮抗作用,能减少植物对Se(Ⅵ)的吸收,溶液中含SO_4^(2-)量超过2dS m^(-1),植物吸收Se(Ⅵ)减少99％,这是因为Se(Ⅵ)和SO_4^(2-)有相似的化学和物理性质,植物吸收Se(Ⅵ)和SO_4^(2-)的机理是极相似的。因此,当SO_4^(2-)在根的吸收基上成为主要离子时,植物组织中含Se(Ⅵ)量就会大大减少。含Se(Ⅵ)量较高的井水或农业排水是否可以用于灌溉,主要取决于水中的SO_4^(2-)含量。
Alfalfa and barley were grown in sand and solution culture in greenhouse to determine the effects of SO_4^(2-) and Se(Ⅵ) on alfalfa and barley tissue composition and yield as well as antagonism between SO_4^(2-) and Se (Ⅵ). The experiment on alfalfa was conducted with treatments consisting of three Se concentrations (0. 125,0. 25, and lmg Se(Ⅵ)L^(-1) as Na_2SeO_4) and four SO_4^(2-)concentrations (0.5,0.75,1.00, and 1.25 dS m^(-1) as Na_2 SO_4 and CaSO_4·2H_2O) , and on barley with four Se concentrations ( 0.5,0.75,1. 0 and 1.25 mg L^(-1)) and four SO_4^(2-) concentrations (0.2,0.9,1.8 and 5.5 dS m^(-1)). Plant yields are significantly reduced by Se (Ⅵ), when Se (Ⅵ) concentration in treatment solution is more than 0.1mg L^(-1),alfalfa and barley yields reduce 25—35% ,and when Se (Ⅵ) more than lmg L^(-1) ,yields of both alfalfa and barley reduce 50%.Afalfa and barley can potentially accumulate Se(Ⅵ) and it can reach the extremely high concentration that is potentially toxic to animals. Se in plant tissue is positively correlative with Se(Ⅵ) in the irrigation water and solution, and negatively correlative with SO_4^(2-). Antagonism exhibites between Se (Ⅵ) and SO_4^(2-) when SO_4^(2-) is present in treatment solution at a high concentration. When SO_4^(2-) concentration in treatment solution is more than 2 dS m^(-1) ,Se(Ⅵ) concentration in plant tissue reduces 99%. Mechanisms of S snd Se absorption by both alfalfa and barley are similar because of the similar physical and chemical property of S and Se. Whether agricultural drainage and well water with high Se concentration can be used as irrigation or not depends on the concentrations of SO_4^(2-) in the drainage and in the water.
关键词
紫花苜蓿
大麦
吸收
铯
SO_4^(2-), Se(Ⅵ), Alfalfa, Barley, Uptake of Se
