镉硒互作对萝卜种子发芽和幼苗生长的影响

Effects of Selenium on Seedling Growth Under Cadmium Stress in Radish

为减轻土壤镉污染对萝卜生产的危害,本研究采用室内培养皿水培方法,观测了不同浓度镉(Cd)、硒(Se)和镉硒互作对萝卜种子发芽与幼苗生长的影响。结果表明,Cd和不同价态的Se在低浓度时均能促进萝卜种子萌发,提高发芽势和发芽率,促进苗与幼根的生长,Cd和Se分别在5mg.L-1和0.5mg.L-1时促进作用达到最大,高浓度时对萝卜的发芽和幼苗生长有抑制作用;不同价态Se相比,Se4+的促进作用大于Se6+,而Se6+的抑制作用大于Se4+,萝卜的根和苗相比,根对高浓度离子的敏感性比苗更强。不同浓度镉硒互作的效应不同,在低浓度(1mg.L-1)镉条件下,任何浓度的硒对镉都有拮抗作用,即硒降低了低浓度镉对萝卜种子发芽和幼苗生长的促进作用,但高浓度硒和高价硒(Se6+)比低浓度硒和低价硒(Se4+)表现明显;中浓度(10mg.L-1)镉和高浓度(50mg.L-1)镉浓度下,低浓度(0.5mg.L-1)Se4+表现出拮抗作用,即硒减轻了镉对萝卜种子发芽和幼苗生长的抑制,而其他组合处理都表现出协同抑制的效应,即加重了镉对萝卜种子发芽和幼苗生长的抑制;不同价态硒相比,Se4+表现出更强的缓解镉毒害的能力,并且这种现象在中、高镉浓度下表现的更为明显。

With the method of indoor hydroponic culture, the effects of cadmium （Cd）, selenium （Se）and interactions of cad- mium and selenium on radish seed germination and seedling growth were studied to reduce the harm of cadmium in soil to radish. The results were as follows, Cd and different valences of Se at low concentrations could promote the germination of radish seeds, increase germination potential and germination rate, promote the growth of seedlings and young roots, and the promotions of Cd and Se reached maximum at the concentration of 5 mg · L-1 and 0. 5 mg · L-1 respectively. The germination and seedling growth of radish were inhibited at higher concentrations. Compared with different valences, the promotion role of Se4＋ was greater than that of Se6＋ , and the inhibition effect of Se6＋ was larger than that of inhibition Se4＋. Cadmium and selenium with different concentrations had different interaction effect. At low concentrations（1mg · L-1）of CA , all concentration of selenium had antagonistic effect on cadmium, which reduces the promotion role of CA in radish seed germination and seedling growth, but the antagonistic effect was more obvious at high concentrations of selenium and Se6＋ than that at the low concentration of selenium and Se4＋ respectively;At middle concentration （10 mg · L-1 ）and high concentration （50mg · L-1 ）of Cd, the tow concentration（0. 5mg · L-1 ）of Se4＋ had an antagonistic effect on CA, which reduced inhibition effect of Cd on radish seed germination and seedling growth, but the other combinations had a synergistic inhibition effect which enhanced growth inhibition in radish seed germination and seedling growth. Compared with different valences, Se4＋ showed more ability to alleviate Cd toxicity, which was more obvious at the middle and high concentration of Cd.