土壤改良剂与叶面喷硒联合阻控对小白菜吸收镉的影响

Effects of Amendments Combined with Foliar Selenium Fertilizer on Cadmium Uptake by Pakchoi

为探究改良剂与叶面喷硒(Se)联合阻控减轻农产品受镉(Cd)毒害的效果,采用土壤培养及盆栽试验的方法,筛选不同用量的牛粪(7.5、15 g kg^(-1))与石灰(1、2、3、4、5 g kg^(-1))配施钝化土壤Cd有效性的最优处理,并探讨改良剂与叶面喷Se(1、2、4、8 mg L^(-1))联合阻控对不同程度Cd污染土壤(0.5、3、6 mg kg^(-1))中小白菜吸收Cd的影响。结果表明:(1)与未施改良剂处理相比,7.5 g kg^(-1)牛粪与5 g kg^(-1)石灰配施对土壤Cd的钝化效果最显著,土壤有效Cd含量降低了37.9%。(2)与单施改良剂相比,施用改良剂与叶面喷Se显著抑制了小白菜对Cd的吸收,其中在中轻度污染土壤中(0.5和3 mg kg^(-1)Cd)叶面喷施4 mg L^(-1) Se使小白菜Cd含量分别降低了12.9%和78.7%,丙二醛含量分别降低了29.9%和60.6%;在重度污染土壤中(6 mg kg^(-1)Cd)叶面喷施8 mg L^(-1)Se使小白菜Cd含量降低了81.4%,丙二醛含量降低了71.9%;叶面喷Se使小白菜的抗氧化酶活性和谷胱甘肽含量均有不同程度的增加。

The objective was to explore the mechanism of reducing cadmium(Cd)toxicity of agricultural products by combining soil amendments with foliar selenium(Se)fertilizer.Incubation experiment was carried out to study the optimal treatment of available Cd passivation in soil with different amounts of cow manure(7.5 and 15 g kg^(-1))and lime(1,2,3,4 and 5 g kg^(-1)),and pot experiment was carried out to study the effects of combined application of amendments and foliar Se fertilizer(1,2,4 and 8 mg L^(-1))on Cd uptake by pakchoi in different Cd contaminated soils(0.5,3 and 6 mg kg^(-1)).The results showed that:(1)compared with the control treatment,the application of 7.5 g kg^(-1)cow manure combined with 5 g kg^(-1)lime had the most significant passivation effect on soil Cd,and the available Cd content decreased by 37.9%.(2)Compared with the single application of amendments,foliar Se application combined with the amendments significantly inhibited Cd uptake by pakchoi.Spraying 4 mg L^(-1)Se fertilizer to pakchoi leaves in mildly and moderately contaminated soil(0.5 and 3 mg kg^(-1)Cd)decreased Cd uptakes by 12.9% and 78.7%,and the malonaldehyde contents by 29.9% and 60.6%,respectively.The Cd and malonaldehyde contents of pakchoi were decreased by 81.4% and 71.9%,respectively,by spraying 8 mg L^(-1)Se in heavily polluted soil(6 mg kg^(-1)Cd).The activities of antioxidant enzymes and glutathione content of pakchoi were increased after spraying foliar Se fertilizer.