土壤镉污染条件下叶面硒肥对生菜镉积累的影响

Effects of foliar selenium fertilizer on cadmium accumulation in lettuce under cadmium pollution condition

为探讨叶面硒肥对生菜(Lactuca sativa L.)镉胁迫的改善作用,通过盆栽试验,设置2个镉污染浓度(1 mg/kg,Cd1;3 mg/kg,Cd3)和3个叶面硒肥浓度(0 mg/L,Se0;1 mg/L,Se1;3 mg/L,Se3),研究了不同浓度叶面硒肥对生菜镉积累的影响。结果表明:①叶面硒肥的喷施可不同程度降低生菜对镉的吸收积累,较之Cd1+Se0处理,Cd1+Se1处理可显著降低生菜叶镉含量,降幅为26.29%;较之Cd3+Se0处理,Cd3+Se3处理下生菜叶镉含量显著降低49.05%。②喷施适宜浓度的叶面硒肥可不同程度提升生菜过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性,降低丙二醛(MDA)含量,Cd1+Se1处理下,生菜的CAT、SOD活性分别显著高于Cd1+Se0处理40.38%、68.71%,而MDA含量则显著降低44.48%;Cd3+Se3处理下,生菜的CAT、SOD活性较Cd3+Se0处理分别显著提升77.48%、51.70%,而MDA含量则显著降低48.90%。因此,喷施适量的叶面硒肥可明显提升生菜抗逆特性,进而有效阻控生菜对镉的吸收,其中土壤镉含量为1 mg/kg(Cd1)时,叶面硒肥喷施浓度以1 mg/L效果最佳,土壤镉含量为3 mg/kg(Cd3)时,叶面硒肥喷施浓度以3 mg/L效果为最优。

In order to explore the effect of foliar selenium fertilizer on cadmium stress in lettuca sativa L.,the effects of different concentrations of foliar selenium fertilizer on cadmium accumulation in lettuce were studied by potting experiments.Two cadmium pollution concentrations(1 mg/kg,Cd1;3 mg/kg,Cd3)and three foliar selenium fertilizer concentrations(0 mg/L,Se0;1 mg/L,Se1;3 mg/L,Se3)were set up.The results showed that:①The spraying of foliar selenium fertilizer significantly reduced the uptake and accumulation of cadmium by lettuce,compared with the Cd1+Se0 and Cd3+Se0 treatments,and the cadmium content of lettuce leaves in Cd1+Se1 and Cd3+Se3 treatments was significantly reduced by 26.29%and 49.05%,respectively.②Spraying foliar selenium fertilizer at appropriate concentrations increased the activity of catalase(CAT)and superoxide dismutase(SOD)in lettuce,reduced the content of malondialdehyde(MDA),and significantly reduced the MDA content of lettuce under Cd1+Se1 and Cd3+Se3 treatments by 44.48%and 48.90%,compared with Cd1+Se0 and Cd3+Se0 treatments,respectively.CAT and SOD under Cd1+Se1 treatment were more than Cd1+Se0 treatment by 40.38%and 68.71%respectively.And CAT and SOD under Cd3+Se3 treatment were more than Cd3+Se0 treatment by 77.48%and 51.70%respectively.Therefore,it can be seen that the spraying of foliar selenium fertilizer can significantly improve the stress resistance characteristics of lettuce,and then effectively inhibit the absorption of cadmium by lettuce.When the soil cadmium content is 1 mg/kg(Cd1),the optimal foliar selenium fertilizer spray concentration is 1 mg/L,while when the soil cadmium content is 3 mg/kg(Cd3),and the optimal foliar selenium fertilizer spray concentration is 3 mg/L.