Cu-Cd复合处理对小白菜硝酸盐含量的影响

Effects of the Composite Treatment of Cu-Cd on the Nitrate Content in Brassica campestris ssp.chinensis

[目的]为蔬菜硝酸盐的控制及食物的安全性提供参考。[方法]采用模拟污染盆栽方法,研究Cu、Cd单一及复合处理对小白菜硝酸盐含量及硝酸还原酶的影响。[结果]各处理组小白菜叶柄中硝酸盐含量明显比叶片中高,叶片中硝酸还原酶活性显著高于叶柄。1 mg/kg Cd促进硝酸盐的积累,102、0 mg/kg Cd明显抑制叶部硝酸盐的积累。在试验浓度范围内,Cu显著降低了小白菜中硝酸盐含量。Cu+Cd复合处理组硝酸盐含量低于对照组和相同浓度Cd的单一处理,高于相同浓度Cu的单一处理。Cu+Cd复合处理极大地刺激了小白菜叶片中硝酸还原酶的活性,高于对照组。25 mg/kg Cu+15 mg/kg Cd的复合处理使叶片和叶柄中硝酸还原酶活性增加,硝酸盐含量降低。[结论]Cu对Cd造成的硝酸盐累积增高的危害有缓解作用,适量的Cu可以增加小白菜硝酸还原酶的活性,减少硝酸盐的累积。

[Objective]The study aimed to provide references for the control of nitrate in vegetable and the safety of food.[Method] The influences of the single and composite treatments of Cu and Cd on the nitrate content and nitrate reductase in Brassica campestris ssp.chinensis and nitrate reductase were studied through pot experiment with simulating pollution.[Result]In each treatment group,the nitrate content in the leafstock of B.campestris was obviously higher than that in its leaf,but the activity of nitrate reductase in the leaf was significantly higher than that in the leafstock.1.0 mg/kg Cd promoted the accumulation of nitrate,and 10 and 20 mg/kg Cd obviously restrained the accumulation of nitrate in the leaf.In the scope of experimental concentration,Cu significantly decreased the nitrate content in B.campestris.The nitrate content in the composite treatment group of Cu and Cd was lower than that of CK group and the single treatment of Cd with the same concentration and higher than that of the single treatment of Cu with the same concentration.The composite treatment of Cu and Cd greatly stimulated the activity of nitrate reductase in the leaf of B.campestris,which was higher than that in CK group.The composite treatment of 25 mg/kg Cu and 15 mg/kg Cd increased the activity of nitrate reductase in the leaf and leafstock and decreased their nitrate contents.[Conclusion]Cu had alleviating effect on the harm of the increment of nitrate accumulation caused by Cd.The appropriate Cu can increase the activity of nitrate reductase in B.campestris,and reduce the accumulation of nitrate.