不同有机酸对小白菜镉污染毒性和品质的影响

以小白菜为试材,以贵州典型黄壤为盆栽试验基质,在黄土中共设置5个不同处理,1)原始无污染土壤(CK);2)单一镉污染土壤处理(Cd);3)镉污染土壤加草酸处理(Cd+OA);4)镉污染土壤加柠檬酸处理(Cd+CA);5)镉污染土壤加酒石酸处理(Cd+TA),探究镉胁迫下不同有机酸对提高小白菜品质的效果,以期为改善蔬菜品质提供参考依据。结果表明:外源添加镉导致小白菜单株鲜质量降低了41.1%,植株体内镉大量积累,活性氧类物质、丙二醛(MDA)和脯氨酸含量升高。与对照组相比,镉污染小白菜叶片内硝酸盐含量增加了2.9倍,维生素C和可溶性糖含量分别降低了19.3%和9.9%。在镉污染土壤上施入草酸、柠檬酸和酒石酸后均显著改善了小白菜的生长状态。与镉污染处理小白菜相比,柠檬酸对小白菜的促生效果最显著,生物量相对增加了48.5%,叶片和根的镉含量分别降低了45.3%和42.6%。酒石酸对超氧阴离子的影响大于草酸和柠檬酸,对过氧化氢和脯氨酸的影响小于草酸和柠檬酸,但草酸抑制硝酸盐积累和提高可溶性糖含量的作用大于其它有机酸。上述结果说明,在镉污染土壤施用柠檬酸可以有效缓解镉对小白菜的毒害作用,提高小白菜的产量和品质。

Effects of Different Organic Acids on Cadmium Toxicity and Quality in Pakchoi Cabbage

Pakchoi cabbage was used as experiment material.A pot experiment was conducted to investigate the physiological and resistance responses of pakchoi cabbage to different organic acids under Cd stress by adding oxalic acid(OA),citric acid(CA)and tartaric acid(TA)into Cd spiked yellow soil.The effects of different organic acids on improving the quality of pakchoi cabbage were studied,in order to provide a reference for improving the quality of vegetables.The results were summarized as follows:Cd stress caused notably Cd accumulation in pakchoi cabbage and decreased the fresh weight of plants by 41.1%.Additionally,the content of reactive oxygen species,malondialdehyde(MDA),proline and nitrate in pakchoi cabbage all significantly increased due to Cd stress,while the vitamin C content and soluble sugar content decreased by 19.3%and 9.9%,respectively.What is more,organic acid,especially OA,could relieve Cd-toxicity on pakchoi cabbage growth,which increased the fresh weight of pakchoi cabbage by 48.5%,the Cd content in leaves and roots decreased by 45.3%and 42.6%,respectively.Although OA,CA and TA could inhibit the generation of reactive oxygen species,MDA,proline and the accumulation of nitrate induced by Cd toxicity in pakchoi cabbage leaf,and promote the content of vitamin C and soluble sugar,TA affected more on superoxide anion and less on hydrogen peroxide and proline,while OA had a greater influence on nitrate and soluble sugar.It′s suggested that the application of organic acids in Cd contaminated soil could effectively alleviate the Cd-toxic effects on pakchoi cabbage and improve the yield and nutritional quality of pakchoi cabbage.