中文摘要：

通过水培试验，探讨了主要盐基离子（NO3-、SO4^2-、SiO3^2-）对小白菜Cr（VI）污染毒性的调控作用，结果表明：①Cr对小白菜有极强的致毒能力，可有效抑制小白菜生长、Fe养分吸收和小白菜叶片硝酸还原酶活性，故妨碍碳氮代谢进而降低小白菜产量品质；②适度提高NO3-N浓度可有效缓减Cr对小白菜吸收Fe和硝酸还原酶活性的抑制毒性，并刺激小白菜生长，但NO3-同时也有协同促进小白菜吸收Cr的明显效果；③适当提高SO4^2-浓度能有效抑制小白菜对Cr吸收，并提高小白菜硝酸还原酶活性，但过高SO4^2-浓度有一定盐胁迫毒害效应，会影响其对降低小白菜Cr生物毒性的作用效果；④SiO3^2-对小白菜吸收Cr有较强的抑制作用，但这种作用未起到缓减小白菜Cr生理毒性的明显效果。试验结果表明，适当控制营养液NO3-浓度是抑制小白菜Cr吸收的关键，针对不同的Cr污染水平来调节NO3-、SO4^2-、SiO3^2-浓度配比，是抑制小白菜吸收Cr的有效技术措施。

英文摘要：

By hydroponics experiment, the effects of main base anions（NO3-、SO4^2-、SiO3^2-） on Cr（VI） toxicity ofpakchoi cabbage （Brassica campestris L. ssp. chinensis（L.）） and its mechanism were studied. The results showed that： （1）With the increase of Cr content in water culture, the growth of pakchoi cabbage and its iron uptake were restrained obviously by Cr, therefore the activity of nitrate reductase and the metabolism of carbon, nitrogen were also inhibited intensively, which showed that Cr was highly toxic to pakchoi cabbage in this hydroponics experiments. （2）Cr uptake by pakchoi cabbage can be promoted significantly by nitrate anions （NO3）, and from it the inhibition of iron uptake by pakchoi cabbage reduced and leaf nitrate reductase activity which abated by Cr in nutrient solution was also mitigated, showing that the toxicity of Cr to pakchoi cabbage can be mitigated by nitrate anions when applied properly. （3）On the condition of the same content of Cr in nutrient solution, at the proper range, with the increasing of sulfate anions （SO4^2-） concentration in nutrient solution, Cr uptake by pakchoi cabbage decreased obviously and leaf nitrate reductase activity was also enhanced. However, high sulfate anions concentration in water culture resulted in salt toxicity somewhat to pakchoi cabbage and therefore reduced its resistance of Cr toxicity. （4）lt obviously showed that Cr uptake by pakchoi cabbage can be restrained from the increase of silicate anions concentration in water culture, but there was no positive effect in leaf nitrate reductase activity from these effects of silicate anions, and the growth ofpakchoi cabbage which restrained by Cr was also not obviously promoted by it, showing that these effects on Cr uptake by silicate anions can not obviously detoxify for pakchoi cabbage. In this study, results showed that the proper rate of nitrate concentration is the key that restraining Cr uptake by pakchoi cabbage in water culture, and it was an effective technologi