纳米银与镉的复合毒性对拟南芥根系形态及叶片生理指标的影响

为研究纳米银（AgNPs）与镉（Cd²⁺）对拟南芥的复合毒性，本文以不同浓度的PVP coated-AgNPs和Cd²⁺处理拟南芥幼苗一周后，测定了拟南芥幼苗主根长度，根毛数量，叶片中光合色素和可溶性蛋白含量及抗氧化系统相关酶活性.结果表明，高浓度（5mg/L） Cd²⁺能显著抑制根长，提高可溶性蛋白含量及SOD（超氧化物歧化酶）和POD（过氧化物酶）的活性.在高浓度Cd²⁺（5mg/L）中加入AgNPs能显著增强Cd²⁺对根长的抑制作用，而高浓度的Cd²⁺能缓解AgNPs对根毛的抑制作用；在低浓度Cd²⁺（0.1mg/L和1mg/L）中加入AgNPs能显著增强Cd²⁺对色素含量抑制作用；在含有Cd²⁺的处理中，SOD和POD在1mg/L AgNPs下活性最高；以上结果说明Cd²⁺和AgNPs对拟南芥幼苗根系形态及叶片生理指标都存在交互影响.

Effects of AgNPs and cadmium on root morphology and leaves physiological indexes of Arabidopsis thalian

To investigate the combined toxictiy of AgNPs and Cd²⁺ on Arabidopsis thaliana seedlings, the root length, the number of root hairs, the content of photosynthetic pigment and protein, superoxide dismutade (SOD) and peroxidase (POD) activity were measured after one week exposure to different concentrations of PVP coated-AgNPs and Cd²⁺. Results showed that high concentration (5mg/L) of Cd²⁺ could significantly inhibit root elongation and increase the protein content and SOD, POD activity. After adding AgNPs in high concentration (5mg/L) of Cd²⁺ treatment, the inhibition effect of Cd²⁺ on Arabidopsis thaliana root length was significantly increased while the inhibition effect of AgNPs on Arabidopsis thaliana root hairs was decreased. After adding AgNPs in low concentration (0.1and 1mg/L) of Cd²⁺ treatment, the inhibition effect of Cd²⁺ on Arabidopsis thaliana photosynthetic pigment content were significantly increased. In Cd²⁺ treatment, SOD, POD activity reached the highest when the seedlings were exposured to 1mg/L AgNPs. Above results showed that Cd²⁺ and AgNPs had interaction effects on root morphology and leaves physiological indexes of Arabidopsis thaliana.