间作对莎草与蚕豆体内铅镉锌化学形态分布的影响

通过室内盆栽实验,研究了莎草(Cyperus glomeratus L.)和蚕豆(Vicia faba L.)间作条件下两种植物体内Pb、Cd、Zn化学形态分布的变化,并进一步探讨了间作体系影响莎草与蚕豆对重金属Cd、Pb、Zn吸收累积的主要机制。结果表明:与单作相比,间作使莎草地上部生物量减少了54.55%,根部生物量减少了41.67%,叶绿素与可溶性糖含量分别减少了33.33%与36.39%;间作后蚕豆地上部的生物量提高了11.71%。蚕豆根际土壤有效态Pb、Cd和Zn含量显著降低。Pb在两种植物体内的化学形态以氯化钠提取态(FNa Cl)为主,间作使莎草地上部乙醇提取态(FE)Pb含量显著增加了23.43%,根部各化学形态Pb含量增加6.92%~17.80%;间作后蚕豆地上部活性较强的FE-Pb和FW-Pb含量显著降低了16.00%和42.60%,根部各化学形态Pb含量降低了1.32%~44.76%。Cd在两种植物体内的化学形态以FNa Cl和FHCl为主,间作使莎草地上部残渣态(FR)含量显著增加了43.45%,根部FHCl和FR含量显著增加了6.26%和30.01%;间作后蚕豆地上部FHCl-Cd含量显著降低了26.37%,根部各化学形态Cd含量降低了6.09%~68.33%;在两种植物体内的化学形态以FHAc、FW和FNa Cl占优,间作使莎草地上部FE-Zn含量显著增加了12.5%,根部各化学形态Zn含量增加5.32%~23.54%;间作后蚕豆地上部和根部各化学形态Zn含量均降低。蚕豆地上部和根部Pb、Cd、Zn均与土壤有效态Pb、Cd、Zn含量呈显著正相关,表明间作降低蚕豆Pb、Cd、Zn的含量与体系植物根际土壤有效态Pb、Cd、Zn含量下降密切相关。

Effects of intercropping on Pb, Cd, and Zn compounds in Cyperus glomeratus and Vicia faba

Indoor pot experiments were performed to investigate the effects of Cyperus glomeratus L. and Vicia faba L. intercropping on the chemical forms of Cd, Pb, and Zn found in the plants and soil. Intercropping reduced the biomass of the shoots and roots, soluble sugar content, and chlorophyll content of C. glomeratus by 54.55%, 41.67%, 36.39%, and 33.33%, respectively, but increased the biomass of V. faba shoots by 11.71%. Intercropping reduced the amount of available Pb, Cd, and Zn in the soil. F_NaCl(NaCl extractable fraction) as the main form of Pb found in the plants. Intercropping increased the F_E-Pb(ethanol-extractable fraction-Pb) contents of C. glomeratus shoots by 23.43% and total Pb contents of C. glomeratus roots by 6.92%~17.80% but reduced the F_E-Pb and F_W-Pb contents of V. faba shoots by 16.00% and 42.60%, respectively, and total Pb contents of V. faba roots by 1.32%~44.76%. F_NaCl and F_HCl(HCl extractable fraction) were the main forms of Cd found in the plants. Intercropping increased the F_R-Cd(residue fraction-Cd) contents of C. glomeratus shoots by 43.45% and the F_HCl-Cd and F_R-Cd contents by 6.26% and 30.01% but reduced the F_HCl-Cd contents of V. faba shoots by 26.37% and total Cd contents in V. faba roots by 6.09%~68.33%. F_HAc(HAc extractable fraction), F_W(water extractable fraction), and F_NaCl were the main forms of Zn found in the plants. Intercropping increased the F_E-Zn contents of C. glomeratus shoots by 12.5% and the total Zn contents of C. glomeratus roots by 5.32%~23.54% but decreased the levels of six Zn forms in V. faba shoots and roots. There was a significant positive correlation between soil available Pb, Cd, and Zn contents and the Pb, Cd, and Zn contents of the shoots and roots of intercropped V. faba. Intercropping reduced the Pb, Cd and Zn contents in the plants of V. faba and was closely related to the decrease in the available Pb, Cd and Zn content in the soil.