Effects of Hyperaccumulators on Cadmium Migration in Tea Plant and Rhizosphere Soil
In order to explore the enrichment characteristics of heavy metal cadmium(Cd)in intercropping between tea trees and ul-tra-rich plants under the same ecological position and the influence of root interaction on tea tree'growth and Cd competition ab-sorption,artificial simulation of Cd-polluted tea garden enviriment was adopted,and two kinds of tea trees(Longjing 43 and Tie-guanyin)were selected for intecropping with four kinds of hyperaccumulator plants[Solanum nigrum L.,Bidens pilosa L.,Erigeron canadensis L.,and Erigeron annuus(L.)Pers.]respectively.The results show that:(1)Compared with single cropping,there were sig-nificant differences in chlorophyll a and b contents in leaves of Longjing 43 tea tree and Tieguanyin tea tree under different inter-cropping modes.Among them,the intercropping effect of Erigeron canadensis L.was the best,and the content of chlorophyll a and b in Longjing 43 tea tree increased by 66.7%and 42.1%respectively after intercropping with Erigeron canadensis L.,while the con-tent of chlorophyll a and b in Tieguanyin tea trees increased by 66.2%and 40.2%,respectively.(2)The Cd content in leaves of Longjing 43 tea tree and Tieguanyin tea tree interplanted with four hyperenriched plants was significantly decreased compared with that of single cropping,and the decrease order from high to low was Bidens pilosa(L.)Pers.Erigeron annuus(L.)Pers.Conyza ca-nadensis L.and Solanum nigrum L.Among them,after intercropping with Bidens Pilosa L.and Erigeron annuus(L.),the Cd con-tent in the leaves decreased by more than 70%.The Cd content of Longjing 43 tea tree and Tieguanyin tea tree was significantly different from that of 4 hyperenriched plants,and the Cd content of Longjing 43 tea tree and Tieguanyin tea tree was reduced by more than 60%after interplanting with Bidens pilosa L.(3)There were significant differences in the aboveground accumulation coef-ficients of the four hyperaccumulators when intercropped with 2 tea trees,but no significant differences in the root accumulation co-efficients when intercropped with Longjing 43 tea tree.However,there were significant differences in the root accumulation coeffi-cients when intercropped with Tieguanyin tea trees.There were no significant differences in the translocation coefficients among the four hyperaccumulators.(4)Compared with the single cropping of Longjing 43 and Tieguanyin tea trees,the proportion of Cd extract-ed from weak acid in rhizosphere soil of 4 intercropping plants increased,and the proportion of Cd oxidized was decreased.Both in-tercropping modes significantly reduced Cd migration and availability in rhizosphere soil.The results showed that Bidens pilosa L.interplanting with two kinds of tea trees can better promote the growth of tea trees,reduce the cadmium content in the leaves and roots of tea trees,and the enrichment coefficient was higher than that of Erigeron annuus(L.)Pers.,Erigeron canadensist L.and So-lanum nigrum L.Therefore,Bidens pilosa L.can be used as one of the soil remediation plants for Cd pollution in tea gardens.
NETL
NSTL
万方数据
