Accumulation Of Cd By Six Garden Plants And Their Combinations From Water

With the rapid development of industry,unreasonable use of water resources and the indiscriminate disposition of various types of sewage,the Cd content in the water-body has caused higher and higher,and it has harmed human health through the food chain into animals and humans.Compared with physical and chemical remediation methods,phytoremediation has the advantages of high efficiency,low consumption,beautifying environment,and a wide range of application prospects.In In this study,hydroponic experiments were used to systematically study the absorption and accumulation characteristics of heavy metal Cd by six kinds of native garden plants and their combinations,such as Polygonum chinense,Phalaris arundinacea,Gardenia jasminoides,Triarrhena lutarioriparia,Loropetalum chinense var.rubrum and Euonymus japonicus.And its photosynthetic effect.The potentiality of its remediation in Cd-polluted waters was explored.The main results and findings are as follows:1.Six kinds of garden plants had great differences in Cd enrichment ability.Under the 50?g·L^-1 treatment,the enrichment coefficients of cadmium in the upper parts of P.chinense,G.jasminoides,L.chinense var.rubrum,T.lutarioriparia,and P.arundinacea were all greater than 1,and the transfer coefficients of P.chinense and T.lutarioriparia were greater than 1,and P.chinense and T.lutarioriparia were potential plants for extracting Cd.The enrichment coefficient of the root system of P.arundinacea was up to 3.17 in six kinds of garden plants,and its translocation coefficient was 0.44,which could be used as an alternative plant to remove Cd in water.2.The distribution of Cd in the six garden plant organs was different.The distribution pattern of Cd in the plants of P.chinense and T.lutarioriparia was aboveground>root.The distribution pattern of Cd in the plants of E.japonicus,G.jasminoides,L.chinense var.rubrum,and P.arundinacea was as follows:root>aboveground.3.The combination of plants significantly promoted the enrichment of heavy metal Cd by roots.Among three plant combinations,the highest accumulation rate of cadmium in roots of P.chinense was 1.35mg·kg^-1·d^-1,and the highest accumulation rate of cadmium in roots of T.lutarioriparia was 0.60 mg·kg^-1·d^-1.The highest accumulation rate of cadmium was 1.60 mg·kg^-1·d^-1 in roots of P.arundinacea.However,their transport coefficients were not high,ranging from 0.11 to 0.24,and the combination of P.arundinacea and T.lutarioriparia could be used as a preferred combination of Cd²⁺in fixed cadmium-contaminated water.4.Under the treatment of 5?g·L^-150?g·L^-1 Cd,the chlorophyll content of six plants had no significant effect.Cd promoted the elevation of Pn?net photosynthetic rate?in the four species of garden plants?Pn fluctuations in T.lutarioriparia?,but the sensitive concentrations of various plants were different.The Pn,Gs?stomatal conductance?,Tr?transpiration rate?of the plants such as P.chinense,E.japonicus,G.jasminoides,L.chinense var.rubrum and T.lutarioriparia gradually increased,and Ci?intercellular co₂ concentration?gradually decreased.It showed that the five plants such as P.chinense had strong tolerance to Cd.