重金属超富集植物及植物修复技术研究进展

第21卷第7期2001年7月生 态 学 报A CTA ECOLO G I CA S I N I CA V o l .21,N o.7Ju l .,2001重金属超富集植物及植物修复技术研究进展韦朝阳,陈同斌(中国科学院地理科学与资源研究所农业生态与环境技术试验站,北京　100101)基金项目:国家自然科学基金(49941003,40071075)和中国科学院知识创新工程重点方向资助项目(KZCX 22401)收稿日期:2000206229;修订日期:2000212214作者简介:韦朝阳(1965～),男,安徽铜陵人,副研究员。

主要从事污染土壤的植物修复与矿区生态环境整治研究工作。

①来源于美国环保局网站的资料摘要:植物修复技术(Phyto rem ediati on )是近年来发展起来的一种主要用于清除土壤重金属污染的绿色生态技术。

重金属超富集植物(hyperaccum ulato r )及植物修复技术是当前学术界研究的热点领域,目前虽已有Cd 、Co 、C r 、Cu 、M n 、N i 、Pb 、Zn 等超富集植物发现的报道,但尚无一例报道来自于中国。

中国具有广袤的国土面积、丰富的植物类型和多种(处)古老的矿山开采与冶炼场所,在中国开展超富集植物的寻找、研究与开发工作,将会有重要突破,并具有重要的理论与实践意义。

本文拟就国内外在这一领域的研究进展作一简要综述。

关键词:超富集植物;植物修复技术;重金属污染土壤Hyperaccu m ula tors and phytorem ed i a tion of heavy m eta l con tam i -na ted so il :a rev iew of stud ies i n Ch i na and abroadW E I Chao 2Yang ,CH EN Tong 2B in (Institu te ofGeog rap h ical S ciences and N atu ral R esou rces R esearch ,Ch i 2nese A cad e my of S ciences ,B eij ing 100101,Ch ina )Abstract :It has been esti m ated that mo re than 20m illi on hectares of farm land have been con tam inated in Ch ina ,accoun ting fo r 20%of the to tal in the coun try .Fu rthermo re ,a reducti on of mo re than 10m illi on ton s of food supp lies resu lts from th is so il con tam inati on .T echn iques cu rren tly emp loyed con tro l so il con 2tam inati on include cover w ith i m p ro ted so il ,app licati on of li m e and chem ical w ash ing .How ever ,mo st of these are expen sive ,labou r 2in ten sive and can resu lt in fu rther con tam inati on p rob lem s o r leach ing depo si 2ti on of nu trien t elem en ts du ring in situ treatm en t .Phyto rem ediati on ,a techn ique u sing p lan ts to remove con tam inati on from so il and w ater ,has becom e a top ical research field in the last decade as it is safe and po 2ten tially cheap compared to traditi onal rem ediati on techn iques.Based on info rm ati on from the Phyto rem e 2diati on B itili ography p roduced by the U S 2EPA ,in 1977there w ere on ly 7repo rts pub lished relating to phy 2to rem ediati on ,w hereas in 1997,the to tal literatu re of phyto rem ediati on increased to 214.In 1583,A .Cesalp ino ,an Italian bo tan ist discovered an unu sual p lan t w h ich grew on so ils over ‘b lack stone ’(u ltram afic rock s ).T h is w as p robab ly the first ever repo rt of a m etal hyperaccum u lato r p lan t .It w as later nam ed as A ly ssum bertolon ii in 1814by D esvaux and the n ickel con ten t of its leaves w as repo rted as 7900Λg g in 1848by C .M inguzzi and O .V ergnano .Si m ilar p lan ts ,designated ‘indicato r p lan ts ’,such as E lsholtz ia ha icho w ensis Sun ,a copper accum u lato r ,w ere discovered early in Ch ina and emp loyed in p ro specting fo r copper m ineralizati on .R .R .B rook s ,a geochem ist from N ew Zealand first nam ed these spe 2cial accum u lato r p lan ts ‘hyperaccum u lato rs ’in 1977,and in 1982R .Chaney from the U SA first suggestedthe concep t of phyto rem ediaton u sing these hyperaccum u lato rs.A hyperaccum u lato r has been defined by Baker and B rook s (1989)as a p lan t that can accum u late cadm ium >100Λg g ,cobalt ,copper ,n ickel ,lead >1000Λg g ,m anganese and zinc >10000Λg g in their shoo t dry m atter .Fu rthermo re ,an operati onal defin i 2ti on w as p ropo sed by Baker (1981)that in accum u lato r p lan ts the m etal con ten ts in shoo ts are invariab ly greater than that in rooo ts ,show ing a special ab ility of the p lan ts to ab so rb and tran spo rt m etals and sto rethem in their above 2ground parts.To date ,mo re than 400species of m etal hyperaccum u lato r p lan ts have been repo rted in the literatu re .Among them ,315are n ickel hyperaccum u lato rs ,24are copper hyperaccu 2m u lato rs bu t the num bers of o ther m etal hyperaccum u lato rs fo r o ther m etals are low and they are restrict 2ed in their distribu ti on in som e specific localities in the w o rld .T he hyperaccum u lato rs are mo stly discovered in the heavy m etal con tam inated area such as m in ingand s m eliting localities.T he au tho r of th is paper suggests that there m ay ex it som e “po ten tial hyperaccu 2m u lato rs ”on the earth .M o re atten ti on shou ld be paid to som e p lan ts that grow ing in som e relatively “low ”heavy m etal con ten t areas .T he p lan ts m ay no t have very h igh to lerance bu t m ay have som e ex ten t degree of accum u lati on ,by cu ltu ring the p lan ts and adding som e k inds of reagen ts in their grow ing m edia ,they m ay reveal character of hyperaccum u lati on .A system atic su rvey of p lan t and so il chem istry in the copper m in ing areas along the low er 2m iddle reaches of Yangtze R iver has revealed a few copper accum u lato rs such as E lsholtz ia ha icho w ensis Sun ,Co m 2m elina co mm un is L .and R um ex acetosa L .;the m ax i m um leaf copper con ten ts are 600,160and 100Λg g (dry m atter basis )respectively ,fo r copper con ten ts in the so il around their roo ts ranging from 5000to 20000Λg g .W e in itiated p i oneering research on hyperaccum u lato rs and phyto rem ediati on in Ch ina early in 1998.Several su rveys w ere conducted in sou th Ch ina ,and th rough system atic field investigati on and glasshou se studies ,w e have now iden tified a hyperaccum u lato r of arsen ic 2P teris v itta ta L .(Ch inese b rake fern ).T h is is the first hyperaccum u lato r discovered in Ch ina .U n like o ther repo rted hyperaccum u lato rs ,th is p lan t can reach 2m in heigh t ,w ith a fresh shoo t b i om ass of up to 36t km 2.T he arsen ic con ten t in shoo ts can be as h igh as 5000Λg g (dry m atter ),and the rati o of arsen ic in leaves ,leafstalk and roo ts is 5:2:1,w h ich reveals a un ique arsen ic accum u lati on capacity .T he m echan is m s of m etal hyperaccum u lati on have no t been fu ll elucidated ,although m any studies have been conducted ,especially on the m echan is m s of hyperaccum u lati on of zinc and cadm ium by the cru 2cifer ,T h lasp i caeru lescens .Early repo rts suggested that som e low mo lecu lar w eigh t o rgan ic acids p lay ani m po rtan t ro le in to lerance and accum u lati on of heavy m etals in p lan ts.How ever ,som e recen t studies have no t found any clear relati on sh i p betw een them .W hat can be concluded now is that to lerance and accum u la 2ti on m ay be independen t characters ;to lerance leads to compartm en tati on of m etals in p lan t cells w hereas accum u lati on relates to a h igh ly efficien t up take and tran spo rt system .It is i m po rtan t to clarify the pattern s of to lerance and accum u lati on in differen t hyperaccum u lato rs fo r differen t m etals under differen t environm en tal conditi on s ,in o rder to m ake phyto rem ediati on p ractical and co st 2effective in field .N u triti on and po t trials have been ci onducted ,and the resu lts show that hyperaccu 2m u lato rs such as T h lasp i caeru lescens can to lerate abno rm ally h igh zinc and cadm inum levels ,and accum u 2late h igh con ten ts of m etals in their shoo ts in very sho rt ti m e peri ods ,even from very low er background m etal concen trati on s in their grow th m edia .T he hyperaccum u lato r p lan ts them selves are the m aj o r facto r that determ ines the capacity of hyperaccum u lati on .How erver ,resu lts also show that several ex ternal fac 2to rs ,such as pH ,nu triti onal statu s and m etal speciati on ,m ay greatly influence the pattern s of m etal accu 2m u lati on ,w h ich h igh ligh ts their i m po rtance in phyto rem ediati on app licati on s.F ield trials of phyto rem e 2diati on u sing hyperaccum u lato rs have also been perfo rm ed and shed ligh t on the w ider app licati on and com 2m ercializati on of th is techn ique in the fu tu re .A rsen ic is very tox ic bu t an analog of pho spho ru s ,it m ay dis 2tu rb the m etabo lis m of p lan ts and cau se clo su re of pho sphate up take channels.T he arsen ic hyperaccum u 2,,,79117期韦朝阳等:重金属超富集植物及植物修复技术研究进展　8911　生　态　学　报21卷elucidated.M o re research and developm en t w o rk w ith th is p lan t shou ld therefo re be conducted in o rder to p roduce cheap and effective techn iques fo r rem ediati on of arsen ic con tam inated so ils.Key words:hyperaccum u lato rs;phyto rem ediati on;heavy m etal con tam inated so il文章编号:100020933(2001)0721196208　中图分类号:Q948　文献标识码:A 据估测,目前中国受污染的耕地面积近2000万hm2,约占耕地总面积的1 5[1],其中工业“三废”污染1000万hm2[2],农田污灌面积已达130多万hm2[3]。