Responses of Abelmoschus esculentus L. (lady s finger) to elevated levels of Zn and Cd

Transcription

1 Tropil Eology 51(2S): , 2010 ISSN Interntionl Soiety for Tropil Eology Responses of Aelmoshus esulentus L. (ldy s finger) to elevted levels of Zn nd Cd RAJESH K. SHARMA 1 & SHASHI BHUSHAN AGRAWAL 2* 1 G.B.Pnt Institute of Himlyn Environment nd Development, Himhl Unit, Mohl Kullu , Indi 2 Eology Reserh Lortory, Deprtment of Botny, Bnrs Hindu University, Vrnsi , Indi Astrt: The pper dels with the umultion of hevy metls nd responses of ldy s finger (Aelmoshus esulentus L.) plnts grown to elevted levels of zin (Zn) nd dmium (Cd), pplied singly s well s in omintion. Results showed tht Zn + Cd pplition inresed Zn umultion in root, stem nd leves of the plnt, ut Cd umultion deresed. The mgnitude of dverse effets on ll the mesured prmeters ws lower under Zn + Cd tretment s ompred to the sum of responses to individul tretments of Zn nd Cd. Evidently, Zn nd Cd exhiited ntgonisti ehviour when pplied in omintion, resulting into redued umultion of Cd in plnts. Resumen: Este rtíulo trt sore l umulión de metles pesdos y ls respuests ls plnts de dedo de dm (Aelmoshus esulentus L.) que reen en niveles ltos de zin (Zn) y dmio (Cd), plidos por seprdo o en ominión. Los resultdos mostrron que l pliión de Zn + Cd produjo un umento en l onentrión de Zn en l ríz, el tllo y ls hojs de l plnt, pero que l umulión de Cd dereió. L mgnitud de los efetos dversos sore todos los prámetros medidos fue menor en el trtmiento Zn + Cd, en omprión on l sum de ls respuests trtmientos individules de Zn y Cd. Evidentmente, el Zn y el Cd mostrron un omportmiento ntgonist undo fueron plidos en ominión, lo ul resultó en un umulión reduid de Cd en ls plnts. Resumo: Este rtigo ord umulção de metis pesdos e s resposts dos dedos de senhor (Aelmoshus esulentus L.), plnts que resem om elevdos níveis de zino (Zn) e ádmio (Cd), plidos seprdmente em omo em ominção. Os resultdos mostrrm que plição de Zn + Cd umentou umulção de Zn n riz, no trono e ns folhs d plnt, ms que umulção de Cd dereseu. A mgnitude dos efeitos dversos em todos os prâmetros medidos foi menor so trtmento Zn + Cd qundo omprdo om som ds resposts os trtmentos individuis om Zn e Cd. Evidentemente o Zn e o Cd exiirm omportmento ntgonist qundo plido em ominção, resultndo num umulção reduzid de Cd ns plnts. Key words: Antioxidnt, dmium, growth, ldy s finger, metl umultion, photosynthesis, zin. Introdution Hevy metl ontmintion of griulturl soil round hevily industrilized res is one of the growing environmentl onerns throughout the world, prtiulrly in the suurn res of developing ities. Erlier studies hve shown tht pplition of industril effluents, sewge sludge, N * Corresponding Author; e-mil: sgrwl56@gmil.om

2 390 RESPONSES OF ABELMOSCHUS ESCULENTUS TO ZN & CD phosphte fertilizers nd wstewter for irrigtion hs inresed the levels of hevy metls in the griulturl soils nd lso in edile portions of vegetle rops (Shrm et l. 2006, 2007; Singh & Kumr 2006). Soil ontmintion y single hevy metl is not ommon phenomenon, wheres multi-metl ontmintion hs een ommonly reported. Shrm & Agrwl (2006) hve shown tht ddition of Zn inresed Cd uptke in rrot plnts, ut M- Kenn et l. (1993) nd Morghn (1993) showed tht ddition of Zn signifintly redued Cd uptke in lettue (Ltu stiv L. vr. Longifoli v Pris Islnd) nd spinh (Spini olere L. v Vienn). Shute & Mfie (2006) reported tht Zn inresed the umultion of Cd in soyen plnts up to toxi levels. Oliver et l. (1994) lso showed tht Tritium estivum plnts grown in Zn defiient soil, when reeived suffiient levels of Zn, deresed Cd onentrtion in the grins. Similr effet ws lso reported for Cd in mustrd (Brssi june (L.) Czern nd Cosson) plnts grown in Cd ontminted soil supplemented with Zn upto 340 mg kg -1, wheres its higher dose (705 mg kg -1 ) stimulted the umultion of Cd (Podr et l. 2004). No intertion etween these metls hs een found for soyen (Glyine mx vr. Merr.) grown in Cd nd Zn mended soils (White & Chney 1980). Hrt et l. (2002) hve reported tht Cd nd Zn re trnsported y ommon rrier protein of root plsm memrne, whih hs greter ffinity for Cd thn Zn. Therefore, Cd nd Zn experiene ompetitive inhiition during their uptke nd trnsport in soil-plnt system. The empiril dt on the physiologil, iohemil nd growth responses due to hevy metl umultion in ldy s finger re rrely ville for multimetl ontminted soil. Therefore, the present study ws onduted with n im to investigte the umultion of hevy metls nd onsequent responses of ldy s finger (Aelmoshus esulentus L.) plnts grown in soil mended with elevted levels of Cd nd Zn, singly s well s in omintion. The ojetive of the study ws to investigte (i) the umultion of Cd nd Zn in different plnt prts, nd (ii) to ssess the growth, physiologil nd iohemil responses of the test plnt to the umultion of Cd nd Zn. Mterils nd methods Experimentl setup The present study ws rried out in the Botnil grden of the Bnrs Hindu University, Vrnsi, Indi (ltitude 25 18' N, longitude 83 01' E, ltitude m ove men se level) during Jnury to Mrh, Eighty kg of surfe soil (0-15 m) ws olleted from the griulturl field, ir dried nd uniformly mixed with reommended doses of nitrogen (69 kg h -1 ), phosphorus (20 kg h -1 ) nd potssium (78 kg h -1 ) s ure, single super phosphte nd murite of potsh, respetively. The physio-hemil properties of the experimentl soil re given in Tle 1. The soil ws divided into three heps. The first hep ws used s ontrol (20 kg soil) i.e. no Cd or Zn ws dded to the soil. The seond (30 kg soil) nd third (30 kg soil) heps were mixed properly with Cd nd 2 nd 20 mg kg -1 of dry soil, respetively. A totl of ten pots were 2 kg pot -1 for eh group. The remining soils from the seond nd the third heps were mixed properly for Cd + Zn tretment (2 mg kg -1 Cd + 20 mg kg -1 Zn) nd ten pots were filled. Five genetilly uniform seeds (soked in wter for 24 h to identify the helthy seeds) of ldy s finger were hnd sown t 2 m depth in eh pot. To mintin the uniform moisture ontent, known volume of wter ws dded to eh pot. Tle 1. Physio-hemil hrteristis of the soil used during experiment. Prmeters Units Soil type Alluvil ph 7.80 ± 0.01 Eletril ondutivity d Sm ± 0.01 Orgni ron % 0.60 ± 0.02 Totl P % 0.17 ± Totl N % 0.05 ± Aville N kg h ± 5.83 Aville P kg h ± 0.59 Aville K kg h ± 5.78 Totl Cd mg kg ± 0.05 Totl Zn mg kg ± 1.20 Aville Cd mg kg ± Aville Zn mg kg ± Vlues re men of three replites ± 1S.E. Mesurement of physiologil prmeters The physiologil prmeters suh s photosyntheti rte (Pn), trnspirtion rte ( E) nd stomtl ondutne (Gs) were mesured on seond lef from top t mient limti onditions using Portle Photosyntheti System (LI-6200,

3 SHARMA et l. 391 LI-COR, INC, Linoln, NE, USA) t 30 nd 40 dys fter germintion (DAG). During mesurements, photosynthetilly tive rdition (PAR) vried etween µmol m -2 s -1. These mesurements were mde on three plnts from eh tretment. Biohemil nlysis Three plnts were rndomly smpled from eh group of pots for vrious iohemil nlyses (photosyntheti pigments, protein ontent nd ntioxidnt enzyme tivities) t 30 nd 40 DAG. Chlorophylls nd rotenoids were quntified on dry weight sis ording to Mlhln & Zlik (1963) nd Duxury & Yentsh (1956), respetively. Peroxidse (POD), superoxide dismutse (SOD) nd sorte peroxidse (APX) tivities in lef tissues were ssessed using the methodology of Britton & Mehley (1955), Beuhmp & Fridovih (1971) nd Nkno & Asd (1981), respetively. Totl solule protein ontent in lef tissues ws quntified y the method of Lowry et l. (1951) using ovine serum lumin s stndrd. Growth nd iomss mesurements Growth prmeters, suh s numer of leves, lef re nd root nd shoot lengths were mesured t 30 nd 45 DAG. Root nd shoot lengths were dded to otin totl plnt length. Lef re ws mesured using portle Lef Are Meter (Model LI-COR-3000, LI-COR, In., Linoln, NE, USA). For iomss determintion, root nd shoot portions were seprted nd oven dried t 80 0 C to onstnt weight. Dry weight of eh plnt prt ws mesured. Anlysis of Cd nd Zn in plnt nd soil smples For nlysis of Cd nd Zn, ir dried soil nd oven dried plnt prts olleted t 50 DAG were digested ording to the method of Allen et l. (1986). The onentrtions of Cd nd Zn in the filtrte were determined y using Atomi Asorption Spetrophotometer (Model 2380, Perkin - Elmer, INC., Norwlk, CT, USA). Preision nd ury of nlyses were ensured through replite nlyses of smples ginst Stndrd Referene Mteril (SRM-1570) of Ntionl Institute of Stndrd nd Tehnology for ll the hevy metls. Sttistil nlysis The sttistil signifine of differenes etween tretment mens ws determined y using Dunn s multiple rnge test (P<0.05). ANOVA ws used to see the effets of vriles suh s tretment, ge nd their intertion on the mesured prmeters. All the sttistil nlysis ws performed with the help of SPSS softwre version 12. Results Cd nd Zn umultion Signifint differenes in Cd nd Zn umultion in root, stem nd lef were found due to Zn nd Cd tretments, singly nd in omintion s ompred to the ontrol (Fig. 1A & 1B). Zn u- Zn (mg kg -1 dry weight) Cd (mg kg -1 dry weight) (A) (B) Root Stem Lef Root Stem Lef Control Zn Cd Cd+Zn Fig. 1. Zn (A) nd Cd (B) umultion in root, stem nd lef of ldy s finger (A. esulentus L.) plnts grown in soil treted with Cd nd Zn t 50 DAG. Brs (men of three replites ± 1S.E.) followed y similr letters re not signifintly different t P 0.05 (Dunn s multiple rnge test).

4 392 RESPONSES OF ABELMOSCHUS ESCULENTUS TO ZN & CD Tle 2. Age wise effets of Cd nd Zn, individully nd in omintion on photosyntheti pigments nd seleted physiologil prmeters of ldy s finger (A. esulentus L.) plnts. Age/ Prmeter Control Zn Cd Zn + Cd Age (A) 30 DAG Totl Chlorophyll 1.14 ± ± ± ± 0.02 (mg g -1 DW) Crotenoids (mg g -1 DW) 0.42 ± ± ± ± 0.01 d Photosynthesis [μmol (CO2) m -2 s -1 ] 7.28 ± ± ± ± 0.10 d Trnspirtion [Mol (H2O) m -2 s -1 ] Stomtl ondutne (m s -1 ) 7.18 ± ± ± ± 0.01 d 1.08 ± ± ± ± 0.02 ANOVA test (T) 40 DAG Totl Chlorophyll (mg g -1 DW) 1.92 ± ± ± ± 0.04 *** *** ** Crotenoids (mg g -1 DW) 0.63 ± ± ± ± 0.01 *** *** ** Photosynthesis [μmol (CO2) m -2 s -1 ] 5.43 ± ± ± ± 0.04 d *** *** *** Trnspirtion [Mol (H2O) m -2 s -1 ] Stomtl ondutne (m s -1 ) 6.36 ± ± ± ± 0.05 *** *** * 0.62 ± ± ± ± 0.02 *** *** *** Vlues (men of three replites ± 1S.E.) in eh row followed y different letters re signifintly different t P 0.05 (Dunn s multiple rnge test). Levels of signifine: *** = p 0.001, ** = p 0.01, * = p multion in ll plnt prts inresed fter Zn + Cd pplition s ompred to individul Zn tretment, wheres Cd umultion deresed under Zn + Cd pplition ompred to Cd tretment. The mximum umultion of oth Cd nd Zn ws reorded in root, followed y stem nd then leves of the test plnt. Physiologil nd iohemil prmeters The responses of plnts under single nd omined tretments of Zn nd Cd with respet to physiologil (photosyntheti rte: Pn, trnspirtion rte: E, stomtl ondutne: Gs) nd iohemil (totl hlorophyll: T, rotenoids: Cr, protein ontent: P, superoxide dismutse: SOD, peroxidse: POD nd sorte peroxidse: APX) prmeters re presented in Tles 2 & 3, respetively. Photosyntheti rte delined signifintly over ontrol due to pplition of Cd nd Zn, singly nd in omintion t oth the ges of oservtions (Tle 2). The omined effets of Cd nd Zn on A T physiologil prmeters were higher s ompred to individul tretments of Zn nd Cd. Totl hlorophyll nd rotenoid ontents were lower in plnts treted with Zn nd Cd singly nd in omintion s ompred to ontrol, the redutions eing higher t Zn + Cd tretment (Tle 2). Pn, E nd Gs delined y 46, 49 nd 48 %, respetively under Zn + Cd tretment s ompred to ontrol plnts t 30 DAG. One wy ANOVA showed signifint effets of ge, tretment nd their intertion on photosyntheti pigments, trnspirtion nd stomtl ondutne (Tle 2). As ompred to ontrol plnts, higher tivities were oserved for SOD, POD nd APX in plnts treted with Zn nd Cd (Tle 3). Comined tretment of Zn + Cd, however, led to higher inrements in SOD, POD nd APX tivities in lef tissues y 132, 92 nd 84 % s ompred to Zn pplied singly nd 26, 90 nd 46 % s ompred to Cd pplied singly, respetively t 30 DAG (Tle 3). As ompred to ontrol, protein ontent delined y 31, 35 nd 47 % under Zn, Cd, nd Zn + Cd

5 SHARMA et l. 393 Tle 3. Age wise effets of Cd nd Zn, individully nd in omintion on protein ontent nd ntioxidtive enzyme tivities in folige of ldy s finger (A. esulentus L.) plnts. Age/ Prmeter Control Zn Cd Zn + Cd Age (A) ANOVA test (T) 30 DAG Protein (mg g -1 DW) 7.07 ± ± ± ± 0.51 d Superoxide dismutse 2.60 ± 0.12 d 4.70 ± ± ± 0.17 (unit g -1 FW) Peroxidse ± ± ± ± 0.81 (µm pur. min -1 g -1 FW) Asorte peroxidse ± 0.41 d ± ± ± 0.62 (nm min -1 g -1 FW) 40 DAG Protein (mg g -1 DW) ± ± ± ± 0.11 *** *** *** Superoxide dismutse (unit g -1 FW) 8.70 ± 0.17 d ± ± ± 0.29 *** *** *** Peroxidse (µm pur. min -1 g -1 FW) ± 0.58 d ± ± ± 0.81 *** *** *** Asorte peroxidse (nm min -1 g -1 FW) ± 0.82 d ± ± ± 1.08 *** *** *** Vlues (men of three replites ± 1S.E.) in eh row followed y different letters re signifintly different t P 0.05 (Dunn s multiple rnge test). Level of signifine: *** = p Tle 4. Age wise effets of Cd nd Zn, individully nd in omintion on growth hrteristis of ldy s finger (A. esulentus L.) plnts. ANOVA test Age/ Prmeter Control Zn Cd Zn + Cd Age A T (A) (T) 30 DAG Numer of leves (plnt -1 ) 3.60 ± ± ± ± 0.01 Lef re (m 2 plnt -1 ) ± ± ± ± 6.12 d Root length 5.80 ± ± ± ± 0.12 (m plnt -1 ) Shoot length ± ± ± ± 0.29 (m plnt -1 ) Totl plnt length ± ± ± ± 0.41 (m plnt -1 ) 45 DAG Numer of leves (plnt -1 ) 3.80 ± ± ± ± 0.01 * *** NS Lef re (m 2 plnt -1 ) ± ± ± ± 6.16 d *** *** *** Root length 8.80 ± ± ± ± 0.20 *** *** ** (m plnt -1 ) Shoot length ± ± ± ± 0.04 *** *** ** (m plnt -1 ) Totl plnt length (m plnt -1 ) ± ± ± ± 0.24 d *** *** * Vlues (men of three replites ± 1S.E.) in eh row followed y different letters re signifintly different t P 0.05 (Dunn s multiple rnge test). Levels of signifine: *** = p 0.001, ** = p 0.01, * = p 0.05, NS = Not Signifint. A T

6 394 RESPONSES OF ABELMOSCHUS ESCULENTUS TO ZN & CD Tle 5. Age wise effets of Cd nd Zn, individully nd in omintion on iomss umultion in ldy s finger (A. esulentus L.) plnts. Age/ Prmeter Control Zn Cd Zn + Cd Age (A) 30 DAG ANOVA test (T) Root (g plnt -1 ) 0.15 ± ± ± ± Shoot (g plnt -1 ) 0.46 ± ± ± ± 0.01 Totl (g plnt -1 ) 0.61 ± ± ± ± DAG Root (g plnt -1 ) 0.20 ± ± ± ± 0.01 d *** *** * Shoot (g plnt -1 ) 0.64 ± ± ± ± 0.06 *** *** NS Totl (g plnt -1 ) 0.84 ± ± ± ± 0.01 d *** *** *** Vlues (men of three replites ± 1S.E.) in eh row followed y different letters re signifintly different t P 0.05 (Dunn s multiple rnge test. Levels of signifine: ***= p 0.001, ** = p 0.01, * = p 0.05, NS = Not Signifint. A T tretments, respetively (Tle 3). One wy ANOVA showed tht ge, tretment nd ge tretment hd signifint effets on ll the iohemil prmeters (Tle 3). Plnt growth nd iomss Signifint differenes in numer of leves nd plnt height were found etween metl treted nd ontrol plnts (Tle 4). Metl pplition in omintion hd less negtive effets on growth prmeters s ompred to the sum of individul tretments. As ompred to ontrol, numer of leves nd totl height of plnts deresed y 8 nd 21 %, respetively under Zn + Cd tretment t 30 DAG. Signifint effets of ge, tretment nd their intertion were reorded for ll the growth prmeters exept for numer of leves (Tle 4). The root, shoot nd totl iomss of the plnts were lso ffeted signifintly due to ge, tretment nd their intertion (Tle 5). Cd tretment used more redution in iomss ompred to Zn, while omined tretment of oth the metls exhiited lower redution in iomss s ompred to the sum of their individul tretment (Tle 5). Disussion In the present study, no symptoms of visile injury on ove ground prts of test plnt were reorded. The onentrtions of oth Cd nd Zn inresed in ll the plnt prts s ompred to ontrol when treted singly or in omintion. Under omined pplition, onentrtion of Zn inresed wheres tht of Cd deresed in ll the plnt prts. These results re onsistent with the erlier oservtion of Shute & Mfie (2006). Zn pplitions retrded root nd shoot elongtions in Vign rdit (green grm) (Veer & Lt 1989), Phseolus vulgris (Choui et l. 1997), Vign rdit nd Sorghum iolor (Blshouri 1995), nd Bop monnier (Ali et l. 1999). Exposure of plnts to exessive mounts of hevy metls in soil my indue mny ltertions in plnts, suh s redution of growth, espeilly root growth (Weigel & Jger 1980) nd disturne in minerl nutrition nd rohydrte metolism (Moy et l. 1993), whih my strongly redue the plnt iomss. Inhiition in growth under metl toxiity leds to redution in iomss prodution (Blshouri 1995; Quriti et l. 1997). The results of the present study suggest tht the mgnitude of iomss redution depends upon the onentrtions of hevy metls umulted in the tissues. The redution in iomss my e onsequene of redution in hlorophyll iosynthesis nd photosynthesis s oserved in the present study. The derese in Pn my e sried to inhiition of vrious retion steps in the Clvin yle, Hill retion nd CO2 fixtion (Prsd & Strzlk 1999). Zn umultion in leves ws found to inhiit the eletron trnsport y ting t the oxidizing site of PSII (Vn Asshe & Clijsters 1986). Bker et l. (1982) proposed site for Zn tion etween PSII nd PSI in the eletron trnsport hin. Ruiso tivity ws lso found to derese under Zn tretment (Vn Asshe et l. 1980). Redutions in stomtl ondutne were oserved under Cd nd Zn tretments during the

7 SHARMA et l. 395 present study. Vn Asshe et l. (1979, 1980) showed redution in stomtl ondutne nd retrded tivities of hloroplsti nd peroxisoml enzymes t supr optiml onentrtion of Zn ompred to plnts reeiving optiml Zn onentrtion. Higher mgnitude of redutions in mesured prmeters under omined tretments of Cd nd Zn ould e onsequene of their intertive interferene with essentil metoli tivities (Ali et l. 1995; Vn Asshe & Clijsters 1990). Signifintly lower folir protein ontent ws reorded in plnts treted with Zn nd Cd, singly nd in omintion. Redutions in protein ontent under hevy metl stress hve een reported (Bhtthry & Choudhuri 1994). Hevy metls re known to produe free rdils, whih indue senesene through enhning tolism of some metolites, suh s hlorophyll, proteins nd RNA (Khudsr et l. 2004). In response to higher prodution of ROS under Cd nd Zn stress, ntioxidtive enzyme tivities suh s SOD, POD nd APX enhned to ountert ginst oxidtive dmge in metl stressed plnts. Cd nd Zn hve een shown to stimulte the tivity of severl ntioxidtive enzymes in different plnts (Hsn et l. 2009; Khudsr et l. 2004). Conlusions Cd umultion in root, stem nd leves deresed when Zn ws pplied in omintion with Cd, though it inresed the umultion of Zn. The ioumultion of oth Zn nd Cd dversely ffeted the growth, iohemil nd physiologil hrteristis tht resulted in redued iomss prodution of ldy s finger. The omined tretment, however, hd lower mgnitude of negtive effets s ompred to the sum of individul effets. Thus, it n e suggested tht Cd umultion in plnts ommonly grown in Cd ontminted soil n e prevented through pplition of Zn fertilizers, ut the dose of Zn pplition needs to e stndrdized t different onentrtions of Cd. Aknowledgments Authors knowledge grtefully to the Inhrge of the Botnil Grden nd Hed, Deprtment of Botny, Bnrs Hindu University, for providing neessry lortory filities during the experiment. Referenes Ali, G., P.S. Srivstv & M. Iql Morphogeni nd iohemil responses of Bop monnier ultures to zin toxiity. Plnt Siene 139: 1-7. Ali, K.V., K.V.S.K. Prsd & P. Prdh Srdhi Effet of zin on free rdils nd proline in Brssi june nd Cjnus jn. Phytohemistry 39: Allen, S.E., H.M. Grimshw & A.P. Rowlnd Chemil nlysis. pp In: P.D. Moore & S.B. Chpmn (eds.) Methods in Plnt Eology. Blkwell Sientifi Pulition, Oxford, London. Bker, N.R., P. Fernyhough & I.T. Meek Light dependent inhiition of photosyntheti eletron trnsport y Zn. Physiologi Plntrum 56: Blshouri, P Effet of Zn on germintion, growth nd pigment ontent nd phytomss of Vign rdit nd Sorghum iolor. Journl of Eoiology 7: Beuhmp, C. & I. Fridovih Superoxide dismutse: improved ssys nd n ssy pplile to rylmide gels. Anlytil Biohemistry 44: Bhtthry, M. & M.A. Choudhuri Effet of P nd Cd on the iohemil hnges in the leves of terrestril (Vign) nd quti (Hydrill) plnt under solution ulture. Indin Journl of Plnt Physiology 37: Britton, C. & A.C. Mehley Assy of tlse nd peroxides. In: S.P. Colowik & N.O. Kpln (eds.) Methods in Enzymology. Vol. II. Ademi Press In., New York. Choui, A., S. Mzhoudi, M.H. Ghorl & E. Ferjni Cdmium nd Zn indution of lipid peroxidtion nd effet on ntioxidnt enzymes tivities in ush en (Phseolus vulgris L.). Plnt Siene 127: Duxury, A.C. & C.S. Yentsh Plnkton pigment monogrphs. Journl of Mrine Reserh 15: Hrt, J.J., R.M. Welh, W.A. Norvell & L.V. Kohin Trnsport intertions etween Cd nd Zn in roots of red nd durum whet seedlings. Physiologi Plntrum 116: Hsn, A.H., B.A. Friduddin, B. Ali, S. Hyt & A. Ahmd Cdmium: Toxiity nd tolerne in plnts. Journl of Environmentl Biology 30: Khudsr, T., M. Iql & R.K. Sirm Zinindued hnges in morpho-physiologil nd iohemil prmeters in Artemisi nnu. Biologi Plntrum 48: Lowry, O.H., F. Rosenrough & R.J. Rndll Protein mesurement with folin phenol regent. Journl of Biologil Chemistry 193:

8 396 RESPONSES OF ABELMOSCHUS ESCULENTUS TO ZN & CD Mlhln, S. & S. Zlik Plstid struture, hlorophyll onentrtion nd free mino id omposition of hlorophyll mutnt on Brley. Cndin Journl of Botny 41: MKenn, I.M., R.L. Chney & F.M. Willims Effets of Cd nd Zn intertions on the umultion nd tissue distriution of Zn nd Cd in lettue nd spinh. Environmentl Pollution 79: Morghn, J.T Aumultion of Cd nd seleted elements in flx seed grown on lreous soil. Plnt nd Soil 96: Moy, J.L., R. Ros & I. Pizo Influene of Cd nd nikel on growth, net photosynthesis nd rohydrte distriution in rie plnts. Photosynthesis Reserh 36: Nkno, Y. & K. Asd Hydrogen peroxide is svenged y sorte-speifi peroxidse in spinh hloroplst. Plnt Cell Physiology 22: Oliver, D. P., R. Hnnm, K. G. Tiller, N. S. Wilhelm, R. H. Merry & G. D. Cozens The effet of Zn fertiliztion on Cd onentrtion in whet grin. Journl of Environmentl Qulity 23: Podr, D., M.H. Rmsey & M.J. Huthings Effet of dmium, zin nd sustrte heterogeneity on yield, shoot metl onentrtion nd metl uptke y Brssi june: implitions for humn helth risk ssessment nd phytoremedition. New Phytologist 163: Prsd, M.N.V. & K. Strzlk Impt of hevy metls on photosynthesis. pp In: M.N.V. Prsd & J. Hgemeyer (eds.) Hevy Metl Stress in Plnts. Springer, Berlin. Quriti, O., H. Goui & M.H. Ghorl Responses of en nd tomto plnts to dmium: growth, minerl nutrition nd nitrte redution. Plnt Physiology nd Biohemistry 35: Shrm, R.K. & M. Agrwl Single nd omined effets of dium nd zin on rrots: uptke nd ioumultion. Journl of Plnt Nutrition 29: Shrm, R. K., M. Agrwl & F. M. Mrshll Hevy metls ontmintion in vegetles grown in wstewter irrigted res of Vrnsi, Indi. Bulletin of Environmentl Contmintion nd Toxiology 77: Shrm, R.K., M. Agrwl & F.M. Mrshll Hevy metls ontmintion of soil nd vegetles in suurn res of Vrnsi, Indi. Eotoxiology nd Environmentl Sfety 66: Shute, T. & S.M. Mfie Cdmium nd zin umultion in soyen: thret to food sfety? Siene of the Totl Environment 371: Singh, S. & M. Kumr Hevy metl lod of soil, wter nd vegetles in peri-urn Delhi. Environmentl Monitoring nd Assessment 120: Vn Asshe, F. & H. Clijsters Inhiition of photosynthesis in Phseolus vulgris y tretment with toxi onentrtion of zin, effet on riulose-1, 5- is phosphte roxylse oxygense. Journl of Plnt Physiology 125: Vn Asshe, F. & H. Clijsters Effets of metls on enzyme tivity in plnts. Plnt Cell Environment 13: Vn Asshe, F., H. Clijsters & R. Mrelle Photosynthesis in Phseolus vulgris L. s influened y supr-optiml zin nutrition. pp In: R. Mrelle, H. Clijsters & M. Vn Pouke (eds.) Photosynthesis nd Plnt Development. Dr. W. Junk, The Hgue. Vn Asshe, F., R. Ceulemns & H. Clijsters Zn medited effets on lef CO2 diffusion ondutnes nd net photosynthesis in Phseolus vulgris L.. Photosynthesis Reserh 1: Veer, B. & K. Lt Response of green grm to Zn tretment. At Botni Indi 17: Weigel, H.J. & H.J. Jger Suellulr distriution nd hemil forms of dmium in en plnts. Plnt Physiology 65: White, M.C. & R.L. Chney Zn, Cd nd Mn uptke y soyen from two Zn- nd Cd-mended ostl plin soils. Soil Siene Soiety of Ameri Journl 44: