Groundnut (Arachis hypogaea L.) )yield has been reported to decrease by  more than 50% with successive croppings.

Filtrates from fresh and decomposed groundnut plant residues were bioassyed for their effects on germination and

radicle elongation of four crop species. Results obtained indicated that the inhibitory substance(s)present in the

residues is soluble in water; heat treatment or prolonged decomposition seemed 10 reduces or possible eliminate the

inhibitory activity of the residues. The production of the inhibitor(s) also seem to follow a cycle and may also be

associated with changes in pH of the residue filtrates.Delaying D planting of the subsequent crop is suggested as a precaution against poor germination and early growth if plant residue Were incorporated or left on Ihe soilsurface after harvest

Razak, Abdul Rahman

Wahab, Zakaria

Universiti Putra Malaysia Institutional Repository

I)ertanika 13(3), 297-~02 (1990)Effect of Groundnut Plant Residues on Germination and RadicleElongation of Four Crop SpeciesIZAKARJA, W. and 'A.R. RAZAKIDejJarlment ofAgronomy and Horticulture2Deprtrlment ofPlant ProledionUniversiti Perlanian Nlalaysia43400 UPM Se,.dallg, Selal/go,. Daml Eltsa'l, Malar,;a.Keywords: groundnut plant residues, phytotoxicity, bioassay.ABSTRAKp,.'lIgeluflrctn JUlsilllacang trwalt (Arachis hypogaea L.) lelalL dilalJO'rkan berkurangan mph'bOI.i 50% dengrl1lpm(lnawrw yang berluntlau. l-lasillumsan 5isa segar dan lerhurai dmilJndajJolwk karallg lanaI! !plah dibio{{sai1l nink kpsa1l1l.)'a ke ataspe'Tambahan dall pemanjangan mdilwlnnpat spesies taJlaman. Kepu l"'sa Jl men 1t1l)1t klUlI1bahan perfil rat da-ripnrla sisa larul di dalam ai,~· Tawalrlll haba alau )angka masa pnlghll mirn1 yang jmnjrwgdapfllmnlgumllgkan atau lIlpnghil.a.l1gkan alrtiviti perpumtall. Pengp[,wmn IJerpnml seolah-olah ada kitm'Il)'adan muughin her/witan den-gan Jlentbahan pH"asit tmnsan sisa. Nl(d(~oalhnll tana lJIan- )'angberilmtll)'a adal~/hdimdaugkrt'1l seoagai lcmglwh unluh mengelok/wn kesan he alas jJerramvahan dan tumbesnmn awnl )ika sisadigaullwn alau ditinp;gallwn di alas permu/wan tanah.ABSTRACTGrount/nllt (Arachis hypogaea L.) )'ieldhas been reported to decreaseb)' more than 50% wilh successive n·Ojl/lings.Filtrates from fresh aud decmnposed gmundnul plant residues were bioassa)'edJar thrirtffects on germination andmdide dongalion ojJOUT crop sperif.s. Results obtained indicated that the inhibilmy suvslana!(s) prpspn! in thpresidups i,i soluble in waler; heal b'lalmenl m"l)rolOllged dewmjJOsition seemed 10 rnhtce or possjb~v flJ:lJlil1a/(~ tlwinhibitory activity of lhe residues. The production of the inhibitor(s) also se(~lIlf'd to Jollow a cyrlfJ and J}1(t')1 also beassocia/txl with dlanges in pH oj the residueJiltmte.s. Delrt)\i1lg planting of Ihe subsequent rrojJ is sUKE{t'stNI as {{.prec.aulion againsl poorgemtillation and early growth ifplant Tesirlues Wf're incorporated or lpft on Ihe soil :i'm/aceafter Itmvesl.INTRODUCTION(;roundllut yield was reponed to decreasemarkedly with successive croppings on the samearea despite the addition of fertilizers (Chan,1968; Cheah, 1987). Yields of the subsequentsecond and third crops were reduced by morethan 50% that of the first crop. In some cases, theyield reduction was attributed to increase indisease or pest damage or depletion of soilnutrients. However, substantial evidence has beenaccumulated to show that phytotoxic substancesare produced in most crops and may beresponsible for the reduced growth and yield(Cochran e( al., 1977; Elliotand Ro)', J982; Garcia,1983; Guenzi & McCalla, 1962; Glienzi elal., 1967;Kimber, 1973; Norstadt & McCalla, 1968;Robinson & Burdick, 1978; Yakle & Cruse, 1983,1984).Residue decomposition, either on the soilsurface or incorporated into the soil, has beenreported to retard growth and development ofsubseqllemcrop (Gucnzi & McCalla 1962; YakJc& Cruse, 1983, 1984). Grollndnllt hulls, forexample, were found to produce substance(.'»)that inhibit germination and shoot growth ofcucumber (Cucu11lissaliva[ .. ) seedlings (Robinsolli'.-\KARL-\. W, .-\..\11) A.R, RAZAK& Burdick, 1978). In addition, increasing thenumber ofyears ofgrounrln lit cropping bet\\'eensuccccding tobacco (Nicotialla fabarum L) cropsresultcd in decreased yield and grade of tobaccoleaves (Elliot and Roy, 1982). These cffecLS maybe due to the release of phytotoxic substances asleachate during rainfall or through micl-obialbreakdown. Howe\,er, as the plant residuesdecompose, the in hihilOry effects of the residuesalso decrease (Guenzi ('/ al., 1967; Kimber, 197~-);Yakle & Cruse, 19S:').Tile objecti\'es of this study were to detenninethc toxicity and thc persistence of groundnutplant residues after periods of decomposition inthe fieldllsinggcrmillation and radicle elongationof [our crop species to bioassay for their effects_MATERIALS AND METHODSPhytoloxirit)' ofPlant ResidueGroundnnt plants (tops only) collected afterhan'est were rinsed wilh distilled water and thendi\'ided into three treatment groups as follows:i) Freshly harvested plan t materials wereblended with distilled water in the ratio I: 15(w/v) and filteredii) Hal'\;ested plant materials were oven-dried atGOGC for 3 days and ground to pass through a0.:' mm sieve before the filtrate was preparediii) Harvested plant materials were allowed todecompose in the field for 14 days, tJ1CnO\'cll-(h-icd and ground as treatment (ii) aboveThe treatments were replicated four timesand the filtrates from each of these treatmentswere bioassayed for phytotoxic activity accordingto procedm'es descrihed by Glienzi e1 al. (1967)using a complctely randomized design.Groulldllut, maize (l..ea ma.ys), mungbean (Vignaradiata) and okra (Hibiscus esculenlus) were lIsed asthe bioassay crop.Ten grams ofthe plantrcsidllewere extractedwilh 130 Illi ofdistilled water by shaking for 2 h atroom telllperature (25-32G C) _After filrering, thefiltrates were tested for phytotoxicity by soakingthe appropriate test seeds in the filtrale for 6 hand (hen incubated between two layers of''''hatman No. 1 filter papers in petri dishes atroom temperature for 72 h. Ten seeds in each offive petri dishes were used to evaluate the activityof each u-eatmelll. Six 1111 of the same filtrate illwhich the seeds had been soaked was added toeach petri dish. As a control, a set ofseec1s ofthetest crop was treated in the same manner butlIsing distilled water instead of the filtrate. Afterthe incubation period, germination pcrcelltageswere scoredand radicle elongation was mea.sured.Persistenrp oj Phytotoxic SubJIa.ucp ill Dp-('o1llposf'dRfSirlUf?Groundllut plants (tops only) collected clirenlyafter harvest were spread evenly on plastic Illeshscreens erected on frames 30 Clll abo\'e t he groundand left to decompose ill the field. The residueswere l-eplicaten thrice and residue toxicil)' \\"CISanalysed at har\'l.'st and after 2, 4,~, 12, 16.20.24and 28 days of decomposition. Samples frollleach trearmellt were oven-dried, ground andtested for phytolOxicity using proceduresdescribed in (I) ahol'e.RESULTS AND DlSCUSSIO rPh)'lotoxirit)' ofPlant ResidueThe phytotoxicity ofgroundnul plant residues tothe germination ann radicle elongatiun of fourcrop species is given in Table I. Filtrates from thevariollS residue treatments, in general, have allinhihitory effect on the germinaliOiI and radicleelongation of the species bioussayed. The degreeofinhibition, howeyer, differswith thepost-han-esttreatments ann the species tes(ed. The filtrates offresh residues have greater inhibitory effect 011lhe germination of maize and okra. Only 16%and 70% of the seeds germinated, respectively.Germination of groundnul and mllllghean.however, was notaJIected. O\"en-<ll}·ingor partiallydecomposing the residues seemed to reduce lheinhibitor, effect. For maize, germinationincreased to 60% and 76% for oven-dried andpartially decomposed residues, respecti\"ely,compared to the fresh residues. Okra, however,were not affected hy the oven-dried or partiallydecomposed residues. Guenzi and McCalla (1962)suggested that the subsr.ances affectinggermination were probably heat sensitive. Inaddition, rnicrobial activity and leaching hyrainfallduring decomposition probably reduccrl thephytotoxicity of the residues.Theeffectofthe filtrate Oil radicle elongationwas more pronounced (Tahle I). Both radiclePERTA~'IKA.VOL. \;\. NO_:t H~lOEFFECT OF GROUNDNUT PLANT RESIDUES ON GERMlNATlON AND RADICLE ELONGAnONTABLE 1InOuence of different residue tre~llmenLSon germination and radicleelongation of four crop species*Residue Gmundm ~aize Mungbean Okratreat·mCIHS Germ. Length Germ. Length Genn. Length Genn. Leng111(%) (em) (%) (em) (%) (em) (%) (ern)Fresh 100 a 3.0 d 16 d 0.7 b 94a 1.9 e 70 b 0.7 e(blended)Fresh 100 a 4.1 e 60e 1.0 b 943 5.1 a 86 ab 1.9 b(oven-dried)Panially 100 a 5.8 a 76 b .?O a 96a 5.1 a 96a 3.1 adecompusc::dCumrol 98 a 4.9 b 92 a :>.3 a 98 a 3.9 b 92 a 2.5 abAllmcan5 in a column not follO\\'cd hy the same letter were signific;ullly different from olleanother <It 5% prohability as determined by Duncan New Multiple Range Test (DNMRT).elongation and morphological appearance o[allthe species were affected. Maize and okra weremore sensitive to the fresh filtrate than groundnutor lTIungbean. The extent of inhihition differedfrom species to species. The order of increasingpercent inhibition of fresh filtrate on radicleelongation of groundnut, mungbean, ok.ra andmaize was 39, 51, 72 and 87, respectively. Thiseffect on growth appeared to be associated withthe browning of the radicle tip in groundnut,maize and okra (Plates, I, 2 and 4). Withmungbean, however, besides apicaldiscolouration, the fresh filtrate stimulatedprofuse lateral rooLS on the hypocotyland delayedemergence of the first pair of leaves (Plale 3).Guenzi et at. (1967) also reported a slightstimulation in growth ofwheat seedlings treatedwith extracts from oat and wheatsrraws. They alsoPlale 1: EJJecl oj residue fillrall' 011 radicle I'lollgntion oJgroundlllll.Pla/f! 2: lif/ec/ oj residuejiltrate 01( radicle elonglilioll of IfIlli7.l'.1)/(,te J: Effect ojrl'.{;l/llP.]illmll! on mdide elongnlioll ofmunf!JPml.obsenred differences in tolerance to phytotoxicsubstances among species. Differences in thetolerance level observed in this study couldpossibly be due to the selective permeability ofthe seed coat to the inhibitorysubstance(s). Otherpossibilities include tolerance of the growingPI::RTANIKA.. VOL. 13. NO.3. 1990 2997AKARJ.A, W. A:\D A.R. RAZAKAlIlllcans in a column nOI followed h)" the same Icllel" weresign ificantJr ~jrfcrent from one allothcr at 5% prohablit)" asrktcrnlilled by D:\ii\'1RT.followed by mungbean and okra; maize showedthe least tolerance based 011 germination scores(Table 3).TAIlL!. 2Influence offiltnncs from diffen.'llt dcc01nposiliOltperiods on germinal ion and radiclee1ong-dtion of the [our crop species,:",.3 de2.8 fl(25g3.5 d~.2 del2.9 cfg:",.5 d4,2 c4.6 b5.2 aLength (cm)9S au92 he87 c94ah91 bt:88 c97 ab92bt:92 bt:100,(lvlean of 4 crops species)Germination (%)o2481216202428ControlDeCOlnposltiollpCI-iods(days)points to the inhibitory substance(s), seed sizeand seed surface area: volume rat.io duringimbibition of the filtrate.Filtrates from the panially decomposedresidues, however, were either stimulatory(gruundnut and l11ungbean) or not significantlydifferent frol11 the control (Table 1). But,brownitlg on the radicle and disl.orted elongationofthe radicle were still presentoll mungbean andokra, respectively (Plalps 3 and 4). SlIbSlance(s)affecting the radicle not only restricted elongationhut were also ph)'toLOxic, as manifested by thebrowning and t\visting of the radicle,Ph,lp 4: ljprf ofrl'sidUl' filtrate on fmlir/p dongaliofl ofokra.All mt:;'IIlt> ill a cohunn nul I()ll(mcd by the sanH" ktter wen'sig-Illficantl}' diffi::rent from one anOther al 5% probahilityas dClennineci by DN\'tRT.TABLE ~Influence of residue filtrates on germinalion andrarlicle elongation of fom- crop speciesThere was an increasing inhibition to radicleelongation from day 0 to day 4 and from day 8 today l6 compared to the control - from 37% to52% and 33% to 44%, respectively (Table 2).After the 16th day, percent inhibition decreasedwith increasing periods of decomposition. InTable I, however, the partially decomposedresidue was not significantly different from thecontrol; this was probably due to the increasedGermination (%) Length (em)(r..'fean of decomposition periods)3.2 b~.4 b4.9 a2.8 c98a8~ c94 b94 bCropsGroundnutMaizeMungbeanOkraPersistence of PhJtotoxir. Substa.nce in DecomposedResidueTable 2 shm\-'s the influence ofthe residue filtratestaken from different decomposition periods onthe germination and radicle elongation of thefour species. Compared to the control, the highestreduction to germination was observed at twodecomposition periods -4 days and 16 days ofdecomposition. According to Kimber (1973),the degree of inhibition varied with the time ofresidue decomposition. In wheat, for example,maximum inhibition was obtained after 2 to fidays of decomposition. Norstadt and McCalla(1968) also observed that the phytotoxic activit)'of wheat residues peaked after 10 to ]3 days and2fi tu 29 days ofdecom positlon. The two periodsobserved in this study were probably the peaks inthe production or release of the inhibitOl1'substance(s) by the groundnut plant residues.There was no correlation between gerrninationand days of decomposition for all the speciestested. In descending order of tolerance,groundnut appeared to be the most tolerantI'ERTA:\:IKA VOL 13. NO.3. 1990EFFECT OF GROUNDNUT PL>\NT RESiDUES ON GERMINATIO. AND RADICLE ELONGATiONGROUNDNUT lAAIZE8 8~E(,) 6 8 Y = 2.29 + O. 071 x~~ r 2 = 0.589 (p = O. 05)0 Y = 2.76 + O. 02715 x • •~ 4 r 2 = 0.393 (p = 0.05, 4.... •0 ••~ • •2 2 •z~0 00 5 10 15 20 25 30 0 5 10 15 20 25 30lAUNGBEAN OKRA8 8~E •(,) 6 • 8 Y = 2.0 + 0.052~ x~ 2 0.729 (p = 0.05)0 r =~ 4 4....•0• • •~ •2 Y = 3.89 + 0.06 x 2 ••§ 2 0.246 (n.s)r =0 00 5 10 15 20 2S 30 0 5 10 15 20 2S 30DAYS OF DECOMPOsmON DAYS OF DECOMPOsmONFig. }: !lIjlUP11(,t' oJ rpsidl;1' dr(olll/)OJirio1/ pnim}s Oil radidp r}o1/gatioll QfJOllr ('lY)p .~/)I'('if'S.microbial breakdown since the residues were incontact with the soil surface. Gl1enzi el aL (1967)and Kimber (1973) also reported that theinhibitory effect of the residues decreased withincreased weathering and that the time taken t.oreduce the inhibitol1' substance(s) to tolerablelevels also differed among plant species. In thisstudy, radicle elongation of okra was inhibitedthe most while mungbean was the most tolerantto the residue filtrates (Table 3). In general,radicle elongation correlated well with days ofdecomposition for all the species tested exceptfor mungbean (Fig. I). The results concur withlhe findings by other researchers that increasingthe periods of decornposition reduced thephytotoxicity of the I"csidues and that speciesdiffered in their susceptibility to the residues.Cyclical and seasonal variation in theproduction ofthe inhibitory substances in residueswcre reported for wheat (Norstadt and McCalla,1968; Coclmm el a{., 1977) and maize (Garcia,1983). The pattern of variation obtained in thisstudy could imply a different rate of residuedecomposition from the different pans of theplalll as suggested by Guenzi el at. (1967). It is alsointeresting to note the decrease in acidity of thefiltrates with increasing days ofdecomposition ofthe residues (Fig. 2). Prolonged decompositionPERTAN'KA VOL. 13. NO. :1, 1990 301ZAI\.A.RIA. \\', :\.\'D :\.it Iv\.7.AJ''00y. 6.143.0.056 x,.2 = 0.865 (p • 0.05)•••Rased on the results of this study, a period of atleast ~O days is suggested before planting the nextcrop as a means 10 reduce or eliminate theinhibi tory effect ifgrolllldnllt plant resid tles wereincorporated into the soil or left on the soilsurface after harvest.REFERENCES".oo+--~--~--_-~__~__o "O~ys of dHOOpoSl tiOI'lFig, 2: In/lur/III' or 1'I',I;d/ll' dp(()/J/!JO.\ilin}l !HTiod, (IJI /)/1 of/iIIltI!t,'i.produced a more alkaline filtrate. It is tooconjectllral to speculate the change in pH withdecomposition time 011 the inhihitory effect ofthe residues. Nevertheless, the results do suggestthat there were more than one substance orgruup of substances involved ill restrictinggermination or radicle elungation, Besides beingheat sensitivc and biodegradable, the substanceorgrollp ofslIbstanceswere acti,'e at different pHranges, Kimber (1973) also noted changes inacidity with differcnt decomposition periods inwheat although there was no olwious correlationbetween toxicity and changes in acidity.CONCLUSIONSGrollndnut plant residues may produce growthinhibitors that reduce germination and radicleelongation ofgroundnuland other crop species.The production ofthe inhibitor(s) seems to followa pattern or cycle. The effect on germination andradicle elongation, however, appears to declineas the number uf days of residue decompositionincreased, The decrease in phytotoxicity mayalsohe associated with the increase in pH of theresidue filtrates. The inhibitor(s) seems to beactive at different pH ranges, besides being heatsensitive and biodegradable. The filtrate fromthe fresh (green) plants was more toxic thanfiltrates from the oven-dried or partiallydecomposed residues. In general, germinationof maize and radicle elongation of okra ,vasinhibited the most by the residue flItrates.GI'otll1dnut and mungbean, however, showedsome degree of tolerance to the inhibitor(s).CfC\:"J, S.K. 1~68. Reccnt Investigations on Short TCrll!CropsorCash CropsatFES. Scnlilllg, III Pmgrl'ssillOil !Jal lll , ed. P.D. Turner. IJ/Or. 21ld iHa!rl)'sirlll OilJ>allll. COil!CHEAll, C.H. 19t{7. Joint UPl\'J-F &: N R('searchProgramlllc on Grollmllllli. UnpuhlislH'd report.COClIR·\N, VI.. , L.F. EU.lOTTand R.I. P·\PE;\lllCK. 1977.The Production ofPhytolOxinsfi·olll Surbee CropResidues. Soil.';ri..)'(w. A/II.). 41: {l()~-)·~)OH.El J .IOT,J. M.and R.c. Roy. I ~)K~. EffcnsofCrop RotationInvolving PC,UlIllS on the Production or Flue-Cured Tobacco in SOlllhenl Ontario. Prot. ..-\.11I('1'".PNmut Nrs. ami !'A. SOt. 14: 117 (Ahstr.)G:\RCIA. A.(;. 1~lH~. Sei.lsOl1;l! Variation ill Allt'lopmhi(EfTect8 of Corn Residucs on Corn and CressSeedlings. Ullpuhlished Ph.D. dissenatioll. IowaStale Univ., Ames. Iowa.GLII'::'\/J, 'V.D. allo T.M. \'lce. \I.L\. I ~)(j~. Inhibition ofGermillatiOll and Seedling Devclop1llellt hr empResidues, .)'oll.\ri. SO(. Alii. !)ror. 26: 4S(i-lSK.Gl;El\I.I, V\T.D., T.l\L MCC\lL\, and F,r\. NORSTAIH.1967, Prescnce and Persistence of PhytotoxicSubstances in \Vhtal. Oil!. Corn, and SorghumResiducs. :\1£1011./_ 59: IG~-)· 16?>.KLvlfWR, R. \V.I .. 197~. PhytolOxicityJi'olll Plallt Rcsi(lilcs.II. The Effect of Time of Rotting of Straw fromSome Grasses and Legumes on Growth of WheatSeedlings. Plant .)'oi/38: :H7-:)lil,NORSTADT, F.Aand T.\'1. McCA1.lA. 19G8. "''licmbiallvInduced PhytO\lIXicity ill Stubble-mulched S(li{,"',·oil,\,'(·i. SO(·. Am, Prot. 32: 241·24:>.RORINSON, E.I .. <11Id D. BlIRDI(KI978.ApparelltGJ'()\\'thInhibitor in Hulls ofPcanliL Croll Sri. 18: 6i'l8~1)8D.\~\Kl.E. G.A and R.!\1. CRLiSF. 198~.). COJ'l1 Plant. ResidueAge and Placement Effens upon Eadv CornGrowth. Cun,].Plrml Sri. 63: 871-877. 'Y.\l\.tJ~, G.A. (\11d R.I\'1. CRLSE. 1984. Elfects ofFrcsh al}(lDecomposing Corn Plant Residue Extracts OilCorn Seedling Development. Soil Sri. Sot. Am. J.48; 114~-1l4li.(!?('I'I'hwl 19 .4./)ljl, 1989jPERTA?\'JKA VOL I:). NO.3, ]990

Effect of Groundnut Plant Residues on Germination and Radicle

Elongation of Four Crop Species

http://psasir.upm.edu.my/2805/1/Effect_of_Groundnut_Plant_Residues_on_Germination_and_Radicle.pdf

Effect of Groundnut Plant Residues on Germination and Radicle Elongation of Four Crop Species

Abstract

Similar works

Full text

Available Versions

Universiti Putra Malaysia Institutional Repository