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SUSTAINAULE AGRICULTURE FOR FOOn. ENERGY A DI DUSTRYpp4SR-460 199H james &: jarnes (Science Publishers) Ltd

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Microorgarns s m the rhizosphere O

useful tropical plantstWOLFGANG TH. KRUSE1

., PETRA MARSCHNER1, FALKO FELDMANN1,

REINHARD LIEBEREI1 ANO LUADIR GASPAROTTO"

'Institut fiir Angewandte Botanik , Universitat Harnburg,Marseillerstr. 7, 20355 Harnburg, Germany

:Tel: +49 4() 4123-2333 Email: \\.kruse@rrz-cip-l.rrz.uni-hamburg.de'Centro de Pesquisa Agroflorestal da Amazônia Ocidental.EM13RAPA-CJ>AA. Rodovia AM ()10 Km 24. Cx.J>. 319,

C,9011-970 Manaus-AM. Braz il

.4 bstract

The CUpU,KU tree (TIICl1bn1Illa )!rt1l1d[f1.>n11ll (II'ILLD. E.\ SPRE.'·G.) SCHU.W.)) and thepupunha tree (Baaris .~";;l'ac, H.B.J..:.) are grown throughour the Amazon region as pare oforchard- or sm311 scale production systernv. 1n a preliminary srudy rhe number of oligorrophicnot nirrogen-fixing. oligorrophic nitrogen-fixing bacreria and fungi associated with the roorsurfrcc. <oil in 2-1 {IJ1ll1l and soil in > 10-2( IJ1lJ1l from lhe root surface we re assessed. The highesrnumber 01 rhe culrur.ible bacteria were associ.ued with rhe rhizoplane. With greater disrancefrom rhe roor surface the total number of b.ictcria decreaved.

INTRODUCTION

Soil microorganivms can increase nurrienr availabil-ity through mineralizarion of soil organic matter andhave special physiological properties like nitrogen-fixation and J>-solubilization (Illmer and Schinner1494, Lee and Pankhurst 19<)2, Sparling 1494,Grayston 1995, Dcl.uca 1996). The colonization ofrhe rhizosphere by microorganisms with diversephysiological properties will have importam conse-

uences for plant growth in mixed culture systerns.The cupuacu tree tThcobronia )!ralld[floTUm) and

ti e pupunha tree (Barrris ,easil'al's H. B. K.) are gro\Vnin mixed culture systems in the Amazon basin forfruit, seed production (cupuaçu, pupunha) and heartof palm (pupunha). Present demand exceeds supplyand is reflected in the relatively high market value(Laker and Trevisan 1992, Venturieri 1993).

T objective of this preliminary study was todeterrr ine the composition of oligotrophic bacteria

* Aurhor [O whom correspondence should be addressed

, wrth and withour the capacity to fix nitrogen as wellas fungi in differenr distances frorn the root surtigro\\'ing in rwo different culture systems of an 5 yold plantation sysr.em near Manaus, Brazil.

MATERIAL AND METHODS

Saniple colleaion

Rhizoplane and rhizosphere soil samples werelected from pupunha- and cupuaçu-plants inmixed cultivation systems (1 and 2) as partrecultivation experiment of a 19 ha fallowplantation on a former terra firme rainforest areaManaus (Feldrnann 1995). The clirnate datau re d near rhe experimental si te (2°51 'so59°52'west) are rypical for humid tropics (1993). Rainfall: 2500mm peryear, 300nuntn

maximum, 110mm monthly minimum Wl

explicit dry season. Air tempera °

averages,30-33°C rnaxima, 21-23°C minima. Rela-tive humidiry: 87% monthly average maximum,82% monthly average minimum.

The soil was determincd as a xanthic ferralsol(FAO-dassification) oflow fertiliry and of a consid-erably high contenr of plant available aluminiurn(Schmidt 1993).

Rhizosphere microorganisms from 2-1 Omm and>20-20mm distance were exrracted by shaking 1gof rhizosphcre soil in 991111of D. <)')1" NaCl solution.The microorganisms of the rhizoplane wcrc ex-rracted by shaking 1g of the roots in 991111of O. 9'Yt,NaCl solurion conraining glass beads (Sg).

The rhizosphere and rhizoplanc samplcs wcreserially diluted (10'" 10-", 10';) and o. l ml suspen-sions spread, in five replicares, on the folJowingmedia: 2g glucose, O.5g K~HPO., O.5g MgSO. x 2H20, Na~Mo04 x 2 H~O, 1 rnl trace elernent solution,dest. water ad 1000ml plus cycloheximid (1ll0flg x l')for enumerarion of oligotrophic not nirrogen-fixingbacteria; the sarne media without nirrogen-source wasused for enumerarion of oligotrophic nirrogen-fixingbactéria; and Sabouraud agar plus srrcptomycin (1OOflgX l-I) for enumeration of fungi.

The tubes were incubated ar 2HoC and counrcdafter 7 days for bactéria and fungi (Alef 19(1).

RESULTS

The majoriry of oligotrophic bactéria was able to fixnitrogen. The highest percentJge of nitrogen fixingbacteria was found on the rhizoplane. Both, thenumber of oligorrophic bacteria and nitrogeri-fixing

~ 2-1Omm :l>10-2Orrm rtuoptaroe 2·1Onwn >1n.2Omm

diatance from root surlaee

bacteria decreases wirh increasing distance from therhizoplane (See Figure 1 and 2).

ln the rhizosphere of pupunha in culture systern1, where pupunha-plants were direccly neighbouredto mamão (passion fruir, Carica papaya), the percent-age of not-nitrogen-fixing bacteria was higher thanin systern 2 (St:t: Figure 2).

In cultivation sysrern 1, the nurnber of fungi W:1Shigher in the rhizosphere of pupunha than in therhizosphere of cupuaçu. ln cultivarion syscem 2 thenumber of fungi W:1Ssimilar in rhe rhizospherc ofboth plant species (See Figure 3 and 4).

CONCLUSION

The plant species have a significant effect on thenurnber of rhe not-nitrogen-fixing and nitrogenfixing bactéria.

The higher arnount of not-nicrogen-fixing bacte-ria and the lower nurnber of nitrogen-fixing bacteriain the rhizosphere of pupunha (>2-20mm) in eu 1-ture systern 1, may be due to che effect of neighbour-ing mamâo-planrs. In cultivation system 1 mamãowas directly neighboured to the row of pupunha .plants until spring 1997. Marnão-plants are known asnutrient suppliers for other planes in sustainablecroppIl1g systems.

ACKNOWLEDGEMENTS

This study has been enabled within the trame of aproject financed by rhe German Federal Ministry ofEducation, Science, Research and Technology

4rflI2Do6WIe 2-10rm1 »10-2Orrwn rh&ZDptw\e 2-1Onwn >10-2Omn

dI.tlne. from root: IUrfac.e

Figure I. Number of not-nitrogen and nitrogen fixing Figure 2. Number of not-nitrogen and nicrogen fixingoligotrophic bacceria in the rhizosphere of cupuaçu wich oligocrophic bacteria in the rhizosphere of pupunha withand without the capacity to fix nicrogen.* and withouc the capacity to fix nitrogen.*

, .• The number of bacteria has been recorded in rerms of colony forming units per gram soil or root. All samples have been collectedin O-Scm soil depth. Every column re .csents 5 planes wirh rhree repeats. The plants have been rnonitored from April [O May1997. At this time all planes were ~.5 years old,

6

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460 SL'S·/:'l/X.·1HLE .~CR/C( 'LTl'I<!: FOR 1'000, EXERCI' ASD /XDL'STRI'

õe~ 6~J?2c

'".Q

syslem 1 ~

.--.--- -

n ~rrnzootano 2-10mm >10-20mm rtuzoplanc 2-10mm >10-20

distance from root surtace

Figure 3. Number of fungi in the rhizosphere ofcupuaçu.*

(BMBF: Bu nd c sm in isr e ri u m fii r lril du ng.WisscllSchat!:. Forschung und Tcchnologic: projcctNo. ()3}<)4:;7 A), bv the Brazilian National Couneiltor Scie ntific and T cchnological I k\'clopclllcnr(C Pq: Conselho acional de DesenvolvimentoCientifico e Tecnológico) and rhe Brazilian lnstirurcfor Env ir o n m c nr a nd Rellc\\'able Rc so u r ce s(IBAMA: lnstituro Br.\',ikiro de Meio Ambiente eRecurso» Rcnov.ivcis). Thc projcct i, parr of the(; crru.m- Braz il ia 11 S H IFT -Prour.nn (Sru di es onHuman Impact 011 Forcsts and Floodplaius in thcTropics).

REFERENCES

I. 1'. 11I1llL'r.1I1d F. Schmncr. ""lllllhdl7.It"", 01' }lHlr~.lI1'l'c.rlcrum phovph.ucv-voluhihz.mou mcc h.uuvrn-,". ~lld IlI()I.Brochcm.. Vol. 27. }lU..' (1')')4):2:;7-21,.\.K.E. Lce .llld (:,[, Pankhur-a. "voil org.uu-m-. .md \ll\LIIIl-

.Ibk producnvrrv". Auvt. J. Soil Rl·'. :'\fI (I ')')2): H:;:;-H')2.(;,1'. Sr~lrhl1g. "Low-rnput .1~r1L·ldtl1rl': l\1.nching org.lnirrcsourccs . voi] microhi.il .unvirv .llld plJIH nurncnt dc-m.md ". Soil BHH.l: M.lll.l~l·llll·llt 111-uvt.un.ihl« tJnllillg

'Y'lL'lll< (Adcl.udc. Au-rr.ili.r. 1')')4). 211')-2 II,.S.J. Gr.ivsron .uu! t :.1). Cnmpbcll. "I lincnon.il biodl\'l'r,ltyollllicrohl.t1çollllllllllltic\ in thc rhizovphcrv of hvbnd l.mb(L,,.,.\" I'lIftl"'/".") .uul \](J...l 'l'nll'l' (I'/lf'tI .\I/(/'nl-'I'<)", 1 H'C

I'h\'"ology li, (I ')']:i): W.'\ I-III.IH.

3.

-\

rhl.zoplane 2·1Ornm :a.10-2Omm rhlZoplane 2·1Omm >10-2Ornm

dlslance from roa! surface

Figure 4. Number of fungi in the rhizosphere ofpupunha.*

:>. T.H. dcl.uca, l.E. Drinkwater. B.A. Wiefling and O.M,ek Nicol,i. "Frcc-Iiving nicrogen-fixiug bacteria in tempera-rure cropping Systt'lllS: influcnce of nitrogcn source" 1 Biol.Fert. Soil-, ~:'\(2) (llJW,): 140-144.

ív. H.A. Lakcr and O. Trevisan, "Thc increasing importance ofCupuawu (Theobroma grandi florum) in the Amazon regionof Br.izil", Cocoa Growers Bullenn 45 (llJlJ2): 45-52.

I. C;.A. Vcnturicri. "Cupuaçu: J Espécie. sua Cultura, Usos, eI'roe C",lIllCIltO", Clube do cupu-Hclém. IOB p.

x. I. Fcldm.mn. E. Idz.IL'.c. Martins.}. unev.L. Gasparotto,H.l'rci'lllgcr. V.H.F. Moracs and R. Lieberci, "Rccultivation"f ekgr,lclcd. fillo\\' IYlIlg arcas in central Amazonia withcquihbr.ucd polycultures: rc:spOI1SL'of useful plants to inocu-l.inon with VA-Ill\'L'orrbizal (ungi", Angcw, Bot. 69 (1995):III-IIH.

I). O.M.I~. Cabr.il and C. Doza.l'Mctcor ological observationsJt rhe EMIJRAI'A-sitc ncar Manaus-Afv; in 1993, com-p.ircd to thr .l\'l'rage of IlJ71-1'.!'J3. In: jahresberich; ..SH I FT -Projecr E IV -2.~. Rekulnvierung degradiertet.,hr.ic hhcgcudc r Mo nok ulrurfl ãc h cn in ausgewogc1UiMiscb k ulturflãchen unt er bcsonderer BerücksichtiguDghodcllh,,)fo~i\(h"'r Fakt~)rL'n; Hamburg. Manaus (1993:. . III-IH.

111. 1'. ~L'hlllidt. "Biomasscproduktion und Nahrelementgelult-.1I1\ge\\'Jhltcr Pflanzcnartcn auroforsrlicher Plamagen iIllAIl;JZOIl,l'gL'hict". 111:jJltrcshL'·richt. SHIFT-I'roject ENV2.~. Rl'klllti\'iL'rllllg d e g r ad icrt c r , brachliegendMonokulturfl.ichcn III allsgl'\\'O~l'IH' Mischkulturf};jcu nt cr hcvondcrcr Ikrück,ichtigllll~ bodenbiologischFakrorcn: Hamburu, Man.iu« (I'.!'.!:'\): '.!9-11(1.

I I. K. Alcf. Mcthodenhandbuch Ilodenmikrobiologie (ecoI'.!'JI). 2H4 p.