~EWBLIOLIE DU SENEGAL INSTITUT SENEGALAIS D...
~EWBLIOLIE DU SENEGAL
INSTITUT SENEGALAIS
D E
MINISTERE DE LA RECHERCHIE SCIENTIFIQUE
RECHERCHES AGRICOLES
ET TECHNIOUE.
DEPARTEMENT DE RECHERCHES FORESTIE-
JES ET HYDROBIOLOGIQUES.
DEPARTEMENT DE RECHERCHES SUR LES
PRODUCTIONS VEGETALES
PRELIMINARY STUDIES ON FOUR NITROGEN FIXING
TREES
FROM SENECALESE SOILS
Ousmane DIAGNE et Mamadou GUEYE
Microbiologi&es à l'Institut Sénégalais
de Rec:herches Agricoles BP. 3120 Dakar
.&illet 1984
Office de la Recherche
Centre National de
Centre National de
Scientifique et Technique
Recherche Forostièr e
Recherche
Agronomique
!Outre M e r
(ORSTOM)
@NRF)
(cNRA)
PRELIMINARY CN FOUR NITROCEN FIXING TREES
FROM SENEGALESE SOILS
0. DIAGNE' and M. GUEYE2
(1) : ORSTOM L b
a oratoire de flicrobiologie BP. 1386 Dakar
(Senegal)
(2) : MIRCEN/CNRA BP. 53 Bambey (Senagal)
SUMK1RY
-n-
Because of the destruction of forests for agricultural
needs, there
is a continuous degradation of soils. TO reforest
these soils, itis
necessary to use trees that cari thrive in urasted soils, Fortunately
such trees exist
: they are
Nitrogen Fixing Trees
(NFT).
We studied four species
of NFT :
prosopis africana, Prosopis
.juli-
flrra,
Albizia lebbeck and Leucaena leucocephalq.
-
-
Prosopis africana
and Albizia lebbeck uere uell nodulated
in Seuth
Seneqal soils uheraas PrrJposis .iuliflora
and Leucaena leucocephala
-LI-
uere not nodulated in thiç area.
Rhizcbium strains luere
isolated from those NFT species and their
host
spectrum
uras determined. Nitrogen
fixation \\uas estimated in the labo-
ratory by measuring
of the shnat and nodules dry
weight and shoot to-
tal N content.
The four
NFT species studied fell into twn categories :
1)
NFT for
which nitrngen fixation
could significantly be in-
creased
by inoculation urith the strains UKI had isolated :
Proposif ,afri,cana
and Jlbizia lebbeck;. Rhizobium strains
A1,0 and pa?, were
most effective strains
on Proposis
africana and Albizia lebbeck.
-
-
2) NFT for
urhich nitrcgen fixation could n& significantly 5s
incrcased by
inoculation uJi.th wr strains : Propoaiq juli;
flnra and Leucaena leu.cocephala. The reason
of thie failure
ia proberbly
that straine
native to sensgalesa SOL~S u1ere not
effective on Proposi,e
$~Iiflhra and $eucaena leucocephala.
- 2-
1. INTRODUCTICN
Our first objective mas tn study the nodulation of four
Nitrogen Fixing Trees
(NFT), Prosnpis africanq, Pr3sopis
juliflora,
Albizia 1eSbeck and Leucaena .leucocephnla, thon
to isolate Rhizobium strains from thO3ts fd1-T t%nj firj?ls}t tu asti-
mate nitrogen fixation in the laboratory.
2. MATERIALS AND METHODS
For
isolating Rhizobium strains fram the fiwe diffarent sri1s8
me studied (table
l), me planted germinated seeds of the four
speoies in plastic 24 x 11 cm pouches fi.Lled UP u&th the dff-
ferent smils.
The seeds had been sterilized by
immersion in
cancentrated
sulfuric acid (table Z), a treatment mhich u1as
also necessary
Cp allow the germinatian (chemical
scarifica-
tirn).
Tha oxporimeht
utere cr?nducted with three
seedlings per
pouche
for the four NFT and fifteen replicates par treatment.
Rhizo-
bium uere isalated frorn ths
nodules that appearod after 55 43~s.
Iaolates ~ero plated in Petri
dishes containing the routina
YEMA medium (VINCENT, 1970).
Infection plant tests were carried out in GIBSON tube (1963)
crntaining agar
JENSEN medium (1942). Seedlings were inocula-
ted with a 7-day-•ld cultura ef tho isolated Rhizrbium strains
and the ORS 911 and CB 7% Rhi?nbium as reference strains.
Nitrogen fixation was cstimatcd by differencs betiuesn the total
N content alf non inocufated and incculatsd plants. In addition,
nodules and shoots IJJWZ ureightod aftar bsing oven drisd.
3. RESULTS
3.1. Modulation of the
NFT
Prosopis africana
and Albizia labboclc nodulatod in a11 sriils
usod. The nombor
of nodules was highor in
Dabo soil. Proeo-
& .iuliflrra
and Leucaena laucrcophala did not nodulate in
any scil (table 3).
3.2. Isclaticn of !?hirobium strain_anQ
&udy of the-ir
host -ramqe
Ten strains wcr~
Asol;--ttcd, a11
of thom from Prosopis africana
-
-
- 5 -
Prosopis
africana and Albizia lobback and most of them
-
-
wre
effective nn both hosts. Only t.tJo of these stroins
(Pal from Prosopis africana and A16 from
Albizia lebback)
tirer 0
abla ta effoctively nodulats Leucaona leucocephalz.
-
-
None of the tan strains isolated uras able to nodulato
ProsoPis
juliflora.
Interestingly ORS 911
(isolated from
Acacia farnasiana)
was able t3 nodulate leucaena leucocaphala (table 4).
The cffectivity of
the strains tuas di2terminatod
only iuibh
Prossop.is africans and Albizia lebbeck, the best strains
being Al;oand pa7 (Fig. 1, 2, 3).
CONCLUSION
Our
proiiminary investigations of thc four specics of NFT shn-
wed that those species fol1 into two inoculation groups accor-
ding to ths Rhizobium that nodulated thon1 :
the first group including prosopis africana
and Albizia labbeck
-
-
ürhjch noduLatr;d rosdily ujith Rhizobium strains distributed in
tho fivo stinegslesc soils studied (which ara probably
ubiqui-
tcu 3
strains) . Intortistingly,
sorne of tho Rhizobium strains
uùre fast grouing,
other were SLOW growing,
tho tu3 catagLries
of Rhizobia. Thore
was no relation boturoon tha efficiency of
these strains
and their growth rate.
Tho sticond group including Prosopis Juliffora
and Loucaena
loucoc:jphnlz; tuhich did not nodulatYd iuith thc native Rhizobium
strains Froiii thcsa scils, which suggsst thet thc: Rhizobium
raquiert.w?ent;s of Prosopis juliflora
end LwcaeT'a ltiucoçaphala
Lzrc m o r s sPC?cificthon th2
cnss of thc first
group. it aPpe3rs
necossery to initiate invastigations in th-t field.
L
=---
-
I
D.
D
IA 0
0
0
CJ
OY
Ln 0
3
0’
r
0
u 0
0
0’
0
o-
LA 0
0
0
N
133
W
fi
v- u?
Y- 0
T-
F 0
h
V
0
T-
In
0
0
0 0
0
CG- 0
CJ 0
0
0
CY
CY 0
V
r?
W
,T
h
x-- OI
T-
Lr’i
r- 0
Y-
lr,
v-
M
0
rc
M M
V
v- Ln
T- In
<j”
\\a 0
m
h
0
W
V
.---.
v- In
o*
0 c3
0
7
L”
0”
0 0
CZY
0 0
V
F--.
a
v- Ln
0”
0 0
V
h
0
v-
In
0
0 u
Table 4 - Host spectrum of ten Rhizobium strains ielated
From prosopis aFricana and Albizia lebbeck.
-3-
Straine
prosopis
Albizia
Leucaena
?roaopio
tested
africana
lebbeck
leucocephala ,iiliflorz
pa 1
fast
E
E
c1.i.
pa 3
fast
'e
e
n.i.
Pas
Sl.OW
E
n.i.
n.i.
Pa7
sl ow
E
n..i.
nri.
Pa9
sl.ow
E
n.i.
n.i.
A12
fast
e
kl
A14
fast
E
ri.i.
A16
slow
n.i,
n.i,
A18
SlOW
n.i,
E)
FI110
fabt
n.i.
r1.i.
ORS 911
f3.St
E
E
El
CB7 56
SlOW
e
n.i.
n.i.
E = effective ; e xz ineffective ; n.i.= non in?eCtiVe
*
= Plants of this treatment were contaminated.
- -
. . .,
t
F
I.,,
..s
..I
i
.,
.
,.
_
. .
1
5
REFERENCES
CORNET, F., 1982. Rscherches preliminaires sur la symbiose de deux Acacia
0.
tropicaux (A. raddisna et A. holasericea) avec
Rhizobium sp, et
un chamoignon endomycorhizien (Glomus mosseas)
-
-
D.E.A. Microbio-
loqie. Eniuers. Claude Bernard,
L y o n I.
+i DREYFUS, R.L., and DOMWEHGUES, Y.R., 1981. Nodulation of s p c
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b y Fast-
and Slow-growing Trripical Strains
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and Environ. Microb. 4 1 (11, 97-99.
GIBSON, A .H .,
1963. Physical environment in symbiotic nitrogen
fixation.
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-
-
research
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Nov. 1982. p. 27-32.
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