गुरुवार, 28 फ़रवरी 2013

plant sciences / FUSARIUM OXYSPORUM








289
N
S
ave Nature to
S
urvive
6(1) : 289-291, 2011
www.thebioscan.in
EFFECT OF DIFFERENT pH LEVELS ON THE GROWTH AND
SPORULATION OF
FUSARIUM OXYSPORUM
SCHLECHT. F. SP.
LENTIS
(VASUDEVA AND SRINIVASAN) THE CAUSAL ORGANISM
OF WILT DISEASE OF LENTIL
HIMANSHU BHUSHAN JARUHAR* AND AJAY PRASAD
1
Department of Botany, S. P. D. College, Garhwa - 822 114, Jharkhand
1
Department of Botany, S. S. J. S. N. College, Garhwa - 822 114, Jharkhand
E-mail: hbjaruhar@gmail.com
INTRODUCTION
Fusarium oxysporum
Schlecht f sp.
lentis
(Vasudeva and
Srinivasan) causes a serious wilt disease in lentil (
Lens esculenta
Moench.) which is an important pulse crop of Palamu
commissionary (23º52’North latitude and 84º17’East
longitude). Due to this disease there is huge loss of the yield in
lentil. Vasudeva and Srinivasan (1952) have reported that Wilt
disease of lentil caused by
Fusarium
spp
.
is one of the serious
disease and it causes huge loss of the standing crop throughout
the world. The extent of the damage to the crop due to the
disease ranges from 20-24% annually, (Saxena
and
Johansen,
1990 and Ali, 2007). There were various reports that indicate
Fusarium
spp grow at different pH levels for growth and
sporulation (Wilson, 1946; Srobar, 1978; Prasad
et al
., 1992;
Souramma and Singh, 2004; Groenewald, 2005). The
pathogen is soil born and infects the host during seedling
stage through root and blocks the vascular system (Vasudeva
and Srinivasan, 1952). For the successful cultivation of the
lentil it is necessary to investigate the physiology of the fungus.
Therefore, effect of different pH level on the growth and
sporulation of
Fusarium oxysporum
Schlecht. f. sp.
lentis
was
undertaken.
MATERIALS AND METHODS
The fungus was isolated from the infected plant of lentil (
Lens
esculenta
Moench). Monospore culture as described by
Prasad and Chaudhary (1966, 1967) was employed in the
present study. From the culture of the isolates, pure culture
was obtained using 10
-5
decimal level dilution plate technique.
Sucrose nitrate medium consisting of sucrose (50.0g), KNO
3
(10.0g), KH
2
PO
4
(5.0g), MgSO
4
. 7H
2
O (2.5g) and 1000 mL
double distilled water used as basal medium. There were 10
different pH level ranging from 2.0 to 6.5 with a difference of
0.5 were prepared by using pocket size pH meter HANNA
Instrument Co. Mouritius by using either N/10 HCl or NaOH
before autoclaving. 100 mL of the medium was taken in 250
mL conical flask and five replicate sets were used in each
case. The solution was autoclaved at 15 psi for 15 minutes.
The inoculation was done with 3 mm discs of the fungus
culture cut with a sterilized cork borer from a margin of 10
days old colony growing in Potato Dextrose Agar (PDA)
medium. Flasks’ were then inoculated at 26ºC ± 2ºC for two
weeks. The mean dry weight of the mycelium was determined
as described by Prasad and Chaudhary (1966). The number
of spores was counted using known depth of Haemocytometer
slide (0.01 cm) using the formula:
Where,
ABSTRACT
Effect of pH on the growth and sporulation of
Fusarium oxysporum
Schlecht . f . sp.
lentis
(Vasudeva and
Srinivansan) after incubation of two weeks
in vitro
culture in sucrose nitrate medium was studied. pH level 6.0
was found optimum for the growth as well as sporulation of the fungus. Sporulation of chlamydospore was
however found best in the pH level 4.0. Further increases in the pH level show retarding effect on growth and
sporulation. Size of the spores increases with increase in the pH range.
KEY WORDS
Fusarium oxysporum
f .
sp.
lentis
Macro conidia
Micro conidia
Chlamydospores
Received on :
16.02.2011
Accepted on :
19.04.2011
*Corresponding
author
Number of spores / 100 mL = V/NX100
N = Average number of spores per square of the four corner
square of haemocytometer counted.

290
HIMANSHU BHUSHAN JARUHAR AND AJAY PRASAD
and sporulation of the fungus. On the other hand sporulation
of chlamydospores at more acidic range indicates that this
spore is characteristically different from other two spores and
more tolerable to stressed condition than the macro and micro
conidia.
ACKNOWLEDGEMENT
The
authors are happy to record the grateful cooperation of
the persons concerned of the G.L. A. College, Medininagar, in
the completion of this work.
REFERENCES
Ali, M. 2007.
Augmentation of Pulses Production. Mission2007: IIPR
Kanpur-24: pp: 16-21
Chaudhary, S. K. 1971.
Studies of the Physiology of the
Fusarium
oxysporum
f.
udum
(Butler) Snyder and Hansen (Causal Organism of
Wilt of
Cajanus cajan
(Linn.) Millsp) Ph.D. Thesis, Deptt. of Bot.
Ranchi University Ranchi, p. 297.
Groenewald, S. 2005.
Biology, Pathogenicity and Diversity of
Fusarium oxysporum
f. sp.
cubense
. M.Sc. (Agri.) Thesis. Faculty of
Natural and Agricultural Science, Universiity of Pretoria etd, Pretoria.
p. 176.
Jat, R. G. and Goyal, J. P. 1978.
Physiological Studies of
Claviceps
microcephala
Causing Ergot Diseases of Bajra.
Ind. J. Mycol. and Pl.
Pathol.
8:
21.
Kishore, R., Pandey, M., Dubey, K. and Kumar, Y. 2009.
Effect of
Temperature and pH on Growth and Sporulation of
Fusarium
oxysporum
f. sp.
lini
(Bolley) Snyder and Hensan Causing Linseed
Wilting.
Prog. Agric
.
9(1):
147-149.
Mix, A. J. 1933.
Factors Affecting the Sporulation of
Phyllosticta
solitaria
in Culture.
Phytopath.
23:
503.
Munjal, R. L. and Gautam, S. R. 1977.
Effect of vitamins on growth
and sporulation of
Septoria humuli
. Indian Phytopath.
30:
566-567.
Nair, P. N. 1957.
Factors Affecting Resistance of Flax to
Fusarium
oxysporum lini
(Belley). Dis. Abstr.
17(5):
942.
Prasad, A., Chaudhary, R. S. and Chaudhary, S. K. 1992.
Effect of
Different pH levels on Growth and Sporulation of
Fusarium
moniliforme
V.
subglutinans
Wr. and Rg., The Causal Organism of
Wilt of Maize.
Bio. J.
4(1 and 2):
75-78.
S. No. pH range Dry wt. in mg. Spores in millions /100mL medium* Size of spores in μ*
Macro conidia Micro conidia Chlamydo spores Macro conidia Micro conidia Chlamydo spores
1 2.0 37.00 0.67 2.62 0.39 26.20 7.20 4.90
2 2.5 53.00 0.78 3.63 3.51 27.70 7.30 4.90
3 3.0 73.00 1.17 4.06 3.64 28.20 8.10 6.10
4 3.5 93.00 1.55 7.42 5.20 28.90 8.90 6.30
5 4.0 124.00 1.69 9.37
4.03 29.20 9.60 7.30
6 4.5 169.00 1.95
13.68 3.71 30.70 9.80 7.50
7 5.0 198.00 2.19
19.68 3.71 31.20 10.70 7.50
8 5.5 276.00 2.62
69.14 2.73 33.30 12.30 8.20
9 6.0 476.00 5.86 154.03
2.19 34.20 12.90 8.30
10 6.5 210.00 3.69 132.42
3.51 31.10 9.20 8.50
SE± 15.24 1.50 5.78 1.74 0.05 0.18 0.24
C.D. at p= (5%) 30.97 3.14
11.75 3.54 0.11 0.36 0.48
Table 1: Effect of different pH levels of mycelia growth, spore population and size of spore change of
Fusarium oxysporum Schlecht. F.
sp.
Lentis
(Vasudeva and Srinivasan). Incubation period: 2 Weeks
*mean of five replicates
V = Volume of haemocytometer (0.256 x10
-5
) cc
Length of the spores was measured by calibrated ocular
micrometer under compound microscope (10 x 45 x of
magnification).
RESULTS AND DISCUSSION
The mean dry weight of mycelium and sporulation of three
spore forms of the fungus on different pH levels is recorded in
Table 1. The perusal of the results showed that
Fusarium
oxysporum
Schlecht. f. sp. l
entis
grew maximum in pH 6.0.
Very high acidic range of pH showed very poor growth of
mycelium. Mycelial mat accumulation increased with increase
in pH but declined after pH 6.0. Sporulation of the
macroconidia and microconidia was observed to be
maximum at pH 6.0. Least sporulation occurred in pH 2.0.
Chlamydospores produced were noted to be the maximum at
pH 4.0. Length of macroconidia and microconidia were the
maximum at pH 6.0 and thereafter it started to decline. Diameter
of chlamydospores increased with increase in pH level.
The growth and sporulation of many fungi have been studied
under the influence of various pH levels. Mix (1933) found
that pH range from 4 to 8 showed good growth for
Phyllosticta
solitaria.
Wilson (1946) observed acid soil (pH 4.2) support
growth of
Fusarium
spp. where as a pH near neutrality prevents
growth. Chaudhary (1971) and Prasad
et al
. (1992) reported
6.0 pH level as the best for the growth and sporulation of
Fusarium moniliforme
v
subglutinanse
Wr. and Rg. Munjal
and Gautam (1977) observed that maximum fungal growth
and sporulation occurred at pH 6.0 and 5.5 respectively for
Septoria humuli
. Srobar (1978) found pH 6 to be the most
suitable for the growth of all species while a highly acidic
medium was unsuitable for sporulation of all species causing
fusarioses disease in wheat. Jat and Goyal (1978) found that
growth and sporulation of
Claviceps microcephala
to be
optimum at pH 7.5 and 6.0 respectively. Nair(1957); Souramma
and Singh (2004); Groenewald (2005); Kishore
et al.
(2009)
also found pH 5.5 to 7.0 to be the best for growth and
sporulation of
Fusarium oxysporum f.
sp
. lini
( Belley). Such
reports are in agreement with present findings for this pathogen.
This indicates that unusual acidity badly hampered the growth

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