AGRICULTURE AND BIOLOGY JOURNAL OF NORTH AMERICA
ISSN Print: 2151-7517, ISSN Online: 2151-7525
© 2010, ScienceHuβ, http://www.scihub.org/ABJNA
Screening for abiotic stress resistance in three tropical edible mushrooms
*1Ayodele, S.M., 2Ohwojero, D. and 2Odii, I.K
1
Department of Biological Sciences, Kogi State University, P. M. B. 1008, Anyigba, Kogi
State, Nigeria, 2Department of Botany, Delta State University, P. M. B. 1, Abraka, Delta
State, Nigeria, Email: [email protected]
.ABSTRACT
Three tropical edible mushrooms (Lentinus squarrosulus, Psathyrella atroumbonata and
Pleurotus sajor-caju) were screened for abiotic stress resistance (Drought and Solar radiation
extreme). The three mushrooms responded differently to the abiotic stress. The effect of the
abiotic stress was most apparent after the mycelia colonized the substrates. There was no
significant difference, (ρ≥0.05) in mycelial growth and mycelial density in the mushrooms under
the abiotic conditions. However, there was significant difference (ρ≥0.05) in time of fruit body
formation and yield. Highest yield was recorded in Lentinus squarrosulus (9.50g) while the least
yield was recorded in Psathyrella atroumbonata (3.80g). The study showed that Lentinus
squarrosulus can resist abiotic stress more than Psathyrella atroumbonata and Pleurotus sajorcaju. This means that Lentinus squarrosulus can be cultivated all year round in the tropics with
little environmental manipulation. However, higher yield and quality of the mushroom could be
achieved by cultivating it under shades and cool environmental conditions.
Keywords: Abiotic stress, resistance, Psathyrella atroumbonata, Lentinus squarrosulus,
Pleurotus saju-cajus
INTRODUCTION
Mushrooms are fleshy saprophytic fungi found
growing on damp rotten log of woods, trunk of trees,
decaying organic matters and in damp soils rich in
organic substances (Oei, 2003). They can be grown
on agricultural and industrial wastes such as grass
straws, leaves, stems and saw dust of different plant
species as substrates. A warm and humid climate
provides a perfect condition for growing mushrooms
(Zadrazill 1978).
Mushroom cultivation provides a good economic
cash crop, but requires technological skills on
scientific principles (Ito, 1978). Cultivation involves a
delicate operation which requires hygienic conditions,
adequate environmental conditions and a certain
degree of expertise (Cho and Woo, 2004). The initial
problem associated with mushroom cultivation was
lack of understanding of the biology of mushrooms,
such as moisture and temperature requirements (Oei,
2003). Environmental manipulation of mushrooms is
achieved by heavy watering, shading or positioning
the substrates in area of microclimate (Cho and Woo,
2004).
Abiotic factors are the most serious worldwide
problems in agriculture. Transient drought can cause
death of live stock, farm produce, famine and social
dislocation (Bray, 1997). Abiotic stress is considered
one of the most important factors limiting plant
performance and yield (Boyer, 1982). Crop yields are
reduced by water stress. It influences crop growth in
many ways. The effect of drought stress depends on
the severity, duration and time of stress in relation to
stages of growth of plants (Bray, 1962). All vegetable
plants have been reported to be sensitive to drought
stress, although their responses differ from plant
species to plant species (Bray, 1987).
Each mushroom has optimum environmental
conditions, tolerances and sensitivities. These
conditions minimize stress and result in good yield.
Mushrooms productivity can be constrained by
various environmental stresses. The environment in
which mushrooms grow consists of physical,
chemical and biological factors. An imbalance in any
of these factors causes stress. Stress may reduce
the yield and quality of plants (Ekanayake, 1994).
Environmental stress could be biotic which are
caused by biological factors such as diseases,
insects or contaminants which compete with the
plants for the available nutrients. Stress could also be
abiotic factors which are caused by physical and
chemical factors such as high temperature, salinity,
excess substrate moisture etc (Ekanayake, 1998).
The effect of one stress factor can be reduced or
enhanced by another stress factor. For instance, the
combination of high temperature and drought during
Agric. Biol. J. N. Am., 2010, 1(4): 711-714
The study was carried out between December and
March when solar radiation is usually high and
relative humidity very low. The following parameters
were determined.
the dry season in some tropical countries may
increase dehydration stress in plants. Main abiotic
stress factors affecting plants in the tropics are
drought, temperature extremes, solar radiation
extremes and nutrient imbalances.
a. Time for complete colonization of the
substrates.
b. Mycelial density in each substrate
c. Time of sporophore emergence
d. Fresh weight of mushrooms
The results were analyzed using simple descriptive
statistics such as mean and standard error. The
mean were separated using Analysis Of Variance
(ANOVA).
Growing of mushrooms in most tropical regions is
restricted to a season (rainy season) when the
condition is favorable for cultivation (Chang and
Hayes, 1978). Screening of mushrooms for abiotic
stress resistance may make mushroom cultivation
possible all year round. This is very important to
maximize the economic efficiency of mushrooms
production in the tropics. A block house with a
regulated air condition supply makes it possible to
grow mushrooms almost anywhere all year round,
but the cost of building block house and air
conditioning it is prohibitive in most cases to the local
farmers. The aim of this study is to screen three
edible mushrooms commonly found in Nigeria for
abiotic stress resistance with the hope to make them
available all year round. The abiotic stresses selected
in this study are water stress and solar radiation
extreme.
RESULTS AND DISCUSSION
The response of the three edible mushrooms to
drought and solar radiation differed as evidenced in
the rate of growth; development and yield during this
study. It is observed that both water stress and
radiation extreme greatly affect the growth and
development of the mushrooms. The mean days of
complete mycelial colonization and sporophore
emergence under solar radiation was found to be
longer in Psathyrella atroumbonata (22 and 41 days
respectively) while under the drought stress, it was
longer in Pleurotus sajor-caju (17 and 42 days
respectively) (Tables 1 and 2). The mushrooms grew
well vegetatively at initial stage, but with time, under
the abiotic stress, there was reduction in the rate of
growth. This observation was in line with Tonomura
(1978) who observed that temperature, moisture and
humidity control mycelial growth and fruit body
formation in Flammulina velutipes and that at high
temperature, growth ceases.
MATERIALS AND METHODS
The pure cultures of the three edible mushrooms
Lentinus
squarrosulus
Monts,
Psathyrella
atroumbonata Pegler and Pleurotus sajor-caju) were
collected from the mushroom unit of the Department
of Plant Biology and Biotechnology, University of
Benin, Benin City, Nigeria. The spawn of the
mushrooms were raised on guinea corn (Sorghum
bicolor) grains. The spawns (mushroom seeds) were
inoculated into Gmelina arborea saw dust substrate
which was collected from a local sawmill in Abraka,
Delta State, Nigeria. The substrates were prepared
according to Ayodele and Okhuoya (2007).
There was no significant difference in mycelia growth
and mycelia density in the three mushrooms under
the abiotic condition, however, there was significant
difference (ρ≥0.05) in the mean time of fruit body
formation and fresh weight of the mushrooms (Tables
1 and 2). The highest fresh weight was recorded in
Lentinus squarrosulus, (9.50g) under the drought
while the least was recorded in Psathyrella
atroumbonata (3.80g) under solar radiation extreme.
The result showed that Lentinus squarrosulus can
resist abiotic stress more than Psathyrella
atroumbonata and Pleurotus sajor-caju
The abiotic treatments were introduced immediately
when the spawn were inoculated into the substrates.
For drought treatment, three sets of substrate bags of
each mushroom were watered (150mL of distilled
water/bag) every other day (control) while another
three sets of inoculated substrate bags were watered
(150mL of distilled water/bag) per week. For solar
radiation, three sets of inoculated substrate bags of
each mushroom were kept under laboratory
conditions and watered periodically (control) while
another 3 bags were kept under direct sunlight in a
screen house roofed with white transparent
corrugated roofing sheets which allow penetration of
sunlight. The bags were also watered periodically.
Chang and Hayes, (1978) observed that mushroom
can survive in a wide range of environments but for
satisfactory commercial production, it must be given
conditions fairly near to the ideal at each successive
stage of growth. Failure to do this, results in weaker
or slower growth.
712
Agric. Biol. J. N. Am., 2010, 1(4): 711-714
Fruit bodies grow better in the control than under
solar radiation extreme. Small and slender fruit
bodies developed in Psathyrella atroumbonata. This
observation is in line with Tonomura (1978) who
reported that solar radiation extreme make fruit body
of mushrooms grow rapidly but usually slender, long
and of poor quality. Tokimoto and Komatsu (1973)
also reported that shapes and yield of fruit bodies are
affected by high temperature during fruit body
development in Lentinus edodes. Tonumura (1978)
observed that mycelia of Flammulina velutipes grow
quickly under the shade and frequent moisture supply
than under solar radiation and drought regime.
The effect of solar radiation on the mushrooms was
most apparent after colonization of the substrates.
There was delay in sporophore formation and
reduction in sporophore yield (Table2). Senescence
takes place faster in the mushrooms under abiotic
stress than in the control. This observation is in line
with Tevini and Teramura (1989) who observed that
responses of plants to UVR is physiological,
biochemical and anatomical. Teramura (1983)
reported that though solar radiation could be
beneficial to plant growth, but the extreme could be
harmful as it may lead to water shortage through
evaporation and cause dehydration. A similar
observation was recorded in this study under solar
radiation. The fruit bodies of the mushrooms were
reduced in growth, size and numbers compared to
the fruit bodies in the control. There was sign of
drying up of some sporophores some hours after they
emerged.
Zoberi (1972) observed that the
basidiocarp of Coprinus species he studied would
grow at low humidity (40%) but would not open.
Kurtzman (1978) also reported that dehydration in
Coprinus prevents the basidioscarp to open.
According to Chang and Hayes (1978), the effect of
drought or solar radiation extremes induce the
physiological changes from vegetative growth of the
mycelium to fructification which is the most critical
stage in the whole course of mushroom cultivation.
In this study, it was observed that the three
mushrooms are poor in resisting abiotic stress
(drought and solar radiation extreme). However, their
resistance differed from one another. Lentinus
squarrosulus is more resistant to abiotic stress
followed by Pleurotus sajor-caju and Psathyrella
atroumbonata in that order. This means that the
mushrooms can be cultivated all year round with little
environmental manipulation in the tropics. However,
high yield and quality of the mushroom could be
achieved by cultivating them under shades and cool
environmental conditions.
Table 1. The effects of drought on the vegetative growth of Lentinus squarrosulus Mont, Psathyrella atroumbonata
Pegler and Pleurotus sajor-caju
Mushroom sp
Lentinus squarrosulud
Psathyrella atroumbonata
Pleurotus sajor-caju
Mean time for
Substrate colonization
( days)
Mycelial Mean time for
Fresh
density
fruit body formation
(a)
( days)
weight
(g)
13.3± 0.5
15.10±0.14
17.60±0.4
++
++
++
9.50±0.36
6.30±0.12
7.40±0.50
Values are mean of 3 replicates + Standard Error. ρ ≥ 0.05
a = Visual observation according to Fasidi and Kadiri, (1993)
+ - +++ = increasing level of mycelia density
713
31.70 0.6
33.02 0.33
42.14 0.11
Agric. Biol. J. N. Am., 2010, 1(4): 711-714
Table 2. The effects of solar radiation on the vegetative growth of Lentinus squarrosulus Mont, Psathyrella
atroumbonata Pegler and Pleurotus sajor-caju
Mushroom sp
Lentinus squarrosulus
Psathyrella atroumbonata
Pleurotus sajor-caju
Mean time for
Substrate colonization
( days)
Mycelial Mean time for
Fresh
density
fruit body formation
(a)
( days)
weight
(g)
19.02±0.6
22.01±0.34
21.60±0.1
+++
+++
+++
8.20±1.2
3.80±0.8
6.20±0.4
34.70±0.4
41.20±0.6
38.80±08
Values are mean of 3 replicates + Standard Error.ρ ≥ 0.05
(a) = Visual observation according to Fasidi and Kadiri, (1993)
+ - +++ = increasing level of mycelia density
REFERENCES
Ayodele, S.M. and Okhuoya, J.A. (2007). Cultivation
studies on Psathyrella atroumbonata Pegler, A
Nigerian edible mushroom on different agro industrial
wastes. Int. J. Bot., 3(4):394-397
Boyer, J.S. (1982). Plant productivity and environment.
Science. 218:443-448
Kurtzman, R.H. Jr. (1978). Coprinus fimetarius In: The
biology and cultivation of edible mushrooms. (S.T.
Chang and W. A. Hayes (eds) Academic Press, New
York pp 393-408
Oei, P. (2003). Mushroom cultivation, appropriate technology
for mushroom growers. Backhugs Publishers, London.
Netherlands pp 80-84
Bray, E. (1997). Plant responses to water deficit. Trends
Plant Sci. 2:48-54
Teramura, A.H. (1983). Effects of Ultraviolet β-radiation on
the growth and yield of crop plants. Physiology 58:415417
Chang, S.I. and Hayes, W.A. (1978). The biology and
Cultivation of Edible mushrooms. Academic Press,
New York pp. 819
Tevini, M. and Teramura, A.H. (1989). UV-β effects on
terrestrial plants photochemistry. Photobiology, 50:479487
Cho, S.B. and Woo, S.K. (2004). Mushroom growers
handbook I-oyster mushroom cultivation.
Mush
world. Heineary Incorporated, Korea, pp 298
Tokimoto, K. and Komatsu, M. (1978). Biological Nature of
Lentinus edodes. In S.T. Chang and W.A. Hayes (eds).
The biology and cultivation of edible mushrooms.
Academic Press, New York. pp 445-459
Ekanayake, I.J. (1998). Screening for abiotic Stress
resitance in root and tuber crops. IITA Research
guide No. 68, IITA, Ibadan, Nigeria pp 46
Fasidi, I.O. and Kadiri, M. (1993). Effect of sporophore
maturity on chemical composition of Volvariella
esculenta. Die Nahrung, 37:269-273
Ho, M.S. (1978). Cultivation of mushrooms in Asian
countries. In S.T. Chang and W.A. Hayes (eds). The
biology and cultivation of edible mushrooms.
Academic Press, New York pp 337-343
Ito, T. 1978. Cultivation of Lentinus edodes. In the
Biology and Cultivation of Edible Mushrooms, edited
by Chang and Hayes. Academic Press, New York pp
461-467
Tonomura, H. (1978). Flammulina velutipes. In S.T. Chang
and W.A. Hayes (eds). The biology and cultivation of
edible mushrooms. Academic Press, New York. pp 409421
Zadrazil, H. (1978). Cultivation of Pleurotus. In S.T. Chang
and W.A. Hayes (eds). The biology and cultivation of
edible mushrooms. Academic Press, New York. pp 521557
Zoberi, M.H. (1972). Transpiration and water uptake in fruit
bodies of some hymenomycetes. Physiol. Plant. 26:215220
714