Introduction
The Nilgiri Biosphere Reserve is located in
Western Ghats between 76o15' -77o15'E
and 11o15’ - 12o15’N.
The study areas selected for the proposed project
include different forest ecosystems such as
Natural Forests (Tropical Wet Evergreen Forests,
Shola-Grassland Ecosystem) and Man-made Plantation
Forests in the Nilgiri Hill areas of the Nilgiri
Biosphere Reserve. Among the various soil organisms,
the most important and known to us are the mycorrhizal
fungi. The mycorrhizal fungus can be classified
into two groups viz., Ectomycorrhizas (ECM)
and Endomycorrhizas.
The mycorrhizal fungi improve seedling growth
and survival by enhancing the uptake of nutrients
and water and increasing root life span. They
also help to protect the roots against other
pathogenic organisms and against environmental
stresses such as heavy metal toxicity or soil
salinity etc. The mycorrhizal fungi have a great
influence on the survival of plants in new and
reclaimed sites, the tree health and site quality
and they are the cornerstone to proper establishment
of functional forest ecosystem.
Among different mycorrhizal fungi, the ectomycorrhizal
(ECM) fungi occur in about 10% of the world’s
flora that include most of the gymnosperms especially
the conifers and certain angiosperm families
such as Betulaceae, Casuarinaceae, Juglandaceae,
Myrtaceae, etc. The mycorrhizal fungi enhance
the uptake of nutrients, especially phosphorus,
increase the surface area of the roots of host
plants and act as a bio-control agents against
soil-borne or root-borne pathogens. In the past
few decades the extent of tropical forests has
changed dramatically with the ever increasing
demand for wood fibre.
Because above and below ground organisms are
tightly linked, such changes result in dramatic
losses which decreases hope for restoration
of degraded sites through natural regeneration.
Hence, it is essential to collect and assess
indigenous mycorrhizal fungi for successful
conservation and establishment of potential
and promising mycorrhizal cultures for future
use in the forestry sector.
Methodology
Place of collection
Periodical surveys were undertaken in manmade
plantations such as Acacia mearnsii, Acacia
melanoxylon, Cupressus macrocarpum, Eucalyptus
globulus, Eucalyptus grandis and Pinus
patula in the Nilgiri Biosphere Reserve
areas of Nilgiri Hills, Tamil Nadu, South India
and Hopea parviflora at Nilambur, Kerala
(Table 1). The selected sampling areas were
visited at regular intervals during April 2004
to March 2006 and recorded the occurrence and
distribution of Ectomycorrhizal (ECM) fungi.
The basidiomata samples were collected for pure
culture production of the ECM fungi.
Collection and
processing of Ectomycorrhizal (ECM) fungi
In the field, all the sporocarps of basidiomycetes
occurring in the vicinity of different tree
species from the sampling sites in the Nilgiri
Biosphere Reserve areas were collected at periodical
intervals. The fruit-bodies were observed at
the first sight for their connection with the
roots of nearby plants for confirming their
mycorrhizal nature. Notes on the general type
of habit, habitat, collection number, date of
collection and proper hosts were recorded for
all the fungi. Morphological features of the
sporocarps/
fruit bodies such as shape, texture, colour
etc were recorded when the fungi were in fresh
condition. To provide a clear visual record
of the main characteristics of the fungal sporocarps/
fruit bodies, photographs were taken in the
field itself. As far as possible, detection
of the hyphal connection between sporocarps/fruit
bodies and mycorrhizal roots was made. ECM fungal
fruit bodies at their different stages and mycorrhizal
roots were collected and kept in paper bags/
cotton cloth bags and transported to the laboratory.
Spore prints were prepared and both macroscopic
and microscopic details on the fungi were recorded
and identification of the fungi up to species
level made. Fungal specimens were air-dried
and preserved.
For describing the colour of the sporocarps/
fruit bodies of different ECM fungi, Methuen
Handbook of Colour (Kornerup and Wanscher, 1978)
was used.
Morphological
characters
The sporocarps/ fruit bodies were collected
and recorded the morphological features from
the field. The macroscopic characters like colour,
size and shape of the pileus, gills and or tubes,
stipe, attachment of gills or tubes, presence
or absence of stipe, annulus and volva, presence
or absence of rhizomorphs, etc. were recorded
in the field.
Preservation
of fruit bodies
Attempt was made to isolate the axenic cultures
from fresh fruit bodies of different ECM fungi
and then the specimens were air dried using
an electric hot air oven. The dried specimens
were preserved in polythene covers containing
naphthalene balls to prevent from pests and
mites attack and brought to the laboratory for
further microscopical analysis for proper identification.
Microscopical
characters
The dried specimens were revived in 10% Potassium
hydroxide (KOH) solution and made thin hand
sections. The sections were stained with aqueous
phloxine, cotton blue and creysyl blue and observed
under microscope. The microscopical characters
such as colour of the spore in KOH, size and
shape of the spores, ornamentation if any, type
of basidia, presence or absence of cystidia,
type of trama, presence or absence of clamp-connections,
etc. were noted.
Counting the
number of ECM fungal basidiomata/fruit bodies
in different plantations
The occurrence and distribution of basidiomata/
fruit bodies of different ECM fungi in Acacia
mearnsii, Acacia melanoxylon, Cupressus macrocarpum,
Eucalyptus globulus, Eucalyptus grandis
and Pinus patula plantations in different
study locations in the Nilgiri Biosphere Reserve
areas in the Nilgiri Hills, Tamil Nadu were
made. For recording the ECM fungal population,
one hundred trees in each of tree plantations
were selected. The type and number of different
ECM fungi observed were recorded in all the
tree plantations in the selected study locations
over a period of two years from April 2004 to
March 2006 by following
standard procedures (Mason et al.,
1983; Mohan, 1991).
Results and Discussion
Ectomycorrhizal
association and biodiversity of ECM fungi in
forest ecosystem
Based on both morphological and microscopical
characters, total of 20 different ECM fungi
such as Alnicola sp., Amanita
sp., Amanita muscaria, Cortinariuss
sp., Geastrum sp. Hebeloma
sp., Inocybe sp., Laccaria fraterna,
Laccaria laccata, Leucophleps
sp., Lycoperdon sp., Lycopedon
perlatum, Rhizopogan luteolus,
Russula sp., Russula parazurea,
Scleroderma sp., Scleroderma citrinum,
Suillus brevipus, Suillus subluteus
and Thelephora terrestris belonging
to 10 different families viz., Amanitaceae,
Cortinariaceae,Leucogastraceae,Lycoperdaceae,Rhizopoganaceae,Russulaceae,Sclerodermataceae,Suillaceae,
Thelephoraceae and Tricholomataceae were recorded
and identified. All these fungi associated with
different tree species in the Nilgiri Biosphere
Reserve areas were collected and assigned up
to their order and group levels. Of these, 12
species belonging to the group Hymenomycetes
and the remaining were belonging to Gasteromycetes
(Table 2).
It was also observed that ECM fungi viz., Laccaria
fraterna and Scleroderma sp. were found to be
associated with five different tree species
(Acacia mearnsii, Acacia melanoxylon, Cupressus
macrocarpa, Eucalyptus globulus and Eucalyptus
grandis). ECM fungal species like Lycoperdon
perlatum (Acacia mearnsii, Acacia melanoxylon,
Cupressus macrocarpa, Eucalyptus globulus);
Russula (Acacia mearnsii, Cupressus
macrocarpa, Eucalyptus globulus, Hopea parviflora)
and Suillus brevipes (Acacia mearnsii,
Cupressus macrocarpa, Eucalyptus globulus
and Pinus patula) were found in association
with four different tree species each in the
study areas during the period under investigation
(Table 3). The ECM fungi such as Amanita
muscaria, Laccaria laccata, Lycoperdon perlatum,
Rhizopogan luteolus, Russula parasurea, Suillus
brevipes, Suillus subluteus, Scleroderma citrinum
and Thelephora terrestris were exclusively
found in association with Pinus patula. It was
also observed that the ECM fungi viz., Laccaria
fraterna, Leucophleps sp. and
Scleroderma sp. were found in association
with Acaciamelanoxylon and Eucalyptus
grandis. The ECM fungus Inocybe
sp. was found in association with 3 different
tree species (Acacia mearnsii, Cupressus
macrocarpum and Eucalyptus globulus).
The ECM fungus Leucophleps sp. was found only
in association with E. grandis plantation at
Naduvattam during the period under investigation.
The ECM fungal species like Amanita, Geastrum
and Russula were found only in association
with Hopea parviflora trees in Nilambur,
Kerala.
Out of 20 different ECM fungi recorded, the
ECM fungal species viz., Alnicola, Amanita
muscaria, Cortinarius, Hebeloma, Inocybe, Laccaria
fraterna, Lycoperdon perlatum, Russula, Scleroderma
were recorded for the first time in association
with Acacia mearnsii, Acacia melanoxylon,
Cupressus macrocarpum, Eucalyptus globulus
and E. grandis plantations in the Nilgiri
Hills, Tamil Nadu (Plate 1). The other ECM fungal
species such as Amanita, Geastrum and
Russula were reported as new records
in association with Hopea parviflora
plantation at Nilambur, Kerala. Young and fresh
basidiomata were collected and pure cultures
were made by using suitable culture media for
the growth of isolates of these ECM fungi. The
isolates of the ECM fungal species viz., Alnicola
(2 isolates), Laccaria fraterna, Scleroderma,
Suillus brevipes, Suillus subluteus and
Russula sp. were raised and being maintained
as germ plasm (culture bank) bank in the institute
for further studies.
References
Kornerup, A. and Wanscher, J.H.(1978). Methuen
Hanbook of Colour. 3rd edition. Eyre Methuen,
London. 1-252.
Mason, P.A., Wilson, J., Last, F.T. and Walker,
C. (1983). The concept of succession in relation
to the spread of sheathing mycorrhizal fungi
on inoculated tree seedlings growing in unsterilized
soils. Plant and Soil., 71,
247-256.
Mohan, V. (1991). Studies on ectomycorrhizal
association in Pinus patula plantations
in the Nilgiri Hills, Tamil Nadu. Ph.D. thesis,
University of Madras, Madras, India. 260.
Table 1. List of study areas selected
for the collection of data on ECM fungi in the
Nilgiri Biosphere Reserve, Tamil Nadu and Kerala.
S.No |
Study
Locations |
Tree
plantations |
1 |
Aramby Shola
(Ootacamund) |
Acacia mearnsii, Cupressus
macrocarpumand Eucalyptus globulus |
2 |
Doddabetta
(Ootacamund) |
Acacia mearnsii, Cupressus
macrocarpum and Eucalyptus globulus |
3 |
Glenmorgan
(Ootacamund) |
Acacia mearnsii and
Eucalyptus globulus & Shola |
4 |
Naduvattam |
Eucalyptus grandis |
5 |
(Ootacamund) |
Acacia mearnsii, Acacia
melanoxylon, Cupressus
macrocarpum, Eucalyptus globulus and Pinus
patula |
6 |
Pykara
(Ootacamund) |
Acacia mearnsii and
Eucalyptus globulus |
7 |
Reescorner
(Ootacamund) |
Acacia mearnsii, Acacia
melanoxylon, Cupressus
macrocarpum, Eucalyptus globulus and Pinus
patula |
8 |
Sandynalla
(Ootacamund) |
Acacia mearnsii, Acacia
melanoxylon, Eucalyptus globulus and Pinus
patula |
9 |
Thalakundha
(Ootacamund) |
Cupressus macrocarpum,
Eucalyptus globulus and Pinus patula |
10 |
Wenlockdowns
(Ootacamund) |
Acacia mearnsii, Eucalyptus
globulus and Pinus patula |
11 |
Nilambur (Kerala) |
Hopea parviflora |
Table 2. List of Ectomycorrhizal (ECM)
fungi recorded from Nilgiri Biosphere Reserve
areas.
|
Group |
Order |
Family |
ECMfungi |
|
Hymenomycetes |
Agaricales
Boletales
Russulales |
Tricholomataceae
Amanitaceae
Cortinariaceae
Suillaceae
Russulaceae |
Laccaria fraterna, L. laccata
Amanita muscaria, Amanita sp.
Alnicola sp., Inocybe sp., Cortinarius
sp.,
Hebeloma sp.
Suillus brevipus, Suillus subluteus
Russula parazurea, Russula sp. |
|
Aphyllophorales |
Thelephorales |
Thelephoraceae |
Thelephora terrestris |
| Gasteromycetes |
Sclerodermatales
Rhizopoganales
Leucogastrales
Lycoperdales |
Sclerodermataceae
Rhizopoganaceae
Leucogastraceae
Lycoperdaceae |
Scleroderma citrinum Scleroderma sp.
Rhizopogan luteolus
Leucophleps sp.
Lycoperdon perlatum, Lycoperdon sp. Geastrum
sp. |
Table 3. Distribution of ECM fungi
in association with different tree species in
the Nilgiri Biosphere Reserve areas of Tamil
Nadu and Kerala.
S.No |
ECM
Fungi |
Name
of tree species |
No
of tree species |
1 |
Alnicola
sp. |
Acacia mearnsii,
Cupressus
macrocarpum and Eucalyptus
globulus |
3 |
2 |
Amanita
muscaria |
Acacia mearnsii,
Cupressus
macrocarpum, Eucalyptus globulus
and Pinus patula |
4 |
3 |
Amanita sp. |
Hopea parviflora |
1 |
4 |
Cortinarius
sp. |
Acacia mearnsii,
Cupressus
macrocarpum, Eucalyptus globulus |
3 |
5 |
Geastrum
sp. |
Hopea parviflora |
1 |
6 |
Hebeloma
sp. |
Acacia mearnsii,
Cupressus
macrocarpum Eucalyptus globulus |
3 |
7 |
Inocybe sp. |
Acacia mearnsii,
Cupressus
macrocarpum Eucalyptus globulus |
3 |
| 8 |
Laccaria
fraterna |
Acacia mearnsii,
Acacia
melanoxylon, Cupressus
macrocarpum, Eucalyptus globulus, Eucalyptus
grandis |
5 |
9 |
Laccaria
laccata |
Pinus patula |
1 |
10 |
Leucophleps
sp. |
Eucalyptus grandis |
1 |
11 |
Lycoperdon
perlatum |
Pinus patula |
|
12 |
Lycoperdon
sp. |
Acacia mearnsii,
Acacia
melanoxylon, Cupressus
macrocarpum, Eucalyptus globulus |
4 |
13 |
Rhizopogan
luteolus |
Pinus patula |
1 |
14 |
Russula sp. |
Acacia mearnsii,
Cupressus
macrocarpum, Eucalyptus globulus, Hopea
parviflora |
4 |
15 |
Russula
parazurea |
Pinus patula |
1 |
16 |
Scleroderma
sp. |
Acacia mearnsii,
Acacia
melanoxylon, Cupressus
macrocarpum, Eucalyptus globulus
and E. grandis |
5 |
17 |
Scleroderma
citrinum |
Pinus patula |
1 |
18 |
Suillus brevipes |
Acacia mearnsii,
Cupressus
macrocarpum, Eucalyptus globulus
and Pinus patula |
4 |
19 |
Suillus
subluteus |
Pinus patula |
1 |
20 |
Thelephora terrestris |
Pinus patula |
1 |
PLATE
– 1
1. Alnicola
sp.
2. Amanita muscaria
3. Cortinarius
sp.
1. Cortinarius
sp.
2. Hebeloma sp.
3. Laccaria fraterna
.
1. Lycoperdon sp
2. Laccaria fraterna
3. Suillus brevipes
1.Scleroderma
sp.
2. Amanita
sp.
New Records of ECM Fungi
in the Nilgiri Biosphere
Reserve, Nilgiri Hills, Tamil Nadu.
