Mycorrhizal association of Ochlandratravancorica in Kerala, India
P.P. Rajeshkumar 1, V.B.
Hosagoudar 2 & B. Gopakumar 3
1,2,3 Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Palode, Thiruvananthapuram, Kerala 695562, India
1 pprajeshkumar1981@gmail.com, 2 vbhosagoudar@rediffmail.com (corresponding author), 3 gopugokulam@rediffmail.com
doi: http://dx.doi.org/10.11609/JoTT.o3235.3673-77
Editor: H.C. Nagaveni,
Institute of Wood Science and Technology, Bengaluru, India. Date of publication:26 February 2013 (online & print)
Manuscript details: Ms #
o3235 | Received 13 June 2012 | Final received 10 January 2013 | Finally
accepted 14 February 2013
Citation: Rajeshkumar, P.P., V.B. Hosagoudar & B. Gopakumar(2013). Mycorrhizal association of Ochlandra travancorica in Kerala, India. Journal of
Threatened Taxa 5(2): 3673–3677; doi:10.11609/JoTT.o3235.3673-77.
Copyright: © Rajeshkumar et al. 2013. Creative Commons
Attribution 3.0 Unported License. JoTTallows unrestricted use of this article in any medium, reproduction and
distribution by providing adequate credit to the authors and the source of
publication.
Funding: Jawharlal Nehru
Tropical Botanic Garden & Research Institute, Palode.
Competing Interest: None.
Acknowledgements:We thank Dr. P.G. Latha, Director and Dr. K.C. Koshy, Senior
Scientist, JNTBGRI, Palode for the facilities and for
generously permitting us to use the soil samples, respectively. We thank
the head, Department of Agronomy, College of Agriculture, Kerala Agricultural
University, Vellayani, Thiruvananthapuram.
For
figures, images, tables -- click here
Terminal feeder roots and rhizosphere soil samples of the Reed Bamboo Ochlandra travancoricawere collected in July 2011 from different localities in Kollam and
Thiruvananthapuram districts of Kerala State. Composite soil samples (Soil pH
3.9–5.6.) revealed the presence of nine AM fungal taxa, namely, Claroideoglomus etunicatum, Glomus aggregatum,G. boreale, G. macrocarpum,G. multicaule, G. tortuosum, Sclerocystis clavispora,S. rubiformis and S. taiwanensis. Root colonization was 42–72 % and
extensive hyphal and vesicular stages were
observed. The extra-radical hyphae
were hyaline and dichotomously branched on root epidermis showed appressoria. The hyphal coils were observed in the cortex
cells.
The Reed Bamboo is one of the
most important sources of raw material for the paper and pulp industry,
traditional cottage industries and is widely distributed in the Kerala State in
Western Ghats. The genus Ochlandra represents seven species and a variety
(Image 1a). Ochlandra travancorica Benth. ex Gamble is a big size reed occurring widely as an
undergrowth in the low level evergreen and semi-evergreen forests. Pure patches on the banks of rivers and
streams form impenetrable thickets where other tree species cannot grow but
also occurs in abandoned cultivated land. The species grows profusely in southern Kerala, especially in the
forests of Thiruvananthapuram, Thenmala and Ranni. It
prefers diffused light, requires annual rainfall of more than 1500mm and good
drainage for its luxuriant growth. The perfect growth and regeneration of these valuable plants in its
restricted habit and habitat is presumed to be because of certain microbes,
especially mycorrhizal fungi.
Materials and Methods: The feeder roots and rhizosphere soil samples of Ochlandra travancorica were collected from four sites (Bonacaud, Kottoor, Kulathupuzha and Palode) of
Kollam and Thiruvananthapuram districts in Kerala in July 2011. Four soil samples were taken from each
site up to the depth of 20cm and prepared into one composite sample (ca.500gm). The soil was screened to
isolate Arbuscular Mycorrhizal(AM) fungal spores by wet-sieving and decanting technique and the count
expressed as spores per 100g of soil (Gerdemann &
Nicolson 1963).
Terminal feeder root samples
collected from a different area was processed separately; washed in running tap
water, cut into small pieces about 1cm, boiled in 10% KOH (w/v) for one hour,
cooled to room temperature, washed thoroughly in distilled water, stained in lactophenol cotton blue (Philips & Hayman 1970). They were observed under a binocular
microscope to locate vesicles and arbuscules to evaluate
the percentage of mycorrhizal colonization.
No. of mycorrhizalroot segments
Percentage of mycorrhizal colonization =
---------------------------------------------- x 100
Total
no. of root segment observed
The frequency of occurrence
of AM fungi was calculated by using the formula:
Sample unit in which fungal species
occurred
The frequency (%) =
--------------------------------------------------------- x 100
Total number
sample units examined
Numerical species richness
was used in the present study. Index of general diversity
(H’) was calculated by Shannon & Weaver (1949) cited in Odum(1971).
H′= Σ (ni / Nloge ni / N)
where, ni is the importance value of each species and N is the total importance
value.
Index of
dominance (C) (Simpson 1949).
C = Σ (ni/ N)
where ni is the number of individuals of each species and N is the total number of
individuals in that location.
The fungal spores were
identified with the help Schenk & Perez (1990).
The soil from different
sampling sites was analyzed for soil fertility such as pH (Eutechinstruments pH tutor), electric conductivity (Eutechinstruments), organic carbon (Walkley & Black’s
rapid titration method 1934), total nitrogen micro-Kjeldahl method (Jackson 1973), available phosphorous (Bray
& Kurtz 1945) and available potassium was estimated by ammonium
acetate method (Hanway & Heidel1952) using flame photometer (Systronic 3292).
Result
Hyphal structure: The root samples exhibited
the presence of extensive hyphal and vesicular stages
of AM fungal colonization and the colonization varied from 42–72 %. The extra-radical hyphae were hyaline
and dichotomously branched on root epidermis to form an appressoria. The hyphae on the root were hyaline to
yellowish-brown, thick-walled, aseptate, growing
inter and intra cellularly through the cortex and had
penetrated the inner cortex. The hyphal coils were observed in root cortex and globose to subglobose terminal
vesicles (25– 37 × 25–40 µm; Image 1b) were observed in the
cortex cells.
Spore count: Arbuscular mycorrhizal fungi were found to be
present in all the sampling sites in this study and spore count was
272–348 spores per 100g soil (Fig. 1). A total of nine species, namely, Claroideoglomus etunicatum,Glomus aggregatum, G. boreale, G. macrocarpum, G. multicaule, G. tortuosum, Sclerocystis clavispora, S. rubiformis, S. taiwanensis were
isolated from the different sampling areas. Among these, G. aggregatum, S. clavispora andS. rubiformis were common to all the sites.
The frequency of occurrence
of mycorrhizal species associated with O. travancorica varied from one locality to another (Table
1). G. aggregatum, S. clavispora andS. rubiformis were found in all the locations of
the study; whereas, incidence of G. macrocarpum was
75% and G. boreale, G. tortuosum and S. taiwanensis was 50%, Claroideoglomus etunicatum and G. multicaule showed 25% of
frequency. Species richness also varied.Kulathupuzha harboured more
number of species than the other study localities. Simpson’s diversity index
(Ds) and Shannon’s diversity index (Hs) was in the
range of 0.6–0.8 and 2.8–4.4, respectively.
Physiochemical characters of soil: The pH of O. travancorica rhizospheresoils collected from the study sites was 3.9–5.6. The level of phosphorous was very
low. The physiochemical characters
of soil samples are in the Table 2.
Description of the species
Claroideoglomus etunicatum (Image 1c)
(W.N.
Becker & Gerd.) C. Walker & A. Schüßler Gloucester, p. 22, 2010.
Glomus etunicatum W.N.
Becker & Gerd., Mycotaxon 6(1): 29, 1977.
Material examined:25.vii.2011, isolated from rhizosphere soil of Ochlandra travancorica,Kulathupuzha, coll. P.P. Rajesh Kumar (TBGT slide no.
1020).
Chlamydospores formed singly in soil or in dead roots,
adherent to debris, globose to subglobose,
70–135 µm in diam., wall smooth to roughened. Spore wall 4–10 µm thick, outer
wall hyaline, up to 5µm thick, inner wall persistent, yellow to brown,
laminated 2–8 µm thick. Intact outer wall rarely present in matured spores. Hyphalattachments to spores are one; outer wall extending down up to attached hypha
for a short distance. Attached
hypha thickened by extension of inner spore wall for up to 30µm, spore contents
separated from attached hypha by a thin curved septum at maturity, opening
occluded by inner wall thickening.
Glomus aggregatum (Image 1d)
Schenck & Smith emend. Koske, Mycologia 74(1): 80, 1982.
Materials examined:25.vii.2011, isolated from rhizosphere soil of Ochlandra travancorica,Kulathupuzha, coll. P.P. Rajesh Kumar (TBGT slide no.
1041); 25.vii.2011, Palode (TBGT slide no. 1077);
20.vii.2011, Bonacaud, (TBGT slide no. 1088);
22.vii.2011, Kottur, TBGT slide no. 1090.
Chlamydospores formed in loose clusters, without peridium, hyaline to yellow, globose,subglobose, obovate,
cylindrical to irregular, 40–90 x 45–110 µm; wall yellow to
yellowish-brown, up to 2µm thick, outer walls slightly thicker and lighter in colour than the inner wall; walls separable with slight
pressure. Subtending hyphae at the
point of attachment was 4–10 µm wide, straight to sharply curved at the
spore base. Pore usually open,
2–5 µm wide, often closed by a thin curved septum, cytoplasmic plug or
spore wall thickening but not by hyphal wall
thickening.
Glomus boreale (Image 1e)
(Thaxt.) Trappe & Gerd., in Gerd. &
Trappe, Mycol. Mem. 5: 58, 1974 (borealis).
Endogone borealis Thaxt., Proc. Amer. Acad. Arts
& Sci. 57: 318, 1922.
Material examined:25.vii.2011, isolated from rhizosphere soil of Ochlandra travancorica,Kulathupuzha, coll. P.P. Rajesh Kumar (TBGT slide no.
1033); 27.vii.2011, Palode, coll. B. Gopakumar (TBGT slide no. 1051).
Chlamydospores mass irregular, spongy, dark to chocolate
brown, 6–8 mm in diameter. Gleba with loosely woven hyphae, 10–18 µm broad,
contains foreign matter and many abortive spores. Spores borne on slender hyphae and
subtended by the septum, reddish-brown, broadly and symmetrically elliptical,
128–142 x 98–106 µm in diam., wall reddish-brown, up to 8µm thick.
Glomus macrocarpum (Image 1f)
Tul. & C. Tul., G. Bot. Ital. 1(7–8): 63, 1845 (macrocarpus).
Endogone macrocarpa (Tul. & C. Tul.) Tul. & C. Tul., Fungi Hypog.: 182, 1851.
Material examined:25.vii.2011, isolated from rhizosphere soil of Ochlandra travancorica,Kulathupuzha, coll. P.P. Rajesh Kumar (TBGT slide no.
1023); 20.vii.2011, Bonacaud, coll. P.P. Rajesh Kumar
(TBGT slide no. 10 99); 25.vii.2011, 22.vii.2011, Kottur,
coll. P.P. Rajesh Kumar TBGT slide no. 1102).
Chlamydospores slightly longer than wide, globose, subglobose to irregular, 98–130 x 98–130µm. Spore wall composed of two layers, outer
layers thin up to µm thick; inner wall layer yellow, 6–10 µm thick. Spores taper to the point of attachment,
hypha single, persistent, 12µm broad at this point of attachment, inner wall
occlude the pore of the attached hyphae, and the wall thickening continuous in
to the subtending hyphae for up to 75µm from the spore. Pore closed by a septum. Spores
characteristically bear straight, long subtending hyphae
which may extend up to 100µm before branching.
Glomus multicaule (Image 2a)
Gerd. &Bakshi,
Trans. Brit. Mycol. Soc. 66(2): 340, 1976 (multicaulis).
Material examined:25.vii.2011, isolated from rhizosphere soil of Ochlandra travancorica,Kulathupuzha, coll. P.P. Rajesh Kumar (TBGT slide no.
1018).
Sporocarps unknown; chlamydosporesdark brown, 142–240 x 125–150 µm in diam., ellipsoidal, broadly
ellipsoidal, subglobose to occasionally triangular,
with 1–4 hyphal attachments, attachments
generally occurring at opposite ends of the spore. Spore wall 8–22 µm thick, thickest
at the point of hyphal attachments, rounded projections
1–3 µm long, evenly distributed over the wall surface.
Glomus tortuosum (Image
2b)
N.C. Schenck & G.S. Sm., Mycologia 74(1): 83, 1982.
Parapseudoglomus tortuosum (N.C. Schenck &
G.S. Sm.) S.P. Gautam & U.S. Patel, The Mycorrhizae: Diversity, Ecology and Applications, p. 11,
2007.
Sporocarps unknown, chlamydosporesformed singly or in pairs in soil, immature spores subhyaline,
without hyphal mantle. Matured spores yellow to dull
greyish-brown with a mantle of sinuses hyphae closely apprised to the spore and
flattened, 4–10 µm wide, forming a layer of hyphae on the spore surface,
up to 20µm thick, occasionally mantle extended down to the hyphalattachment. Mantle hyphae hyaline
when young, acquiring a brownish pigment with age and originating from the
swelling on the hyphal attachment, 10–20 µm
below the spore or arising from the other hyphae adjacent to the spore. Mantle adhered with debris and soil
particles. Chlamydospores globose to subglobose,
120–210 µm (excluding mantle); spores with single laminate thin wall less
than 1µm. The width of hyphal attachment at the spore base is 8–20 µm,
hyaline to light yellow.
Material examined:25.vii.2011, isolated from rhizosphere soil of Ochlandra travancorica,Kulathupuzha, coll. P.P. Rajesh Kumar (TBGT slide no.
1062); 27.vii.2011, Palode, coll. P.P. Rajesh Kumar
(TBGT slide no. 1097).
Sclerocystis clavispora (Image 2c)
Trappe, Mycotaxon 6(2): 359, 1977.
Material examined: 27.vii.2011, isolated from rhizosphere soil of Ochlandra travancorica, Palode, coll. P.P. Rajesh Kumar (TBGT
slide no. 1068); 25.vii.2011, Kulathupuzha, coll.P.P. Rajesh Kumar (TBGT slide no. 1072); 20.vii.2011,Bonacaud, P.P. Rajesh Kumar (TBGT slide no. 1073); 22.vii.2011, Kottur, coll. P.P. Rajesh Kumar (TBGT slide
no. 1074).
Sporocarps globose to subglobose,
400–710 x 500–710 µm, brownish-black to black, minutely verrucose, spores formed radially in a single, tightly packed layer arounda central plexus of hyphae; peridium lacking. Chlamydospores brown, 142–180 x 20–38 µm, clavate to subcylindrical, tapering towards hyphal attachment,hyphal attachment 7–10 µm broad. Spore wall1–3 µm thick at the sides, 17–22
µm thick at the apex, 5–8 µm thick at the base. Central plexus 145–440 µm in diam., composed of tightly interwoven, pale brown, thin walled hyphae of 3-8 µm broad.
Sclerocystis rubiformis (Image 2d)
Gerd. & Trappe, Mycol. Mem. 5: 60, 1974.
Glomus rubiforme (Gerd. & Trappe) R.T. Almeida & N.C. Schenck, Mycologia 82(6): 709,
1990.
Sclerocystis indica Bhattacharjee & Mukerji in Bhattacharjee, Mukerji & Misra, Acta Bot. Indica 8(1): 99, 1980.
Sclerocystis pachycaulis C.G. Wu & Z.C. Chen, Taiwania 31: 74,
1986.
Material examined:25.vii.2011, Isolated from rhizosphere soil of Ochlandra travancorica,Kulathupuzha, coll. P.P. Rajesh Kumar (TBGT slide
no. 1030); 20.vii.2011, Bonacaud, coll. P.P. Rajesh
Kumar (TBGT slide no. 1032); 27.vii.2011, Palode,
coll. P.P. Rajesh Kumar (TBGT slide no. 1046); 22.vii.2011, Kottur,
coll. P.P. Rajesh Kumar (TBGT slide no. 1057).
Sporocarps dark brown, subgloboseto ellipsoid, 180–370 x 180–370 µm,
consisting of a single layer of chlamydosporessurrounding a central plexus of hyphae, resembling a miniature blackberry. Peridiumnearly absent, individual spores at times partially enclosed in a thin network
of tightly appressed hyphae. Chlamydosporesdark brown, obovoid, ellipsoid to subglobose,
32–110 x 24–80 µm with a small pore
opening into the thick walled subtending hypha. Spore wall laminate, 3–8 µm thick,
up to 13µm thick at spore base, often perforated projections on the inner
surface. A variable stalk-like
projection produced near the base of some spores.
Sclerocystis taiwanensis (Image 2e)
C.G. Wu
& Z.C. Chen, Trans. Mycol. Soc. Rep. China 2(2): 78, 1987; Shaji, Rajeshkumar & Hosag., Indian J. Bot. Res. 5
(1&2): 125–126.
Glomus taiwanense (C.G. Wu
& Z.C. Chen) R.T. Almeida & N.C. Schenck, Mycologia 82(6): 711, 1990.
Glomus taiwanense (C.G. Wu
& Z.C. Chen) R.T. Almeida & N.C. Schenck ex
Y.J. Yao, in Yao, Pegler & Young, Bull. 50(2): 306, 1995.
Material examined:20.vii.2011, isolated from rhizosphere soil of Ochlandra travancorica,Bonacaud, coll. P.P. Rajesh Kumar (TBGT slide no.
1079); 22.vii.2011, Kottur, coll. P.P. Rajesh Kumar
(TBGT slide no. 1080).
Sporocarps globose, brown to
dark brown, 190–250 x 190–250 µm in diameter. Chlamydosporesformed radially in a single, tightly packed layer around the central plexus of
hyphae, clavate to cylindrical, cinnamon brown,
65–80 µm long, 28–32 µm broad at the upper portion, 9–18 µm
broad at the lower portion, with or wit out septum at spore base. Wall two-layered, external one thin and
hyaline, inner layer brown, apical portion of the wall deep golden brown, 9–13
µm thick, 2–3 µm thick laterally. Central portion pale yellow and typically distinct
from the wall. Stalk pale
brown, continuous, 9–22 x 2–4 µm, central plexus up to 70µm in
diameter.
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