- 1. 625 IMPROVED GERMINATION OF GYMNACRANTHERA CANARICA F O R M
A T T E D P R O O F Tambat, B., Vishwanath, K., Chaithra, G.N. and
Hareesh, T.S. (2006), Seed Sci. & Technol., 34, 625-630
Improved germination of Gymnacranthera canarica Warb. an
endangered, endemic tree species of Myristica swamps, Western
Ghats, India B. TAMBAT1 , K. VISHWANATH2 , G.N. CHAITHRA3 AND T.S.
HAREESH4 1 Department of Crop Physiology and University of
Agricultural Sciences, Bangalore, India 1 (E-mail:
[email protected]) 2 Department of Seed Science and Technology,
University of Agricultural Sciences, Bangalore, India 3 College of
Forestry, Sirsi, Uttara Kannada, Karnaraka, India 4 Bio-Science
Department, University of Mysore, Hemagangothri, Hassan, Karnataka,
India (Accepted April 2006) Summary Gymnacranthera canarica Warb,
an endangered, endemic tree species of Western Ghats, India. The
species is exclusively associated with swampy conditions and
habitat destruction seems to be the major threat. Although seed
viability was 98 per cent confirmed by TZ test, initial germination
was only 40% suggesting dormancy problem in this species. Among the
14 treatments, seed coat removal itself enhanced germination by 20
per cent (60%) over control (40%) showing partial permeability of
seed coat to water. GA3 @ 50,100 and 250 ppm with partial removal
of seed coat showed significantly higher germination by 39, 33 and
30 per cent respectively over control. However, higher
concentration of GA3 @ 500 ppm showed inhibitory effect (10%). With
respect to IAA we fail to observe any pattern in this species.
Further, nil germination in boiling water, cold, boiling water+
hormonal treatment confirming the dormancy of seeds. Our results
provide means to enhance the seed germination and helps for
restoration and conservation of an endangered species in Western
Ghats. Introduction Gymnacranthera canarica Warb. is one of the
threatened tree species (IUCN, 2002) that is associated with swampy
habitat in the Western Ghats, a global mega diversity hot spot in
India (Myers et al., 2000). It belongs to family Myristicaceae (or
nutmeg), a family one among the primitive flowering plants and
mostly known for its mace and seeds, which are of high medicinal
importance (Purseglove et al., 1981; Yoganarasimhan, 2000). The
fruits are globose with thick and fleshy pericarp. The seed
conforms to the fruits, testa woody with bright red colored aril
(Gamble, 1935). The seeds contain much fat, probably as an adaptive
mechanism for dispersal and survival under swampy conditions. In
past few decades due to conversion of swamps into areca gardens and
diversion of water for agricultural purpose, regeneration and
survival of G. canarica is drastically affected (Chandran et al.,
1999; Chandran and Mesta, 2001; Tambat et al., 2004). The field
study by Tambat et al., (2004) has demonstrated that species is
exclusively associated with swampy conditions with few meters away
from the swamps the species disappear. Thus,
2. 626 B. TAMBAT, K. VISHWANATH, G.N. CHAITHRA AND T.S. HAREESH
F O R M A T T E D P R O O F habitat destruction, which influences
the local microclimate, could be one of the major cause for reduced
germination and survival of G. canarica. As for as seed germination
is concerned the species possess hard seed coat and shown lower
germination under nursery conditions (unpublished). It is likely
that the species may have seed coat induced dormancy, as observed
in few forest species (Naidu et al., 2000; Tigabu and Oden, 2001).
The present study aims to assess the effective seed treatment that
would enhance seed germination under laboratory conditions and
thereby facilitate conservation of G. canarica an endangered tree
species through re-introduction or enrichment planting. The
reintroduction of species in to its natural habitat is one of the
best strategies for the conservation of critically endangered
endemic species, as it would act as a functional bridge between the
ex situ and in situ conservation methods (Frankel et al., 1995).
Materials and methods Mature seeds of Gymnacranthera canarica Warb.
were collected from Kathlekan forest, Siddapura range (14 16' 250,
74 44' 880) of Uttara Kannada in Karnataka during October and
November 2004. The seeds were washed in water and bulked before
imposing any treatment. The seed viability was confirmed by
following 2,3,5-Triphenyl Tetrazolium Chloride (TTC) test using
randomly selected 300 seeds of 100 seeds in each replications from
the seed lot (Agrawal and Dadlani, 1995). The seeds were allowedto
germinate in pots containing sand under ambient conditions, as Bhat
and Kaveriappa, (2002) have shown better germination by sand method
than blotter in laboratory condition (25-28C) in Gymnocranthera
farquhariana Hook. (Synonymous with Gymnacranthera canarica Warb.,
Gamble 1935). Totally 14 treatments were imposed including control
with three replications of 50 seeds and details as follows; (1)
Control (without any treatment), (2) Entire seed coat removal, (3)
Diaphragm aperture + GA3 @50 ppm (16hrs), (4) Diaphragm aperture +
GA3 @100 ppm (16hrs), (5) Diaphragm aperture + GA3 @250 ppm
(16hrs), (6) Diaphragm aperture + GA3 @500 ppm (16hrs), (7)
Diaphragm aperture + IAA @50 ppm (16hrs), (8) Diaphragm aperture +
IAA @100 ppm (16hrs), (9) Diaphragm aperture + IAA @250 ppm
(16hrs), (10) Diaphragm aperture + IAA @500 ppm (16hrs), (11)
Boiling water (100C for 15 sec), (12) Boiling water (100C for 15
sec)+ IAA @100 ppm (16 hrs), (13) Boiling water (100C for 15 sec) +
GA3 @100 ppm (16 hrs) and (14) Cold (-12C for 12 hrs). The number
of seeds germinated was recorded by taking out the seedling from
the sand bed. Per cent germination was computed based on normal
seedling basis. The data of germination was subjected to arcsin
transformation for statistical analysis. Following Completely
Randomized Design (CRD) and adopting Fischers Analysis of Variance
Technique critical difference values were calculated at 5 per cent
probability level (where F test was significant). Dunnetts t test
was then performed to compare control with all other treatments
(Panse and Sukhatme, 1967). 3. 627 IMPROVED GERMINATION OF
GYMNACRANTHERA CANARICA F O R M A T T E D P R O O F Results and
discussion From Tetrazolium test it was confirmed that viability of
seeds selected for imposing dormancy treatments was 98 per cent and
were showed deep red embryonic axis and cotyledons. Only two per
cent of seeds were showed unstained embryonic axis and pale red
staining with unstained areas in cotyledons. However, we could
observe only 40 per cent germination under ambient condition,
emphasizing the presence of dormancy in these seeds. Pre sowing
treatments have been shown to enhancing seed germination in many
species (Kattimani et al., 1999; Pandey et al., 2000; Joshi and
Dhar, 2003). The effect of seed treatment on germination of
Gymnocranthera canarica after four months has been shown in figure
1. Per cent germination of seeds with 14 treatments varied from 0
to 79 per cent. As for as improved germination, seed coat removal
alone increased the germination by 20 per cent indicating the
partial permeability of seed coat to the water. Such results were
also noticed by Naidu et al., (2000) in Sapindus trifoilatus and
Tigabu and Oden, (2001) in Albizia sp. The application of GA3 along
with partial seed coat removal further enhanced the germination
(40% over control). However, the per cent germination varied with
the concentration of GA3; we observed maximum germination (79%) in
seeds treated with 100 ppm GA3 then that of other treatments (i. e.
73 % @ 50 ppm and 70% @ 250 ppm). Forest species are known to
contain certain inhibitory compounds in seed coat and (or) Figure
1. Mean seed germination (%) as influenced by the treatment in
Gymnacranthera canarica. (Note: Hormonal treatments was imposed by
soaking the seeds in different concentrations of hormone solution
after diaphragm aperture / partial removal of seed coat for 16
hours). * 1 - Significantly superior over control * 2 -
Significantly inferior over control NS - Non significant over
control 0 10 20 30 40 50 60 70 80 90 Control Entireseedcoatremovel
HormoneGA350(16hr) HormoneGA3100(16hr) HormoneGA3250(16hr)
HormoneGA3500(16hr) HormoneIAA50(16hr) HormoneIAA100(16hr)
HormoneIAA250(16hr) HormoneIAA500(16hr) Boilingwater(100oC-15sec)
Bolingwater+IAA100 Bolingwater+GA3100 Cold(-12oC-12hrs)
MeanGermination(%) LSD(P
