EFFECT
OF
LEAF EXUDATES
AND
LEAF TISSUE SAP
ON
SPORE
GERMINATION
EFFECT OF LEAF EXUDATES AND LEAF
TISSUE SAP ON SPORE GERMINATION
Apart from the envirorunental factors the leaf exudates and leaf tissue sap plays
an important role in the germination of spores/conidia which are present on the surface
of the leaves. A number of plant species have also reported to have some natural
chemical substances in their exudates and tissue sap, which were toxic to fungi. The
effect of leaf exudates and leaf tissue sap on the germination of spores/conidia varies
with the species of fungi. In present investigation the percentage of spore germination
and percentage of inhibition was observed both for leaf exudates and leaf tissue sap. The
percentage of germination of spores/conidia is expressed in term of percentage inhibition
of spore germination to indicate direct influence of chemical substances present in leaf
exudates and leaf tissue sap.
In the present investigation the effect of leaf exudates and leaf tissue sap of
Mentha arvensis Linn. on the germination of spores/conodia was observed for most
frequent species fungal species found on leaf surface mycoflora i.e. Alternaria alternata,
Aspergillus niger, Curvularia clavata, Curoularia lunata and Curoularia avaidea. After each
incubation period (2, 4, 8, 16 and 24 hours), five microscopic fields were examined to
encounter the percentage germination and inhibition of these spores of above mentioned
fungal species. (Table XVII), (Fig- 21)
The result indicated that the percentage of germination of spores/conidia in all
the tested fungi was more in control in comparison to leaf exudates and leaf tissue sap
i.e. Altemaria altemata (96.52%),Aspergillus niger (5.94), Curoularia clavata (92%), Curou/aria
opoidea (84.09%), Curvularia lunata (80.28%) and Aspergillus niger (5.94%).
1l1e conidial germination of Altemaria altemata in control after 02 hours was
64.61%, while in leaf exudates 24.79% and in leaf tissue sap 17.34%. After 04 hours,
49
germination in control was 91.13% while in leaf exudates 38.54% and in leaf tissue sap
20.51%. After 08 hours germination in control was 93.80% while in leaf exudates 62.98%
and in leaf tissue sap 23.11%. After 16 hours, germination in control was 96.01% while in
leaf exudates 70.65% and in leaf tissue sap 23.13% and After 24 hours, germination in
control was 96.52% while in leaf exudates 75.49% and in leaf tissue sap 24.15%.
The conidia of Aspergillus niger were unable to germinate in control, in leaf
exudates and in leaf tissue sap even up to 08 hours. After 16 hours, germination in
control was 2.46% and after 24 hours, germination in control was 5.94%. The conidia of
Aspergillus niger fail to germinate in leaf exudates and leaf tissue sap even up to 24 hours.
In control, the germination of conidia of Curvularia clavata after 02 hours was
5.88%, while in leaf exudates 51.20% and in leaf tissue sap 42.28%. After 04 hours,
germination in control was 21.68% while in leaf exudates 56.21% and in leaf tissue sap
43.77%. After 08 hours germination in control was 86.40% while in leaf exudates 58.08%
and in leaf tissue sap 48.18%. After 16 hours, germination in control was 89.07% while in
leaf exudates 61.58% and in leaf tissue sap 52.25% and After 24 hours, germination in
control was 92% while in leaf exudates 68.50% and in leaf tissue sap 53.70%.
The conidial germination of Curvularia lunata in control after 02 hours was 16.31%,
while in leaf exudates 23.27% and in leaf tissue sap 17.47%. After 04 hours, germination
in control was 22.90% while in leaf exudates 45.39% and in leaf tissue sap 38.31%. After
08 hours germination in control was 76.19% while in leaf exudates 53.93% and in leaf
tissue sap 45.62%. After 16 hours, germination in control was 78.03% while in leaf
exudates 62.84% and in leaf tissue sap 48.78% and After 24 hours, germination in control
was 80.28% while in leaf exudates 69.88% and in leaf tissue sap 55%.
The germination of conidia of Curvularia ovoidea in control after 02 hours was
16.31%, while in leaf exudates 23.36% and in leaf tissue sap 21.58%. After 04 hours,
germination in control was 22.90% while in leaf exudates 38.25% and in leaf tissue sap
26.66%. After 08 hours germination in control was 70.63% while in leaf exudates 45.18%
and in leaf tissue sap 41.53%. After 16 hours, germination in control was 78.26% while in
leaf exudates 56.39% and in leaf tissue sap 43.80% and After 24 hours, germination in
control was 84.09% while in leaf exudates 67.05% and in leaf tissue sap 47.50%.
50
Above results indicating that the percentage of germination of spores/conidia of
all the tested fungi is decreases gradually in leaf exudates and leaf tissue sap as
compared to control. Similar findings have also been reported by Kono (1960), Kasuge
and Hewitt (1964), Bahadur and Sinha (1966), Dunn et al. (1969), Godferey (1976),
Chandra! and Karkun (2000), Kamble and Bhale (2004). Leaf exudate contain some
specific substances which is responsible for the inhibition of germination of
spores/conidia (Mac and Veechi, 1973; Brillova, 1971; Godferey and Clements,1978). The
inhibition of germination is due to fungistatic properties of leaf exudates (Toppas and
Wain, 1957). Chandrol and Karkun (2000) reported the antifungal properties of some
plant extracts.
The results also indicating that the percentage of inhibition of spore germination
was less in case of leaf exudates and more in case of leaf tissue sap. In case of Alternaria
altrrnata, 24.51% inhibition (After 24 hours) was observed in leaf exudates whereas in
leaf tissue sap, inhibition was 75.85%. In Aspergillus niger, the inhibition of germination
was 100% both in leaf exudates and leaf tissue sap. In Curvularia clavata, inhibition was
31.50% in leaf exudates and 46.30% in leaf tissue sap. Maximum inhibition was recorded
in leaf tissue sap. In case of Curvularia lunata, 30.12% inhibition was observed in leaf
exudates whereas in leaf tissue sap, inhibition was 45%. In Curvularia avoidea, inhibition
was 32.95% in leaf exudates and 52.50% in leaf tissue sap.
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