Friesia X, 4-5

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toxicity on the acid side is due to the presence of free nitrous acid
in the medium (COCHRANE & CONN 1950), which produces destructive
effect on the proteins and aminoacids of fungal cells (LILLY & BAR­
NETT 1951). Ammonium compounds (except ammonium nitrate) were
unsatisfactory sources as they supported moderate or poor growth of
the present organism. This may be due to the sharp fall in pH level
which resulted due to the more rapid utilization of anions of the
ammonium nitrogen than cations. With ammonium nitrate, however,
pH values remained within favourable limits.
All the aminoacids (except leucine and histidine) supported good
growth of the fungus. Leucine proved moderate while histidine supported
poor growth. The differences of growth on various aminoacids
may be due to the different degrees of availability of carbon skeleton
of aminoacids for the synthesis of carbohydrates, proteins and fats
(GOTTLIEB & CIFERRI 1956). Present results are in agreement with
those of CHATURVEDI (1964) on Colletotrichum capeici.
The present organism was capable of growing on a wide range of
sulphur compounds, but all the sulphur compounds did not support
equal growth. Absence of growth on zinc sulphate may be related to
the toxic effect of zinc.
In the present investigation there was no definite correlation between
growth and sporulation and practically all grades of sporulation
were recorded with significantly good or poor sources of carbon,
nitrogen and sulphur.
ACKNOWLEDGEMENTS
The senior author is grateful to ICAR, New Delhi, for the award of
fellowship. The authors wish to thank Director of Research at this UniversitY
for research facilities.
REFERENCES
Agnihotri, V. P. (1968): Studies on Golletotrichum capsici. V. Utilization
of organic acids. - Path. Microbiol. 32: 29-34.
Bais, B. S., S. B. Singh & D. V. Singh (1970): Effect of different carbon
and nitrogen compounds on the growth and sporulation of Curvularia
pallescens. - Indian Phytopath. 23: 511-517.
Bonn, W. G. & R. A. Cappellini (1970): Sporulation of Gibberella zeae, III.
Carbon and nitrogen nutrition on growth and marcroconidium
production. - Can. J. Bot. 48 (7): 1335-1337.