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in medium lacking carbon. Best growt h of the or ganism wa s observed
on sucrose. It was poor on inulin and sugar alcohols viz. dulcitol and
mannitol. Rest of the carbon sources were good or moderate for
growth.
Some correlation existed between growt h and sporulation on certain
compounds. Glucose, maltose, laetose and suerose which were
good for growth also supported good or excellent sporulation. Conversely
sources like dulcitol, mannitol and inulin which were poor for
growth completely failed to induce sporulation. On rest of t he compounds,
however, such correlations were not possible. The pH of the
culture filtrates in general drifted towards neutral point except in few
cases viz. dulcitol, mannitol, dextrin and inulin where a slight increase
in pH was observed.
c. Nitrogen nutrition.
The growth and sporulation results given in Table III r evealed
that C. truncatu m could not grow on sodium nitrite and on a medium
lacking nitrogen. Glutamic acid support ed best growt h. Except calcium
nitrate and leucine all other nitrates and ami noacids proved to be
a good source of nitrogen for growth. It was al so good on peptone
and asparagine. Ammonium compounds were moderate sources for
growth. Rest of the compounds either support ed poor growt h or
completely failed to deve lop t he mycelium.
In few cases evidences were there when good growth of the
organism was associated with good or excellent sporulat ion (nitrate s
of potassium, sodium and ammonium, asparagine, alanine, arginine
and aspartic acid) and poor sources supporting t he development of
few spores only or completely suppressing the sporulat ion (a mmonium
chloride, acetamide and t hiour ea ). Such a correlation, however, did
not exist on rest of the nitrogen compounds wher e the pathogen
failed to develop any sp ores or induced onl y poor or fai r sporulat ion
inspite of the fact that they were good sources fo r growth.
A maked alteration in pH at the end of the incubation period was
observed with different sources. It drifted t owar ds neutrality with
all nitrates and with asparagine, ala nine and hist idine. F inal pH of
the culture filtrates drifted to wards al kalinit y in case of urea, peptone,
ammonium oxala te, valine, glutamic acid and aspartic acid while it
drifted towards acidity in rest of the comp ounds except serine wher e
there was no any marked change in pH.