The exudates of three fungal species (Aspergillus niger, Fusarium sambucinum and Penicillium
canescens)
have
been
tested
for
their

effect on the algal population and diversity of
El-Ibrahemia Canal. It has been found that the
exudates of F. sambucinum was stimulatory
for the algal population, whereas that of A. niger was inhibitory. Penicillium canscens exudate,

in comparison, displayed the weakest effect. The results imply a great variation in
the effectiveness of different types of
fungal exudates on the different algal taxa. Chlorella
fusca has been studied intensively, because it was the only chlorophycean species that survived
and tolerated all applied concentration of the
exudates of the three studied fungi.
The growth of C. fusca has been enhanced by F. sambucinum exudates, but not by that of A.
niger. The effect of fungal exudates on some metabolic components of C. fusca is discussed.