In the present study some morphological alterations in the hyphal tips when calcium ionophore was added to Aspergillus nidulans wild type (wt) and to plcA gene depletion mutant were studied. Hyphal morphology from both strains was also compared when they were grown on glucose or pectin as only carbohydrate source.  Conidia from 7-day-old culture were inoculated onto dialysis membrane overlying Cove's solid medium supplemented with glucose or pectin (0.5%) and incubated at 30°C for 30 h. After, calcium ionophore (100mM) was applied directly onto the cultures, which were reincubated for 6 and 8h. The hyphae were photographed with T MAX 400 film using a Zeiss binocular stereomicroscope with transmitted light. Increase in hyphal branching was detected in A. nidulans (wt) submitted to calcium ionophore treatment after 6h in glucose or pectin but in the mutant similar morphology was detected in calcium ionophore absence. Calcium ionophore in the mutant (plcA) didn't alter its morphology maybe because Ca2+ levels were already affected by the depletion of plcA gene. These results suggest that the depletion on plcA gene altered the Ca2+ gradient and the polarity of hyphae. On the other hand the mutant response to glucose or pectin was similar, probably because it lost the capacity to recognize different carbon sources. The results presented here reinforce the calcium gradient role in the maintenance of hyphal polarity during the growth of A. nidulans and the importance of phospholipase C on the recognition of carbohydrate source.