دراسة النشاط الإنزيمي لبعض أنواع الجنس Alternaria و تأثير يعض العوامل البيئية على نموها القطري

The enzymatic activity of nine Alternaria species (Alternaria alternata, A. chlamydospora, A. citri, A. dennisi, A. longipes, A. petroselini, A.plurispetata, A. raphani, and A. triticina) was tested and most of the isolates showed positive status for detection of the tested enzymes( cellulase, lipase, protease amylase, pectinase, and phenol oxidase).The influence of some environmental factors on the radial growth of the isolated species have been studied. Considering temperature effect, the tested isolates grew within temperature range of 15-35°C with optimum rage of 25-30°C. The growth was inhibited at 10 and 40°C. For the NaCl influence, Alternaria isolates tolerated different concentrations of the salt even at 10% and the growth stopped at a concentration of 12.5% for all the tested isolates. The fungus species grew in different tested pH ranges(3-9) with the optimum of 6-7.