บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

The dynamics of bud development in ratooning stubble of sugar cane varieties.

Ferraris, R. and Chapman, L. S.

Proceedings of the Australian Society of Sugar Cane Technologists. Year: 1991 Issue: No. 13 Pages: 164-171 Ref: 4 ref.

1991

บทคัดย่อ

Cellulolytic activity of Penicillium digitatum and P. italicum related to fungal growth and to pathogenesis in citrus fruit.

Cultural conditions were found to be important in determining the extent of Cx-cellulase activity in P. digitatum and P. italicum, post harvest decay pathogens of citrus. At pH 5.5-7.5, activity was correlated with mycelial dry wt. However, at pH 4.5 and more so at pH 3.5, activity was markedly reduced while fungal growth was not affected. Induction of Cx-cellulases of both species was delayed by the presence of carboxymethyl cellulose as a carbon source, indicating that the cellulases are constituent enzymes. Cellulase activity of the 2 species on different carbon sources was detected prior to the initiation of sporulation. A sporeless mutant of P. digitatum exhibited cellulolytic activity similar to that of the normal strain, suggesting no role for sporulation in the Cx-cellulase synthesis. Cx-cellulase activity in orange cv. Valencia started during the early stages of pathogenesis, before the appearance of symptoms. A correlation between cellulase activity and symptom severity was apparent during the first 2 d after inoculation. At the end of the incubation period both fungi almost attained their max. enzymic activity, whereas the disease index continued to rise gradually until total rot was achieved. A possible role of Cx-cellulases of the 2 species in the early stages of pathogenesis was suggested.