| Abstract: | Gibberellic acid at 10-4Mxxx was optimal for enhancement of growth, O2 evolution, photosystem II and I and the activity of glycollate dehydrogenase of Anacystis nidulans. A stimulatory effect was observed on photosystem II. Other concentrations of gibberellic acid were inhibitory to O2 evolution and photosystem I. Syntheses of phycocyanin, phycoerythrin and  -carotene were significantly enhanced after 48 h incubation with gibberellic acid at 10-3Mxxx but the chlorophyll content began to increase 3 h after adding 10-4Mxxx gibberellic acid.The author is with the Department of Biological Sciences, Faculty of Science, University of Science and Technology, Irbid, Jordan. |
