Some physiological effects of abscisic acid on vicia faba plants III- changes in gibberellins and cytokinins contents

The activity levels of the endogenous gibberellins and cytokinins were followed in the extracts of radicles and plumules of Vicia faba seedlings at different stages of germination and seedling growth. It has been observed that the changes in the activity levels of both gibberellins and cytokinins were detected after treatment with the concentration of ABA [10-6 M]. Low concentration of ABA [10-9 M] induced marked increase in the contents of the same hormone in the radicles and plumules extracts throughout the experimental period

Some physiological effects of abscisic acid on vicia faba plants I- morphological characteristics and metabolic activities during germination and seedling growth

The effect of ABA on germination, growth, carbohydrates, nitrogenous constituents, nucleic acids and the activity of certain enzymes of Vicia faba seedlings throughout an experimental period of 192 hours were studied. It was found that the highest concentration of ABA [10-3 M] delayed the start of germination, while the relatively low concentration [10-9 M] induced nonsignificant effect on this parameter. The high concentration of ABA induced highly significant decreases in radicle and plumule lengths, fresh and dry weights of the seedlings, while the lowest concentration [10-9 M] highly significantly increased these characters. 10-6 and 10-9 M ABA decreased the reducing sugars content whereas the polysaccharides and total sugars were increased. 10-9 M ABA induced significant increases in total soluble nitrogen, decreased nonsignificantly the protein nitrogen whereas 10-6 M decreased the protein-N content and increased the total N. The activities of protease, RN-ase were decreased at all test concentrations

Some physiological effects of abscisic acid on vicia faba plants II- changes in the endogenous auxins, growth inhibitors and certain oxidative enzymes

The activities of IAA-oxidase, peroxidase and catalase in the extract of radicles and plumules of Vicia faba seedlings throughout an experimental period of 192 hours germination are markers to get information about the effect of abscisic acid on the endogenous auxins and growth inhibitors. It was found that 10-6 M ABA markedly reduced the biological activities of auxins and markedly increased the growth inhibitors particularly the unsaturated lactone compounds and ABA. On the other hand, the low concentration of ABA [10-9 M] induced opposite changes. The activities of IAA-oxidase and peroxidase were increased while the activity of catalase was decreased at all concentrations of ABA used