Role of gibberellins and cytokinins in regulation of germination during development and ripening of Triticale caryopses

The germination of caryopses of M-T3 Triticale generation, which were freshly harvested in different growth and developmental phases has been studied. A significant influence of the abscisic acid (ABA) accumulation on the increment of number of germinating caryopses has been found. Already in the first phase af the embryogenesis considerable stimulating effects of kinetin and gibberellin-A3 (GA3) on the germination of embryos which were isolated from freshly collected grains have been shown. When both stimulators were used together marked synergetic reaction occurred. It has been also determined that in the initial period of embryogensis premature germination occurs, to a higher extent, under the action of cytokinins than! Whether in the further phases of the caryopse development, when embryo develop mainly through the cell elongation, mostly gibberellins seem to be responsible for the activation of germination processes. The more mature were seeds the quicker germinated whole caryopses and embryos isolated from them at different ripeness, after 3-month storage. The highest stimulation of germination by phytohormones has been found for the most mature caryopses. The action of gibberellic acid has been particulary strong.