EFFECT OF ABSCISIC-ACID AND BLUE RADIATION ON PHOTOSYNTHESIS AND GROWTH OF PEA-PLANTS

The effect of abscisic acid (ABA) on the net photosynthetic rate (P-N) , the ribulose 1,5-bisphosphate carboxylase (RuBPC) and the phosphoeno lpyruvate carboxylase (PEPC) activities, the chlorophyll (Chl) content and growth of pea plants (Pisum sativum L.) grown under ''white'' (WR ) or blue radiation (BR), were investigated. BR as compared to WR enha nced P-N, the activities of examined enzymes, and Chl content. In spit e of higher P-N of the plants grown under BR, dry matter of their shoo ts was lower in comparison with WR. ABA-treated plants grown under bot h WR and BR showed reduction in P-N. ABA had no effect on the activiti es of both RuBPC and PEPC and the Chl content. Independent on the radi ation quality, ABA reduced stem elongation, but did not affect the bio mass of whole shoots.