The balance of endogenous phytohormones in immature embryos of maize linescompetent and incompetent to somatic embryogenesis

The contents of endogenous phytohormones were determined in immature embryo s of morphogenic and nonmorphogenic maize (Zea mais L.) fines. The embryos competent to somatic embryogenesis irt vitro were characterized by relative ly low contents of IAA and cytokinins and high contents of ABA. In the embr yos that did not produce embryogenic callus, the levels of IAA and cytokini n were higher and that of ABA lower than in embryogenic tissues. The shifts in the, hormonal balance of the maize explants by their incubation with co factors of IAA-oxidase, p-coumaric acid and, 2,4-dichlorophenol as well as with ABA, allowed the frequency of formation of embryogenic callus in the l ow-morphogenic line to increase significantly. This confirms the interrelat ion between the hormonal status elf the explants and their ability toward m orphogenesis.