Embryonic dormancy persists in the calli derived from apple embryo

Abstract

Growth rate and differentiation ability of calli obtained form apple embryos depended on the depth of embryo dormancy and on the organ of callus origin. We wanted to answer whether some dormancy – related metabolic activities persist also in calli and whether they are affected by the dormancy status. The activities of invertases and proteases were determined in the calli obtained from axes and cotyledons of embryos after different periods of cold stratification. Patterns of changes in activities of alkaline invertase, albumine hydrolysing protease and cystine-aminopeptydase in extracts of different calli corresponded precisely to changes of these activities in axes and cotyledons of intact embryos submitted to stratification. These findings indicate that embryonic dormancy persists in undifferentiated cells of calli. The involvement of an unknown factor responsible for maintenance of the dormancy, which is transmitted to daughter cells during callus growth is suggested.