BIOCHEMICAL-CHANGES DURING REGENERATION OF SUNFLOWER (HELIANTHUS-ANNUUS L)

The main developmental stages in Helianthus annuus organogenesis have been studied in the sunflower hybrid ''Giove''. Shoot regeneration was obtained with high efficiency from mature seed cotyledons. Two-dimens ional electrophoresis of protein extracts as well as the isozyme patte rns of acid phosphatase, alcohol dehydrogenase, esterase, gluconate-6- phosphate dehydrogenase and phosphoglucomutase were compared during gr owth, callusing and regeneration. Two-dimensional protein patterns wer e similar, although polypeptides specific for each developmental phase could be identified. Different 2,4-dichlorophenoxyacetic acid concent rations or the sampling of specific regions of the seed did not result in significant differences in protein patterns. The activity of alcoh ol dehydrogenase and phosphoglucomutase appeared very low. For glucona te-6-phosphate dehydrogenase no difference, related either to the geno type or to different morphological stages, could be observed; the expr ession of acid phosphatase varied in a nonsystematic fashion. The isoz yme pattern of esterase was related to the genotype as well as to the morphogenic phase.