SEEDLESSNESS - STRUCTURE AND METABOLIC-ACTIVITY OF VITIS-VINIFERA L FEMALE GAMETOPHYTE (CV KISHMISH-CHERNYI)

Comparative cytological and embryological studies of reproductive orga ns in seeded and seedless grape (Vitis vinifera L.) cultivars (Kara Dz handzhal and Kishmish chernyi, respectively) did not reveal any differ ences in the development of female gametophytes at the stage of embryo sac formation. The ovules of seeded and seedless cultivars were of th e same protein content and revealed identical antigen spectra at the s tages of pollination and fertilization whereas glutamate dehydrogenase (GDH) activity of seedless cultivar ovules was twice as high as that of the seeded cultivar ovules at these stages of development. At the s tage of zygote ''dormancy,'' the reverse situation was true; i.e., GDH activity of seeded cultivar ovules was higher than that of the seedle ss cultivar ovules. The first symptoms of ovule degeneration (absence of the sclerenchyma layer in external integument, cessation of endospe rm nucleus divisions, exfoliation of integuments) were detected in the seedless grape ovules only at the initial stages of embryogenesis. Th e conclusion is drawn that the seedlessness of stenospermocarpic grape cultivars is not conditioned by the sterility of male and female game tophytes but arises from the inhibition of the growth of the male game tophyte in the course of its interaction with the female gametophyte d uring fertilization.