Histological study of embryogenesis and organogenesis from anthers ofVitis rupestris du Lot cultured in vitro

Anthers of Vitis rupestris du Lot were cultured in vitro at the uninucleate stage of the microspore, in order to investigate the histology of embryogenic and organogenic processes in this genotype. Microspores divided in the anther loculi resulting in the formation of globular structures with a ruptured exine. Somatic embryogenesis and, occasionally, caulogenesis and rhizogenesis occurred in calli produced from all anther tissues except the endothecium. The initial cell of the embryoid was surrounded by a jacket layer when situated deep within the callus. When the embryoid's initial cell was situated in the peripheral callus, a cutinized wall was present and the three-celled proembryoid was almost always segmented, showing the same embryonal type as the zygotic proembryo. Root differentiation and elongation and cap differentiation occurred during the growth phase in liquid medium. The mature root was diarch and contained cells with calcium-oxalate raphides, as seen in vivo. No starch or tannin deposition was ever observed in the mature embryoids.