In this study, development of anther wall of Helianthus annuus L. male fertile HA 89 B line and cytoplasmic male sterile HA 89 A line were compared by light and electron microscopy. It was observed that there was no difference between male fertile HA 89 B line and male sterile HA 89 A line development of anther wall until tetrads were formed. After tetrad stage in male fertile HA 89 B line, middle layer was lost and tapetum was parted from anther wall and surrounded the microspores. In cytoplasmic male sterile HA 89 A line middle layer became vacuolated and widened, tapetum also enlarged and filled anther sac. Besides it was determined that middle layer and tapetum were permanent with epidermis and endothecial cell during the further development of anther wall and also there was no secondary thickening in endothecial cells. In conclusion we suggest that the plasmodial tapetum which developed in fertile HA 89 B line transferred nutrients to microspores and helped them develop normally, but in cytoplasmic male sterile HA 89 A line the plasmodial structure did not develop. The inner tangential wall of tapetum, which was adjacent to the tetrads did not degenerate, so that sufficient nutrients were not transferred to microspores and thus they degenerated while in their callose walls.
Ciler Meric, Feruzan Dane and Goksel Olgun, 2004. Histological Aspects of Anther Wall in Male Fertile and Cytoplasmic Male Sterile
Helianthus annuus L. (Sunflower). Asian Journal of Plant Sciences, 3: 145-150.