Abstract:

Studies on the cell ultrastructure and calcium distribution during tomato pedicel abscission by using scanning electron microscopy and antimoniate precipitate calcium electromicroscopic cytochemical methods. Those enabled us to document that the abscission was initialed in cortex and cellule around vascular bundle in which appearance two inconsecutive cell interspaces, later the cell interspaces of vascular bundle forming consecutive separation parts gradually. As the abscission procession, separation parts were extended to middle of abscission plate, then vascular bundle ruptured, and the marrow tissue and outer epidermis separated latest .Ca2+ location analysis showed that before abscission calcium iron mainly concentrated within vascular and vacuole, cell wall and cell membrane of cortex and marrow. After abscission there was mass calcium deposition in vascular bundle, when marrow separated, calcium grain mainly in degraded cell wall and intercellular space, little detected in cytoplasm. In abscission there were great difference of calcium location and contents between cortex, vascular and marrow which would be mainly caused for different separation procession of the abscission zone tissue.

Key words: Tomato, Pedicel, Abscission, Calcium distribution, Cell ultrastructure