Anatomical and histochemical studies of separation process on the juncture tissues between peduncle and bourse on apple fruit
In Japan, apple production for early-ripening cultivars has sometimes been struck by typhoon damages. Most of the damage was significant fruit abscission by its strong wind. Thus, storms have become a serious problem for apple farmers. 'Tsugaru' and 'Akane' are major early-ripening apple cultivars in Japan. As to abscission of fruit, 'Tsugaru' is an easy to separate cultivar in contrast to 'Akane'. This difference in abscission of fruit among cultivars occurred in the abscission zone. 'Tsugaru', with easy to abscise fruit, was treated with the plant growth regulator STOPFALL to prevent fruit abscission. However, there has been no detailed information about abscission zone formation and abscission process on the juncture tissues between peduncle and bourse among these apple cultivars, or treated with STOPFALL. Thus, we observed abscission zone formation and its process anatomically and histochemically by using 'Tsugaru' and 'Akane', or treated with STOPFALL application. As a result, the cells of the abscission zone formed and the abscission process was observed clearly in non-treated with STOPFALL on 'Tsugaru'. The cells of the abscission zone were characterized thin and included large nucleus, and accumulated high densely cytoplasm compared to the adjacent cells. The cell walls showed breakdown during separation. However, with treatment with STOPFALL in 'Tsugaru' and 'Akane' the abscission zone was not observed. In these results, we concluded that separation of the fruit from the tree on 'Tsugaru' applied with 1000 ppm STOPFALL was not observed. Because STOPFALL inhibits formation of cells of the abscission zone like 'Akane'.
Yamada, T., Kobayashi, T. and Tabuchi, T. (2018). Anatomical and histochemical studies of separation process on the juncture tissues between peduncle and bourse on apple fruit. Acta Hortic. 1206, 129-136
abscission, anatomy, histochemistry, STOPFALL