1978 Volume 47 Issue 2 Pages 188-194
In the present experiment, some observations with the morphological and histological aspects were made concerning self-incompatibility in Hyuganatsu, Citrus tamurana Hort. ex Tanaka. The results are summarized as follows.
1. By means of scanning electron microscopy, the pollen behavior on stigmas when self-pollinated was compared with that when cross-pollinated with Hassaku, Citrus hassaku Hort. ex Tanaka. Soon after cross-pollination, the pollen grains began to be covered by the stigma exudate; 12 hours after pollination, the pollen grains were completely covered by the exudate. While the self-pollinated pollen grains were not covered by the exudate so soon as in the case of cross-pollination, and individual pollen grains were observed rather clearly in some parts of the stigma even 12 hours after pollination.
2. By means of fluorescent microscopy, the pathway of pollen tubes in styles was examined. In the upper portion of styles, the pollen tubes grew not only in the stylar canal along the wall of stigmatoid cells but also through the intercellular space of parenchymatous tissues. In the middle and lower portions of styles, all the pollen tubes grew in the stylar canal along the wall of stigmatoid cells.
The pollen tubes of Hassaku reached the upper, middle and lower portions of the styles in 1, 3 and 5 days after pollination, respectively. On the 5th day after pollination, some pollen tubes were observed to have penetrated into ovaries. While, almost all the pollen tubes of its own did not reach the uppermost portion of the style even 7 days after pollination.
