Effect of Cultural Condition on the in vitro Development of Ovules in Petunia hybrida Vilm.

The successful development of the young ovules excised separately from placenta soon aLter fertilization has not been obtained in Petunia sp.. This experiment was carried out to find a favourable condition for the in vitro develop-ment of the excised young ovules of Petunia hybrida Vilm. The results are as follow : (1) The medium containing 6% sucrose was most favourable for development of the free ovules excised 4 days after pollination. And also when osmotic value of the medium were adjusted to equivalent to 6% sucrose solution by adding cucumber fruit-juice, the ovules were developed at same rate of the former. Therefore, it is recognized that high osmotic value of the medium act upon the development of young ovules. (2) When the ovules excised 3 days after pollination were inoculated, the most favourable bsmotic value of a medium was equivalent to 8% sucrose solution which was higher than one L0r culturing the ovules excised 4 days aLter pollination. Moreover, it was observed that the range of osmotic value for culturing younger ovules was narrow than that for older one. Therefore, it is recognized the osmotic value of medium affects more remarkably the development of younger ovules.