Physiological researches on the fertility of the buckwheat. (V) Further studies on the behavior of pollen and pollen-tube.

The behavior of pollen and pollen-tube between 1-8 hours after pollination was reported in the previous pa.per (TATEBE 1950). The present paper describes the behavior between 10-30 minutes after pollination. Results obtained may be summarized as follows : 1. Pollen grains on stigmas in all mating combinations germinated well (table . 1.). However, the total number of pollen grains on stigmas were few in some of the long-styled flowers and also in short-styled flowers generally. It may be due to the reason that most of the pollen grains which failed to germinate had been washed off in the treatment of fixing and staining. Consequently, it seems very likely that in some cases the actual percentage of pollen germination was somewhat 10wer than that of the data. The percentage of empty grains which had exhausted their contents into their tubes was lower in short-styled flowers, and especially in the illegitimate unions. Various experiments of pollen germination on artificial media were tried without success.