Studies on the Fertilization and the Seed Formation of Thea sinensis L.

Abstract

In the previous report (UENO and MIZUNO 1955), the abortion of fertilized ovule, which resulted in failure of normal seed formation, occurred more frequently at the lower ovule than at the upper one.In the present paper the cytological observations were performed concerning the orders of the embryo sac formation and fertilization as well as the relations between the flowering and the fruiting.The results were as follows: -The formation of the embryo sac in the upper part was faster than that in the lower one; even when the formation of the embryo sac in the upper ovules was finished, the megaspore nucleus of the sac in the lower ovules was still in the stage of 8 nuclei or in the more advanced stage of the two out of the 8 nuclei beginning to transfer towards the polar plate of the sac. The double fertilization took place in about 40 hours after pollination in the upper ovules, but the fertilization in the lower ovules was about 10 hours later than the upper ones. The first mitosis of the primary endosperm nucleus took place in about 99 hours after the pollination at the upper ovules and in about 123 hours in at the lower ones.Next with regard to the flowering and fruiting; the formations of the embryo sac in the early flowering showed a phenomenal decrease, but both in the best flowering and in the late one the embryo sac formation was better.Next, the decrease of the fertilization was only found in the late flowering. From the fruiting .one month after flowering, it was found, the later the flowers opened, the more the development of the fruit was hindered.