The study of fertilization and duration of its different phase in Lycopersicum esculentum Mill.
WANG Qiu-Hong, SHEN Jia-Heng
Related Articles |
Observe the whole process of fertilization of Lycopersicum esculentum Mill.by means of paraffin wax. The main results are as follows: (1) In 2 hours after pollination, pollen grains germinate on the tissues of the stigma. In about 2~4 hours, pollen tubes enter the stigma with enlargement of the distal portion. In about 8 hours, the genital cell comes into division cycle. After 2 hours, the genital cell divides into 2 sperm cells. (2) In about 14 hours, the pollen tube enters the ovary. In about 18~24 hours, the pollen tube enters the embryo sac and destroys one of the two synergids, releasing 2 sperms in the micropylar end. Then the 2 sperms move to the place between the egg cell and the secondary nucleus. (3) In about 30 hours after pollination, sperm nucleus enters the egg cell. In about 34 hours the egg nucleus and sperm nucleus begin fusing. In egg nucleus there is the male chromatin scattered, and then a small male nucleolus appears. In 40~50 hours, male and female nucleoli are fusing, it means the formation of zygote. The dormancy stage of zygote is about 10 hours long. In 60 hours after pollination, zygote begins dividing into 2-cell proembryo. (4) In about 26 hours after pollination, the sperm nucleus of another sperm nestles on the nucleus membranes of the secondary nucleus, and then fuses with it. In about 30~34 hours, it emerges male chromatin scattered, and a small male nucleolus appears. In about 38~42 hours after pollination male and female nucleoli are fusing, it means the formation of primary endosperm nucleus. After 44 hours, the primary endosperm nucleus begins dividing, and then forms 2 endosperm cells. Accordingly, the development of endosperm in Lycopersicum esculentum Mill. belongs to the cellular type. There is no dormancy stage in the development of primary endosperm nucleus. (5) The fusion of sperm nucleus with the polar nucleus is faster than that with the egg cell. (6) Double fertilization is the type of the Premitotic gametogamy.