Abstract
This paper was designed to study the seed germination and embryogenesis in Cymbidium goeringii and Paphiopedilum insigne var. sanderae. The results may be summarized as follows.
1. The column of Cymbidium became thick and green after pollination, and side wall of the column curved inside. This column withered about 100 days after polination.
2. The ovary of Cymbidium rapidly increased in size and reached the definite size after 60 to 100 days after pollination. The ovary of Paphiopedilum scarcely increased in lenghth from flowering through maturation, while slowly increased in width after pollination.
3. The embryo and seeds of Cymbidium rapidly increased and reached the definite size 80 days and 110 to 120 days after fertilization. Those of Paphiopedilum increased in size after fertilization and reached the difinite size, although the increase was interrupted for a time.
4. Ovule formation occurred 43 to 45 days after pollination in Cymbidium, and 58 to 60 days after in Paphiopedilum.
The double fertilization occurred 48 to 50 days after pollination in Cymbidium, and 68 to 70 days after in Paphiopedilum.
The mature embryo sac was observed to have 8 nuclei in both Cymbidium and Paphiopedilum.
For the maturation of embryo, 115 to 120 days and 195 to 200 days after pollination were required, respectively, in Cymbidium and Paphiopedilum.
5. Proembryos of Cymbidium and Paphiopedilum at the tetrad stage were classified to the C1 and C2 type, respectively, according to Veyret′s classification. Similarly, embryos at and after the quadrant stage seemed to belong to the H (Angraecum distichum type) and F (Coelogyne parishii type) types in Cymbidium and Paphiopedidilum, respectively.
The mature embryo was observed to be derived from the apical cells of proembryo in both Cymbium and Paphiopedilum.
6. Three to five endosperm nuclei were observed in the embryo sac after fertilization in both Cymbidium and Paphiopedilum.
7. Seeds of Cymbidium had an ability to germinate after the time between the octant and intermediary stages (80 days after pollination), and those of Paphiopedilum after the octant stage (160 days after pollination).
The highest percentage of seed germination was obtained when the seeds were harvested near the mature embryo stage. As the germination medium, the Hyponex medium was better than the Murashige and Skoog medium.
