POLLINATION, SEED DEVELOPMENT AND IN VITRO GERMINATION OF CYMBIDIUM SINENSE

Abstract

The flowers of Cymbidium sinense 'Huang Dao' were hand-pollinated within 1 to 7 days after flowering, resulting in 74 to 97% fruit set and no significant differences in seed or embryo size at 150 days after pollination (DAP). The germination percentages of 1 x 1 day and 3 x 3 day (stigma x pollen maturity) pollination treatments at 150 DAP were 4.6 and 5.2%, respectively. The capsules were harvested every 4 weeks until 40 weeks after pollination (WAP) to observe the seed development and germination ability. Seeds became apparent at 12 WAP, and then developed to a maximum length of 1,178 μm at 24 WAP. Meanwhile, the embryo length increased from 20 WAP, reaching a maximum of 206 μm at 32 WAP. The seeds did not germinate before 16 WAP. Globular embryo formation occurred at 20 WAP, causing the seed water content to decrease. Seed germination percentage was higher at 32 WAP. Furthermore, rhizome formation percentage was higher for 22 WAP seeds. In conclusion, experiments involving capsule maturity and pollination treatment exhibited similar results. Younger seeds germinated slowly in early culture but increased rapidly and formed more rhizomes in later culture. In contrast, older seeds germinated quickly during early culture but formed less rhizomes during later culture.