A Study on Seed Germination and Seedling Development of Spathoglottis Bl. Orchids

Abstract

                The experiments were conducted to study characteristics of seed from self-pollination, intraspecific and interspecific crosses, seed germination and seedling growth of S. plicata and S. kimballiana in vitro.

                Seeds of S. plicata from capsule at 15, 20, 25 and 30 days and of S. kimballiana at 30, 35 and 40 days of age after pollination were germinated in modified VW solid and liquid media in vitro. The results showed that immature seeds in 15-day-old capsules of S. plicata had the lowest percentage of fertile seeds, germination rate and germination index. Self-pollinated seeds of S. kimballiana had lower percentage of fertile seeds in 30-day-old capsule while there was no difference in either intraspecific and interspecifics crosses. Seeds in liquid medium showed faster and better germination percentage than that on solid medium.

                 After in vitro germination at 33±2 °C and 3,000 lux of light intensity, seeds were swollen and showed green embryos in liquid medium in 17-22 days which was 6 days faster than in solid medium. The germination rate and index were observed one month after sowing the seeds. There was no germination in 15-day-old capsule of all crosses of S. plicata. The 25- and 30-day-old capsules of S. plicata and 30-, 35- and 40-day-old capsules of S. kimballiana showed high germination rate and germination index. Seeds in liquid medium developed better than those in solid medium. After one month from germination, seeds in 15 day capsule of S. plicata germinated and developed to large-sized seedlings within 4 months.

                  The 0, 0.01, 0.1 and 1 mg/l paclobutrazol had no significant effects on seedling growth of interspecifics cross (S. kimballiana x S. plicata) while 100 g/l blended banana in modified VW medium promoted seedling growth in fresh weight, plant height, leaf number, leaf length and root number.