Floral development pattern and in vitro propagation of paraphalaenopsis labukensi P.S. Shim, A. Lamb & C.L. Chan

• Main Author: Heira Vanessa Ak Nelson
• Format: Thesis
• Language: English; English
• Published: 2021
• Subjects: QK495 Angiosperms
• Online Access: https://eprints.ums.edu.my/id/eprint/42981/1/24%20PAGES.pdf; https://eprints.ums.edu.my/id/eprint/42981/2/FULLTEXT.pdf; https://eprints.ums.edu.my/id/eprint/42981/

Paraphalaenopsis labukensis is a monopodial epiphytic species that only can be found in Sabah. P. labukensis orchids have unique characteristics in which it has a long floral lifespan as compared to other orchid species. The flower developmental pattern of P. labukensis greatly influenced the capsule formation and seed maturation. Through morphological studies and flower development stages, the maturity period of the orchid pod can be observed. The present research was conducted to record the initiation of flower morphological and development patterns as well as the effect of growth hormones on asymbiotic seed germination and their subsequent development into plantlets. By identifying the duration of the whole flowering developmental process, this will aid in the production of capsules to attain a reliable and adequate seed source for in vitro seed germination. The flowering stages were observed based on the length of inflorescence, diameter and length of bud, a number of flowers produced, and length of capsule formed. As a result, overall there were twelve stages of floral development involved. In this study, 120 days after pollination (DAP) capsule was selected as the most suitable capsule age for germination as it had reached its maturation period. After 90 days of culture, the highest germination percentage was achieved in Knudson C (KC) medium, with 98.78±0.89% followed by Murashige & Skoog (MS) and Vacin & Went (VW) medium (92.80±3.26%, 84.17±1.68%) respectively. Medium containing banana homogenate (BH) (5 mg/L) was the best complex additive for protocorm proliferation with 15.75±0.96% compared to coconut water. In addition, treatment with single PGRs has shown that 0.5 mg/L NAA has the highest percentage of proliferation (17.25±0.96%) followed by 1.5 mg/L NAA (16.50±0.50%). Meanwhile, for shoot induction, the highest rate recorded was in 1.0 mg/L NAA+0.5 mg/L BAP (34.75±0.56%). Combination of 1.0 mg/L NAA+0.5 mg/L BAP has recorded the highest percentage of root induction with 18.50±0.57%. This study showed that asymbiotic seed germination and seedlings development of P. labukensis is an efficient technique and can be applied as a conservation tool to protect the local orchid species.