Somatic embryogenesis of phalaenopsis gigantea (orchidaceae) from leaf tip, leaf Base and protocorm sections

• Main Author: Lau, Eileen Ding Feng
• Format: Academic Exercise
• Language: English
• Published: 2008
• Subjects: QK Botany
• Online Access: https://eprints.ums.edu.my/id/eprint/20146/1/Somatic%20embryogenesis%20of%20phalaenopsis.pdf; https://eprints.ums.edu.my/id/eprint/20146/
• Institution: Universiti Malaysia Sabah

This study was conducted to determine the effects of plant growth regulators (PGR) 2,4-dichlorophenoxyacetic acid (2,4-D) and benzyladenine (BA) on the formation of callus from leaf tip, leaf base and protocorm segments of Phalaenopsis gigantea. Thus, to identify the best combination of 2,4-D and BA in the formation of callus from the segments. This experiment was carried out for 12 weeks in the Tissue Culture Laboratory of Universiti Malaysia Sabah using a complete random experimental design (CRD). Young leaves of P. gigantea were cut into half showed leaf tip and leaf base while protocorm were bisected into half and cultured on the Murashige and Skoog (MS) basal medium supplemented with 16 different combinations ofPGR (0 mgl⁻¹0.1 mgl⁻¹, 0.5 mgl⁻¹, 1.0 mgl⁻¹ 2,4-D and 0 mgl⁻¹, 0.01 mgl⁻¹, 0.1 mgl⁻¹ 0.2 mgl⁻¹ BA). Each medium was replicated 4 times with 6 leaf sections showing 3 leaf tips and 3 leaf bases. The protocorm segments were replicated 4 times with 10 segments each. The parameters observed were the average percentage of protocorm segments formed C+++ callus (more than 70% of the explant formed callus), average percentage of protocorm segments formed C++ callus (more than 30% and below 70% of the explant formed callus), average percentage of protocorm segments formed C+ callus (less than 30% of the explant formed callus), average percentage of protocorm segments dead and the percentage of explants formed callus. The leaf tip and leaf base did not show any response to the 16 treatments. The leaf segments started chlorosis and necrosis after two weeks of culture and died after five weeks. ANOV A test showed significant difference on the percentage of protocorm segments formed C++ and C+ callus among all the treatments in week 4. MS basal medium supplemented with 0.5 mgl⁻¹ 2,4-D and 0.2 mgl⁻¹ BA had 2S±2.887% of explants formed callus in week 4. Result proved that MS basal medium supplemented with 0.5 mgl⁻¹ 2,4-D and 0.2 mgl⁻¹ BA showed the earliest callus formation. However, result also showed that MS basal medium supplemented with 0.5 mgl⁻¹ 2,4-D and 0.1 mgl⁻¹ BA was considered the best treatment as the percentage of explants formed callus was high which was 12.5±4.787% with 10±5.774% formed C+++ callus with large globular structures in week 10. Besides, the protocorms segments cultured on medium supplemented with 0.5 mgl⁻¹ 2,4-D and 0.1 mgl⁻¹ BA can sustain their growth over longer period of time.