Effect of Basal Media and Sugar Types on in Vitro Regeneration of Grammatophyllum speciosum Blume

Abstract

Protocorms of Grammatophyllum speciosum Blume. were initiated from immature seeds on solid MS medium containing 15% (v/v) coconut water (CW) and 3% (w/v) sucrose. Protocorms, 2-4 mm in length were used as explants and subcultured to MS and VW (Vacin and Went, 1949) media containing 15% (v/v) CW and 2 or 3% (w/v) sucrose. Protocorms gave the highest formation of PLBs (protocorm-like bodies) at 3.1 PLBs/explant on MS solid medium containing 15% CW and 2% sucrose. For the test with different carbon sources, protocorms were cultured in liquid MS medium supplemented with 4 kinds of sugar, namely sucrose, glucose, sorbitol and mannitol at 2, 4, 6 or 8% (w/v) and cultured for 1, 2, 3 or 4 weeks. They were then transferred to MS solid medium containing 15% CW and 2% sucrose. Results revealed that after 4 weeks in MS liquid medium, sucrose and glucose had an inhibitory effect and 8% glucose gave a high percentage of protocorm browning. In contrast, sorbitol and mannitol were effective for protocorm regeneration and both sugar alcohols had a positive effect on the formation of PLBs and the development of PLBs into plantlets.