Protocorm-like body proliferation of Grammatophyllum speciosum through asymbiotic seed germination

Abstract

Viability of Grammatophyllum speciosum seeds was evaluated by a TTC (2, 3, 5-triphenyl tetrazolium chloride) test. The seeds were then asymbiotically germinated on different agar media under aseptic conditions. The results showed that keeping the seeds in the dark at 30 °C for 1 day gave 99% of red staining embryos (referred to as viable). After sowing the seeds on half-strength Gamborg's B5 medium supplemented with 0.1% activated charcoal (AC) for 30 days, germination of those seeds was observed. Half-strength MS medium (1/2 MS) supplemented with 1 mg/l 6-benzylaminopurine in combination with 0.5 mg/l alpha;-naphthalene acetic acid, 15% coconut water, 0.2% AC, and 0.7% agar gave the highest percentage of protocorm-like body (PLB) induction and proliferation. The PLBs could be regenerated into complete plantlets with vigorous shoot and root formation on 1/2 MS medium without any plant growth regulators. The survival rate of plantlets was 70% after hardening off in the greenhouse for 1 month.