Effects of BA and NAA on shoot multiplication of Grammatophyllum speciosum Blume in vitro

Grammatophyllum speciosum Blume is the largest orchid species in the world and has many medicinal properties. It is also listed in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) because it is relatively rare in nature. The effects of N6-benzyladenine (BA) and α-naphthalene acetic acid (NAA) on shoot multiplication of Grammatophyllum speciosum Blume were investigated. The 2-mm diameter protocorms were cultured in Murashige and Skoog (MS) liquid and on agar medium supplemented with BA (0, 1, 2, and 4 mg L^‑1) and NAA (0, 0.5, and 1 mg L^‑1) for 8 weeks. The results showed that the MS liquid medium was more effective for shoot multiplications (shoot number, shoot height, and leaf number) compared to MS agar medium. The MS liquid medium supplemented with 2 mg L^‑1 BA yielded the highest average shoot multiplication (44.20 shoots protocorm^‑1). The lowest average shoot multiplication was found in MS agar medium supplemented with 0.5 mg L^‑1 NAA at 4.60 shoots protocorm^‑1.