Effect of Plant Growth Regulators and Light Quality on Protocorm Development of Cymbidium mastersii Griff. Ex Lindl. under in vitro Culture

Abstract

Protocorms of Cymbidium mastersii Griff. ex Lindl. were cultured on semi solid Murashige and Skoog (MS) medium added with cytokinins including BA, kinetin, TDZ or auxins including IBA, IAA, NAA, and 2,4-D at 0.5, 1.0, and 2.0 mg/L for 12 weeks of culture. The results found that a culture medium supplemented with 1.0 mg/L TDZ could promote new shoot buds and new shoots higher than other cytokinins (11.7 shoot buds and 8.9 shoots). At the same time, the culture medium added with IBA at 0.5 mg/L or IAA 1.0 mg/L gave higher new protocorms than other auxins (11.1 and 9.4 protocorms/explant respectively). Furthermore, protocorm cultured on MS medium supplemented with 1.0 mg/L TDZ under LED warm white could provide the highest protocorm and shoot bud formation (9.5 protocorm/explant and 1.8 shoot buds/explant). Nevertheless, the highest number of shoots was found under LED warm-white (4.2 shoots per explant).