Abstract
In this study we investigated the effect of 5-aminolevulinic acid (ALA) on the in vitro regulation of protocorm-like bodies (PLBs) of Cymbidium spp. PLBs of Cymbidium species were explanted on modified Murashige and Skoog (MS) medium supplemented with various concentrations of ALA. In Cymbidium insigne, 1 mg L−1 ALA induced the highest PLB (100%) proliferation rate with an average of 7.9 PLBs/explant, whereas the control treatment had 1.6 PLBs/explant. The highest shoot formation rate (66.7%) and the highest number of shoots (1.3 shoots/explant) were observed at 0.1 mg L−1 ALA. In Cymbidium finlaysonianum, the highest PLB formation rate (100%) and the highest average number of PLBs of (7.4 PLBs/explant) were observed for explants cultured on medium supplemented with 0.01 mg L−1 ALA. The highest number of shoots (0.7 shoots/explants) with a shoot proliferation rate of 33% was observed on medium supplemented with 0.1 mg L−1 ALA. The results of this study suggest that a low concentration of ALA can induce PLB and shoot formation and that ALA can serve as a novel additive for plant tissue culture acting as a growth regulator for Cymbidium micropropagation.
