EFFECT OF MEDIUM COMPOSITION ON ASYMBIOTIC SEED GERMINATION OF FIVE PHALAENOPSIS SPECIES

Abstract

Phalaenopsis has become one of the most important flowering potted plants in the world. In order to create novel flower colors and types, various species have been introduced in breeding programs. For the conservation and sustainable utilization of the germplasm, here, we investigated the effect of medium composition on the asymbiotic germination and seedling development of five Phalaenopsis species. Seeds germinated well on 1/10, 1/4 and 1/2 MS media; however, the survival percentage of young protocorms differed depending on the species and the concentrations of MS media. The optimum strength for protocorm survival of P. aphrodite subsp. formosana and P. philippinensis was 1/10 MS salts. For P. appendiculata, the protocorm survival was significantly higher in 1/2 MS medium than the others. For P. lindenii and P. viridis, the optimum strength was found in 1/4 and 1/10 MS media. For the organic supplements tested, the higher survival percentage and better growth of protocorms were found on the supplements of either potato homogenate or coconut water. From the results of this study, the requirements of inorganic salt and organic supplements for seed germination and protocorm development in vitro are dissimilar with the modern hybrids. The various responses to the basal salt concentrations among these species may be related to the diversity of their natural habitats.