KARAKTERISASI MERISTEM UJUNG TAJUK PLANLET Dendrobium (Orchidaceae) SETELAH PENAMBAHAN ZAT PENGATUR TUMBUH BA (Benzyl Adenin)

Abstract

Vegetative and reproductive phase transition relies on shoot apical meristem dynamic. Flowering is an important step in orchids breeding, but long juvenile period have hampered the breeders to quickly evaluate the quality of the flowers. Induction of in vitro flowering can be done by adjusting the medium and environment necessary for vegetative-generative phase transition. The aim of this study was to determine the effect of BA on meristem behavior of plantlet of the  hybrid of Dendrobium schulleri J. J. Sm.  x Dendrobium striaenopsis M. A. Clem. & D. L. Jones.

This study used a Completely Randomized Design (CRD) with adding exogenous cytokinin in the form of Benzyl Adenine (BA). BA with a concentration of 5 ppm, 10 ppm, 20 ppm and 40 ppm applied in solid agar medium enriched with MS modified in the P / N ratio (i.e. 1.25 times higher than normal) and with the addition of 15% coconut water. The variables measured were the number of roots, the number of leaves, plant height and increase the number of shoots were analyzed by ANOVA, if there is a further significant difference test followed DMRT. Microscopic meristem development observations analyzed descriptively.

The results showed that the concentration of BA in 0 ppm to 40 ppm has no significant effect on the vegetative growth on all parameters except the number of new roots. High primary shoots, number of new leaves, and axillary buds, were not significantly different between the treatments of BA compared with controls. The highest average root emergence at 0 ppm BA and decreased with increasing concentrations of BA. Microscopic observations showed differences in shape of the apical meristem. The control without BA have apical dome in plateau form, whereas higher concentrations of cytokinin 40 ppm formed more pointed. Apical meristem form at a concentration of 40 ppm is predicted to have the possibility of forming a flower.

Keywords: Dendrobium, Benzyl Adenine, meristem