Effect of Light on in vitro Seed Germination and Development of Dendrobium ochreatum Lindl.

Abstract

The effect of light on in vitro germination and development of young seedlings of
Dendrobium ochreatum Lindl. was studied. Seeds from 8 months-old pods were germinated on
modified semi-solid Vacin and Went (VW) (1949) medium supplemented with 20 g/l sucrose, 150
ml/l coconut water, 150 g/l potato and 8 g/l agar. The cultures were kept under various light duration
periods; 8 hrs of light per day for 16 weeks, 24 hrs of light per day for 16 weeks, 4 weeks in the dark
then exposed to the light (8 hrs per day) for a further 12 weeks, 8 weeks in the dark then exposed to
the light (8 hrs per day) for a further 8 weeks, and then 16 weeks in a dark condition. The results
indicated that young seedlings with 3-4 leaves and 1 root could be observed after 12 weeks of
culture in all treatments. However, the highest percentage of seed germination (92.64 %) was
obtained when seeds were incubated in the dark for 4 weeks then exposed to the light (8 hrs per day)
for further 12 weeks.

Keywords: orchid seed, Dendrobium ochreatum Lindl., light, in vitro