Abstract:
This experiment was conducted with the aim of studying the germinating ability of
Senna by evaluating the germination percentages and survival rates of seeds in different
media with time, under in vivo and in vitro conditions. A set of seeds were surface
sterilized either using four different concentrations of Clorox (Sodium Hypochlorite-NaOCl) (5%, 10%, 15% and 20%) with four different exposure time durations (5,10, 15
and 20 minutes), 50% ethanol for 1 minutes or 70% ethanol for 2 minutes. After an
over night soaking seeds were established on MS (Murashige and Skoog’s medium,
1962), WPM: McCown’s Woody Plant Medium (Lloyd and Me Cown, 1981) and
Anderson medium (Anderson, W.C. 1984) with and without adding lg/1 activated
charcoal. Seeds were established in vivo in trays having sand, coir dust and sand: coir
dust mixture at 1:1 ratio in a plant house. Data were collected in weekly intervals and
analysed using SAS computer software package.
Results revealed that concentrations of Clorox and exposure time minimized
contaminations as 100% survival rates for seeds were obtained both with 5% Clorox
with 20 minutes exposure time and 20% Clorox with 5 minutes exposure time after four
weeks. However lower concentrations of Clorox and longer exposure time facilitated
germination where 83.33% germination was obtained only from 5% Clorox with 20
minutes exposure time, while germination reduced to 33.33% with 20% Clorox with 5
minutes exposure time. WPM activated charcoal free medium showed highest (87.5 %)
germination percentage. Application of activated charcoal to culture media had no
effect on germination. After eight mont hs, in vitro germinated plantlets were
transferred to polybags containing sand: top soil: cow dung 2:1:1 ratio and placed under
shaded conditions in a plant house where 75% plants survived. In vitro germinated
plants introduced to plant house were free from pest and diseases. After four weeks
40% germination was observed in seeds sown in sand tray under in vivo conditions.
However, due to leaf eating caterpillar damage, survival rate was reduced to 20% after
5th week. Remaining plants were introduced to polybags. Growth performances of in
vitro derived plants have to be evaluated. In vitro plantlets can also be used to develop a
micro propagation protocol for Senna.
