Attached
Shoot tips of Hevea brasiliensis Muell .-Arg removed
from aseptically grown seedlings could be established on liquid
or solid media supplemented with or without growth regulators.
Four different basal media were tested. The Murashige and Skoog
medium (1962), which is a high salt strength medium was found
to be the most suitable for axillary shoot proliferation. The
other media tested were, the Woody Plant Medium (WPM), the
White's medium (1943) which is a low salt strength medium and a
modified medium containing MS (1962) salts and vitamins used in
Skirvin and Chu (1980) medium. Different cytokinins were tested
for shoot proliferation. Benzylaminopurine (BAP), gave better
results than zeatin, kinetin or N
6 (~2 - isopentenyl) adenine
(2iP). It was found that axillary bud proliferation could be
easily induced. The elongation of these buds into shoots however,
was a very slow process. The newly formed shoots with 2-4 axillary
VIII
buds had to be separated and subcultured. They had to be
incubated for a long period for them to get stabilized in
the medium. After this period, buds in the separated segments
showed rapid elongation into shoots which could then be
subcultured again, inducing further proliferation of buds.
+
A multiplication rate of 30 - 2.0 shoots per explant was
obtained after 165 days of incubation. A concentration of
0.5 mg/l of the Gibberellic acid GA3 had no effect on shoot
elongation, whereas at a concentration of 2.0 mg/l dwarf shoots
were produced.
Rooting of the proliferated shoots was not attempted.
Shoot tips removed from aseptically grown seedlings could be
rooted on solid & liquid media. The rooting medium was supple-
-mented with indolebutyric acid (IBA) and activated charcoal
(AC) or IBA, BAP and AC.
