MSc

A research project entitled "In Vitro propagation of Ailanthus triphysa
(Dennst.)" was carried out at the College of Forestry, Vellanikkara during 1996-98
to standardise a protocol for micropropagation of A. triphysa through tissue culture.
To achieve the present objective, different media combinations for shoot production
and rooting of micro shoots were tried using axillary and terminal buds from three to
four year old seedlings as explants.
The extent of culture contamination principally due to fungus was found
to be high and more so during rainy season. To get contamination free cultures,
dipping of explants in a fungicidal mixture of 0.1 per cent each of Bavistin
(Carbendazim) and Indofil M-45 (Mancozeb) for 30 min. and their sterilization with
mercuric chloride (0.1 %) for 20 min. was found relatively effective. Small sized
explants «0.5 cm dia) with significantly low culture contamination as well as
phenol exudation in comparison with big sized explants (>0.5 cm dia), were found
to be optimum for culture establishment Washing of explants in running tap water
for 30 min. and further culturing in media containing activated charcoal (0.25%)
was found to significantly lower phenol exudation in both sizes of explants.
Murashige and Skoog (MS) medium was found to be the best basal
medium for culture establishment and shoot production in comparison to half
strength MS medium and WPM. Of the various media combinations attempted, MS
supplemented with 3.0 mg r' benzyl adenine was found to be the best for shoot
production. Highest mean number of leaves (lO.2/explant) and leaflets
(21.8/explant) were obtained from this treatment with an average shoot number of
2.43 per explant



Multiple shoots were obtained in almost all the combinations of benzyl
adenine (BA) and kinetin in MS medium. The treatment, MS + 3.0 mg r' BA + 1.0
mg r' kinetin that produced as many as 4.25 shoots from a single bud on an
average, was found to be the best among these. Many of the combinations of GAJ,
BA and/or kinetin also produced multiple shoots. As many as 15 shoots from one
bud were obtained in MS medium supplemented with 3.0 mg r' kinetin and 5.0
mg r' GAJ. Half - strength MS was found to be totally inefficient for shoot
production even when supplemented with growth regulators.
Notable shoot elongation was obtained in few cultures of MS media
containing 3.0 mg r' BA + 1.0 mg r' GAJ and 2.0 mg r' BA + 2.0 mg r' kinetin.
Callusing at the base of bud explants was noticed in very few cultures.
In vitro rooting was successfully obtained in half-strength MS medium
containing 4.0 mg r' IAA + 0.4 mg r' IBA + AC (0.25%). The plantlets that
produced roots ex vitro died due to fungal infection. When planted out into
sterilized sand in crops, the in vitro rooted plantlets survived under high humidity
conditions for two weeks but failed to acclimatize to outside environmental
conditions.
From the present study the protocol for shoot production could be
standardised but more work on rooting of shoots is needed. As far as our extent of
search, this is the first report on standrdisation of the technique of rnicropropagation
of A. triphysa using mature plant tissues as explant.