Protocols for Micropropagation of Woody Trees and Fruits

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R.I. IYER
Figure 2. Formation of somatic embryo plants of Myristica fragrans. A) Plantlet formation by
shoot emergence. B) In vitro rooting in medium B 5. C) Formation of multiple shoots in
medium B 5 (bar = 1mm).
2.3. Organogenesis and Somatic Embryogenesis from Other Explants
In vitro propagation from other explants has been attempted using nodal explants,
stem segments, laminar pieces and petioles from 4-year-old juvenile plants. Somatic
embryogenesis from leaves was achieved (Iyer et al., 1995, 2002). Regeneration of
single axillary shoots from nodal explants and formation of adventitious buds from
stem segments and petioles were some of the other responses obtained (Iyer et al.,
1995, 2002). Though, there are reports of attempts of in vitro propagation using
nodal explants (Mallika et al., 1997; Rao et al., 1997) no shoot elongation and
plantlet formation has been obtained. A protocol for regeneration of single axillary
shoots from nodal explants and induction of somatic embryogenesis from immature
leaves is being described.
2.3.1. Explant Preparation
Growing conditions of mother plants. Leafy shoots obtained from 4-year-old
juvenile plants growing in Lalbagh Botanical Garden, Bangalore, India (12.58° N,
77.38ºE), with predominantly lateritic soil were used as the sources of nodal
explants, stem segments and leaf pieces.
Explant excision and sterilization. The leafy shoots were washed in running tap
water for half an hour. All further operations were carried out in a laminar flow
cabinet.
Nodal explants
1. Shoot was trimmed and cut transversely into 3 or 4-node segments .
2. Segments were then sterilized with 0.1% HgCl2 for 5 min followed by
several rinses with sterile distilled water.