Protocols for Micropropagation of Woody Trees and Fruits

MICROPROPAGATION OF BETULA PENDULA ROTH
when callus has been formed, generally in 4 weeks, transfer it to shoot initiation
medium. Shoot and callus initiation can be achieved in 16-h photoperiod
generally between 60 and 114 µmol m –2 s –1 medium or transferred to new initiation medium within a few days (Figure
1A). Place the leaf or twig pieces first on callus induction medium and
at 23–25° C, with subculturing
every fourth week (Ryynänen, 1999; Keinonen, 1999; Valjakka et al., 2000).
2. For shoot multiplication and elongation transfer individual shoots on shoot
initiation/multiplication medium. In silver birch it is possible to achieve
both adventitous (Figure 1B) or axillary bud induction and shoot multiplication
on the same medium (i.e. WPM or MS with 2.2 µM BA and 2.85
µM IAA or WPM with 4.4 µM BA) (Figure 1C). Cultivate in the same
photoperiod as during initiation.
Figure 1. Micropropagation of silver birch (Betula pendula Roth) using dormant vegetative
buds as explant material. A) Early stages of in vitro cultivation of vegetative buds on explants
showing severe leakage of phenols into the initiation medium (on the left) and the initiation of
new growth (on the right). B) Anatomy of the adventitious buds developing at the base of the
in vitro shoots. C) Shoot cultures multiplicated on N6 medium (on the left) and on the WPM
medium (on the right). D) Silver birch shoot rooted on WPM medium. Permission for the use
of picture A has been kindly provided by Plenum Publishing Corporation.
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