Protocols for Micropropagation of Woody Trees and Fruits

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D.T. NHUT ET AL.
Table 5. Effect of in vitro and ex vitro derived shoot and stem explants on axillary shoot length
(cm) and on percentages of explants with shoots.
Medium Explants Axillary
shoot length
(cm)
Explants
with
shoots (%)
Note
C10 Stem e 3.00 ± 0.15 100 Green needles
C11 Stem e 6.25 ± 1.25 85.7 Green needles
C10 Stem i 1.93 ± 0.92 52.9 Green needles
C11 Stem i 2.29 ± 1.04 56.3 Green needles, 15.6%
C10 Shoot e 4.24 ± 1.69 *
2.21 ± 1.59
explants had 2 shoots
100 36.8% had axillary shoot and
52.6% explants showed
yellowish needles
C11 Shoot e 3.92 ± 2.06 * 85.7 The longest shoot were 9.5
3.75 ± 2.25
cm. 28.6% had yellowish
needles, followed by the
growth of axillary shoots
C10 Shoot i 0 0 No growth observed. Needles
were browning and died
C11 Shoot i 0 0 No growth observed. Needles
were browning and died
Stem and shoot e: ex vitro-derived stem (newly-sterilized stem and shoot).
Stem and shoot i: in vitro stem and shoot.
*
shoots tip length.
After 12 weeks of culture, the number of explants that induced adventitious buds was
increased on both AB1 and AB4 media. On AB1 medium, 80.7% of explants were
able to produce adventitious buds (Figure 5). Among them, 17.4% of explants
formed two buds and 1.8%, 0.9%, and 0.9% of explants formed three, four, and six
buds, respectively. On AB4 medium, 41.9% of explants induced adventitious buds.
54.2% of explants forming calli.
According to Ahuja (1985), when activated charcoal was used, shoot elongation
and leaf size of Eucalyptus citriodora increased but the number of shoots decreased.
Webb et al. (1988) found that shoot elongation was promoted by charcoal but this
substance inhibited shoot induction when it was included with BA. The T. wallichiana
explants could be induced on both AB1 and AB4 medium. However, on AB1 medium
the explants induced more than one bud per explant, but the shoots were shorter than
those ones on the AB4 medium.
2.6. Root Induction
Select and excise shoots (1.5–2.0 cm long) for root induction and place them on
culture media supplemented with various auxins (Table 4).
After 10 weeks of culture, all explants placed on R1, R2, and R3 media showed
vigorous growth, green needles, and no callus formation was observed at their cut