3. Results
3.1. Establishment of primary cultures
Shoot apices and nodal segments excised from seedlings gave
rise to shoots via development of preexisting meristems (1.0 ± 0.0
shoot per explant), with frequencies of 100% and 84%, respectively,
after 60 days of culture on ½ MSM. However, shoot elongation was
slow, and the resulting plantlets displayed minimal growth after
60 days culture, thus impairing their use as explant sources.
Therefore, in order to improve shoot elongation, stem segments
were cultured on B5, ½ B5 or on ½ MSM medium supplemented
with coconut water. Explants cultured on B5 medium resulted in
development of large, yellowish leaves, in addition to formation of
basal calluses, and root development after 30 days culture. Cultures
maintained on half-strength B5 medium (½ B5) showed only callus
formation at the bottom of the explants (data not shown).
Stem segments cultured on ½ MSM medium plus coconut water
developed plants without callus formation. Higher heights were
observed in shoots derived from segments cultured on ½ MSM
medium supplemented with 10% coconut water (Table 1; Fig. 1a).
Moreover, explants cultured on ½ MSM supplemented with 5 or
10% coconut water showed greater number of nodes (Table 1).
Approximately half of the leaves of plants obtained in the different
treatments became senescent and fell off during the initial
establishment in vitro.