Foliar micro-morphology: a promising tool to improve survival percentage of tissue culture raised plantlets with special reference to in vitro propagation of Vitex negundo L.

The in vitro induced anomalies during micropropagation affect acclimatization process of the regenerants, which influence the survival success of tissue culture raised plantlets. The comparative foliar micro-morphological analysis of in vitro developed; ex vitro adapted and field transferred plantlets could help in understanding the acclimatization of micropropagated plants. An enhanced shoot regeneration system for Vitex negundo L. was developed through axillary shoot regeneration and ex vitro rooting methods in present study. Murashige and Skoog’s medium (MS) incorporated with 1.5 mg L −1 6-benzylaminopurine (BAP) was recorded optimum for shoot regeneration from nodal segments. The shoots were further amplified (34.5 ± 0.21 shoots per culture vessel with 11.9 ± 0.10 cm average length) on full strength MS medium containing 0.5 mg L −1 BAP and 0.25 mg L −1 indole-3 acetic acid (IAA). The in vitro regenerated shoots were rooted under laboratory conditions (on half strength of MS medium incorporated with 1.0 mg L −1 IBA) as well as in greenhouse (ex vitro) when the shoots were treated with 300 mg L −1 IBA for 5 min. The hardened plantlets were successfully transferred to the field. The micro-morphological changes were observed in stomatal structure, index, veins and trichome density on the leaves developed in each stage of propagation of V. negundo . In vitro induced micro-morphological anomalies reduced stability of plant health and survival percentage which ultimately lead to the reduction in number of plantlets. The keen foliar micro-morphological analysis at subsequent stages assisted in developing plantlets with 100% survival success in V. negundo .