Effect of photoperiod <em>In vitro</em> callus induction and regeneration of Guggul [<em>Commiphora wightii</em> (Arnott)

Abstract

The impact of various photoperiod regimes on callus induction from callus culture in guggul leaf explants was carried out in present investigation. The leaf explants showing the maximum callus (0.90g) induction on MS medium supplemented with 2.0 mg/l 2,4-D with 100 per cent frequency were tested for their response to different regimes (10:14, 12:12, 14:10, 16:8) of photoperiod. The cultures were incubated with a light intensity of 3000 lux at 25±2 ° C. Maximum callus induction was observed (0.95 g)in leaf explants incubated at 14:10 hours photoperiod with 100 per cent frequency followed by (0.88 g) with 100 per cent frequency at 10:14 hours photoperiod. Minimum callus induction (0.69g) was observed with 90 per cent at 12: 12 hours photoperiod regimes. Callus induction in leaf explant completely inhibited at 16:8 hours photoperiod. 14:10 was most suitable photoperiod regime for callus induction in leaf explants. Leaf derived callus (2.0 mg/l 2, 4-D, 5.0 mg/l Kn + 0.5 mg/l NAA and 1.0 mg/l Kn) was subcultured at the same level of plant growth regulator to maintain the stock cultures. Shoot/ embryo morphogenesis was not observed on any of the these plant growth regulators except 2.0 mg/l 2, 4-D. Semi compact, light green callus proliferating from cut surface of the leaf explants on the medium supplemented with 2, 4-D (2.0 mg/l) when assessed for its organogenetic capacity. Upon subculture on cytokinin (BAP 0.1-3.0 mg/l) and auxin (2, 4-D 0.1-3.0 mg/l) added singly in the medium and in combination de novo shoot morphogenesis was observed. The reproducibility of this morphogenesis was only 25-30 per cent.