Relative examination of antioxidative enzymatic activities in plantlets of Cardiospermum halicacabum L. differentiated from hypocotyls in in vivo and ex vitro environment.

A plant regeneration protocol was devised for Cardiospermum halicacabum by means of aseptically extracted 7 days old hypocotyls forming adventitious shoots on Murashige and Skoog (MS) medium harmonized with 0.7 µM thidiazuron (TDZ) producing a maximum of 18.20 ± 0.98 number of shoots in 94% cultures following 4 weeks. Subsequent subculturing for five passages, on a medium without plant growth regulators, tempted the highest shoot number (40.00 ± 1.15) with an average shoot length of 6.53 ± 0.49 cm after the fourth subculture. Histological sections confirmed the formation of multiple buds from hypocotyl explants. The expression of antioxidant enzymes like superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase was found to be higher in acclimatized plants than in the in vitro cultured ones suggesting the involvement of these enzymes in shoot differentiation and in growth under external environment partly due to their ability to cope up with oxidative stress.

Preconditioning of axillary buds in thidiazuron-supplemented liquid media improves in vitro shoot multiplication in Nyctanthes arbor-tristis L.

An efficient tissue culture technology has been designed for mass multiplication of Nyctanthes arbor-tristis L. by preculturing nodal explants in thidiazuron (TDZ)-supplemented liquid Murashige and Skoog (MS) media. Direct inoculation of nodal segments on semi-solid MS medium augmented with various concentrations of TDZ (0.1 to 0.9 µM) produced shoots but with low regeneration response and few shoots per explant. Hence, nodal explants were pretreated with greater concentrations of TDZ (5 to 100 µM) in liquid MS media for different durations (4, 8, 12, and 16 days) with the aim of improving shoot regeneration response from cultured explants. After pretreatment, explants were transferred to agar-solidified hormone-free MS medium. Best response in terms of percent regeneration (94%), number of shoots per explant (20.00 ± 1.15), and greatest shoot length (7.23 ± 0.83 cm) were obtained with nodal segments pretreated in 75 µM TDZ for 8 days. Similarly, root induction was obtained from pulse-treated microshoots for 24 h with 200 µM indole-3-butyric acid (IBA) followed by their transfer to 1/2 MS medium which produced an average of 5.50 ± 0.92 roots per microshoot. The rooted plantlets were transplanted to soil with 80% success rate.