Optimized in vitro regeneration and salicylic acid-induced callus enhancement in Lantana camara L.

Lantana camara, a widely used medicinal plant in traditional therapeutics, attracts attention as a reservoir of various highly desirable bioactive compounds of pharmacological importance. Secondary metabolite production in intact plants is limited by various environmental factors and anthropogenic activities that disrupt ecosystems. Therefore, plant cell and organ cultures are prominent alternatives for continuous production and consistency in terms of quality and quantity of high value products. A systematic manipulation of cells can produce desired metabolites that can be sequestered either directly from the medium or from the cells. Surface sterilization of the explants is often difficult. Studies indicate that callus cultures of L. camara can produce the same allelochemicals in vitro as in vivo, which may interfere with healthy callus growth and regeneration. The current investigation aimed to develop an efficient protocol for establishing in vitro shoots and callus cultures of L. camara and to assess the effect of Salicylic acid (SA) on callus cultures. MS medium supplementation with 35.2 µML−1 BAP was best for shoot multiplication, with 2.3 ± 0.28 and 2.0 ± 0.35 shoots for shoot tip and nodal explants, respectively, and 4.6 µML−1 Kin was best for shoot elongation, resulting in 6.05 ± 0.28 and 7.92 ± 0.79 cm long shoots for the two explants, respectively . The highest number of roots per plant (3.80 ± 0.59) was obtained with 7.5 µML−1 IBA. Embryogenic calli resulted in light-incubated cultures. For leaf explants, the highest frequency of callus induction (90%) and biomass (0.41 ± 0.04 g) were obtained at 5.4 µML−1 NAA + 0.88 µML−1 BAP. For internodal explants, the phytohormone combination of 5 µML−1 BAP + 1 µML−1 NAA + 1 µML−1 2,4-D was best for callus induction (90%), while 40 µML−1 NAA + 4 µML−1 BAP proved to be best for callus proliferation (2.01 ± 0.09 g). In dark incubation, 40 µML−1 NAA + 4 µML−1 BAP and 5.4 µML−1 NAA + 0.88 µML−1 BAP were found best for callus induction and proliferation from leaf and internodal explants, respectively. For elicitation response, MS medium fortified with 5.4 µML−1 NAA + 0.88 µML−1 BAP and a low SA concentration (125 µML−1) favored callus biomass accumulation more in dark incubation than in light.