Smoke–water stimulates secondary metabolites during in vitro seedling development in Tulbaghia species

Abstract

Tulbaghia species (Alliaceae) are well-known for their medicinal, horticultural and ornamental potential. The current study investigated the effect of varying smoke–water (SW) dilutions on in vitro germination, seedling growth and phytochemical content in Tulbaghia ludwigiana and Tulbaghia violacea. The mean germination time (MGT) was considerably reduced by approximately 2-fold in SW (1:500) treatment when compared to the control. High germination (≥80%) percentage was observed in all cases; however, there was no significant difference in germination (%) with and without SW. At post-germination stage, previous treatment with SW (1:500) produced more roots in T. ludwigiana seedlings. There was no significant improvement in growth parameters in SW-treated T. violacea seedlings. T. ludwigiana treated with SW (1:500) had significantly higher phenolic, flavonoid and condensed tannin contents when compared to the control. However, SW had no stimulatory effect in the level of phenolic, flavonoid and condensed tannin observed in T. violacea seedlings. These findings suggest the potential of SW treatment in enhancing the aforementioned phytochemical content in in vitro T. ludwigiana plants, which could be important during ex vitro growth and resultant biological efficacy of this widely used plant.