Improving seedling vigour of indigenous medicinal plants with smoke

The application of smoke and aqueous smoke solutions stimulates seed germination in a number of plant species. This study highlights the effects of aerosol smoke and smoke solutions on the germination and seedling vigour of three South African indigenous medicinal plants Albuca pachychlamys, Merwilla natalensis and Tulbaghia violacea. The vigour index of one-week-old seedlings of all three species examined was increased with the application of dry smoke and smoke extract dilutions, as compared to control treatments. Seedlings of A. pachychlamys germinated with smoke solutions showed a significant (P <= 0.05) gain in bulb and leaf mass (27.9 and 197.6 mg respectively) compared to untreated seedlings (9.9 and 124.7 mg respectively) when grown in vitro for 75 days. The leaf mass of smoke solution-treated seedlings of T violacea was significantly (p <= 0.05) higher (120.4 mg) than that of untreated seedlings (47.6 mg). Subsequently, the height of seedlings in both species was also significantly (P <= 0.05) greater. Seedlings germinated in water and then transferred to smoke solutions (1:2000) showed enhancement of some of the growth parameters studied. Albuca pachychlamys and T violacea seeds exposed to aerosol smoke exhibited higher seedling survival percentages than from non-smoked seeds, while no significant effect was observed for M. natalensis seedlings. This investigation shows that the application of smoke technology can be adopted to produce high vigour seedlings. (c) 2005 Elsevier Ltd. All rights reserved.