Cytokinin-and auxin-like activity of a butenolide isolated from plant-derived smoke

Abstract

Smoke and aqueous smoke extracts enhance both seed germination and seedling vigour in a wide variety of plants. The butenolide, 3-methyl-2H-furo[2,3-c]pyran-2-one, has been identified as a highly active germination promoter from plant-derived smoke. The present study was undertaken to determine the cytokinin- and auxin-like activity of the smoke-derived butenolide using the soybean callus and mungbean rooting bioassays respectively. A range of butenolide concentrations (10−20–10−8 M) were tested alone and supplemented with either 2.5×10−8 M (5 μg/L) kinetin or 10−7 M indole-3-butyric acid (IBA) in the soybean callus and mungbean bioassays respectively. In the soybean callus bioassay, a concentration-dependent response was recorded for both the fresh and dry weight of calli after 28 days in culture. The cellular dimensions of calli grown in the various treatments were statistically insignificant (p≤0.05) indicating that the increased weight of the callus is due to an increase in cell number rather than a change in cellular dimensions. Cytokinin-like activity of the butenolide (10−18–10−10 M) was equivalent to 2.5×10−8 M kinetin. Butenolide treatments supplemented with 2.5×10−8 M kinetin increased the response of the calli with the optimum treatment (10−16 M butenolide) having activity equivalent to 5×10−8 M (10 μg/L) kinetin. A similar concentration-dependant response was recorded in the mungbean bioassay. The optimum butenolide concentration (10−6 M) for auxin-like activity was equivalent to 10−7–10−6 M IBA. The addition of 10−7 M IBA to the various butenolide treatments increased the rooting response with the optimum treatment (10−18 M butenolide) having activity equivalent to 10−6–10−5 M IBA. These results demonstrated that the smoke-derived butenolide has both cytokinin- and auxin-like activity when applied at low concentrations as well as a synergistic effect when application is combined with either kinetin or IBA, depending on the bioassay.