Smoke-saturated Water and Karrikinolide Modulate Germination, Growth, Photosynthesis and Nutritional Values of Carrot (Daucus carota L.)

Plant-derived smoke is a positive regulator of seed germination and growth with regard to many plant species. Of the several compounds present in plant-derived smoke, karrikinolide or KAR(1) (3-methyl-2H-furo[2,3-c]pyran-2-one) is considered to be the major active growth-promoting compound. To test the efficacy of smoke-saturated water (SSW) and KAR(1) on carrot (Daucus carota L.), two separate pot experiments were simultaneously conducted in the same environmental conditions. SSW and KAR(1) treatments were applied to the plants in the form of aqueous solutions of variable concentrations. Prior to sowing, seeds were soaked in the solutions of SSW (25.8 mu g L-,(-1) 51.6 mu g L-1,103.2 mu g L-1 and 258.0 mu g L-1) and KAR(1) (0.015 mu g L-1, 0.150 mu g L-1, 1.501 mu g L-1 and 15.013 mu g L-1). Percent seed germination, vegetative growth, photosynthesis and nutritional values were the major parameters through which the plant response to the applied treatments was investigated. The results obtained indicated a significant improvement in all the plant attributes studied. In general, SSW (51.6 mu g L-1) and KAR(1) (1.501 mu g L-1) proved optimum treatments for most the parameters. As compared to the control, 51.6 mu g L-1 of SSW and 1.501 mu g L-1 of KAR(1) increased the percent seed germination by 58.0% and 54.4%, respectively. Over the control, the values of plant height and net photosynthetic rate were enhanced by 33.9% and 40.9%, respectively, due to 51.6 mu g L-1 of SSW, while the values of these parameters were increased by 25.2% and 34.0%, respectively, due to 1.501 mu g L-1 of KAR(1). In comparison with the control, treatment 51.6 mu g L-1 of SSW increased the contents of beta-carotene and ascorbic acid by 32.7% and 37.9%, respectively, while the treatment 1.501 mu g L-1 M of KAR(1) enhanced these contents by 42.0% and 48.4%, respectively. This study provides an insight into an affordable and feasible method of crop improvement.