Isopropyl alcohol and auxin application method affect phytotoxicity of herbaceous stem cuttings©
In response to commercial propagatorsRSQUO inquiries regarding potential phytotoxicity of alcohol used in root-promoting solutions for cutting propagation, three experiments were conducted using stem cuttings of three herbaceous plant taxa. Solutions were prepared with three rates of isopropyl alcohol (0, 25 or 50%) in combination with three rates of indole-3-butyric acid (IBA): 0, 1000, or 2000 ppm (Exp. 1); 0, 100, or 200 ppm (Exp. 2); or a mixture of IBA and 1-naphthalene acetic acid (NAA): 0+0, 500+250, or 1000+500 ppm IBA+NAA, respectively (Exp. 3) and applied to cuttings using the basal quick-dip method (Exps. 1 and 3) or total immersion method (Exp. 2). No stem or leaf burn occurred using the basal quick-dip method, whereas foliar and stem burn occurred on cuttings of Pelargonium LSQUOMary HelenRSQUO using the total immersion method with solutions containing alcohol (regardless of IBA rate). Results indicate that solutions containing up to 50% alcohol can be used safely when applied using either basal quick-dip or total immersion methods for stem cuttings of Chrysanthemum MammothTM and Impatiens LSQUOCoralRSQUO.
Ray, J.T., Blythe, E.K., Bi, Guihong, Knight, P.R., Reynolds, D.B. and Bachman, G.R. (2018). Isopropyl alcohol and auxin application method affect phytotoxicity of herbaceous stem cuttings©. Acta Hortic. 1212, 307-314