Stems Age, Nitrogen Fertilizer And Salicylic Acid Application In Cutting Induction Of Noble Dendrobium Orchid Of The Yamamoto Series Cultivars

Propagation of noble dendrobium orchid (Dendrobium nobile Lindl.) by cutting was studied in two experiments. In the first experiment we evaluated the effect stem age on propagation success: mature stems - from already bloomed stems; and young stems - yet to bloom; and Nitrogen fertilizer application, from two sources: as Nitrate and Ammonium (respectively as Calcium Nitrate at concentrations of: 5.81 gL(-1); 11.61 gL(-1); 17.42 gL(-1); and Urea at concentrations of 2.00 gL(-1); 4.00 gL(-1) and 6.00 gL(-1) plus control treatments). We evaluated the following parameters: the number of cuttings stalks that launched shoots and/or roots, vigor, number of roots per plant and root length per plant. Factorial analysis of variance (stems age x source of Nitrogen; and age of stem x Nitrogen level) was applied using a Generalized Linear Model (GLM) approach. Where significant differences were observed, averages were compared using post-hoc tests (Tukey). Propagation success was higher using cuttings from mature stems (60.2%), a value 1.6 times higher than obtained with stem cuttings from young stems (38.0%). Application of Nitrogen, in both forms, did not influence any of the evaluated parameters. In the second experiment we treated cuttings from mature stems with Salicylic acid in 3 concentrations (0.10 mM; 0.50 mM; 1.00 mM and plus a control treatment). Evaluated parameters included proportion of cuttings stalks that launched shoots and/or roots, leaf length, root length, and number of roots per stem cutting. Factorial analysis of variance was applied with post-hoc tests. Application of 0.50 mM of Salicylic acid increased the proportion of cuttings stalks that launched shoots and/or roots by 20.5% relative to the control treatment.