Influence of auxin on acclimatization of Oncidium baueri (Orchidaceae)

Abstract

The objective of this study was to evaluate roots formation and vegetative development of Oncidium baueri (Orchidaceae) using naftalen acetic acid (NAA) during the acclimatization phase. The experiment was set up at the Agronomy Department – Universidade Estadual de Londrina – Paraná State, between March and October of 2005. Seedlings were obtained from seeds grew up “in vitro”, with culture medium (MS). Seedlings were taken out from dishes and washed using flow water, in order to remove the medium. After this, they were transplanted on trail, with sphagnum substrate and were set up on elevated tables at greenhouse (50% of solar radiation). Auxin was used by two ways: fast plants immersion, during 10 seconds (T2, T3, T4) and four weekly spraying on beds (T5, T6, T7). Treatments with NAA were: T1 – 0 mg.L-1; T2 – 40 mg.L-1; T3 – 200 mg.L-1; T4 – 1 g.L-1; T5 – 40 mg.L-1; T6 – 200 mg.L-1; T7 – 1 g.L-1. A randomized design with seven treatments and three replications was used as statistical model and ten plants composed each plot. Seven months after the trial settle the plants were evaluated by root length; roots number; plant height; sprouts number; and total fresh mass. It was observed that 200 mg.L-1 NAA spraying on seedlings of Oncidium baueri had better rooting and vegetative development, but seedlings immersion had no satisfactory results.