ENVIRONMENT AND FLOWERING BACKGROUND IN GROWTH, INDUCTION AND FLOWER DEVELOPMENT IN Laelia anceps subsp. anceps (ORCHIDACEAE)

Abstract

Environmental factors management is important in the control of flower induction in orchids. Therefore, the objective of this study was to investigate the effect of two controlled environments and greenhouse conditions, as well as the influence of the flowering background in Laelia anceps Lindl. subesp. anceps, on four years old plants during their growth, induction, and indicators of flower development. The evaluated environments were: 1) greenhouse environment (AInv), with an average day/night 29/13 °C temperature, natural photoperiod of 12 h with a photosynthetic photon flux (FFF) of 90 mmol. m-2 s-1, 2) controlled environment 1 (AC1) with metal-halide lamps + high-pressure sodium lamps + fluorescent tubes lights with a FFF of 80 µmol m-2 s-1, and 3) controlled environment 2 (AC2) with light emitting diodes with a FFF of 64 mmol m-2 s-1. Both controlled environments had a 9/15 h photoperiod and 25/13 °C day/night temperature. Flowering background: plants with previous flowering (CFA) and without previous flowering (SFA). The experimental design was completely random with treatments: AInv + CFA, AInv + SFA, AC1 + CFA, AC1 + SFA, AC2 + CFA and AC2 + SFA, with 20 repetitions. Each plant was an experimental unit. Statistical analyses were ANOVA and Tukey test (p£0.05) for means comparison, logistic regression, and Pearson correlation. The evaluated environments did not have any influence on the vegetative growth of flowering induced plants, but the non-induced plants, mainly those in AC2 + CFA, decreased their growth. The CFA plants promoted a higher probability of flowering induction. The AInv generated the highest percentage of flower induction. Both controlled environments reduced the anthesis 45 and 30 d. For blooming, flower size and labellum were correlated among themselves in the three environments, meanwhile, in greenhouse conditions, they relate to the number of flowers. The length of the flower stalk was correlated with the days to anthesis in controlled environments.