Influence of different substrates and concentrations of acetylene in the blossom of Catasetum fimbriatum (C. Morren) Lindl. & Paxton (Catasetinae, Orchidaceae).

Abstract

Due the difficulty of obtaining female flowers utilized in hybridization, fact related to the balance of ethylene, and the scarcity of works focusing the propagation of this specie, the present study aimed to evaluate the effects of the association among different substrates and concentrations of acetylene in floral characteristics of Catasetum fimbriatum. Were utilized 160 individuals, planted in Pinus bark, coir, coconut chip and fern fiber, which were individually submitted by 10 times, in glass bellflower, to water and concentrations of 0.5, 1.0 and 2.0% of acetylene, originated to the reaction between calcium carbide and water. Before 45 days of the acetylene exposure, the concentration of 1.0% stood out, being that, associated as coconut chip and as fern fiber, obtained the best results for male floral rachis length (MFRL) and female floral rachis length (FFRL), and, together with the cultivation in fern fiber, obtained the higher averages in the variables number of male flowers per inflorescences (NMFI), diameter of male flowers (DMF) and diameter of female flowers (DFF), such combinations can be utilized for production of commercial flowers. The concentration of acetylene in 2.0%, inducing female diclinous flower, together with the vigor proved by fern fiber, was superior to the variable number of female flowers for inflorescence (NFFI) can be used to aim at the hybrids production.