Multiplicação in vitro de Schomburgkia crispa (Orchidaceae) com diferentes espectros luminosos, com e sem adição de zeatina

Abstract

The perception of the different luminous spectra and the translation of the signal by the plant results in different physiological and morphological responses, this way the modification of the light spectrum in growth rooms is an alternative to replace the application of exogenous growth regulators during the in vitro culture process. The present work was carried out with the objective of verifying the hypothesis that the light spectrum replaces the addition of cytoninin in the culture medium during in vitro multiplication. To test the hypothesis, we evaluated the effect of different luminous spectra during the in vitro multiplication of Schomburgkia crispa Lindl. (Orquidaceae), cultivated in WPM (Wood Plant Medium) with and without the addition of zeatin, in a completely randomized experimental design. The treatments consisted of two formulations of the WPM, with and without the addition of 0.1 mg L-1 of zeatin and different luminous spectra, white light (control), blue, orange, green and red, totalizing 10 treatments. At 60 days of cultivation, it was evaluated the number of leaves, shoots and roots. In addition, it was measured the length of leafs, shoots and roots, and fresh and dry mass (g) of aerial part and root system. It is concluded that, for the in vitro multiplication of Schomburgkia crispa, having as principle the main objective of this phase, that is, the development of buds and induction of shoots, among the tested spectra, if the cultivation of the explants is carried out in a medium containing zeatina cultivation under the green light spectrum is suggested, however, if the objective is to reduce costs and accelerate the stages of seedling development, cultivation under the spectrum of red or orange light in the absence of zeatin in the culture medium is suggested, because in addition to inducing a good number of shoots, it also favors rooting, which in turn, eliminates the use of auxins in the next, rooting. Thus, for the species studied, the light spectrum can replace the addition of growth regulators in the culture medium.