Effect of different types of in vitro rooting and substrates on the aclimatation of Zigopetalum maculatum (Orchidaceae)

Abstract

Orchids have great potential, but they require specialized growing media to be propagated, since naturally less than 5 % manage to germinate and they need to associate with symbiotic fungi. In this sense, the present work aims to evaluate the effect of in vitro rooting agents (sucrose and auxin) and types of substrate on the acclimatization of Zigopetalum maculatum. For rooting, the shoots were sown with IAA (3, 6 and 9 mg L^-1) and sucrose (30, 50 and 70 g L^-1). In acclimatization, they were sown in substrates with coconut fruit fiber (Cocos sp.), pieces of tree fern root (Cyathea sp.), and moss (Sphagnum sp.), with different proportions of worm castings (0.5, 1 and 2). The design used was DCA with a two-factor arrangement. The response variables for rooting are: length and number of roots, plant height and number of leaves. In acclimatization they are: plant height and number of leaves (all after 90 days). In rooting, the interaction presented significant differences, in the combination with 6 mg L^-1 IAA*70 g of sucrose it presented a greater number of roots (6.10). The application of IAA presented significant differences, of which with 3 and 6 mg L^-1 IAA they expressed greater plant length (4.27 and 4.17 cm). The sucrose concentration presented significant differences, with 30 and 50 g L^-1 they have a greater number of leaves of 5.35 and 5.32. In acclimatization, the height of the plants presented significant differences in terms of type of substrate, Shagnnun sp. was the most favorable in obtaining a greater height of 7.8 cm. It is concluded that in Z. maculatum with the combination of 6 mg L^-1AIA*70 g of sucrose presented a greater number of roots and in acclimatization, Shagnnun sp. was the most favorable during this process.