THE NUTRIENT SOLUTION MODIFIES THE GROWTH OF TWO ORCHID SPECIES

Abstract

Orchids (Orchidaceae) develop in a wide range of environmental conditions, so they have specific nutrition requirements. In the nutrition of orchids there is lack of knowledge on the effects of fertilizers and their use throughout the cycle of these plants. The objective of this research was to study the effect of three nutrient solutions on the development and growth of Laelia autumnalis and Paphiopedilum insigne. The experiment was conducted over a period of 27 months under greenhouse conditions. The variables evaluated were number of leaves, leaf area, fresh and dry total weight of the plant, root and leaf, and SPAD readings in mature leaves; in addition, in L. autumnalis the number of pseudobulbs, thickness and length, as well as the fresh and dry weight of these pseudobulbs were evaluated. It was found that in L. autumnalis the Steiner solution increased the number of leaves (100 %), pseudobulbs (133 %), leaf area (80 %), total fresh weight (78 %) and total dry weight (125 %), compared to plants treated only with water (control). In P. insigne the Hoagland-Arnon solution improved the vegetative growth, increased the number of leaves (65 %), leaf area (83 %), SPAD readings (79 %), total fresh weight (33 %) and total dry weight (27 %), compared to the control plants. Results show that nutrient solutions positively influence growth of the two orchid species, and that each species has particular nutritional requirements; likewise, these results could be useful in conservation and exploitation programs of these species.