Initial growth of Amazonian and Brazilian cerrado yellow ipe cultivated under different shading intensities and spectral wavelength

Abstract

The initial growth of Handroanthus serratifolius (Vahl) S.O. Grose. (Amazon yellow ipe) and Handroanthus ochraceus (Cham.) Mattos (Brazilian Cerrado yellow ipe), cultivated under black and colored shading net, was evaluated. The experimental design was completely randomized in a 2×5 factorial scheme (species × coverings) with 16 replications, in two experiments: the first one with the treatments of full sun and black nets with 37.89, 57.57, 71.17 and 85.66% retention of global radiation; and the second with nets of ~60% shading in red, blue, green, silver and black colors. The variables height, stem diameter and number of leaves and leaflets were measured every 20 days. A destructive analysis with 7 of the replicates was done at the end of the experimental period to obtain the dry masses of leaves, stem and root, as well as the leaf area. Data were submitted to analysis of variance, regressions and Tukey test at 5%. H. serratifolius and H. ochraceus differed for all variables. The full sun and black net conditions of 37.89% led to the best growth responses in all variables and the plants shaded by more than 57.57% the worst. The use of the red colored net permitted greater vegetative growth of the species, while growth under blue net was inhibited. It is concluded that the intensity and the quality of the retained and transmitted global radiation influence the initial growth of H. serratifolius and H. ochraceus seedlings.