Luminosidade, ácido indolbutírico e comprimentos de miniestacas na propagação de Peltophorum dubium (Sprengel) Taubert

The need for recovering degraded lands and the increased demand for forest products have been raising interest on Brazilian plant species and forest plantation technology. We aimed to evaluate the influence of mini-cutting length, indole-3-butyric acid (IBA) concentration and different environments on the propagation of copperpod (Peltophorum dubium). The experiment was conducted in a mini clonal garden at the Silviculture sector of FCA/UFGD. We tested: (1) four mini-cutting lengths (3.0; 4.5; 6.0; and 7.5 cm) in the absence and presence of 2,000 mg L-1 IBA for 100 days; and (2) two environments (shade and full sun) with three doses of IBA (0; 3,000; and 6,000 mg L-1) for 80 days. We evaluated stem diameter, number of leaves, fresh and dry weight of roots and shoots, weight of total fresh and dry matter, shoot length, and the Dickson quality index. Data was subjected to analysis of variance and quantitative means were evaluated by regression while qualitative variables were compared by Tukey’s test, both at 5% probability. According to the studied parameters of plantlet production, we observed that mini-cuttings 7.5 cm long are the most suitable for vegetative propagation of copperpod, with no need for exogenous application of IBA. Mini-cuttings 6.0 cm long yield plantlets with higher values of the evaluated quality parameters when cultivated in full sun and with exogenous application of 6,000 mg L-1 IBA.A atual necessidade de recuperação de áreas degradadas e a demanda por produtos de origem florestal têm aumentado o interesse sobre as espécies brasileiras e tecnologias de plantios florestais. Entretanto pouco se conhece sobre a propagação vegetativa em espécies florestais nativas. Assim, o trabalho objetivou avaliar diferentes comprimentos de miniestacas, ambientes e concentrações de AIB em canafístula (Peltophorum dubium). A implantação do minijardim clonal foi conduzida no viveiro de mudas do setor de Silvicultura da FCA/UFGD. Foram estudadas quatro alturas de miniestacas (3,0; 4,5; 6,0 e 7,5 cm) na ausência e presença de AIB (2.000 mg L-1), assim como dois ambientes (sombreado e pleno sol) em três doses desse hormônio (0; 3.000 e 6.000 mg L-1). Foram avaliadas a altura da parte aérea, diâmetro do coleto, número de folhas, peso da matéria seca da parte aérea e sistema radicular, matéria seca total, as relações entre essas variáveis e o índice de qualidade de Dickson. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste Tukey, a 5 % de probabilidade. A partir dos resultados obtidos, conclui-se que: entre os tamanhos de miniestacas, as de comprimento 7,5 cm são as mais indicadas para a propagação vegetativa de canafístula, independente da ausência ou presença de AIB; quanto menor o tamanho das miniestacas, maior a necessidade de hormônio para promoção do enraizamento; para miniestacas de 6,0 cm, o ambiente a pleno sol e a aplicação exógena de 6.000 mg L-1 de AIB proporcionam melhores parâmetros de qualidade de mudas

Effects of intra-specific tree competition on dendrometric parameters of Peltophorum dubium

Abstract The purpose of this research was to assess the performance of dendrometric parameters of Peltophorum dubium in several trees competition and stand age. The experiment was carried out in Brazil from 2009 to 2013. The experimental evaluations were done on variables such as cylindrical volume (CV), crown diameter (CD), diameter at beast height (DBH 1.3 m ), crown area (CA) and total height of tree (THT). The experiment was performed in a Nelder wheel competition, which is used in forestry research to test tree competition in a single plot. The interaction between the treatments (tree competition and stand age) was statistically significant (p≤0.01) for all variables assessed. The correlation between THT with the other dendrometric variables was strongly negative. These results might be attributed to the tree competition, where the tree competition was higher the THT was higher, as well. This increase in THT caused depletion in DBH 1.3 m , CD, CA and CV. The higher THT did not guarantee higher DBH 1.3 m and CV of P. dubium, because these dendrometric parameters showed strong and negative correlation during 37 months of stand age. Even with these depletions on dendrometric parameters in higher tree competition, it was possible to affirm that P. dubium is a forestry species that show a high adaptation in the variation of the tree competition ranged from 179 to 1,324 tree ha -1 until 37 months of stand age