ABSTRACT Khaya senegalensis, is a promising species for forest production, as it has excellent timber properties and adapts well to local edaphoclimatic conditions. To achieve better results in plant production and growth, some factors are important, such as nutrients, water and light. Light interferes directly with photosynthesis, plant growth and biomass. This study aims to investigate the morphological response and nutrient accumulation in seedlings of Khaya senegalensis under luminosity levels. An experiment was installed in the forest nursery during 150 days. The seedlings were distributed in a completely randomized design with five treatments in luminosity levels (full sun, 70%, 50%, 30% and natural shade), and 16 replicates. Height and diameter were measured in 30 days intervals. At the end of the experiment, mass weights (leaf, stem, root and total) were measured, and the root-shoot ratio and seed quality index proposed by Dickson were calculated. The accumulated macro and micronutrient contents were determined from the dry leaf material. The highest plants, diameters and total dry matter were found at levels of 70%, 50%, 30%, respectively. Plants exposed to natural shade grew less, in relation to plants with higher luminosity levels. As for nutrient accumulation, plants under natural shade accumulated higher levels of iron, while plants in the full sun accumulated more nitrogen contents. Plants with partial light conditions (70%, 50%, and 30%) were heavier in total biomass. Thus, the initial growth of Khaya senegalensis in low light conditions is compromised, whereas partial luminosities favor the growth and quality of seedlings.

Acrocarpus fraxinifolius é uma espécie produtora de madeira dura que ocorre naturalmente na Índia, Miamar (Birmânis) e Bangla Desh. Considerando seu potencial madeireiro e sua possibilidade de desenvolvimento no Brasil, realizou-se o presente trabalho, com o objetivo de verificar as influências de diferentes espaçamentos e idades no desempenho silvicultural dessa espécie, visando à obtenção de madeira para a produção de biomassa e serraria. O experimento foi realizado em blocos inteiramente casualizados, com quatro tratamentos e quatro repetições. Foram amostradas nove árvores em cada tratamento, ou seja, 36 árvores por bloco num total de 144 árvores amostradas. Os tratamentos se constituíram de quatro espaçamentos (1,5 m x 3m; 2m x 3m; 2,5m x 3m; 3m x 3 m). Foram analisados: diâmetro a altura do peito (DAP), altura total (HT), sobrevivência, e foi calculada a área seccional (G/pl), a área basal (G), o volume de madeira por planta (V/pl), o volume de madeira por hectare (V), incremento corrente anual em volume (ICA), e o incremento médio anual em volume (IMA). As variáveis avaliadas HT, G/pl e V/pl apresentaram maiores valores nos espaçamentos 3 m x 3m e 2m x 3 m. Todos os espaçamentos, com exceção do 3 m x 1,5 m favoreceram o crescimento em DAP. As demais variáveis não apresentaram diferenças estatísticas quando analisadas pelo teste de Scott-Knott a 5% de probabilidade. Conclui-se que os melhores espaçamentos de plantio para o Acrocarpus fraxinifolius até os 72 meses foram o 3 m x 3m e 3m x 2m.

Acrocarpus fraxinifolius is a hard wood tree species occurring mainly in Indonesia, Malaysia and India. Considering its potential for producing lumber and its development possibilities in Brazil, an experiment was carried out aiming to verify the effects of different spacing on the silvicultural performance of this species in order to produce wood biomass and sawnwood. The experiment was developed in completely randomized blocks with 4 treatments and 4 repetitions. Nine trees were sampled in each treatment, i.e., 36 trees per block, 144 trees overall. The treatments were constituted of four spacing: 1.5 m x 3m; 2m x 3m; 2.5m x 3m; 3m x 3 m. The following parameters were analyzed: diameter at breast height (DBH), total height (HT) and survival; and sectional area (G/pl), basal area (G), volume per plant (V/pl), volume per hectare (V), current annual volume increase and the annual mean increment in volume were calculated. The spacing 3m x 3m and 2m x 3 m presented the highest values of HT, G/pl and V/pl. All tested spacings favored the growth in DBH, except 3 m x 1.5 m. Other variables did not present statistical differences according to the Scott-Knott test at 5% probability. It was concluded that the best planting spacing for Acrocarpus fraxinifolius at 72 months are 3m x 3m and 3m x 2m.

RESUMO Com o objetivo de avaliar os aspectos nutricionais e os efeitos da omissão de nutrientes no desenvolvimento de plântulas de ipê-roxo (Tabebuia impetiginosa (Mart.) Sandwith), foi conduzido um experimento em casa de vegetação, em substrato de Latossolo Vermelho-Amarelo de baixa fertilidade. Foram utilizados dez tratamentos dispostos em delineamento de blocos inteiramente casualizados, com cinco repetições e uma planta por vaso; usando-se a técnica do nutriente faltante. Foi aplicado um tratamento completo com (N, P, K, Ca, Mg, S, B e Zn), outros oitos com omissão de um nutriente por vez (-N, -P, -K, - Ca, -Mg, -S, -B e -Zn) e um como testemunha (substrato natural). Foram avaliadas as seguintes característica aos 110 dias do plantio: altura da parte aérea, diâmetro de colo e produção de matéria seca. Os resultados obtidos nas condições do presente estudo permitiram concluir que: a) os nutrientes P e N devem ser prioritários aos estudos de fertilização mineral da espécie; b) seqüência de exigência nutricional apresentada pelas mudas de ipê-roxo em relação ao tratamento completo, considerando a produção de matéria seca da parte aérea em ordem decrescente foi: P> N> S> B> Zn> Mg> Ca> K.

ABSTRACT In order to study nutritional aspects and lack of nutrients on the development of plants, a greenhouse experiment was carried out with seedlings of ipê-roxo (Tabebuia impetiginosa (Mart.) Sandwith). As substrate, an oxisol with low nutrients availability was used and distributed in 10 treatments: a complete one (N, P, K, Ca, Mg, S, B and Zn), the others lacking one element in each treatment (-N, -P, -K, -Ca, -Mg, -B and -Zn) and a control (natural substrate). The following characteristics were assessed: diameter growth, plant height and dry matter production. Based on the results, it was conclude that: a) the N and P nutrients must be priority in mineral fertilization of this species; b) sequence of demand nutrition presented by the Tabebuia impetiginosa (Mart.) Sandwith seedlings in relation to the complete treatment, considering the production of dry matter of the aerial part in decreasing order was: P> N> S> B> Zn> Mg> Ca> K.