Caracterização da ontogenética do pau-brasil (Caesalpinia echinata Lam.)

Abstract

The reforestation with Brazil wood (Caesalpinia echinata Lam.) depends upon information from their ecophysiological characteristics subject to the ontogenetic and environmental variations. The objective of this study was to characterize some morphological, anatomical, physiological and structural aspects of the cell wall of C. echinata in juvenile, young and adult phases in natural conditions in a fragment of Atlantic Forest. Biometrics, nutrient concentration and of pigments chloroplastidic, anatomy leaf and stem secondary xylem and and the constitution of cell wall structural polymers was analyzed. The juveniles in the lower stratum of the forest have stood out by the higher specific leaf area and higher pigment contents and the cells larger guards provided by the higher concentrations of foliar K and Ca. Structurally the juveniles had lower vessel elements and lignin. The young individuals showed intermediate values of the variables analyzed. Have the adults, whose crowns reached the canopy, stood out for greater thickening of the limbus, cuticle and spongy parenchyma, leaf water content, stomatal density and lignin content of leaf and stem whose synthesis capacity was possibly stimulated by higher content of P leaf. The content of leaf and stem cellulose did not vary between the different ontogenetic phases. The hemicelluloses are the xylans type with the possibility of the presence of xyloglucan given the larger fraction of xylose (± 12% DM) and galactose (± 1% DM). Glucose was the most representative monosaccharide (± 40% DM) without ontogenetic differences. The morphological, anatomical, physiological and structural differences also seem to be under control of more intense irradiance in the canopy of mature individuals. The results denote that the associated planting with fast growing species is the best action for reforestation C. echinata.