This study evaluated the ability of plants of Araucaria angustifolia in adjusting some aspects of their morphology and physiology to different light conditions. Plants were submitted to full irradiance and shaded (90% reduction) conditions. During the course of a greenhouse experiment, four harvests were made (31, 49, 75 and 158 days after planting) and growth measurements of the shoot and roots were taken. A reduction in dry mass accumulation was observed in the shaded plants. These plants also had an initial enhancement of height growth, accumulated more chlorophyll, and, by the end of the experiment, had branched less and attained a greater leaf area ratio than the control plants. These morphological and physiological changes, which exhibited a temporally discontinuous expression, were interpreted as adjustments towards a more efficient light absorption and resource conservation under shading, which may contribute to the reported hade tolerance of the species.
Brazilian pine; light; shade tolerance
