Leaf architecture of Impatiens walleriana Hook. f. (Balsaminaceae) - DOI: 10.4025/actascibiolsci.v31i1.935

Abstract

The leaf architecture, defined as the tri-dimensional organization of the leaves on the stem axis, influences the plant capacity to intercept sun light. This study investigated the leaf architecture of Impatiens walleriana, a species of the understorey of forests, to evaluate the existence of variation among distinctive positions of the leaves and identify the morphological characteristics that influence the leaf overlapping and, consequently, the process of light capture. Thirty plants, under the same light condition, were collected in a remnant of “Floresta Ombrófila Mista” (25º25’S e 49º17’W), in Curitiba, Paraná. Leaf width, leaf length, lamina thickness, leaf area, petiole length, leaf angles, and divergence angles were measured. The mean values of leaf angles, divergence angles, and petiole length varied significantly in relation to leaf position. Apparently, leaf overlapping is minimized by the synergic effect of leaf angles, divergence angles, elliptic form of the lamina, and long petioles, which, together, allow for a spatial organization around the stem axis, where most leaves can receive the difuse light at the understorey forest. These morphological characteristics, associated with reproductive strategies, appear to be responsible for this species´ success on the colonization of disturbed understorey, replacing native vegetation.