Patterns of growth, development and herbivory of Palicourea rigida are affected more by sun/shade conditions than by cerrado phytophysiognomy

Abstract

Plant development is infiuenced by several abiotic factors, which in turn infiuence morphological traits and life history. We investigated whether leaf area, herbivory, toughness, fiuctuating asymmetry, structural complexity and the number of infiorescences of Palicourea rigida are infiuenced by sun/shade conditions or by Cerrado phytophysiognomy (typical cerrado or rupestrian field). We expected to find greater structural complexity, leaf toughness and more infiorescences in sun plants; shaded plants were expected to exhibit a greater degree of fiuctuating asymmetry (an index of plant stress), reduced leaf toughness and greater herbivory. As for phytophysiognomies, we expected to find higher levels of leaf toughness and reduced structural complexity in plants from the rupestrian field. We sampled plants in the sun and shade from both phytophysiognomies. Leaf area, toughness, herbivory and fiuctuating asymmetry, were infiuenced more by sun/shade conditions than phytophysiognomy; leaf toughness was the only variable to show greater values in conditions of sun. Our results indicate that exposure to sunlight is not a requirement for increased plant development, but plants in shade are experiencing stress, as shown by increased fiuctuating asymmetry; increased leaf area, a strategy to compensate for lower light exposure for plants and higher herbivory, which depicts lower toughness.