Variação fenotípica em Curatella americana L. (Dilleniaceae) em tipologias abertas da Amazônia Oriental.

Abstract

The environmental heterogeneity translates into a wide variation in the availability of nutrients and water in the soil and in different light conditions, transforming open areas into a model environment to study the phenotypic variation capacity of co-occurring species, predicting responses in the face of extreme weather events. Understanding that variations occur in functional attributes according to the physiological requirements and with the soil and climatic conditions, this study wants to evaluate if there are variations in the leaf morphology and anatomical attributes of the branches in Curatella americana, adopting the hypothesis that the availability of resources in the environment (water and nutrients) lead to plastic responses in C. americana. Branches and soil samples of 10 ind/area were collected in the eastern portion of the Amazon in seven areas (two meadows, three savannas and two sandplains (restinga)), in the dry Amazonian period. For morphological attributes, leaf area (LA), specific leaf area (SLA), leaf thickness (LT), leaf dry matter content (LDMC) and wood density (WD) (N = 10 ind./area) were calculated. The usual techniques in wood anatomy were used to calculate the anatomical attributes: vessel diameter (D), vessel density (VD), average vessel area (AV), vulnerability index (VI), vessel lumen-fraction (F), non-lumen fraction (NF), hydraulic conductivity (Kh) and lumen resistivity (RL) (N = 3 ind./area). C. americana was able to develop structural responses to edaphic and climatic variations with more expressive variations in leaves than in wood. The morphological attributes showed plastic responses more significant than the anatomical attributes. Regarding the hydraulic strategy, the specie invested in efficiency of water transport instead of hydraulic security. Therefore, our results show that the specie presents plasticity in the construction and allocation of resources for the construction of its leaf attributes and branch density.