Sympatric and phenotypic variation between two representative species of the Atlantic Forest: an analysis of the hydraulic system

ABSTRACT

Tropical forests are the most diverse on the planet, and it is essential to understand how plant species adapt to the environmental differences inherent in this environment. This study describes the wood anatomy and hydraulic architecture of Bathysa cuspidata and Bathysa nicholsonii in two remnants of the Atlantic Forest through a paired analysis of the hydraulic system related to taxonomic and environmental aspects. Samples were collected non-destructively, processed following techniques of wood anatomy. Sympatric species differ taxonomically in Bathysa cuspidata showed vessels either solitary or radial multiples of 2 to 4 elements, septate fibre-tracheids with thick walls, and larger rays with sheath cells. At the same time, B. nicholsonii has a higher vessel frequency, septate fibre-tracheids with thin walls, narrower rays, vessels with smaller diameters. Although each species’ hydraulic system shows acclimatization variations to different sites of occurrence, the structural differences in wood ensure the segregation between the species in each site. Our results corroborate the relevance of the anatomical wood anatomy studies as a subsidy for a better definition of morphologically similar taxa and show structural aspects aimed at survival in the Atlantic Forest. This data combination has often been neglected in understanding biodiversity in the tropics.

Keywords:
Intraspecific Variation; Wood Anatomy; Anatomical Taxonomy; Wood Ecophysiology; Adaptive Strategies.