Abstract This study investigates whether intraspecific variations in the secondary xylem traits of Tapirira guianensis occur in response to local edaphic conditions, despite a uniform climate and vegetation type. Wood samples from this species were collected from two soil types—Podzol and Histosol—in the lowland Atlantic Forest along Brazil’s southern coastal plain. Histological sections and dissociated material were prepared for qualitative and quantitative anatomical analyses. Principal component analysis and mean comparison tests were used to assess anatomical differences between soil types. The results reveal significant trait variation, with greater vessel grouping, higher vessel density, smaller vessel diameter, and shorter vessel elements in Podzol, a mesic soil, compared to Histosol, an organic and hydromorphic soil. This suggests an investment strategy in xylem that enhances resistance to cavitation in soils with lower water availability, aligning with interspecific and intraspecific trends observed in other studies. Trees in Histosol exhibited a higher percentage of gelatinous fibers, suggesting these cells may help stabilize stem growth in response to substrate instability and/or mitigate the physiological drought effects from prolonged flooding. Allometric patterns were also detected: vessel diameter was negatively correlated with vessel density, and positively correlated with vessel element length and fiber length. Vessel grouping was positively correlated with vessel density. The results indicate that even under homogeneous climatic and vegetational conditions, edaphic gradients can significantly influence xylem anatomy. These findings highlight T. guianensis ’s xylem plasticity, which may contribute to its resilience to both flooding and drought stress.
Gogosz et al. (Fri,) studied this question.