Medina, J.; Gusman, E.; Pierick, K.; Benítez, A.; Cumbicus Torres, N. & Homeier, J. (2025): <b>Anatomical variation in root traits reflects the continuum from slow to fast growth strategies among tropical tree species</b>. <i>Plants</i> <b>14</b>, 3590.
Resource Description
Title:
Anatomical variation in root traits reflects the continuum from slow to fast growth strategies among tropical tree species
email:
jhomeie <at> gwdg.de
Faculty of Resource Management
University of Applied Sciences and Arts (HAWK)
37077 Göttingen
Germany
Abstract:
Root anatomical traits regulate water transport and resource acquisition in forest ecosystems,<br/>
yet their variation and coordination with aboveground traits remain poorly understood<br/>
in tropical forests. We investigated patterns of interspecific variation in four root<br/>
anatomical traits (vessel diameter, vessel density, vessel lumen fraction, and theoretical<br/>
hydraulic conductivity) across 20 tree species representing contrasting growth strategies<br/>
in a premontane tropical forest of southern Ecuador. Using 160 root samples from transport<br/>
roots (4–8 mm diameter), we quantified anatomical traits through microscopy and<br/>
calculated theoretical hydraulic conductivity. We analyzed correlations with wood density<br/>
and leaf functional traits and performed principal component analyses to assess trait coordination.<br/>
Species exhibited substantial variation in root anatomical traits, ranging from<br/>
acquisitive strategies with large vessel diameters (67.6 μm in Ocotea sp.) and high hydraulic<br/>
conductivity (73.9 kg m−1 MPa−1 s−1 in Alchornea glandulosa) to conservative strategies<br/>
with high vessel density (>185 vessels/mm2 in Leonia crassa and Aspidosperma rigidum).<br/>
However, 60% of species displayed intermediate trait values, suggesting compensatory<br/>
strategies rather than extreme specialization. We documented strong negative correlations<br/>
between vessel diameter and both vessel density (r = −0.74) and wood density (r = −0.51),<br/>
pointing at hydraulic efficiency-safety trade-offs. Principal component analysis revealed<br/>
that leaf traits operated orthogonally to root anatomical traits, indicating independent<br/>
axes of functional variation rather than coordinated whole-plant strategies. These decoupling<br/>
challenges traditional plant economics spectrum assumptions and evidence that<br/>
plants optimize above- and belowground functions through independent evolutionary<br/>
pathways. Our findings highlight the prevalence of intermediate hydraulic strategies in<br/>
tropical tree communities and provide new insights into the functional organization of<br/>
diverse forest ecosystems.
