Universal hydraulics of the flowering plants: vessel diameter scales with stem length across angiosperm lineages, habits and climates.
Angiosperm hydraulic performance is crucially affected by the diameters of vessels, the water conducting conduits in the wood. Hydraulic optimality models suggest that vessels should widen predictably from stem tip to base, buffering hydrodynamic resistance accruing as stems, and therefore conductive path, increase in length. Data from 257 species (609 samples) show that vessels widen as predicted with distance from the stem apex across angiosperm orders, habits and habitats. Standardising for stem length, vessels are only slightly wider in warm/moist climates and in lianas, showing that, rather than climate or habit, plant size is by far the main driver of global variation in mean vessel diameter. Terminal twig vessels become wider as plant height increases, while vessel density decreases slightly less than expected tip to base. These patterns lead to testable predictions regarding evolutionary strategies allowing plants to minimise carbon costs per unit leaf area even as height increases.
Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de CU, México, DF, 04510, Mexico.
Mark E
ME
Olson
Tommaso
T
Anfodillo
Julieta A
JA
Rosell
Giai
G
Petit
Alan
A
Crivellaro
Sandrine
S
Isnard
Calixto
C
León-Gómez
Leonardo O
LO
Alvarado-Cárdenas
Matiss
M
Castorena
D005075:Biological Evolution; D002980:Climate; D017753:Ecosystem; D016014:Linear Models; D019684:Magnoliopsida / Q000033:anatomy & histology* / Q000145:classification / Q000502:physiology*; D018547:Plant Stems / Q000033:anatomy & histology / Q000502:physiology
Adaptation; allometry; convergence; hydraulic architecture; lianas; linear models; optimality models; vessel density; vessel taper; xylem