The present study investigated to what extent there is a link between root
tissue structure and ecological strategies of plant species; such a link is
known for leaf tissue structure. We investigated experimentally root tissu
e mass density, root diameter and several characteristics of root anatomy i
n the axile roots of 19 perennial grass species from different habitats al
td related these parameters to the ecological behaviour of the species. Roo
t characteristics were assessed ill new roots produced by mature plants gro
wn under standardized conditions. The ecological behaviour was characterizc
d in terms of relative growth rate (RGR), plant height at maturity and ecol
ogical indicator values for nutrients, light and. tolerance to mowing accor
ding to Ellenberg. We found a striking dichotomy between root anatomical ch
aracteristics associated with interspecific variation ill RGR and those ass
ociated with variation in plant height. RGR correlated with anatomical char
acteristics that contribute to root robustness, whereas plant height correl
ated with characteristics associated with axile root hydraulic conductance.
RGR correlated negatively with tissue mass density (TMDr) in roots. Inters
pecific variation in TMDr was explained bg the proportion of style in the c
ross-sectional area (CSA) of the axile root and the proportion of cell wall
in the CSA of the stele. For a given root diameter, slow growing species h
ad smaller, albeit more numerous, xylem vessels, indicating a higher resist
ance to cavitation and protection against embolisms. Plant height correlate
d positively with root CSA, total xylem CSA and mean xylem vessel CSA, indi
cating a need for a high transport capacity in roots of species that attain
a large size at maturity. TMDr correlated positively with growth matter co
ntent in leaves. The results emphasize the dose relationship between tissue
structure and growth characteristics at the whole-plant level.