This paper analyses relationships between relative growth rate
(rgr), seed mass, biomass allocation, photosynthetic
rate and other plant traits as well as habitat factors (rainfall and altitude)
in 20 wild species of Aegilops L. and one
closely related species of Amblyopyrum (Jaub. & Spach) Eig.,
which differ in ploidy level (diploid, tetraploid and
hexaploid). The plants were grown hydroponically for 20 d in a growth chamber.
The relationships between
parameters were calculated either using the phylogenetic information (phylogenetically
independent contrasts,
PIC) or without using the phylogenetic information (trait values of taxa,
TIP). The results using the two
approaches were very similar, but there were a few exceptions in which
the results were different (e.g. rgr vs. seed
mass). Specific leaf area (sla) was positively correlated with
leaf area ratio (lar) and negatively correlated with net
assimilation rate (nar), which together resulted in the absence
of a correlation between sla and rgr. Leaf
photosynthetic rates (expressed on a mass or area basis) showed no correlation
with rgr. rgr was positively
correlated with the stem mass ratio and negatively with root mass ratio.
Species with a lower d. wt percentage have
a higher rgr. Aegilops species from locations with higher
annual rainfall invested less biomass in roots and more
in shoots (leaves and stems) and had a higher rgr. Diploid species
had a lower seed mass and initial mass than the
hybrids (tetraploid and hexaploid species), but there was no correlation
of rgr with ploidy level. Polyploid species,
which have higher seed mass, occur at a higher altitude than diploid species.
Our results show that variation in
rgr in Aegilops and Amblyopyrum spp. is associated
mainly with variation in biomass allocation (proportion of
biomass in stems and roots) and d. wt percentage, and not with variation
in sla, leaf photosynthetic rates or seed
mass.