Abstrakt
Fine roots can vary in their morphological traits, which usually leads to shift in function. The variation happens on species level, but also on the population or individual level.
Despite a recent progress in the study of fine root trait differences, most of our knowledge remains confined to interspecific comparisons. Whereas non-clonal species' roots are restricted to a single spot, clonal species can often explore wider area thanks to more extensive root system spread along a rhizome.
However, whether this property leads to within-individual root trait shifts is poorly understood. In this study, our main aim was to assess the differences of fine root traits between roots originating from young and old part of rhizomes.
To address this goal, we conducted field diggings in Czech Republic and obtained 10 specimen of 10 eudicot herbaceous species. In each plant we took fine root samples from young and old part of the rhizome.
We scanned the samples and used an image analysis software to obtain data on specific root length (SRL) and root tissue density (RTD). In half of the species, roots in the young part had higher SRL and lower RTD than roots in the old part, suggesting a more acquisitive economy in the young part.
In other species, the trend was less marked or absent, possibly due to field soil heterogeneity. Trait variation was often correlated with diameter in SRL, but only rarely in RTD.
In conclusion, some rhizomatous species are capable of division of labor (root functions) along a rhizome, which might be a competitive advantage. Also, these findings imply constraints on the use of average species trait values.