Root traits are more than analogues of leaf traits: the case for diaspore mass

The relationship between roots and leaves has a bigger implication.

http://ow.ly/21ZO30fgHee

• Root traits are often thought to be analogues of leaf traits along the plant economics spectrum. But evolutionary pressures have most likely shaped above- and below-ground patterns differentially. Here, we aimed to identify the most important above-ground traits for explaining root traits without an a priori focus on known concepts.
• We measured morphological root traits in a glasshouse experiment on 141 common Central European grassland species. Using random forest algorithms, we built predictive models of six root traits from 97 above-ground morphological, ecological and life history traits. 
• Root tissue density was best predicted by leaf dry matter content, whereas traits related to root fineness were best predicted by diaspore mass: the heavier the diaspore, the coarser the root system. Specific leaf area (SLA) was not an important predictor for any of the root traits. 
• This study confirms the hypothesis that root traits are more than analogues of leaf traits within a plant economics spectrum. The results reveal a novel ecological pattern and highlight the power of root data to close important knowledge gaps in trait-based ecology.