Non-native plant species often bring traits with them to their newly occupied ranges that potentially change the nature of interaction among species within communities. The possibility of biochemical exudates that act as toxic “Novel Weapons” has been explored and documented, but the possibility that root exudates, typical for some invading plant species, can act as means to cope with allelopathic compounds exuded by native competitors, received much less attention. Phenolic compounds are allelopathic signal molecules exuded by the roots of many plants and detected by the roots of other plants. Invasive plants – plants that often were introduced from far-away regions - may not respond appropriately to these interspecies signals. Root enzymes that destroy phenolic compounds may be involved in the process of permitting an invasive plant to (a) ignore the signal molecules exuded by plants in the native community and (b) to render such allelopathic compounds ineffective. We screened and assayed roots of a wide range of invasive and native grasses for polyphenolic oxidases and peroxidase enzymes and tested whether grasses with differing levels of such oxidase activity also differ in performance in environments enriched in phenolics and in competition with allelopathic, native species.
Results/Conclusions
An analysis of large number of grass genera and species showed that all members of the genus Bromus exhibit elevated levels of phenolics-oxidizing enzymes in their root zone. Species from that genus are known to be problematic invaders in many parts of
