Antioxidant System in Species Assemblages: Species and Stress Specific Effects of Abiotic Stress in Secondary Meadows of the Caucasus Mountains

Abstract

Plant fitness relies on metabolic adaptability to abiotic stress, in which the antioxidant system plays a crucial role. This system is intensively studied, yet our existing knowledge of the matter is almost entirely derived from experiments at molecular and species levels, whilst studies on multiple species assemblages under a range of abiotic stressors are exceedingly rare. Therefore, here we ask: how does the plant antioxidant system behave at the community scale? We know that although plants experience the same stressor, their metabolic responses can differ substantially, while certain antioxidant metabolites may be associated with specific stress types. We hypothesized that the majority of the forb species in a hay meadow assemblage produce similar antioxidant responses specific to a given abiotic stress, while species-specific effects contribute little to the behavior of the antioxidant system at the community scale. We measured 12 key metabolites in 13 forb species co-occurring at three climatically distinct locations. Using ordination and cluster analyses, we evaluated response patterns. Combining a core set of common forb species with a suite of metabolites across three climatically distinct locations in one study enabled us to show that the majority of the forb species produced similar antioxidant responses specific to a given abiotic stress, thus overriding the species-specific differences. We conclude that a stress-specific pattern prevailed in the subset of forb species representing traditionally managed hay meadows, as predicted by our hypothesis.