Exogenous phosphorus treatment facilitates chelation-mediated cadmium detoxification in perennial ryegrass (Lolium perenne L.)

Abstract Cadmium (Cd) is an on-going environmental pollutant associated with hindered plant growth. In response, plants possess various strategies to alleviate Cd stress, including reactive oxygen species (ROS) scavenging and chelation-mediated Cd detoxification. The present study examined the Cd defense mechanism of perennial ryegrass (Lolium perenne L.), taking into account the effect of exogenous phosphorus (P) input. It was found that despite triggering antioxidant enzyme activity, Cd stress heightened lipid peroxidation levels. Exogenous P input partially mitigated the lipid peroxidation impact and decreased the levels of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) antioxidant enzymes, revealing reduced ROS-scavenging activity. Importantly, notable relationships were determined between the amount of Cd uptake in the root and the amount of non-protein thiols (R2 = 0.914), glutathione (R2 = 0.805) and phytochelatins (R2 = 0.904) in proportion to the amount of exogenous P applied. The levels of amino acids proline and cysteine were also enhanced by exogenous P input showing their influence in alleviating Cd stress. Overall, it is reported that Cd detoxification in ryegrass plants can be stimulated by exogenous P input, which facilitates chelation-mediated Cd detoxification processes.