Toxicity of a phenoxy herbicide on the lichen Ramalina fraxinea

2-Methyl-4-chlorophenoxyacetic acid has been widely used as herbicide in the United States and Europe. This study aims to quantify its effects at concentrations of 0-100 mg/L for up to 48 h on the physiological status of the lichen Ramalina fraxinea. 2-Methyl-4-chlorophenoxyacetic acid exposure induced a reduction in the maximum capacity of PSII, in chlorophyll content along with chlorophyll degradation, and in adverse effects on cell membrane integrity, and induced oxidative stress in a dose- and time-dependent manner.