The invention refers to plants comprising wild-type or mutated Alopecurus PPO enzymes, and methods of obtaining such plants. The present invention further refers to a method for controlling weeds at a plant cultivation site, the method comprising the steps of providing, at said site, a plant that comprises at least one nucleic acid comprising a nucleotide sequence encoding a wild-type or a mutated Alopecurus PPO enzyme which is resistant or tolerant to a PPO-inhibiting herbicide by applying to said site an effective amount of said herbicide.