A new study found that cadmium (Cd2+) in growth media inhibits the mycelial growth of oyster mushrooms (Pleurotus ostreatus), but calcium (Ca2+) can counteract these effects. In simple terms, when oyster mushrooms were exposed to high levels of cadmium, their growth slowed down, and important cell components, like fats in their membranes, were affected. Adding calcium helped the mushrooms recover, grow normally, and restore their cell health—suggesting calcium could help protect mushrooms from harmful heavy metals.