Arenchyma is a type of specialized parenchyma tissue found in some aquatic plants, characterized by large intercellular air spaces that facilitate buoyancy and gas exchange. This adaptation allows plants to float and absorb oxygen directly from the air, enhancing their survival in submerged environments. Arenchyma also plays a role in storage, as it can retain water and nutrients. Overall, it is crucial for the structural support and physiological functions of certain plants in wetland habitats.