Aerenchyma is an airy tissue found in roots of plants, which allows exchange of gases between the shoot and the root. It contains large air-filled cavities, which provide a low-resistance internal pathway for the exchange of gases such as oxygen and ethylene between the plant parts above the water and the submerged tissues. It is found in roots that are submitted to anaerobic conditions such as flooding. For example, Blom et al (1994) researched adaptive responses of plants to flooding along the… (More on Aerenchyma)