Mechanisms of aerenchyma formation in maize roots

Abstract

Respiration is very sensitive to waterlogged conditions. Under these conditions, plant roots suffer from lack of available oxygen. In fact, waterlogging reduces the exchange of gases between the plant and the atmosphere. When plants cannot receive sufficient oxygen level for respiration, they form aerenchyma in their roots which function as reservoirs of oxygen in the submerged plant. Aerenchyma is formed in maize (Zea mays) roots in response to different types of stress such as waterlogging, mechanical impedance, drought and nutrient deficiencies. Ethylene plays a crucial role in aerenchyma formation. Under waterlogged conditions, it can be cumulated in the submerged tissue and induces genes implicated in aerenchyma formation. These genes are related to calcium signaling, cell wall degradation and reactive oxygen species (ROS). In this review, the authors focused on the recent findings on aerenchyma in maize roots and explained the mechanisms of its formation under waterlogged conditions.