aerenchima

Aerenchyma is a specialized plant tissue characterized by large intercellular air spaces. This tissue is found primarily in the stems and roots of plants that grow in aquatic or waterlogged environments, such as mangroves, rice, and water lilies. The primary function of aerenchyma is to facilitate gas exchange, allowing oxygen to diffuse from the aerial parts of the plant down to the submerged roots and rhizomes, and carbon dioxide to move in the opposite direction. This is crucial for root respiration in anoxic soil conditions where oxygen is scarce.

The formation of aerenchyma can occur through two main processes: lysigenous and schizogenous. Lysigenous aerenchyma develops through the programmed cell death and subsequent breakdown of cells within the tissue, creating the air spaces. Schizogenous aerenchyma, on the other hand, forms when cells separate from each other as they grow, leaving gaps between them. The presence of aerenchyma is a key adaptation that allows these plants to thrive in environments that would be lethal to many other terrestrial species. It also plays a role in buoyancy for some aquatic plants.