Aerenchyma

A specialized tissue in plants for gas exchange

Aerenchyma

Aerenchyma tissue in a plant stem

Aerenchyma is a type of plant tissue characterized by extensive interconnected air spaces. It is primarily found in aquatic plants and plants that grow in waterlogged conditions. The presence of aerenchyma facilitates the exchange of gases between the plant and its environment, allowing for efficient oxygen transport to submerged tissues.

Structure

Aerenchyma is formed by the modification of parenchyma cells, which develop large intercellular spaces. These spaces are created through either cell separation or cell death, resulting in a spongy tissue that is highly permeable to gases. The structure of aerenchyma can vary between species, but it generally consists of large air-filled cavities that reduce the overall density of the plant tissue, aiding in buoyancy.

Function

The primary function of aerenchyma is to facilitate the movement of gases such as oxygen and carbon dioxide within the plant. This is particularly important for plants in anaerobic environments, where oxygen availability is limited. Aerenchyma allows oxygen to diffuse from the aerial parts of the plant to the roots, enabling aerobic respiration in root tissues that would otherwise be deprived of oxygen.

Formation

Aerenchyma can form through two main processes:

• Schizogeny: This involves the separation of cells to create intercellular spaces. It is a common method of aerenchyma formation in many plant species.
• Lysigeny: This involves the programmed cell death of certain cells, leading to the formation of cavities. Lysigeny is often induced by environmental stressors such as flooding.

Ecological Significance

Aerenchyma plays a crucial role in the survival of plants in waterlogged and aquatic environments. By providing a pathway for gas exchange, it enables plants to maintain metabolic functions under hypoxic conditions. This adaptation is vital for the growth and reproduction of many wetland species.

Related pages

• Parenchyma
• Aquatic plant
• Oxygen transport in plants
• Plant respiration