exudation

Exudation is the process by which liquids are released from tissues, often through intact barriers or after damage, as part of normal physiology or in response to stress. The liquids released are collectively called exudates, and they may include water, sugars, minerals, resins, mucilages, or other organic compounds. Exudation occurs in plants, animals, and microorganisms and can operate over short or extended time scales.

In plants, exudation includes root exudates and various specialized secretions such as latex, gum, and resin. Root exudates are a complex mixture released by roots into the surrounding soil and include sugars, amino acids, organic acids, phenolics, and enzymes. These substances influence nutrient availability, microbial community structure in the rhizosphere, and plant defenses, and are affected by soil type, moisture, and nutrient status.

In clinical contexts, exudate refers to fluid emitted by wounds or inflamed tissues. Wound exudate can be serous, serosanguinous, purulent, or fibrinous, varying in viscosity and color. The rate and composition of exudation reflect vascular permeability and the inflammatory state, and monitoring exudate is an important aspect of wound assessment and management.

In microbiology and ecology, microorganisms also produce exudates, including enzymes, organic acids, and signaling molecules, which participate in nutrient cycling and interspecies interactions. Root and microbial exudates contribute to soil organic matter formation and influence nutrient availability for plants.