Plant Absorption by Roots

Absorption by Roots

Mechanisms of Absorption

• Passive Absorption: movement of water and ions into the root through diffusion and osmosis, driven by concentration gradients
• Active Absorption: movement of ions against their concentration gradients, requiring energy from the plant

Factors Affecting Absorption

• Root Hair Structure: increased surface area for absorption
• Soil Water Potential: affects water availability and uptake
• Ion Concentration: affects ion uptake and absorption rates
• Temperature: influences metabolic rate and absorption
• pH: affects availability and uptake of ions

Types of Absorption

• Apparent Free Space (AFS) Uptake: rapid, non-selective uptake of ions into the root
• Donnan Free Space (DFS) Uptake: slower, selective uptake of ions into the root

Role of Root Hairs

• Increase Surface Area: for absorption and uptake
• Secretion of Organic Acids: to solubilize minerals and increase availability
• Production of Enzymes: to break down organic matter and increase nutrient availability

Regulation of Absorption

• Hormonal Regulation: plant hormones, such as auxins and cytokinins, regulate absorption and uptake
• Feedback Mechanisms: plants regulate absorption based on internal nutrient levels and availability