Transportation in Plants

Transportation in Plants

Types of Transportation

• Xylem transportation: water and minerals from roots to leaves
• Phloem transportation: sugars and amino acids from leaves to roots and other parts of the plant

Xylem Transportation

• Transpiration stream: water evaporates from leaves, creating a suction force that pulls water up the xylem
• Cohesion-tension theory: water molecules stick together, allowing them to be pulled up the xylem
• Root pressure: roots absorb water and exert pressure to push water up the xylem

Phloem Transportation

• Translocation: sugars and amino acids are transported from source (leaves) to sink (roots and other parts)
• Phloem sap: a mixture of sugars, amino acids, and other organic compounds
• Mass flow hypothesis: phloem sap is transported through the phloem under pressure, driven by osmotic pressure differences

Mechanisms of Transportation

• Active transport: cells use energy to pump ions and molecules across cell membranes
• Passive transport: molecules move down their concentration gradient through diffusion or osmosis
• Bulk flow: movement of fluid through the xylem and phloem under pressure

Importance of Transportation in Plants

• Supports photosynthesis: provides water and minerals necessary for photosynthesis
• Supports growth and development: provides sugars and amino acids necessary for growth and development
• Responds to environmental changes: plants adjust transportation to respond to changes in light, temperature, and water availability