4.2- water balance in vascular plants

• Water Balance in Plants

  Water is essential for various plant functions such as transportation, support, photosynthesis, cooling, and maintaining turgor pressure
• Regulatory Mechanisms


  • Plants have mechanisms to regulate water balance, including active responses and structural adaptations
• Root Systems


  • Plants have different root systems like fibrous roots in grasses and tap roots in dicots for water absorption and balance
• Root Growth and Adaptation

  • Roots are dynamic and responsive to soil conditions, modifying based on water potential and nutrient distribution
• Absorption Process


  Water is absorbed through root hairs passively via osmosis and facilitated diffusion, driven by the water potential gradient
• Water Potential Gradient


  The difference in water potential between soil water and root cells drives water movement into roots for absorption
• Lack of available water

  Can lead to water stress in plants, triggering responses like root elongation and osmotic adjustment
• Waterlogging


  Can cause oxygen deprivation in plants, leading to root damage, wilting, and the development of adventitious roots
• Transpiration


  • Transpiration is crucial for plants, influenced by factors like humidity, wind speed, temperature, and light intensity, impacting water uptake and cooling
• Stomata Regulation


  • Stomata play a vital role in regulating water loss through transpiration, controlled by guard cell hydration levels and the hormone abscisic acid (ABA)
• Transpiration is the process whereby water evaporates from the surfaces of plant tissues.
• Water moves out of the leaf by diffusion through the stomata, driven by the high concentration of water molecules inside the leaf compared to the low concentration outside.
• The rate of transpiration depends on several environmental factors such as air temperature, relative humidity, wind speed, and light intensity.