transpiration

Examples of transpiration in the following topics:

• Movement of Water and Minerals in the Xylem

  • Transpiration is the loss of water from the plant through evaporation at the leaf surface.
  • However, transpiration is tightly controlled.
  • Up to 90 percent of the water taken up by roots may be lost through transpiration.
  • Plants have evolved over time to adapt to their local environment and reduce transpiration.
  • These adaptations impede air flow across the stomatal pore and reduce transpiration.

• The Chemical Composition of Plants

  • As water vapor is lost from the leaves, the process of transpiration and the polarity of water molecules (which enables them to form hydrogen bonds) draws more water from the roots up through the plant to the leaves .

• Leaf Structure, Function, and Adaptation

  • However, in plants that grow in very hot or very cold conditions, the epidermis may be several layers thick to protect against excessive water loss from transpiration.
  • They can also reduce the rate of transpiration by blocking air flow across the leaf surface .

• Transportation of Photosynthates in the Phloem

  • Water diffuses from the phloem by osmosis and is then transpired or recycled via the xylem back into the phloem sap .
  • Transpiration causes water to return to the leaves through the xylem vessels.

• Inorganic Nutrients and Other Factors

  • Wind can be an important abiotic factor because it influences the rate of evaporation and transpiration.

• Abiotic Factors Influencing Plant Growth

  • Photosynthesis can proceed at a high rate, enzymes can work most efficiently, and stomata can remain open without the risk of excessive transpiration.

• Pressure, Gravity, and Matric Potential

  • Water is lost from the leaves via transpiration (approaching Ψp = 0 MPa at the wilting point) and restored by uptake via the roots.

• Temperature and Water

  • Plants have a number of interesting features on their leaves, such as leaf hairs and a waxy cuticle, that serve to decrease the rate of water loss via transpiration.

• Water and Solute Potential

  • Therefore, for water to move through the plant from the soil to the air (a process called transpiration), the conditions must exist as such:

• Stem Anatomy

  • They help to reduce transpiration (the loss of water by aboveground plant parts), increase solar reflectance, and store compounds that defend the leaves against predation by herbivores.