Stomata in Leaves

Our Objective 

To observe the Stomata in leaves. 


The Theory 

What is a Stomata? 

Stomata are minute pores found on the epidermis of leaves and young shoots of plants that are used to control exchange of gases. The pore is surrounded by a pair of specialized cells called the guard cells that are responsible in regulating the size of the opening. 

Mechanism of Stomatal opening and closing 

The turgor pressure, which is brought on by the osmotic movement of water in the guard cells, controls the opening and closing of the Stomata. The expansion of the guard cells during turgidity leads to the opening of the Stomata. Guard cells become flaccid when they lose water, which causes Stomatal closure. Normally, Stomata open when light reaches the leaf and close at night. 



Functions of Stomata 

Water is released through the Stomata into the atmosphere in the form of water vapour through the process called transpiration. Besides this, Stomata facilitates carbon dioxide uptake and release of oxygen during the process of photosynthesis. It maintains the moisture balance according to weather by opening and closing. Stomata, which resemble mouths like cellular clusters at the epidermis that control gas exchange between plants and the atmosphere. For example, in leaves,  normally open during the day to facilitate CO2 diffusion when there is enough light for photosynthesis, and close at night to reduce transpiration and conserve water. 



Learning Outcomes 

  • Students will understand the term Stomata. 
  • Students get to know the mechanism and functions of Stomatal opening and closing. 
  • Students will be able to do the experiment more accurately in the real lab once they understand the steps through the animation and simulation.