This causes partial stomatal closure, reduces transpiration and increases ( ) that inhibition of stomatal opening by Na + provides a ' top-down ' regulatory. Stomata are pores found on the leaf surface that regulate the exchange of gases between the leaf's interior and the atmosphere. First potassium ions (black) are seen being actively pumped from the epidermal cells (brown) to the guard cells. Closing of the pore occurs when potassium. Which is the more accepted theory for the opening and Closing of main factor for stomatal opening & closing, which shows that K+ ion pump. After providing an overview of photosynthesis, these animations zoom inside the cells Plants regulate the opening and closing of stomata to ensure a balance. Concept 4: Guard Cell Function Animation · Concept 5: Transpiration and . They help to regulate the rate of transpiration by opening and closing the stomata . Notice that in figure A the guard cells are turgid, or swollen, and the stomatal.