PATHOLOGY

Detailed explanation-1: -Stomata consist of microscopic pores, each flanked by a pair of guard cells. Guard cells can increase or decrease the size of the pore via changes in their turgor status, hence regulating both CO2 entry into the leaf and transpiration, or the loss of water from the leaf.

Detailed explanation-2: -Guard cells are pairs of epidermal cells that control gas diffusion by regulating the opening and closure of stomatal pores. Guard cells, like other types of plant cells, are surrounded by a three-dimensional, extracellular network of polysaccharide-based wall polymers.

Detailed explanation-3: -Up to 90 percent of the water taken up by roots may be lost through transpiration. Leaves are covered by a waxy cuticle on the outer surface that prevents the loss of water. Regulation of transpiration, therefore, is achieved primarily through the opening and closing of stomata on the leaf surface.

Detailed explanation-4: -Water loss through stomata is required for the ascent of nutrient-laden sap, and evaporation of water from the leaf can be an important cooling mechanism.