Lab Activity

To prepare a temporary mount of aleaf peel to show stomata.
B) Materials required:- Fresh leaves of plant, compound microscope, glass slides, cover slips, water, glycerine, safranine, blotting paper, needles, brush etc.
C) Theory :-
i) Stomata are minutepore present on the surface of the leaves. ii) Though they are found on both the upper and lower epidermis of the leaf, they are more in number on the lower epidermis. iii) Each stoma has two bean shaped cellscalled guard cells surrounded by epidermal cells. iv) Each guard cell hasa nucleus and a number of chloroplasts. The inner wall of the guard cell is thicker than the outer wall.
v) The guard cells controls the opening and closing of the stomatal pore. vi) The opening and closing of the stomatal pore is controlled by the entry and exit of water to and from the guard cells. vii) The function of the stomata is the exchange of gases and water vapour between the atmosphere and the leaf.
D) Procedure :-
i) Take a thin peel of the leaf by tearing it tangentially from its lower surface. ii) Put the leaf in a watch glass containing water. iii) Add a few drops of safranine into the watch glass to stain the peel. iv) Take a clean glass slide and with the help of a fine brush transfer the peel on to the glass slide.
v) Remove the excess water and stain by using blotting paper. vi) Put a drop of glycerine over the peel and gently place a cover slip over itwith the help of a needle avoiding any air bubbles. vii) Observe the peel first under the low power and then under the high power of a microscope.
E) Observations and inference:-
i) Several stomata areobserved surrounded by a layer of epidermal cells. ii) Each stoma has a stomatal pore and two bean shaped guard cells containing a nucleus