Class XII Practical: Biochemical & Physiological Experiments - Distribution of Stomata

Objective

To study and compare the distribution of stomata on the upper and lower surfaces of dicotyledonous and monocotyledonous leaves.

Guidelines

1. Leaf Selection: Obtain fresh leaves from a dicot plant (e.g., bean, peepal) and a monocot plant (e.g., maize, grass).
2. Epidermal Peel Preparation: Carefully peel off a thin epidermal layer from both the upper and lower surfaces of each leaf. This can be done by tearing the leaf or using forceps.
3. Mounting: Mount each peel in a drop of water on a clean glass slide and cover with a coverslip.
4. Observation: Observe each slide under a compound microscope at high power. Count the number of stomata in a defined field of view for both surfaces of both leaf types.
5. Comparison: Compare the density of stomata on the upper vs. lower surface for each leaf type, and then compare the overall distribution between dicot and monocot leaves.

Expected Outcome

Observation that stomata are typically more abundant on the lower surface of dicot leaves (hypostomatous), while they are more or less equally distributed on both surfaces of monocot leaves (amphistomatous).