Class XII Practical: Slide Preparation - L.S. of Monocot & Dicot Seeds

Objective

To prepare a temporary longitudinal section (L.S.) of monocotyledonous and dicotyledonous seeds and observe their internal structures.

Guidelines

1. Seed Preparation: Soak monocot (e.g., maize, rice) and dicot (e.g., pea, bean) seeds in water overnight to soften them.
2. Sectioning: Carefully cut a very thin longitudinal section of each seed using a sharp blade. It's crucial to cut through the embryo.
3. Staining (Optional): Stain the sections with a dilute stain like safranin or iodine (for starch in endosperm).
4. Mounting: Mount the stained section in a drop of water on a clean glass slide and cover with a coverslip.
5. Observation: Observe the slides under a compound microscope. Identify and compare:
   • Seed Coat: Outer protective layer.
   • Embryo: Radicle, plumule, cotyledon(s).
   • Endosperm: Food storage tissue (present in monocots, often absent/reduced in dicots).
   • Hilum/Micropyle: Scar and pore on the seed coat.
6. Drawing: Draw neat, labeled diagrams of both monocot and dicot seed L.S., highlighting key differences.

Expected Outcome

Clear microscopic observation and differentiation between the internal anatomical structures of monocot and dicot seeds, particularly the number of cotyledons and presence/absence of endosperm.