Class XI Practical: Cytology - T.S. of Monocot & Dicot Stems

Objective

To prepare and observe temporary transverse sections (T.S.) of monocotyledonous and dicotyledonous stems to study their anatomical differences.

Guidelines

1. Sectioning: Obtain fresh monocot (e.g., maize, bamboo) and dicot (e.g., sunflower, pea) stems. Cut very thin transverse sections using a sharp blade.
2. Staining: Stain the sections with appropriate stains (e.g., safranin and fast green for differential staining of lignified and cellulosic tissues).
3. Mounting: Mount the stained sections in glycerine or water on a clean slide and cover with a coverslip.
4. Observation: Observe the slides under a compound microscope. Identify and compare:
   • Epidermis: Outer protective layer.
   • Cortex: Ground tissue beneath epidermis.
   • Vascular Bundles: Arrangement (scattered in monocots, ring in dicots), presence/absence of cambium.
   • Pith: Central ground tissue (present in dicots, absent/reduced in monocots).
5. Drawing: Draw neat, labeled diagrams of both monocot and dicot stem T.S., highlighting key differences.

Expected Outcome

Clear understanding and ability to differentiate between the internal anatomical structures of monocot and dicot stems.