Class XII Practical: Slide Preparation - T.S. of Ovary (Marginal/Axile Placentation)

Objective

To prepare a temporary transverse section (T.S.) of a flower ovary and observe different types of placentation (marginal or axile).

Guidelines

1. Ovary Selection: Obtain a fresh flower with a suitable ovary (e.g., pea flower for marginal placentation, Hibiscus or tomato for axile placentation).
2. Sectioning: Carefully cut a very thin transverse section of the ovary using a sharp blade.
3. Staining (Optional): Stain the section with a dilute stain like safranin.
4. Mounting: Mount the stained section in a drop of water or glycerine on a clean glass slide and cover with a coverslip.
5. Observation: Observe the slide under a compound microscope. Identify the ovary wall, locules (chambers), ovules, and the arrangement of ovules on the placenta.
6. Identification of Placentation: Based on the arrangement, identify whether it is marginal (e.g., ovules on the ventral suture of a single carpel) or axile (e.g., ovules on the central axis in a multilocular ovary).
7. Drawing: Draw a neat, labeled diagram of the observed T.S. of the ovary, highlighting the placentation type.

Expected Outcome

Clear microscopic observation and differentiation between marginal and axile placentation types within a flower ovary.