Practical Assignment: Vertical Section of Pezziza Apothecium

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Aim:
To study the vertical section (V.S.) of the apothecium of Pezziza under the microscope and understand its structural organization.

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Introduction

Pezziza is a genus of fungi belonging to the phylum Ascomycota. It produces a cup-shaped fruiting body called an apothecium. This structure is involved in the sexual reproduction of the fungus, containing specialized cells known as asci, which house the ascospores. The V.S. of the apothecium reveals layers such as the hymenium, subhymenium, and the excipulum, demonstrating the arrangement of reproductive and supportive tissues.

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Materials Required

• Fresh or preserved specimen of Pezziza apothecium
• Compound microscope
• Razor blade
• Glass slide and coverslip
• Stain (e.g., cotton blue or lactophenol)
• Forceps
• Brush
• Dropper

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Procedure

1. Take a fresh or preserved Pezziza apothecium.
2. Use a sharp razor blade to carefully cut a thin vertical section (V.S.) through the apothecium.
3. Place the section on a glass slide with a drop of water or stain (cotton blue/lactophenol) for better visibility.
4. Carefully place a coverslip over the section, ensuring no air bubbles are trapped.
5. Observe the slide under a compound microscope at low and high magnifications.
6. Record your observations and make a labeled diagram based on what you observe.

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Observations

When viewed under the microscope, the following structural features are visible in the V.S. of the Pezziza apothecium:

1. Hymenium (Fertile Layer):

• The topmost layer of the apothecium.
• Contains asci (sac-like structures) with 8 ascospores inside each.
• Interspersed with paraphyses (sterile filaments).

1. Subhymenium (Supportive Layer):

• A thin layer located just beneath the hymenium.
• Provides support to the asci and paraphyses.

1. Excipulum (Protective Layer):

• Forms the basal and lateral parts of the apothecium.
• Made up of compact hyphae, providing structure to the apothecium.

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Comment

The apothecium of Pezziza is a cup-shaped structure, characteristic of fungi in the phylum Ascomycota. The presence of asci in the hymenium reflects its role in sexual reproduction, where each ascus contains 8 ascospores. The sterile paraphyses ensure the spacing between asci, facilitating spore release. This study highlights the well-organized layering of the apothecium, essential for the reproductive success of Pezziza fungi.

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Conclusion

The V.S. of the Pezziza apothecium reveals a highly organized structure with distinct layers, demonstrating the arrangement and function of reproductive and supporting tissues. Understanding the structural details of the apothecium provides insight into the reproductive strategies of Ascomycota fungi.

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