Model Answer
0 min readIntroduction
Plant anatomy is a crucial branch of botany, providing insights into the structural organization of plants and their functional adaptations. Understanding the reproductive structures of different plant groups is fundamental to comprehending their life cycles and evolutionary relationships. Bryophytes (Funaria, Chara) and Pteridophytes (Selaginella) represent significant stages in plant evolution, exhibiting varying degrees of complexity in their reproductive organs. Similarly, fungal structures like cleistothecia demonstrate unique adaptations for survival and propagation. This answer will provide well-labeled diagrams of the requested structures, highlighting their key features.
(a) L.S. Cone of Selaginella
Selaginella reproduces via spores produced within sporangia located on specialized leaf-like structures called sporophylls, which are arranged in cones. The cone is typically a compact, elongated structure.
Key Labels: Apical bud, Sporophylls (microsporophylls & megasporophylls), Microsporangia, Megasporangia, Stomata, Rhizome.
(b) L.S. Capsule of Funaria
Funaria is a common moss. The capsule is the spore-bearing structure, developing from the archegonium after fertilization. It is characterized by a seta (stalk), operculum (lid), peristome teeth, and elaters.
Key Labels: Operculum, Peristome teeth, Capsule wall, Spores, Elaters, Seta, Calyptra.
(c) Sex Organs of Chara
Chara is a genus of green algae. It exhibits advanced sex organs – antheridia (male) and archegonia (female). Antheridia are globular structures releasing motile sperm, while archegonia are flask-shaped structures containing an egg cell.
Key Labels: Antheridium, Antherozoid, Archegonium, Egg cell, Operculum of Archegonium, Sterile cell.
(d) Cleistothecia of Erysiphe and Phyllactinia
Cleistothecia are closed, spherical fruiting bodies produced by powdery mildew fungi (Erysiphe and Phyllactinia). They contain asci, each of which produces ascospores.
Key Labels: Cleistothecium wall, Asci, Ascospores, Appressoria, Hyphae.
Conclusion
The reproductive structures of Selaginella, Funaria, Chara, and the powdery mildew fungi demonstrate the diversity of strategies employed by plants and fungi for propagation. Detailed understanding of these structures is essential for comprehending plant life cycles, evolutionary adaptations, and the ecological roles of these organisms. Further research into fungal pathogenesis and plant reproductive mechanisms continues to reveal intricate details of these biological processes.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.