Plant Kingdom
NCERT Biology | Class 11 CBSE | NEET-UG Preparation
Chapter overview:
Learn the classification of the plant kingdom, major characteristics of algae, bryophytes, pteridophytes, gymnosperms and angiosperms, plant life cycles, and alternation of generations. This summary highlights important concepts for CBSE examinations and NEET-UG revision.
Pteridophytes
Pteridophytes are seedless vascular plants. They possess true roots, stems and leaves, along with vascular tissues, but reproduce through spores rather than seeds.
Important characteristics
- The sporophyte is the dominant, independent plant body.
- True roots, stems and leaves are generally present.
- Xylem and phloem conduct water, minerals and food.
- Sporangia produce spores and are often borne on sporophylls.
- Spores germinate to form a small gametophyte called the prothallus in many typical examples.
- The gametophyte generally requires suitable moist conditions.
- Water is needed for the motile male gametes to reach the female gamete in typical pteridophytes.
Major groups
- Psilopsida: Includes Psilotum.
- Lycopsida: Includes Lycopodium and Selaginella.
- Sphenopsida: Includes Equisetum.
- Pteropsida: Includes ferns such as Pteris and Dryopteris.
Homosporous and heterosporous plants
- Homosporous: Produce one general type of spore. Examples include many ferns and Lycopodium.
- Heterosporous: Produce two types of spores: microspores and megaspores.
- Microspores develop into male gametophytes, while megaspores develop into female gametophytes.
- Examples of heterospory include Selaginella and Salvinia.
Evolutionary importance: Heterospory is an important evolutionary development associated with the differentiation of male and female gametophytes. It is relevant to understanding the origin of the seed habit.
Importance of pteridophytes
- Many ferns are grown as ornamental plants.
- Some species help stabilise soil and contribute to forest ecosystems.
- Some pteridophytes are used as biofertilisers or in traditional applications.
CBSE and NEET focus: Distinguish bryophytes from pteridophytes by vascular tissue, dominant generation and plant body organisation. Learn the significance of heterospory.
