Pteridophytes are also known as Vascular amphibians/ Reptiles of the Plant Kingdom.
HABITAT
- Limited to narrow geographical regions.
- Prefers cool, shady and damp places.
- Requires water for fertilization.
LIFE CYCLE
Diplo-haplontic Life Cycle
BODY STRUCTURE
SPOROPHYTE
- Main, photosynthetic, independent plant body.
- Well differentiated into true roots, stem and leaves.
- Vascular tissues i.e. Xylem and Phloem are present (First Tracheophytes)
- Stem-Modified into underground rhizomes.
- Roots-Adventitious roots arises from Rhizome.
- Leaves-Shows circinate vernation.
Small sized- Microphyllous Eg. Selaginella, Equisetum
Large sized- Macrophyllous Eg. Salvinia, Ferns
GAMETOPHYTE
- Multicellular, reduced, inconspicuous, heart shaped called Prothallus.
- Photosynthetic, thus independent plant body.
- Dorsiventrally flat.
- Homosporous species-Produce Monoecious gametophyte
- Heterosporous species-Produce Dioecious gametophyte
REPRODUCTION
GAMETE FORMATION
- The gametophyte bears Antheridium and Archegonium (male and female sex organs respectively) and is responsible for formation of Gametes.
- Male gametes- Antherozoids-
• Biflagellated/ Multi-flagellated
• Spirally coiled - Female gametes- Egg/ Oosphere-
• Large, non-motile.
SPORE FORMATION
- Leaves are modified to produce haploid spores by meiosis called Sporophylls
- Process of formation of spores- Sporogenesis
- Site of spore formation- Sporangium
- Cells responsible for spore formation- Spore Mother cells
- Mostly pteridophytes are homosporous i.e. produce only one type of spore.
- Few pteridophytes are heterosporous i.e. produce 2 different types of spores (microspore and megaspore)
Homosporous species- Pteris, Dryopteris, Lycopodium
Heterosporous species- Selaginella, Salvinia, Marselia
#class 11 biology #class 11 botany #life cycle of pteridophytes #plant kingdom
