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MORPHOGENESIS IN PTERIDOPHYTE. DR. O. S. DESHMUKH Department of Botany Mahatma Fule Mahavidyalaya, Warud 2018. Index Introduction Gametophyte Sporophyte Ecology Heterospory Reproduction Life cycle Conclusion References. Introduction.
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MORPHOGENESIS IN PTERIDOPHYTE DR. O. S. DESHMUKH Department of Botany Mahatma Fule Mahavidyalaya, Warud 2018
Index • Introduction • Gametophyte • Sporophyte • Ecology • Heterospory • Reproduction • Life cycle • Conclusion • References
Introduction • A Pteridophyte normally exists in two diverse • morphological forms during its life history. • The small simple haploid gametophyte and the • large morphologically complex diploid • sporophyte in the typical life cycle the two • generations are isolated from each by meiosis • and syngamy. • Pteridophyte- gametophyte is totally • independent for support and nutrition in fern • or fern ally. • Apogamy- haploid sporophyte develop directly • from the prothallus e.g. Pellaea, Trichomanes.
Gametophyte • Prothallus (monoecious/ dioecious) • Free living • Usually photosynthetic • Without vascular tissue, cuticle and stomates • Producing male and female gametangia • (antheridia and archegonia)
Sporophyte • Independent of the gametophyte at maturity • With vascular tissue, cuticle and stomates • Varying in size and complexity • Producing spores- • eusporangiate/leptosporantiate • Spores all of one size (homosporous) • Two sizes, large and small (heterosporous) • Root, stem and leaves. • 3 d
T. S. Stem Rhynia T. S. Stem Selaginella T. S. Stem Selaginella T. S. Stem Equisetum T. S. Stem Marsilea
Ecology • Represented today by a variety of growth habit • (life form) • Hence occupying a wide range of habitat • Notwithstanding the dependence on the • viability of liquid water for sexual reproduction • Aquatic (Marsileales, Salviniales) • Rhizomatous • Clumped • Terrestrial, epiphytic • Arboreal (Dicksoniaceae, tree fern) • Some times extremely weedy (Pteridium) • As a group much more abundant and diverse • Dispersal occurs via spore
Heterospory • Is the production of different kinds of spore • Microspore- male gametophyte • Megaspore- female gametophyte
Reproduction • Reproduce by spore which are produce within • sporangia • Sporophyll • Sorous • Sporocarp
Life cycle • Heteromorphic • This fern life cycle is representative of all • Pteridophyte
Conclusion • Plants with sporophytic organization mainly • because of the factors, physical, pressure, • gradient of growth hormones. • The manifestation of sporophytic organization • environmental factors • Considering alternation of generation as a • morphogenetic problem which still require more • investigation and information with a newer • technique for its complete elucidation
References • Pandey, B.P. (2003). College Botany Vol.II • Rastogi Publication, Merrat: 155-162. • Parihar, N.S. (1977). An introduction to • Embryophyta Vol.II- Pteridophyte, Allahabad • Publication, Allahabad: 62-74. • Vashistha, P. C. (2000). Botany for Degree • Students Pteridophyta (Vascular Cryptogams), • S. Chand and Co. New Delhi: 61-585. • www.peabody.vale.edu/mural/carbdev.htm