Comprehensive Study of Pteridophytes: Structure, Reproduction, and Evolution

Comprehensive Study of Pteridophytes: Structure, Reproduction, and Evolution

• 1.
  Pteridophytes —>Aditya Acharya MBBS, MMC,IOM
• 2.
  Pteridophyta • Origin: Carboniferousperiod of palaeozoic era • Known as the "age of pteridophytes" • First vascular terrestrial plant • Called "snakes of plant kingdom" or "Botanical Snakes" • Require water for reproduction Earth's geographicaltime * Eonsy Era - periods - > Epoch ↓ Precambrian c2PaleozoiPteridophytes MonsterDinosa ← &John Cena ∞ · first Sporophyte-dominantplant ← - ? ⇐ & Coal is obtained from do C BuyO pteriod
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  Pteridophyta: • Pteris: "feather",phytas: "plant" • Feather-like pinnate leaves (fronds) • Are vascular Cryptograms - > diffusiontparenchyma ∞ 3 vascular plants ecryptosuuremsy ⇐ Fevrs α fronds 素 示 웃 d Rpinnated. compound hiddem ⑤ only in reproducers Sporsphyte _ λ Spares => gametophyte ^
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  Stelar System: Pteridophytesare the first plants to evolve a true vascular system (xylem and phloem). The central vascular cylinder (stele) shows great evolutionary diversification: • Protostele: Solid core of xylem surrounded by phloem (e.g., Rhynia, Lycopodium). • Siphonostele: Protostele with a central parenchymatous pith (e.g., Equisetum). • Dictyostele: A dissected siphonostele forming a network of leaf gaps (e.g., Dryopteris). r Oters perigad S tube
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  • The sporophyterepresents the dominant phase in the life cycle of pteridophytes, and it is independent of the gametophyte. • The plant body is well-differentiated into true roots, stems, and leaves. • Root: primary root is ephemeral and is soon replaced by adventitious roots. • Stem: main stem is often an underground structure called a rhizome, which may sometimes be accompanied by aerial stems. • Leaves: Young leaves: circinate venation ( curling inward) Mature leaves: microphylls: simple leaf. Eg: Selaginella) megaphylls: compound leaf ( pinnae or frond) found in ferns. • Specialized leaves known as sporophylls bear sporangia on their ventral (abaxial) surfaces, which produce spores. ⑨ Sporphyte is : fullyindependent of gametophyte [ ← #only independentinintial phase dependent throughout life footd gemetophyte ^ 小 ∝ … * stout lived anything otherthan stemtutizome le a 염 * % curling circimate Venation . 승 車 ← dominant & θ N 女 sporophyre - >>
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  Peridophytes ∞ Xylem phioemt top * tylemi phloem - Vesseld ⑨ Sievetube Liberalltogether ㅓ - >trastried -sieve cally absent companion celle éfrost -albuminous cell ㄻ CaD cast vascular plan) 羊 Tiern to sepimeral unizome replaced adventitious tfrond 고 large compe pinnated leaves Selaginella ∝ simpleleaf
• 7.
  Similarities between Pteridophytes& Bryophytes: • Terrestrial mode of life • Water medium essential for fertilization • Presence of sterile jacket around sex organ • Young sporophyte partially or completely dependent upon gametophyte • Flagellated sperm • Zoogamous reproduction • Heteromorphic alternation of generation multicellutar * & MOJA ↑ jacketed. { Ateridophyte ょ Bryophyte: multiflagellate 고 biflagellated Sporophytic Gametophytis.
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  • Homosporous: One typeof spore Example: Dryopteris, Lycopodium • Heterosporous: Two types of spore. Example: Marsilea, Selaginella, Salvinia, Azolla S ← aspore * [2 = ∞ malefemale some spire forming ∞ = > monoecious Lysopodium ↓ QMOLD Tayopteris difft homospurous ∞ - Eiserious & SAM- Marsilea & Azella Selaginella,salvimia
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  也
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  Development of sporangia: •Eusporangiate: Develop from group of cells. Example: Selaginella, Lycopodium & Equisetum • Leptosporangiate: Develop from single cell. Example: Dryopteris, Marsilea, Salvinia, Azolla. SporangiumCan ∞ Tre bearing structure 고 ↓ Spire bearingleaf csporophyl) at [m) Sporiphyte _ ⑤ Gca ptevidophyte Do Multicellular plant ∝ & Str : many Cells- rune ESSSelaginella Lycopodium Ʃ ensporangiate ,equisetum _ ∞ - osingle - > most of us are single. -
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  Selaginella: • Eusporangiate andheterosporous • Polystelic condition in Selaginella willdenowii. • Also known as Resurrection plant, little club moss, spike moss, & bird's nest moss. • Some species complete their lifecycle in short wet season. Dry season rolls in a ball like structure. Pass out dry season. In wet season, absorb water & become green again (Draught Escapers / Resurrection plant). • Seed bearing: Selaginella rupestris. Also known as precursor of seed bearing plants. • Selaginella bryopteris commonly known as Sanjeevani. µ ← 법 - K Resurrection plant" Bajrambali- > terrace ? ⑨ ¤ - > ー - - - ∞ ^ ← - Z - - Most advanced pteridophyte Crestsgymnospend # *
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  *
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  & SAM 으 Ʃ
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  utizopove 、 Stemtrost Sui-generig aitis ofitsownyreI √ &LESS new organ เร d ensporangiate , &cas celled) · 고
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  *
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  ∅ * tongue-likeprocess microsporophyl/ ∞ RmicrosporangiumX ← ⇌ 고 X - liguleleaves ∝ ー liguleleaves
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  ∞ ⇌ _ ↴ 교 Bryophyte · ex 8ordumb shaped 2 +mallis 2 actively growing point d apical Mutch
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  * · singl club moss Selaginella. fangriaMeck Canal - to 18 cell sells Adiantum: walkingfern, maidenhair ferr Dryopteris : Male shield fern Equisetum: horsetail fern
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  Zycopodium ×
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  *
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  Plant body differentiatedinto root, stem, leaves. • Root: primary root ephemeral, replaced by adventitious root. • Stem: underground called rhizome, covered by brown colored hairs/scales called ramenta. • Leaf: Bipinnately compound with long rachis. Lamina of leaf divide into several lea fl ets (pinnae). Further divide to form smaller segment (pinnule). • Young leaves: circinate verniation. • Furcate venation: lateral vein bifurcated at tip. • Covered by ramenta. • Function: protect from injury & drying. • On ventral (abaxial) surface, sori present. · Adventitiousbuds d & legetative ∞ alsim peridophyte & - bryophytes Frhizome Vegetative protestion reproduction; 3apper part - leaf ·paventi e 媟 separatesnewplantdit growth → - - > rhizome branch dichotomously - >terminal part of rhizome: aerial ← - drib equivalent 6 S -- ㆁ * 3amidii " vacnis fak surcarerenation
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  ∞ Selagimella leaves 录 X frond : compepinnate leaf
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  &
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  adaxial ⇌ 示 JWabatialCventral t dorsa surface sporophyll Ʃ * → ceramentia ㆁ
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  Sexual Reproduction (byspores): • Dryopteris: homosporous & leptosporangiate. Sori: • superficial & marginal on either side of rachis of pinnule on ventral (abaxial) / undersurface. • Brown at maturity (green in young leaves). • Protected by kidney-shaped membrane / shield indusium • Basis of naming Dryopteris—> male shield fern exspirangiateslegsa upperepidermis clesf]) Flower epiteriig Sig : Sorus CMOLD Tklo (singl)e σ ^ - > sporangium ∞ 고 亠 groun of sporangium! sorug 고 group! Sorii.
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  √
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  Placenta: • Cushion-shaped vasculartissue where sporangia develop & is attached. • Water gland at base of stalk. • Help keep sori moist until maturity. Sporangia contain: • Stalk: Multicellular. • Capsule: Oval & biconvex. Single layered jacket or wall. Enclose 12 to 16 diploid mother cells. Meiosis 48-64 haploid spores √ No -of diploid sporemother cell 교 12 to 16 d meiosis 48-64 Spores upptrepidermis cles] ⇐ ← o Flower epidermig -2 surface ventral water gland lost Sig: Sorus α water scarcity o huptire dispersed by wind . 小
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  Capsule wall: Differentiatedinto: • Annulus: Thin cells with greatly thickened hygroscopic inner wall. • Stomium: Large cell but thin-walled. At maturity, Annulus lose water contraction create tension Stomium thin-walled rupture due to differential contraction dispersion by air. … S α 울 문 小 Mout s Watergland ↓ lost ↓ 、
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  Gametophyte: Haploid spore germinate germtube emerge transverse division larger cell smaller cell. Rhizoidal filament apical cell undergo oblique division apical notch Prothallus Gametophytic phase • Gametophytic phase produce gametes. large ∝ Tamatophyte ∝ small & √ dividerepeatedly x α * 」 mca ncte N ㄻ
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  • Prothallus: • Flattened,heart shaped with apical notch. • Rhizoid & sex organ on ventral surface • Photosynthetic - independent & autotrophic. • Monoecious but protandrous (antheridia appear before archegonia). • Archegonia: near apical notch. • Antheridia: below archegonia near posterior end * *> unigellular - > anchorage nutrient waterabsorption malfemale Sex organ w · formed ^ · ·la n λ anchorageR nutriemtR Sowny Water
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  *
• 33.
  Antheridia: • Male reproductiveorgan. • Contain androcytes metamorphosis spirally coiled, uninucleate & multiciliated antherozoid (spermatozoid) ∝ ∞
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  Archegonia: • Female reproductiveorgan in cluster near apical notch. • Multicellular sessile, flask shaped with: (1) swollen venter: embedded in tissue of prothallus with no jacket. Consist of egg cell & VCC. (2)Neck: short-armed made up of vertical rows of cell, binucleated neck canal cell. • On maturity, NCC & VCC breakdown along with tip of neck form mucilage with malic acid excrete from mouth chemotactic agent attract antherozoids gametophyted sporsphyte i ∞ θ pteridophyte gametophyte smaller bryophyte 4- 12 & anchegonialonger - ≠ - &MOJA 超 ∅ nan 5 .7 cells (recksel l δ - - ↓ Gaas lidcellI ∝ * chemoattractant 고 ∞ ^
• 35.
  Sporophytic body: initiallydependent upon gametophytic body draws nutrition through foot Later independent. Antherozoid + Egg → Diploid zygote (first cell of sporophytic phase). Secretes thin wall around it oospore undergo holoblastic development. _ 广 fertilization C2JN CD CD α ↓ · 杀 while embryo embryonic involved in formation development of blastomere ^ * germ layer -whole new baby C ] ∝
• 36.
  • First plantto appear after forest fire: Ferns (due to underground rhizome). • Coal is formed from pteridophytes 二 マ forest X forest fully damage α barrenland first appearing: Bryophyte 고 Pioneer in "succession
• 37.
  Stelar System: Pteridophytesare the first plants to evolve a true vascular system (xylem and phloem). The central vascular cylinder (stele) shows great evolutionary diversification: • Protostele: Solid core of xylem surrounded by phloem (e.g., Rhynia, Lycopodium). • Siphonostele: Protostele with a central parenchymatous pith (e.g., Equisetum). • Dictyostele: A dissected siphonostele forming a network of leaf gaps (e.g., Dryopteris). Apospory and Apogamy: • Apogamy: Development of a sporophyte directly from the gametophyte cells without fertilization (results in a diploid gametophyte turning into a diploid sporophyte). • Apospory: Development of a gametophyte directly from the vegetative cells of the sporophyte without spore formation (results in a haploid sporophyte turning into a haploid gametophyte). Discovered by Farlow.
• 38.
  Economic Importance: • Medication:Dryopteris rhizomes yield an anthelmintic drug (filin) used to expel tapeworms. • Ornamentals: Many ferns are grown in gardens for their delicate, feathery fronds. • Biofertilizers: Azolla (an aquatic fern) is associated with nitrogen-fixing cyanobacteria (Anabaena azollae) and is widely used in paddy fields to increase soil fertility. 丕 ^ ∞ - > > ー ⇐