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Chara
- 1. CHARA Dr SHEEJA TTHARAKAN Assistant Professor Department of Botany Vimala College (Autonomous) Thrissur, Kerala
- 2. CHARA Division Chlorophyta Class Chlorophyceae OrderCharales Family Characeae Genus Chara
- 3. Occurrence Freshwater Plants encrusted withcalcium carbonate - Stone warts
- 4. Vegetative structure Multicellular, macrosopic filamentous,branched Main axis , rhizoids Rhizoids - lower end, branched, multicellular, uniseriate, obliquely septate, no nodes and internodes, Arise from rhizoidal plates fixation
- 5. Main axis Erect, branched Differentiatedinto nodes and internodes Internodes – long, single celled, enveloped by corticating threads Nodes – short, regularly arranged cells Bears branches - Branches of limited growth (short laterals) - Branches of unlimited growth (long laterals)
- 6. Branches of limitedgrowth (short laterals) primary laterals, leaves or branchlets Arise from peripheral cell of the node Limited growth Limited number of nodes and internodes Arise shorter, unicellular branches from nodes - --secondary laterals bear stipules Fertile branches bear sex organs
- 7. Branches of unlimitedgrowth (long laterals) arise from axils of primary laterals Arise singly unlimited growth/indefinitely nodes and internodes, cortication bears primary laterals
- 8. Cell structure Two typesof cells At the apex- & at the nodes Small & isodiametric Central nucleus Granular cytoplasm Chloroplst- numerous, discoid, evenly distributed, no pyrenoids
- 9. Cell structure Internodal cells elongated largevacuole, cytoplasm & nuclei- peripheral Chloroplast- discoid, numerous, longitudinally Cytoplsm – peripheral stationary layer-exoplasm inner fluidy endoplasm Movement- cyclosis Cell wall – cellulose, hemicellulose, lignin, pectin Mucilage covering, Calcium carbonate
- 10. Cortication Internodal cell ensheathedby elongated corticating threads Thread consist of smaller cells Hlf of corticating arise from uppernode, others from lower node
- 11. Reproduction Vegetative & sexualmethods Vegetative – amylum stars, bulbils, 20protenema a)Amylum stars star shaped aggregate of vegetative cells Lower nodes Store reserve food Detach from parent ----- new plants
- 12. Vegetative reproduction b)Bulbils Small, rounded,tuber-like structures, develop on rhizoids c) Secondary protenema nodes/rhizoids Protenema like structures ----new plants
- 13. Sexual reproduction Oogamous Sex organslarge & visible Male sex organ- antheridia/globules Female sex organ – oogonia/nucules Homothallic (monoecious) – both on same plant Heterothallic ( Dioecious)- different plants Nucule is always above the globule
- 14. Globule/antheridium Large, spherical, Red/brightorange coloured Stalk – pedicel Outermost wall -8 large closely fitted curved cells-shield cells encloses an internal cavity
- 15. Globule/antheridium Manubrium – center ofshield cell- rod shaped handle like cell 1o capitula- more or less rounded cells at the end Inturn posess 2o capitula branched or unbranched antheridial filaments/ spermatogenous filaments
- 16. Matre Globule/antheridium Schield cellsmove apart Expose antheridial filaments 200 androytes Elongated coiled biflagellated antherozoid
- 17. OOGONIUM (Nucule) Macroscopic Short stalk Node Homothallic-Nuculeis always above the globule Tube cell- 5 , spirally twisted, cover, except at the tip Corona cell- 5, at the tip Egg- center, uninucleate Rich of food materials- oil drops & starch grains Receptive spot- tip of the egg, hyaline
- 18. Fertilization Numerous biflagellate antherozoidsliberated outside Swim- -water –reach nucule Tube cells elongate near the tip- form neck Narrow central slit in the corona – passage for antherozoids Only one penetrate the wall- fuse with the egg-zygote
- 19. Germination Diploid nucleus migratetowards apex Secrete cellulosic cell wall Yellow/ brown Wall of the tube cell & oogonium -thick & sculpturing Zygote settles at the bottom Undergo resting period
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