Ectocarpus

Ectocarpus

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  TYPE STUDY OF ECTOCARPUS PresentedBy Naveen.A.N I MSc Microbiology Govt Science College Bangalore
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  INTRODUCTION The genus ectocarpusshows many of the simplest features in the phaeophyceae and is one of the best known brown algal genus. It is often seen as a hairy growth in pools mostly attached to rocks and other algae.
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  Fig.1: Vegetative morphologyof Ectocarpus. TAXONOMIC POSITION ❖ Division - Phaeophyta ❖ Class - Isogeneratae ❖ Order - Ectocarpales ❖ Family - Ectocarpaceae ❖ Genus - Ectocarpus
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  Distribution ● Found inabundance ● Worldwide distribution ● Plenty in atlantic coast,pacific coast ● Some are Marine algae ● Few freshwater forms ● Some species occur in shallow water ● 410 species ● 16 species in india
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  Fig.2: Vegetative morphologyof Ectocarpus. Morphology ➢ Brown Algae, Branched Filamentous, Caespitose, Thallus Brown Or Yellow In Colour,30 Cm In Length ➢ Plants are dioecious, because male and female gametes are formed in gametangia borne on different thalli ➢ Heterotrichous ,Monosiphonous( Uniseriate), Lower Parts Become Polysiphonous Due To Longitudinal Division ➢ The Prostate Portion Found Attached To The Substratum ➢ The Branches Of Erect System Develops From The Prostrate System Into A Tuft ➢ The Branches Are Always Lateral And Arise Just Beneath The Septa ➢ Vacuolated Cells With Few Chromatophores Forming A Colourless Hair ➢ Erect System Is Photosynthetic Which Bears Reproductive Organs ➢ in some species sporangia may arise terminally up but burning directly on the prostate base ➢ pseudo parenchymatous
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  CELL STRUCTURE ➢ cellsare small ,rectangular or cylindrical Uninucleate and contain chloroplast with pyrenoid ➢ The pyrenoid is stalked and pear shaped ➢ the cell wall is thick, mucilaginous, consisting of 3 Pectic cellulose liars ➢ the cell wall constitutes alginic acid and fucoidan ➢ photosynthetic pigments are chlorophyll A, chlorophyll c, beta carotene and fucoxanthin. ➢ Vacuoles called as physodes which contains polyphenols the cells are totipotent and gene content ➢ Plurilocular sporangium of some ectocarpus species contain polyhydron virus like particles
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  ➢ Ectocarpus ReproduceBoth Asexually And Sexually ➢ Asexual Reproduction ➢ Takes Place By Means Of Bi Flagellate Zoospores Produced In Two Kinds Of Sporangium Namely ➢ Unicellular Or Unilocular Sporangia ➢ Multicellular Or Pluralocular Sporangia Reproduction Fig.4: Plant body of Ectocarpus.
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  Development Of UnilocularSporangium ➢ The Terminal cell Of a short branchlet develops into an unilocular sporangium ➢ chromatophores increases within the young sporangium And it becomes several fold ➢ The diploid Nucleus of the initial cell first undergoes meiosis followed by Mitotic divisions to produce haploid daughter nuclei. ➢ there is cleavage of the of cytoplasm to form many uninucleate daughter protoplast units ➢ each unit undergoes metamorphosis into a pyriform bi flagellate haploid Swarmer called as meiozoospores ➢ The flagella are unequal and Inserted laterally ➢ acronematic and pantonematic flagella ➢ Liberation of meiozoospores in a gelatinous mass ➢ ultimately meiozoospores come to rest and loses there flagella
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  Germination of meiozoospores ★Each meiozoospores on contact with suitable substratum withdraw its flagella and forms the germ tube ★ Germ tube divides and forms a prostrate filament ★ The plants developed on the germination of these haploid meiozoospores which are gametophytes or sexual plants in the life cycle
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  Development Of PlurilocularSporangia ● Developed from the terminal cell of a lateral branchlet ● Elongated conical multicellular bodies developed singly on diploma or asexual plants ● The apical cell enlarges and functions as sporangial initial. This enlarges and undergoes mitotic division. ● As a result of which a multicellular cone like structure is produced forming a plurilocular sporangium.
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  SEXUAL REPRODUCTION ● Itis of both isogamous and anisogamous type ● Anisogamous may be of 2types ● Morphological anisogamy ● Physiological anisogamy ● These are produced inside the plurilocular gamentangia Fig.5: Some small/dwarf species of Ectocarpus.
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  Development Of PlurilocularGametangia ● Develops from the terminal cell of lateral branchlet ● Large Elongated sessile structures ● These produce haploid gametes ● The terminal cell gets inflated by repeated transverse divisions resulting in the several hundred small cubical cells ● Each cell gives rise to one or two biflagellated pyriform gametes ● The gamete are liberated from the gamentangia and as follows
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  FERTILIZATION AND GERMINATION ●It Is External In Brown Algae Involving Fusion Of Naked Gamete ● Clump Formation Is Seen ● Plasmogamy And Karyogmy Occurs ● Role Of Pheromones in Fertilization ● The Motile Female Gamete Begins To Settle On A Surface And Start To Secure A Chemical Sign A Pheromone ● Biological Function ● Ectocarpene 1st Isolated Algal Pheromone ● Zygote Undergoes Germination With No Reduction And Rest ● Diploid Sporophyte Bears Unilocular And Plurilocular Sporangia On The Same Plant ● Sexual Generation Also Propagates By The Parthenogenitic Development Of The Unfused Gametes
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  Ultrastructure of Gametein Ectocarpus STRUCTURE OF GAMETES ● Gametes Shows The Flagellum With The Eukaryotic Arrangement Of Microtubes ● Chromatophore Is Shown With Thylakoids And Fucixanthin Granules ● Nucleus Is Centrally Located ● Cell Wall Is Thin And Tightly Appressed ● Female Gamete Is Thigmotactic ● Male Gamete Is Chemotaxis
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  Life cycle ● AHaploid Diploid Life Cycle ● Alternation Of Generation Or Isomorphic ● Two Distinct Phases Can Be Seen ● The Diploid Sporophyte ● The Haploid Gametophyte ● Morphologically Both Are Similar So This Type Is Called As Isomorphic ● Reduplication Of Sporophyte ● Reduplication Of Gametophyte
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  Economic importance ● THEIMPORTANT PHYCOCOLLOIDS ALGIN AND FUCOIDEN ARE SECONDARY METABOLITES USED IN MANUFACTURE OF BEER TOOTHPASTE ICE CREAM PAINT SHAVING CREAMS MEDICINE AND SOAPS.