Polysiphonia: Structure, Classification, and Occurrence
Explore the intricate details of Polysiphonia, a red algae with a unique triphasic plant structure. Learn about its taxonomical classification, occurrence in marine environments, and thallus anatomy including rhizoids and branching patterns. Delve into the fascinating world of Polysiphonia's long branches, short trichoblasts, and reproductive structures. Dive deep into the world of this beautiful marine organism through images and detailed descriptions.
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Presentation Transcript
D Dr r. . U Um ma ay ya al l R Ra am ma an na at th ha an n C Co ol ll le eg ge e f fo or r W Wo om me en n K Ka ar ra ai ik ku ud di i Topic: Polysiphonia By, By, Dr. A. Dr. A. Shinyguruce Shinyguruce, , Assistant Professor, Assistant Professor, Department of Microbiology & CLT, Department of Microbiology & CLT, Department of Micro biology & CLT,URCW
Taxonomical Classification Class Sub class : Order Family Genes : Rhodophyceae Florideae Ceramiales : Rhodomelaceae : Polysiphonia : Department of Micro biology & CLT,URCW
Occurrence marine. Red algae Red algae. All species are marine World wide distribution. 900 species. Attached to rocks & stones rocks & stones. Polysiphonia violacea is an epiphyte which grows on large brown algae. P.urceolata is saprophyte saprophyte P.elongata is a lithophyte lithophyte Shore of Tuticorin Tuticorin & in Indian species:- P.fastigata P.platycarpa P.variegata P. elongata epiphyte & in Rameswaram Rameswaram Department of Micro biology & CLT,URCW
Department of Micro biology & CLT,URCW
Thallus structure Triphasic plant 3 phases Haploid gametophyte Diploid carposporophyte Diploid tetrasporophyte Gametophyte & tetrasporophyte are similar and independent. Carposporophyte is attached to gametophyte. Beautiful feather like appearance. Grows upto 5-35cms height. In thallus erect system, creeping system & rhizoids. Made up of branched filaments- serve as perennation. Department of Micro biology & CLT,URCW
Rhizoids: Vertically downward from creeping system. Hold fast helps to attach thallus to the substratum. Erect system grows upward from creeping system. Made up of profusely branched filaments. Filaments heterotrichous 3 types Main axis Long braches Short branches Main axis is polsiphonous or multiaxial many parallel siphons (filaments) Central siphon or axial siphon surrounded by 4-20 pericentral siphons Department of Micro biology & CLT,URCW
Long branches unlimited growth and are similar to main axis. Short braches trichoblasts. They are short & limited growth. Have only central siphons. Pericentral siphons are absent. Monosiphonous Trichoblasts are dichotomously branched, colourless (chromatophore absent) Some trichoblast bear sex organs fertile trichoblast Fertile branches Male trichoblast bears cluster of anthridia female trichoblast -carpogonium Department of Micro biology & CLT,URCW
Department of Micro biology & CLT,URCW
Cell structure Central siphon large axial cell or central cells. Pericentral siphon smaller in size size pericentral cells. Cells interconnected by pit connection connection. Cell is bounded by cell wall 2 layers Outer pectin substance Inner cellulose smaller in pit Department of Micro biology & CLT,URCW
Inside the cell wall plasma membrane membrane- - surrounds the cytoplasm cytoplasm which enclose central vacuole vacuole. In cytoplasm many discoid chromatophores chromatophores. In chromatophores:- chlorophyll a & c. alpha & beta carotenes, a & c. alpha & beta carotenes, xanthophylls, phycocyanin xanthophylls, phycocyanin R, and phycoerythrin and phycoerythrin- -R. R. Reserve food Reserve food Floridean Florideanstarch & & floridoside floridoside plasma central discoid chlorophyll R, starch Department of Micro biology & CLT,URCW
growth Growth takes in the single apical cell the tip of axis. Transverse division Transverse division from the central siphon. Then undergo periclinal periclinal division pericentral cells pericentral cells. single apical cell at division form Department of Micro biology & CLT,URCW
reproduction Sexual and asexual reproduction 1. Gamethophyte 2. Carposporophyte 3. Tetrasporophyte Gametophyte free living, haploid plants. Gametes Zygote carposporophyte carposporophyte diploid asexually produce carpospores. Tetrasporophyte independent germination of carpospore diploid plant tetraspore haploid female & male gametophyte female & male gametophyte. Department of Micro biology & CLT,URCW
