Major Groups of plants - Bryophytes

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About the Bryophytes - one of the four major group of plants

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Major Groups of Plants Bryophytes

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M ajor Groups of Plants Major Groups Bryophytes Seedless Vascular Plants Gymnosperms Angiosperms Mosses Ferns Conifers Flowering plants

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Sporophyte and Gametophyte Alternation of generation One stage – the sporophyte – produces spores. The spores develop into a gametophyte stage plant . Gametophytes produce either sperm or egg gametes. Egg and sperm cells unite and grow into another sporophyte

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M ajor Groups of Plants Major Groups Bryophytes Seedless Vascular Plants Gymnosperms Angiosperms Mosses Ferns Conifers Flowering plants

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Sporophyte (2N) Gametophyte (N) Bryophytes Most primitive of all plants. Characteristics : Lacks a vascular system Disperse through spores Gametophyte stage is dominant Divisions of Bryophytes Mosses Bryophyta Liverworts Hepaticophyta Hornworts Anthocerotophyta Distinguished by: Sporophyte (sporangium) variations Anatomical variations

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Bryophytes: Mosses Characteristics : Usually have radial symmetry Maybe erect or prostrate Most leaves have costa (midrib) Found in moist and shady habitats Rocks and arid location Most water absorption is from the surface cells Can desiccate/dehydrate for long periods Gametophyte Zygote Antheridia Haploid spores Sporophyte Gametophyte Life Cycle of a typical Moss

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Bryophytes: Liverworts Characteristics : May have a cuticle Flattened growth form often prostrate Unicellular rhizoids on lower surface Upper surface smooth with pores for gas exchange The sporophyte "sporangium" or capsule is simple Spores released by hygroscopic elaters (hairs ) Liverworts Thallose Leafy - Thallus (sheet like) shape -About 30 cells thick -Air pores &gas exchange chambers on dorsal side -Apical meristems -Dichotomous branching -Makes conspicuous lobes - Heterthallic -Looks like leaves and stem with leaves overlapping along axis -Usually flattened but not thallose -’Leaves’ 2 or 3; lobed -One or two cells thick and no midrib Life Cycle of a typical Liverwort Long stem with ball shape Sporangium or

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Bryophytes: Hornworts Characteristics: Have rounded, small, thallose -like gametophytes Hornworts have just one chloroplast per cell. The gametophytes may be unisexual or bisexual. The sporophyte is "horn-shaped", and grows from a basal sheath beneath the surface of the gametophyte The sporophyte tip splits releasing spores. Spores continue to mature for some time, and the Sporophyte continues to split . Thus, life cycle is similar to that of liverwort.

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Sr. No. Feature Mosses Liverworts Hornworts 1. Gametophyte E rect “stem” and “leaves” Flat or “leafy” Flat 2. Stomata Yes No (have pores) Yes 3. Distinguish D-methionine Yes No Yes 4. Hydroids & leptoids Yes No No 5. Axial gametophytes Yes No No 6. Protonema Yes No in general No 7. “Leaves ” 1 layer, spiral, with midrib 1 layer, overlapping None 8. Chloroplast M any Many 1 large 9. Symbiotic bacteria No Some Yes 10. Cuticle Yes No Yes 11. Determinate sporophyte Yes Yes No A Comparison of the Structure of the Three Bryophyte Divisions Bryophytes

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References http://www.marietta.edu/~biol/introlab/Plant%20Diversity.pdf http://scitec.uwichill.edu.bb/bcs/bl14apl/bryo1.htm http://scidiv.bellevuecollege.edu/rkr/botany110/lectures/bryophytes.html http://www.elizajewett.com/portfolio/marchantia.htm http://www.saburchill.com/ans02/chapters/chap040.html http://www.bio.miami.edu/dana/226/226F09_19.html http://biology.clc.uc.edu/courses/bio106/gymnospr.htm http:// generalhorticulture.tamu.edu/lectsupl/anatomy/anatomy.html#page12 http:// faculty.unlv.edu/landau/gymnosperms.htm http:// biology.clc.uc.edu/courses/bio106/angio.htm

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