Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae. They are similar in structure and function to the root hairs of vascularland plants. Similar structures are formed by some fungi. Rhizoids may be unicellular or multicellular.[1]
Plants originated in aquatic environments and gradually migrated to land during their long course of evolution. In water or near it, plants could absorb water from their surroundings, with no need for any special absorbing organ or tissue. Additionally, in the primitive states of plant development, tissue differentiation and division of labor was minimal, thus specialized water absorbing tissue was not required. The development of specialized tissues to absorb water efficiently and anchor themselves to the ground enabled the spread of plants to the land.[2]
Descriptionedit
Rhizoids absorb water mainly by capillary action, in which water moves up between threads of rhizoids and not through each of them as it does in roots, but some species of bryophytes do have the ability to take up water inside their rhizoids.[2]
Land plantsedit
In land plants, rhizoids are trichomes that anchor the plant to the ground. In the liverworts, they are absent or unicellular, but multicellular in mosses. In vascular plants they are often called root hairs, and may be unicellular or multicellular.
Algaeedit
In certain algae, there is an extensive rhizoidal system that allows the alga to anchor itself to a sandy substrate from which it can absorb nutrients.[3] Microscopic free-floating species, however, do not have rhizoids at all.[4]
Fungiedit
In fungi, rhizoids are small branching hyphae that grow downwards from the stolons that anchor the fungus to the substrate, where they release digestive enzymes and absorb digested organic material. That is why fungí are called heterotrophs by absorption.
^Fletcher RL (1987). Seaweeds of the British Isles, Volume 3 Fucophyceae (Phaeophyceae). British Museum (Natural History). ISBN0-565-00992-3.
^ abJones VA, Dolan L (July 2012). "The evolution of root hairs and rhizoids". Annals of Botany. 110 (2): 205–212. doi:10.1093/aob/mcs136. PMC3394659. PMID 22730024.
^Demes KW, Littler MM, Littler DS (2010). "Comparative phosphate acquisition in giant-celled rhizophytic algae (Bryopsidales, Chlorophyta): Fleshy vs. calcified forms". Aquatic Botany. 92 (2): 157–160. doi:10.1016/j.aquabot.2009.10.012.
^Smith GM (1955). Cryptogamic Botany, Volume 1 Algae and Fungi. McGraw-Hill Book Company Inc.
Further readingedit
Hogan CM (2010). "Fern". In Basu S, Cleveland C (eds.). Encyclopedia of Earth. Washington DC: National Council for Science and the Environment.
External linksedit
"Rhizoids" . The New Student's Reference Work. 1914.
rhizoid, confused, with, rhizome, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, . Not to be confused with Rhizome This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Rhizoid news newspapers books scholar JSTOR September 2021 Learn how and when to remove this message Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae They are similar in structure and function to the root hairs of vascular land plants Similar structures are formed by some fungi Rhizoids may be unicellular or multicellular 1 Contents 1 Evolutionary development 2 Description 2 1 Land plants 2 2 Algae 2 3 Fungi 3 See also 4 References 5 Further reading 6 External linksEvolutionary development editPlants originated in aquatic environments and gradually migrated to land during their long course of evolution In water or near it plants could absorb water from their surroundings with no need for any special absorbing organ or tissue Additionally in the primitive states of plant development tissue differentiation and division of labor was minimal thus specialized water absorbing tissue was not required The development of specialized tissues to absorb water efficiently and anchor themselves to the ground enabled the spread of plants to the land 2 Description editRhizoids absorb water mainly by capillary action in which water moves up between threads of rhizoids and not through each of them as it does in roots but some species of bryophytes do have the ability to take up water inside their rhizoids 2 Land plants edit In land plants rhizoids are trichomes that anchor the plant to the ground In the liverworts they are absent or unicellular but multicellular in mosses In vascular plants they are often called root hairs and may be unicellular or multicellular Algae edit In certain algae there is an extensive rhizoidal system that allows the alga to anchor itself to a sandy substrate from which it can absorb nutrients 3 Microscopic free floating species however do not have rhizoids at all 4 Fungi edit In fungi rhizoids are small branching hyphae that grow downwards from the stolons that anchor the fungus to the substrate where they release digestive enzymes and absorb digested organic material That is why fungi are called heterotrophs by absorption See also edit nbsp Fungi portal Rhizine the equivalent structure in lichensReferences edit Fletcher RL 1987 Seaweeds of the British Isles Volume 3 Fucophyceae Phaeophyceae British Museum Natural History ISBN 0 565 00992 3 a b Jones VA Dolan L July 2012 The evolution of root hairs and rhizoids Annals of Botany 110 2 205 212 doi 10 1093 aob mcs136 PMC 3394659 PMID 22730024 Demes KW Littler MM Littler DS 2010 Comparative phosphate acquisition in giant celled rhizophytic algae Bryopsidales Chlorophyta Fleshy vs calcified forms Aquatic Botany 92 2 157 160 doi 10 1016 j aquabot 2009 10 012 Smith GM 1955 Cryptogamic Botany Volume 1 Algae and Fungi McGraw Hill Book Company Inc Further reading editHogan CM 2010 Fern In Basu S Cleveland C eds Encyclopedia of Earth Washington DC National Council for Science and the Environment External links edit Rhizoids The New Student s Reference Work 1914 Rhizoids New International Encyclopedia 1905 nbsp This mycology related article is a stub You can help Wikipedia by expanding it vte nbsp This botany article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Rhizoid amp oldid 1156116383, wikipedia, wiki, book, books, library,
