, Volume 15, Issue 1, pp 37–46 | Cite as

Factors controlling the formation of oxidized root channels: A review

  • Irving A. Mendelssohn
  • Barbara A. Kleiss
  • James S. Wakeley


Although root plaques and associated oxidized root channels are used for wetland identification as field indicators of wetland, hydrology, little information is available concerning their reliability as related to the environmental and biotic factors controlling their formation. Therefore, this review describes and evaluates the current state of knowledge of the factors controlling the formation of iron plaques and recommends research to address information gaps.

Both abiotic and biotic factors control the presence and degree of iron plaque formation. The most important abiotic factor is the availability of soil iron. However, the effect of site variation in soil physico-chemical characteristics (e.g., texture, organic matter, pH, Eh, and soil fertility), on iron availability and microbial activity can influence the formation and persistence of root plaques and oxidized root channels. Although the oxidizing capacity of the plant root is the most important biotic factor controlling plaque formation, only a limited number of wetland species have been evaluated for this ability, so species-specific differences are generally unknown.

Unlike some of the other hydrologic indicators used in wetland delineation (e.g., water marks on trees or sediment deposits) root plaques and oxidized root channels indicate soil saturation for a sufficient period to produce anaerobic soil conditions. Additionally, when found in conjunction with a living root, oxidized root channels indicate that the anaerobic conditions occurred within the life span of the plant root. Therefore, the presence of oxidized root channels and iron plaque surrounding living roots is a relatively good indicator of current wetland hydrologic conditions. However, research is needed to elucidate the relative abilities of different plant species to produce oxidized root channels, the temporal persistence of the root iron plaque and the role that soil physico-chemical condition plays in controlling plaque formation. Without a better understanding of the controls on iron plaque formation and disappearance, the absence of oxidized root channels, in itself, should not be used to indicate the absence of a wetland.

Key Words

wetland ecology wetland delineation iron plaques or deposits root oxygen loss wetland hydrologic indicators waterlogging 


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Literature Cited

  1. Armstrong, J. and W. Armstrong. 1988.Phragmites australis-a preliminary study of soil-oxidizing sites and internal gas transport pathways. New Phytologist 108:373–382.CrossRefGoogle Scholar
  2. Armstrong, W. 1964. Oxygen diffusion from the roots of some British bog plants. Nature 204:801–802.CrossRefGoogle Scholar
  3. Armstrong, W. 1967a. The oxidizing activity of roots in waterlogged soils. Physiologia Plantarum 20:920–926.CrossRefGoogle Scholar
  4. Armstrong, W. 1967b. The use of polarography in the assay of oxygen diffusing from roots in anaerobic media. Physiologia Plantarum 20:540–553.CrossRefGoogle Scholar
  5. Armstrong, W. 1968. Oxygen diffusion from the roots of woody species. Physiologia Plantarum 21:539–543.CrossRefGoogle Scholar
  6. Armstrong, W. 1971. Radial oxygen loss from intact rice roots as affected by distance from the apex, respiration and waterlogging. Physiologia Plantarum 25:192–197.CrossRefGoogle Scholar
  7. Armstrong, W. and D. J. Boatman. 1967. Some field observations relating the growth of bog plants to conditions of soil aeration. Journal of Ecology 55:101–110.CrossRefGoogle Scholar
  8. Bacha, R. E. and L. R. Hossner. 1977. Characteristics of coatings formed on rice roots as affected by iron and manganese additions. Soil Science Society of American Journal 41: 931–935.Google Scholar
  9. Bartlett, R. J. 1961. Iron oxidation proximate to plant roots. Soil Science 92:372–379.CrossRefGoogle Scholar
  10. Boone, C. M., J. M. Bristow, and G. W. van Loon. 1983. The relative efficiency of ionic iron (III) and iron (II) utilization by the rice plant. Journal of Plant Nutrition 6:201–218.CrossRefGoogle Scholar
  11. Chen, C. C., J. B. Dixon, and F. T. Turner. 1980a. Iron coatings on rice roots: morphology and models of development. Soil Science Society of America Journal 44:1113–1119.Google Scholar
  12. Chen, C. C., J. B. Dixon, and F. T. Turner. 1980b. Iron coatings on rice roots: mineralogy and quantity influencing factors. Soil Science Society of America Journal 44:635–639.CrossRefGoogle Scholar
  13. Coult, D. A. and K. B. Vallance. 1958. Observations on the gaseous exchange which takes place betweenMenyanthes trifoliata L. and its environment. Part II. Journal of Experimental Botany 9:390–402.CrossRefGoogle Scholar
  14. Crowder, A. A. and S. M. Macfie 1986. Seasonal deposition of ferric hydroxide plaque on roots of wetland plants. Canadian Journal of Botany 64:2120–2121.CrossRefGoogle Scholar
  15. Federal Interagency Committee for Wetland Delineation. 1989. Federal manual for identifying and delineating jurisdictional wetlands. U. S. Army Corps of Engineers, U. S. Environmental Protection Agency, U. S. Fish and Wildlife Service, USDA Soil Conservation Service, Washington, D.C., USA.Google Scholar
  16. Gambrell, R. P. and W. H. Patrick, Jr. 1978. Chemical and microbiological properties of anaerobic soils and sediments. p. 119–136.In: D. D. Hook and R. M. M. Crawford (eds.) Plant Life in Anaerobic Environments. Ann Arbor Press. Ann Arbor, MI, USA.Google Scholar
  17. Ghiorse, W. C. 1984. Biology of iron- and manganese-depositing bacteria. Annual Review of Microbiology 38:515–550.PubMedGoogle Scholar
  18. Good, B. J., S. P. Faulkner, and W. H. Patrick, Jr. 1986. Evalution of green ash root responses as a soil wetness indicator. Soil Science Society of America Journal 50:1570–1575.CrossRefGoogle Scholar
  19. Green, M. S. and J. R. Etherington. 1977. Oxidation of ferrous iron by rice (Oryza sativa L.) roots: A mechanism for waterlogging tolerance. Journal of Experimental Botany 28:678–690.CrossRefGoogle Scholar
  20. Howeler, R. H. 1973. Iron-induced oranging disease of rice in relation to physio-chemical changes in a flooded oxisol. Soil Science Society of America, Proceedings 37:898–903.Google Scholar
  21. Johnson-Green, P. C. 1988. Interactions between the rhizoplan microflora and iron oxide deposition on rice (Oryza sativa) roots. M Sc. Thesis. Queen’s University, Kingston, Ontario, Canada.Google Scholar
  22. Joshi, M. M., I. K. A. Ibrahim, and J. P. Hollis. 1973. Oxygen release from rice seedlings. Physiologia Plantarum 29:269–271.CrossRefGoogle Scholar
  23. Laan, P., A. Smolders, C. W. P. M. Blom, and W. Armstrong. 1989. The relative roles of internal acration, radial oxygen losses, iron exclusion and nutrient balances in flood-tolerance ofRumex species. Acta Botanica Neerlandica 38:131–145.Google Scholar
  24. Mendelssohn, I. A. and M. T. Postek. 1982. Elemental analysis of deposits on the roots ofSpartina alterniflora Loisel. American Journal of Botany 69:904–912.CrossRefGoogle Scholar
  25. Mitsch, W. J. and J. G. Gosselink. 1993. Wetlands. Van Nostrand Reinhold Company, New York, NY, USA.Google Scholar
  26. Mitsui, S., K. Kumazawa, J. Yazaki, H. Hirata, and K. Ishizuka. 1962. Dynamic aspects of N, P, K uptake and O2 secretion in relation to the metabolic pathways within the plant roots. Soil Science and Plant Nutrition 8:25–30.Google Scholar
  27. Okuda, A. and E. Takahashi. 1965. The role of silicon. p. 123–146. In: Mineral Nutrition of the Rice Plant. The Johns Hopkins Press, Baltimore, MD, USA.Google Scholar
  28. Otte, M. L., J. Rozema, L. Koster, M. S. Haarsma, and R. A. Broekman. 1989. Iron plaque on rotos ofAster tripolium L.: Interaction with zine uptake. New Phytologist 111:309–317.CrossRefGoogle Scholar
  29. Russell, E. W. 1973. Soil Conditions and Plant Growth. Longman Group Limited, London, UK.Google Scholar
  30. Schwertmann, U. and R. M. Taylor. 1977. Iron Oxides. p. 145–180.In: J. B. Dixon and S. B. Wead (eds.) Minerals in Soil Environments. Soil Science Society of America Proceedings, Madison, WI, USA.Google Scholar
  31. Shwertmann, U. and H. Thalmann. 1976. The influence of [Fe (II)], [Si], and pH on the formation of lepidocrocite and ferrihydrite during oxidation of aqueous FeCl2 solutions. Clay Minerals 11: 189–200.CrossRefGoogle Scholar
  32. St-Cyr, L. and A. A. Crowder. 1987. Relation between Fe, Mn, Cu, Zn in root plaque and leaves ofPhramites australis. p. 466–468. In: S. E. Lindberg and T. C. Hutchinson (eds.) Proceedings of the Conference on Heavy Metals in the Environment, Volume 1, New Orleans, LA, USA.Google Scholar
  33. St-Cyr, L. and A. A. Crowder. 1988. Iron oxide deposits on the roots ofPhragmites australis related to the iron bound to carbonates in the soil. Journal of Plant Nutrition 11:1253–1261.CrossRefGoogle Scholar
  34. St-Cyr, L. and A. A. Crowder. 1989. Factors affecting iron plaque on the roots ofPhragmites australis (Cav.) Trin ex Steudel. Plant and Soil 116:85–93.CrossRefGoogle Scholar
  35. St-Cyr, L. and A. A. Crowder. 1990. Manganese and copper in the root plaque ofPhragmites australis (Cav.) Trin ex Steudel. Soil Science 149:191–198.CrossRefGoogle Scholar
  36. Takijima, Y. 1965. Studies on the mechanism of root damage of rice plants in the peat paddy fields (Part 2). Status of roots in the rhizosphere and occurrence of root damage. Soil Science and Plant Nutrition 11:20–27.Google Scholar
  37. Tanaka, A., R. Loe, and S. A. Navasero. 1966. Some mechanisms involved in the development of iron toxicity symptoms in the rice plant. Soil Science and Plant Nutrition 12:29–33.Google Scholar
  38. Taylor, G. J. and A. A. Crowder. 1983. Use of the DCB technique for extractions of hydrous iron oxides from roots of wetland plants. American Journal of Botany 70:1254–1257.CrossRefGoogle Scholar
  39. Taylor, G. J., A. A. Crowder, and R. Rodden. 1984. Formation and morphology of an iron plaque on the roots ofTypha latifolia L. grown in solution culture. American Journal of Botany 71:666–675.CrossRefGoogle Scholar
  40. Trolldenier, G. 1988. Visualization of oxidizing power of rice roots and of possible participation of bacteria in iron deposition. Zeitschrift fur Pflanzenernaehrung und Bodenkunde 151:117–121.CrossRefGoogle Scholar
  41. Vale, C., F. M. Cartarino, C. Cortesao, and M. I. Cacador. 1988. Presence of metal-rich rhizoconcretions on the roots ofSpartina maritima from salt marshes Tagus estuary. International Symposium on the Fate and Effects of Toxic Chemicals in Large Rivers and their estuaries, Quebec, Canada. Abstract. (referenced in St.-Cyr & Crowder, 1989).Google Scholar
  42. van Raalte, M. H. 1944. On the oxidation of the environment by the roots of rice (Oryza sativa L.). Syokubutu-Iho 1:15–34.Google Scholar
  43. Wallace, A. L. M. Shannon, O. R. Lunt, and R. L. Impey. 1957. Some aspects of the use of metal chelates as micronutrient fertilizer sources. Soil Science 84:27–41.CrossRefGoogle Scholar
  44. Wright, R. J. and L. R. Hossner. 1984. Cultivar differences in iron coatings formed on rice roots. Cereal Research Communications 12:265–266.Google Scholar

Copyright information

© Society of Wetland Scientists 1995

Authors and Affiliations

  • Irving A. Mendelssohn
    • 1
  • Barbara A. Kleiss
    • 2
  • James S. Wakeley
    • 2
  1. 1.Wetland Biogeochemistry Institute Center for Coastal, Energy, and Environmental ResourcesLouisiana State UniversityBaton Rouge
  2. 2.U.S. Army Corps of EngineersWaterways Experiment StationVicksburg

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