Abstract
Mucilages from the root tips of axenically-grown maize and from a bacterium (Cytophaga sp.) isolated from the rhizosheaths of field-grown roots, were immobilized by drying onto nylon blotting membrane. The mucilage plaques remained in place through repeated rewettings and histochemical treatments. Staining of the plaques showed that both mucilages included acidic groups, and 1,2 diols (the latter notably fewer in bacterial mucilage). Bacterial mucilage plaques stained strongly for protein, plant mucilage was unstained. Plaques of both mucilages bound soil particles strongly if soil was applied to wet mucilage and then dried. Bound soil was not lost with rewetting. Dry weight and densitometer measurements showed that bacterial mucilage bound about 10% more soil than the same surface area of root-cap mucilage. Pretreatment of plaques with periodate oxidation eliminated most soil binding by root-cap mucilage but this was completely reversible by reduction with borohydride. Soil binding to bacterial mucilage was unaffected by periodate but much diminished by borohydride pretreatment (partially restored by subsequent oxidation). Neither pretreatment with cationic dyes nor preincubation in pectinase, pectin methylesterase or protease affected subsequent soil binding by the mucilage plaques. Pretreatment of root-cap mucilage plaques with lectins specific for component sugars also did not alter soil binding. It is concluded that mucilages of both plant and bacterial origin can contribute to the adhesion and cohesion of maize rhizosheaths, but each by a different mechanism. Binding by root-cap mucilage depends on 1,2 diol groups of component sugars, that of bacterial mucilage does not, and is likely to be protein mediated. ei]Section editor: R O D Dixon
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References
Arber A 1934 The Gramineae. Cambridge University Press, Cambridge, 480 p.
Bacic A, Moody S F and Clarke A E 1986 Structural analysis of secreted root slime from maize (Zea mays L.). Plant Physiol. 80, 771–777.
Bashan Y and Levanony H 1988a Adsorption of the rhizosphere bacterium Azospirillum brasilense Cd. to soil, sand and peat particles. J. Gen. Microbiol. 134, 1811–1820.
Bashan Y and Levanony H 1988b. Active attachment of Azospirillum brasilense Cd. to quartz sand and to a light-textured soil by protein bridging. J. Gen. Microbiol. 134, 2269–2279.
Burchard R P and Bloodgood R A 1990 Surface proteins of the gliding bacterium Cytophaga sp. Strain U67 and its mutant defective in adhesion and motility. J. Bacteriol. 0 172, 3379–3387.
Chaboud A 1983 Isolation, purification and chemical composition of maize root-cap slime. Plant and Soil 73, 395–402.
Chaboud A and MRougier 1990 Comparison of maize root mucilages isolated from root exudates and root surface extracts by complementary cytological and biochemical investigations. Protoplasma 156, 163–173.
Cheshire M V 1979 Nature and Origin of Carbohydrates in Soils. Academic Press, London. 216 p.
Christensen P J 1973 Studies on Soil and Freshwater Cytophagas. Ph.D. Thesis. University of Alberta, Canada. 475 p.
Clarke K J, McCully M E and Miki N K 1979 A developmental study of the epidermis of young roots of Zea mays L. Protoplasma 98, 283–309.
Denny M W 1984 Mechanical properties of pedal mucus and their consequences for gastropod structure and performance. Am. Zool. 24, 23–36.
Duell R W and G RPeacock 1985 Rhizosheaths on mesophytic grasses. Crop Sci. 25, 880–883.
Gessa C and Deianna S 1990 Fibrillar structure of Ca-polygalacturonate as a model for a soil-root interface. I. A hypothesis on the arrangement of the polymeric chains inside the fibrils. Plant and Soil 129, 211–217.
Gessa C and Deianna S 1992 Ca-polygalacturonate as model for a soil-root interface. II. Fibrillar structure and comparison with natural root mucilage. Plant and Soil 140, 1–13.
Gochnauer M B, McCully M E and Labbé H 1989 Different populations of bacteria associated with sheathed and bare regions of roots of field-grown maize. Plant and Soil 114, 107–120.
Gochnauer M B, Sealey L J and McCully M E 1990 Do detached root-cap cells influence bacteria associated with maize roots? Plant Cell Environ. 13, 793–801.
Guinel F C and McCully M E 1985 Evaluation of the specificity of lectin binding to sections of plant tissue. Histochemistry 83, 265–277.
Horobin R W 1988 Understanding Histochemistry. Ellis Horwood Ltd., Chichester, UK. 172 p.
Jenny H and Grossenbacher K 1963 Root-soil boundary zones as seen in the electron microscope. Soil Sci. Soc. Am. Proc. 27, 273–277.
Jones D D and Morré D J 1973 Golgi apparatus mediated polysaccharide secretion by outer root-cap cells Zea mays. III. Control by exogenous sugars. Physiol. Plant. 29, 68–75.
Kinloch A J 1987 Adhesion and Adhesives. Chapman and Hall Ltd. London. 441 p.
Leppard G G and Ramamoorthy S 1975 The aggregation of wheat rhizoplane fibrils and the accumulation of soil-bound cations. Can. J. Bot. 53, 1729–1735.
McCully M E and Canny M J 1988 Pathways and processes of water and nutrient movement in roots. Plant and Soil 111, 159–170.
Miki N K, Clarke K J and McCully M E 1980 A histological and histochemical comparison of the mucilages on the root tips of several grasses. Can. J. Bot. 58, 2581–2593.
Morel J L, Andreux F, Habib L, Guckert A 1987 Comparison of the adsorption of maize root mucilage and polygalacturonic acid on montmorillonite homoionic to divalent lead and cadmium. Biol. Fert. Soils 5, 13–17.
Oades J M 1978 Mucilages at the root surface. J. Soil Sci. 29, 1–16.
O'Brien T P and McCully M E 1981 The Study of Plant Structure. Principles and Selected Methods. Termarcarphi Publishers, Melbourne, Australia. 276 p.
Pate J L and de Jong D M 1990 Use of nonmotile mutants to identify a set of membrane proteins related to gliding motility in Cytophaga johnsonae. J Bacteriol. 172, 3117–3124.
Pearse A G E 1968 Histochemistry Theoretical and Applied. Vol 1. JA Churchill Ltd., London. 758 p.
Pearse A G E 1985 Histochemistry, Theoretical and Applied. Vol 2. Churchill Livingstone, London. 1055 p.
Schwenke H and Wagner E 1992 A new concept of root exudation. Plant Cell Environ. 15, 289–299.
Sharon N and HLis 1989 Lectins. Chapman and Hall, New York. 127 p.
Sposito G 1984 The Surface Chemistry of Soils. Oxford University Press, New York. 287 p.
Stanier R Y 1942 The Cytophaga group: A contribution to the biology of the Myxobacteria. Bacteriol. Rev. 6, 143–196.
Sutherland I W 1977 Bacterial exopolysaccharides—their nature and production. In Surface Carbohydrates of the Prokaryotic Cell. Ed. IW Sutherland. Academic Press, New York. 472 p.
Vančura V 1988 Soil microbial associations. In Developments in Agricultural and Managed Forest Ecology. Vol 17. Eds. V Vančura and F Kunc, pp 57–78. Elsevier Publishers, New York.
Vermeer J and McCully M E 1982 The rhizosphere in Zea: New insight into its structure and development. Planta 156, 45–61.
Wang X L, Canny M J and McCully M E 1991 The water status of the roots of soil-grown maize in relation to the maturity of their xylem. Physiol. Plant. 82, 157–162.
Wullstein L H and Pratt S A 1981 Scanning electron microscopy of rhiosheaths of Oryzopsis hymenoides. Am. J. Bot. 63, 408–419.
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Watt, M., McCully, M.E. & Jeffree, C.E. Plant and bacterial mucilages of the maize rhizosphere: Comparison of their soil binding properties and histochemistry in a model system. Plant Soil 151, 151–165 (1993). https://doi.org/10.1007/BF00016280
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DOI: https://doi.org/10.1007/BF00016280