Premium
Effect of Rhizobial Extracellular Polysaccharide on Solution Phosphate Levels of Acid Soils
Author(s) -
Cunningham Scott D.,
Munns Donald N.
Publication year - 1985
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1985.03615995004900030015x
Subject(s) - gibbsite , phosphate , chemistry , extracellular polymeric substance , polysaccharide , suspension (topology) , sorption , adsorption , environmental chemistry , inorganic chemistry , biochemistry , kaolinite , mineralogy , bacteria , biology , organic chemistry , biofilm , mathematics , homotopy , pure mathematics , genetics
Previous work has shown a positive correlation between the ability of a strain to colonize acidic agar and its production of extracellular polysaccharide (EPS) in solution culture. This paper examines the relationship between EPS production and phosphate levels in solution, determining: (i) the interaction of EPS with an oxide (gibbsite) surface, (ii) the effect of EPS on phosphate sorption, and (iii) the effect of EPS on previously sorbed phosphate. Rhizobial EPS was readily adsorbed onto gibbsite. When EPS was present before the addition of phosphate, both the quantity of EPS and its source significantly influenced the amount of phosphate sorbed. Addition of standard amounts of EPS from different strains to a gibbsite suspension with previously sorbed phosphate produced solution phosphate levels which differed significantly. The pH of the EPS added to the gibbsite‐phosphate suspension was also varied; added EPS decreased solution phosphate levels if the EPS was more acidic than the gibbsite suspension, and increased solution phosphate levels if it was more alkaline. Rhizobium in an acid soil may be able to influence the phosphate level of their immediate micro‐environment through the excretion of extracellular polysaccharide at an appropriate pH.