Co-occurring increased phosphatase activity and labile P depletion in the rhizosphere of Lupinus angustifolius assessed with a novel, combined 2D-imaging approach

Innovative non-destructive 2D imaging methods such as zymography and diffusive gradients in thin films (DGT) have been developed recently to assess the distribution of phosphatase activity labile solutes at root-soil interface. We report on first combination these techniques for spatial potential interaction phosphorus (P) associated acid rhizosphere blue lupin (Lupinus angustifolius) two contrasting soils (‘Sand’ ‘Loam’). Zymography, based 4-methylumbelliferylphosphate (MU-P) mapping, DGT gels capable binding P were deployed individual root axes visualise mobilisation depletion grown rhizotrons glasshouse conditions 45 days. Acid was evidently higher co-occurred with P-depletion zones around roots both soils. Lateral profiles showed that elevated well extended up 2 mm from centre into rhizosphere. Despite larger total organic pools Loam, less plant available (DGT P) than Sand. However, activities contents similar These results indicate enzyme-catalysed hydrolysis limited due low availability, hence explaining lupins did not accumulate indicating supply via could compensate plants demand resulting zones. While our work demonstrates applicability combined deployments study processes microscale, we also discuss limitations perspectives this approach.