In situ observation of localized, sub-mm scale changes of phosphorus biogeochemistry in the rhizosphere

Abstract

AimsWe imaged the sub-mm distribution of labile P and pH in the rhizosphere of three plant species to localize zones and hot spots of P depletion and accumulation along individual root axes and to relate our findings to nutrient acquisition / root exudation strategies in P-limited conditions at different soil pH, and to mobilization pattern of other elements (Al, Fe, Ca, Mg, Mn) in the rhizosphere.MethodsSub-mm distributions of labile elemental patterns were sampled using diffusive gradients in thin films and analysed using laser ablation inductively coupled plasma mass spectrometry. pH images were taken using planar optodes.ResultsWe found distinct patterns of highly localized labile P depletion and accumulation reflecting the complex interaction of plant P acquisition strategies with soil pH, fertilizer treatment, root age, and elements (Al, Fe, Ca) that are involved in P biogeochemistry in soil. We show that the plants respond to P deficiency either by acidification or alkalization, depending on initial bulk soil pH and other factors of P solubility.ConclusionsP solubilization activities of roots are highly localized, typically around root apices, but may also extend towards the extension / root hair zone.Electronic supplementary materialThe online version of this article (10.1007/s11104-017-3542-0) contains supplementary material, which is available to authorized users.

Role of Organic Anions and Phosphatase Enzymes in Phosphorus Acquisition in the Rhizospheres of Legumes and Grasses Grown in a Low Phosphorus Pasture Soil

“…Changes in rhizosphere pH have been reported in P-deficient soils and in response to nutrient addition, with decreases and increases according to plant species, soil types, initial soil pH, and nutrient forms [ 77 , 78 , 79 , 80 , 81 ]. In this study, rhizosphere pH values were affected by plant species, but were similar across nutrient treatments.…”

Soil types select for plants with matching nutrient‐acquisition and ‐use traits in hyperdiverse and severely nutrient‐impoverished campos rupestres and cerrado in Central Brazil

“…We predicted that leaf [Mn] would be a good indicator of the amount of carboxylates released, because of their solubilizing effect on soil Mn (Kreuzeder et al, ; Lambers, Hayes, et al, ; Pang et al, ). Additionally, AM fungi significantly decrease the amount of Mn transferred to the host plants (Bethlenfalvay & Franson, ; Kothari et al, ; Nogueira et al, ).…”

“…As a result of the release of organic anions (carboxylates) by the roots, soil manganese (Mn) is mobilized (Gardner, Parbery, & Barber, ; Kreuzeder et al, ) and can accumulate in leaves (Gardner & Boundy, ). Therefore, leaf [Mn] has been suggested as a proxy for carboxylate release in P‐poor soils (Lambers, Hayes, Laliberté, Oliveira, & Turner, ; Pang et al, ).…”

Soil heterogeneity and plant species diversity in experimental grassland communities: contrasting effects of soil nutrients and pH at different spatial scales

“…1). The size of the patch was chosen because at this patch size different levels of soil nutrients and pH were detected in the field (Březina et al 2019;Kreuzeder et al 2018;Reynolds et al 2007). In the homogeneous soil nutrient treatment, each plot was filled with a 2:2 (v:v) mixture of black soil and yellow sand.…”