TY - JOUR

T1 - Mineralisation of carbon and plant uptake of phosphorus from microbially-derived organic matter in response to 19 years simulated nitrogen deposition

AU - Kritzler, Ully H.

AU - Johnson, David

PY - 2010/1/31

Y1 - 2010/1/31

N2 - Here we test the hypotheses that 19 years of simulated pollutant N deposition increases both losses of carbon (C) and the ability of plants to access P from organic material in upland heathland. The grass, Dactylis glomerata, and the dwarf shrub, Calluna vulgaris, were grown in soil containing microbial-derived organic matter labelled with 14C and 33P. We found that both soil and root-surface phosphatase activity increased significantly in response to N deposition. We also found a significant positive relationship between root-surface phosphatase activity and 33P uptake for Calluna, but a negative relationship for Dactylis. Efflux of 14C from the microbial-derived organic matter was strongly dependent on an interaction among plant presence, plant species and N deposition. Our results show that mineralisation of C and P, and subsequent plant uptake of P from organic sources is decoupled. In our experimental conditions, stimulation of P turnover coupled with subsequent plant uptake through up-regulation of root phosphatases is little affected by N addition. However, our data indicate that root-surface phosphatases are likely to be more important for uptake of P derived from organic sources for Calluna than for Dactylis.

AB - Here we test the hypotheses that 19 years of simulated pollutant N deposition increases both losses of carbon (C) and the ability of plants to access P from organic material in upland heathland. The grass, Dactylis glomerata, and the dwarf shrub, Calluna vulgaris, were grown in soil containing microbial-derived organic matter labelled with 14C and 33P. We found that both soil and root-surface phosphatase activity increased significantly in response to N deposition. We also found a significant positive relationship between root-surface phosphatase activity and 33P uptake for Calluna, but a negative relationship for Dactylis. Efflux of 14C from the microbial-derived organic matter was strongly dependent on an interaction among plant presence, plant species and N deposition. Our results show that mineralisation of C and P, and subsequent plant uptake of P from organic sources is decoupled. In our experimental conditions, stimulation of P turnover coupled with subsequent plant uptake through up-regulation of root phosphatases is little affected by N addition. However, our data indicate that root-surface phosphatases are likely to be more important for uptake of P derived from organic sources for Calluna than for Dactylis.

KW - Phosphatase

KW - Nitrogen deposition

KW - Heathland

KW - Carbon mineralisation

KW - Organic phosphorus

KW - (33)P

KW - (14)C

U2 - 10.1007/s11104-009-0009-y

DO - 10.1007/s11104-009-0009-y

M3 - Journal article

VL - 326

SP - 311

EP - 319

JO - Plant and Soil

JF - Plant and Soil

SN - 0032-079X

IS - 1-2

ER -