TY - JOUR

T1 - Reductive dissolution of iron phosphate modifies rice root morphology in phosphorus-deficient paddy soils

AU - Wang, Chaoqun

AU - Thielemann, Lukas

AU - Dippold, Michaela A.

AU - Guggenberger, Georg

AU - Kuzyakov, Yakov

AU - Banfield, Callum C.

AU - Ge, Tida

AU - Guenther, Stephanie

AU - Dorodnikov, Maxim

N1 - Funding Information: The authors gratefully acknowledge the China Scholarship Council (CSC) for financial support for Chaoqun Wang. This work was supported by the research grant from German Research Foundation (DO 1533/3–1 ; GU 406/33–1 ) and RUDN University Strategic Academic Leadership Program as well as Project TerrArctic (Tyumen Oblast Government project No. 89-DON (1) and CarboRus (075-15-2021-610). Michaela Dippold was funded by the Robert Bosch Junior Professorship. The authors would like to thank Bernd Kopka and Marvin Blaue of the Laboratory for Radioisotopes (LARI) of the University of Goettingen for their advice, support, and measurements. We also thank Jake Beyer and Dr. Florian Carstens for constructive advice.

PY - 2023/2

Y1 - 2023/2

N2 - Root morphology reflects plant adaptations to phosphorus (P) deficiency. We hypothesized that changes in rice root morphology reflect P deficiency decrease after ferric iron (Fe(III))-bound phosphate (Fe–P) dissolution in low-redox paddy soils. We developed a novel in-situ 32P phosphor-imaging approach under flooding to estimate P uptake by rice roots released from Fe–P dissolution. 32P-labeled ferrihydrite (31 mg P kg−1) was supplied either (1) in polyamide mesh bags (30 μm mesh size) to prevent roots but not microorganisms from direct Fe–P mobilization, or (2) directly mixed with soil to enable roots and microorganisms unrestricted access to the Fe–P. The establishment of low redox conditions (Eh values between −176 and −224 mV) drove the reductive dissolution of Fe–P. Rice root-derived organic acids alone were unable to control Fe–P dissolution, and Fe(III) reduction is predominately a microbially-mediated process. Direct root access to Fe–P raised both the number and mean diameter of crown roots and root tips, and increased P uptake by 149–231%. Crown root elongation rate, 32P activities along roots and root tips were 5–133% higher when roots directly accessed Fe–P compared to Fe–P excluded from roots in mesh bags. Iron accumulation on roots depended on the rice growth stage, but not on their access to Fe–P. Roots’ access to Fe–P increased rice crown roots elongation and branching and increased P accessibility under P deficiency.

AB - Root morphology reflects plant adaptations to phosphorus (P) deficiency. We hypothesized that changes in rice root morphology reflect P deficiency decrease after ferric iron (Fe(III))-bound phosphate (Fe–P) dissolution in low-redox paddy soils. We developed a novel in-situ 32P phosphor-imaging approach under flooding to estimate P uptake by rice roots released from Fe–P dissolution. 32P-labeled ferrihydrite (31 mg P kg−1) was supplied either (1) in polyamide mesh bags (30 μm mesh size) to prevent roots but not microorganisms from direct Fe–P mobilization, or (2) directly mixed with soil to enable roots and microorganisms unrestricted access to the Fe–P. The establishment of low redox conditions (Eh values between −176 and −224 mV) drove the reductive dissolution of Fe–P. Rice root-derived organic acids alone were unable to control Fe–P dissolution, and Fe(III) reduction is predominately a microbially-mediated process. Direct root access to Fe–P raised both the number and mean diameter of crown roots and root tips, and increased P uptake by 149–231%. Crown root elongation rate, 32P activities along roots and root tips were 5–133% higher when roots directly accessed Fe–P compared to Fe–P excluded from roots in mesh bags. Iron accumulation on roots depended on the rice growth stage, but not on their access to Fe–P. Roots’ access to Fe–P increased rice crown roots elongation and branching and increased P accessibility under P deficiency.

KW - P imaging

KW - Ferric iron reduction

KW - Iron accumulation

KW - Phosphorus isotopes

KW - Root architecture

KW - Root tips

UR - http://www.scopus.com/inward/record.url?scp=85143743231&partnerID=8YFLogxK

U2 - 10.1016/j.soilbio.2022.108904

DO - 10.1016/j.soilbio.2022.108904

M3 - Article

AN - SCOPUS:85143743231

VL - 177

JO - Soil Biology and Biochemistry

JF - Soil Biology and Biochemistry

SN - 0038-0717

M1 - 108904

ER -