ORCID Profile
0000-0002-7642-7938
Current Organisation
University of Sydney
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Publisher: Wiley
Date: 22-12-2020
DOI: 10.1111/NPH.17118
Abstract: Rhizodeposition plays an important role in below‐ground carbon (C) cycling. However, quantification of rhizodeposition in intact plant–soil systems has remained elusive due to methodological issues. We used a 13 C‐CO 2 pulse‐labelling method to quantify the contribution of rhizodeposition to below‐ground respiration. Intact plant–soil cores were taken from a grassland field, and in half, shoots and roots were removed (unplanted cores). Both unplanted and planted cores were assigned to drought and nitrogen (N) treatments. Afterwards, shoots in planted cores were pulse labelled with 13 C‐CO 2 and then clipped to determine total below‐ground respiration and its δ 13 C. Simultaneously, δ 13 C was measured for the respiration of live roots, soils with rhizodeposits, and unplanted treatments, and used as endmembers with which to determine root respiration and rhizodeposit C decomposition using two‐source mixing models. Rhizodeposit decomposition accounted for 7–31% of total below‐ground respiration. Drought reduced decomposition of both rhizodeposits and soil organic carbon (SOC), while N addition increased root respiration but not the contribution of rhizodeposit C decomposition to below‐ground respiration. This study provides a new approach for the partitioning of below‐ground respiration into different sources, and indicates that decomposition of rhizodeposit C is an important component of below‐ground respiration that is sensitive to drought and N addition in grassland ecosystems.
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.SCITOTENV.2022.157430
Abstract: Grassland plants allocate photosynthetically fixed carbon (C) belowground to root biomass and rhizodeposition, but also to support arbuscular mycorrhizal fungi (AMF). These C allocation pathways could increase nutrient scavenging, but also mining of nutrients through enhanced organic matter decomposition. While important for grassland ecosystem functioning, methodological constraints have limited our ability to measure these processes under field conditions. We used
Publisher: International Society for Horticultural Science (ISHS)
Date: 11-2017
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/SR19183
Abstract: Plants allocate their photosynthetic carbon (C) belowground through rhizodeposition, which can be incorporated into microbial biomass and organic matter, but can also be directly shared with arbuscular mycorrhizal fungi (AMF). In this study, we investigated how both rhizodeposition and AMF colonisation are affected by nitrogen (N) and phosphorus (P) availability in soil systems, and in turn, how these C allocation pathways influenced plant P uptake in four different wheat genotypes with variable root traits. Wheat genotypes (249, Suntop, Scout and IAW2013) were grown in pots and labelled continuously during their growth period with 13CO2 to determine rhizodeposition. We applied two levels of N (25 and 100 kg ha–1) and P (10 and 40 kg ha–1) fertiliser. Plant root traits, plant P content, soil available P and N, microbial biomass C and P, and AMF colonisation were examined. We constructed a structural equation model to show how C allocation to rhizodeposition and AMF colonisation depended on P and N availability, and how these pathways affected plant P uptake and grain yield. Wheat genotypes with fine roots (Suntop, Scout and IAW2013) were associated with AMF colonisation for plant P uptake, and the genotype with the largest root biomass (249) provided more C to rhizodeposition. Both rhizodeposition and AMF colonisation increased plant P and grain yield under low P and high N availability respectively, while root biomass and root traits, such as specific root length and proportion of fine roots, determined which C allocation pathway was employed by the plant.
Publisher: Elsevier BV
Date: 12-2022
Publisher: Elsevier BV
Date: 03-2020
Publisher: Elsevier BV
Date: 2022
Location: Iran (Islamic Republic of)
No related grants have been discovered for Milad Bagheri Shirvan.