Root-derived carbon in soil respiration and microbial biomass determined by 14C and 13C

Werth, Martin; Kuzyakov, Yakov

doi:10.1016/j.soilbio.2007.09.022

Cited by 90 publications

(55 citation statements)

References 47 publications

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“…The application of 14 C-pulse labeling (e.g. Werth and Kuzyakov 2008) rather than 13 C would help to resolve this concern, but it is not possible to use this approach under field conditions. Incorporation of 13 CO 2 into maize biomass The majority of photosynthate was incorporated into the aboveground (shoot) biomass at each growth stage of maize in this experiment, and this increased with maturity of the plant to a maximum of >80 % in the grainfilling stage.…”

Section: Discussionmentioning

confidence: 99%

“…To determine the contribution of this pool requires differentiation of C 4 -SOC from novel maize rhizoexudates and root turnover, which is possible though the application of 14 C pulse labeling (e.g. Werth and Kuzyakov 2008). The proportion of maize photosynthate allocated to rhizosphere respiration changed with growth stage, but was greatest (25.8 %) during emergence, and similar (15.5 to 16.6 %) during elongation, heading and grainfilling growth stages.…”

Section: Discussionmentioning

confidence: 99%

“…The 13 C recovered did not include shoot respiration as the 13 CO 2 respired by the shoots was returned to the atmosphere and would not affect SOC as described in previous 14 C and 13 C pulse labeling studies (Fan et al 2008;Werth and Kuzyakov 2008). The total 13 C recovered was the sum of the 13 C content in the measured pools: shoots and root biomass, SOC, and respired CO 2 after labeling:…”

Section: Calculationsmentioning

confidence: 99%

“…The photosynthate-C distribution in the different pools of the maize-soil system at each growth stage was estimated using the method described by Gregory and Atwell (1991), Kuzyakov (2001), and Werth and Kuzyakov (2008):…”

Section: Calculationsmentioning

confidence: 99%

“…Partitioning rhizosphere respiration and SOC respiration is prerequisite to calculating gaseous losses derived from recently assimilated C or more stable SOC pools (Werth and Kuzyakov 2008). Estimates indicate that approximately 40 to 50 % (1.5 to 2.2 t C ha −1 ) of net photosynthate-C is allocated belowground for the total vegetative period in graminaceous crops: 19 % in the root biomass, 12 % lost as rhizosphere respiration and 5 % in soil residues (Kuzyakov and Domanski 2000;Jones et al 2009).…”

mentioning

confidence: 99%

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Investigation of photosynthate-C allocation 27 days after 13C-pulse labeling of Zea mays L. at different growth stages

et al. 2013

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Aims Pulse labeling of crops using 13 C is often employed to trace photosynthesized carbon (C) within crop-soil systems. However, few studies have compared the C distribution for different labeling periods. The overall aim of this study was to determine the length of the monitoring interval required after 13 C-pulse labeling to quantify photosynthate C allocation into plant, soil and rhizosphere respiration pools for the entire growing season of maize (Zea mays L.). Methods Pot grown maize was pulse-labeled with 13 CO 2 (98 at.%) at the beginning of emergence, elongation, heading and grainfilling growth stages. The routing of 13 C into shoot and root biomass, soil CO 2 flux and soil organic carbon (SOC) pools was monitored for 27-days after 13 C-pulse labeling at the beginning of each growth stage. Results The majority of the 13 C was recovered after 27 d in the maize shoots, i.e., 57 %, 53 %, 70 % and 80 %, at the emergence, elongation, heading, and grainfilling stages, respectively. More 13 C was recovered in the root biomass at elongation (27 %) compared to the least at the grainfilling stage (3 %). The amount recovered in the soil was the smallest pool of 13 C at emergence (2.3 %), elongation (3.8 %), heading and grainfilling (less than 2 %). The amount of 13 C recovered in rhizosphere respiration, i.e. 13 CO 2 , was greatest at emergence (26 %), and similar at the elongation, heading and grainfilling stages (~16 %). Conclusions At least 24 days is required to effectively monitor the recovery of 13 C after pulse labeling with 13 CO 2 for maize in plant and soil pools. The recovery of 13 C differed between growth stages and corresponded to the changing metabolic requirements of the plant, which indicated labeling for the entire growth season would more accurately quantify the C budget in plantsoil system.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Calculationsmentioning

confidence: 99%

Section: Calculationsmentioning

confidence: 99%

mentioning

confidence: 99%

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Investigation of photosynthate-C allocation 27 days after 13C-pulse labeling of Zea mays L. at different growth stages

et al. 2013

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Rhizodeposition of maize: Short‐term carbon budget and composition

Fischer

Eckhardt

Meyer

et al. 2010

Z. Pflanzenernähr. Bodenk.

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The aim of this study was to assess differences in rhizodeposition quantity and composition from maize cropped on soil or on 1:1 (w/w) soil-sand mixture and distribution of recently assimilated C between roots, shoots, soil, soil solution, and CO 2 from root respiration. Maize was labeled in 14 CO 2 atmosphere followed by subsequent simultaneous leaching and air flushing from soil. 14 C was traced after 7.5 h in roots and shoots, soil, soil solution, and soil-borne CO 2 . Rhizodeposits in the leachate of the first 2 h after labeling were identified by high-pressure liquid chromatography (HPLC) and pyrolysis-field ionization mass spectrometry (Py-FIMS). Leachate from soil-sand contained more 14 C than from soil (0.6% vs. 0.4%) and more HPLC-detectable carboxylates (4.36 vs. 2.69 lM), especially acetate and lactate. This is either because of root response to lower nutrient concentrations in the soil-sand mixture or decreasing structural integrity of the root cells during the leaching process, or because carboxylates were more strongly sorbed to the soil compared to carbohydrates and amino acids. In contrast, Py-FIMS total ion intensity was more than 2 times higher in leachate from soil than from soil-sand, mainly due to signals from lignin monomers. HPLC-measured concentrations of total amino acids (1.33 lM [soil] vs. 1.03 lM [soil-sand]) and total carbohydrates (0.73 vs. 0.34 lM) and 14 CO 2 from soil agreed with this pattern. Higher leachate concentrations from soil than from soil-sand for HPLCmeasured carbohydrates and amino acids and for the sum of substances detected by Py-FIMS overcompensated the higher sorption in soil than in sand-soil. A parallel treatment with blow-out of the soil air but without leaching indicated that nearly all of the rhizodeposits in the treatment with leaching face decomposition to CO 2 . Simultaneous application of three methods-14 C-labeling and tracing, HPLC, and Py-FIMS-enabled us to present the budget of rhizodeposition ( 14 C) and to analyze individual carbohydrates, carboxylates, and amino acids (HPLC) and to scan all dissolved organic substances in soil solution (Py-FIMS) as dependent on nutrient status.

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Photoassimilate allocation and dynamics of hotspots in roots visualized by ¹⁴C phosphor imaging

Pausch

Kuzyakov

2011

Z. Pflanzenernähr. Bodenk.

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Understanding photoassimilate allocation into the roots and the release of organic substances from the roots into the rhizosphere is an important prerequisite for characterizing the belowground C input, the spatial and temporal distribution of C, and the interactions between plants and soil microorganisms. Based on 14 C phosphor imaging, we visualized the allocation of assimilates into Lolium perenne roots and estimated the life time of hotspots at the root tips. Lolium shoots were labeled in a 14 CO 2 atmosphere, and herbariums of roots and shoots were prepared 6 h, 2 d, and 11 d after the 14 C pulse. The 14 C distribution in roots and leaves revealed that pulse labeling does not yield homogeneously labeled plant material. The spatial distribution of assimilate allocation was evaluated based on the 14 C specific activity expressed as digital light units (DLU mm -2 ) of the imaging plates. Areas with high relative 14 C activity were classified as hotspots. Strong 14 C hotspots were detected mainly at the root tips already 6 h after the 14 C assimilation, and they remained active for at least 2 d. Eleven days after the 14 C assimilation, the hotspots at the root tips disappeared and the 14 C distribution was much more even than after 6 h or after 2 d. 14 C phosphor imaging proved to be a promising tool to visualize the allocation of photoassimilates into the roots and the rhizosphere and can be used to identify hotspots and their dynamics.

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Root-derived carbon in soil respiration and microbial biomass determined by 14C and 13C

Cited by 90 publications

References 47 publications

Investigation of photosynthate-C allocation 27 days after 13C-pulse labeling of Zea mays L. at different growth stages

Investigation of photosynthate-C allocation 27 days after 13C-pulse labeling of Zea mays L. at different growth stages

Rhizodeposition of maize: Short‐term carbon budget and composition

Photoassimilate allocation and dynamics of hotspots in roots visualized by ¹⁴C phosphor imaging

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Root-derived carbon in soil respiration and microbial biomass determined by 14C and 13C

Cited by 90 publications

References 47 publications

Investigation of photosynthate-C allocation 27 days after 13C-pulse labeling of Zea mays L. at different growth stages

Investigation of photosynthate-C allocation 27 days after 13C-pulse labeling of Zea mays L. at different growth stages

Rhizodeposition of maize: Short‐term carbon budget and composition

Photoassimilate allocation and dynamics of hotspots in roots visualized by 14C phosphor imaging

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Photoassimilate allocation and dynamics of hotspots in roots visualized by ¹⁴C phosphor imaging