13C isotope fractionation during rhizosphere respiration of C3 and C4 plants

Zhu, Biao; Cheng, Weixin

doi:10.1007/s11104-010-0691-9

Cited by 39 publications

(21 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In earlier studies at the Niwot Ridge forest, we found that nocturnal δ R on a nightly basis tended to be more enriched within the vegetation canopy relative to near the ground [ Bowling et al , ; Riveros‐Iregui et al , ]. This is qualitatively consistent with plant‐scale observations of relatively enriched foliar respiration [ Bowling et al , ; Wingate et al , ] and relatively depleted root respiration [ Ghashghaie and Badeck , ; Schnyder and Lattanzi , ; Zhu and Cheng , ]. These results complicate the simple conceptual model we have used (equations –) and suggest that more complex biophysical models [ Baldocchi and Bowling , ; Flanagan et al , ; Wingate et al , ] combined with flux and isotopic flux observations from different ecosystem pools are likely the best way to investigate the isotopic composition of the photosynthesis and respiratory fluxes.…”

Section: Discussionsupporting

confidence: 87%

“…As carbon is transferred from plant pools to other ecosystem pools through herbivory, root exudation, and mortality, there are additional fractionations but most of them are poorly understood. These effects all combine to influence the δ 13 C of leaf, root, and heterotrophic respiration in complex ways [ Barbour et al , ; Brüggemann et al , ; Werner and Gessler , ; Zhu and Cheng , ]. In earlier studies at the Niwot Ridge forest, we found that nocturnal δ R on a nightly basis tended to be more enriched within the vegetation canopy relative to near the ground [ Bowling et al , ; Riveros‐Iregui et al , ].…”

Section: Discussionmentioning

confidence: 67%

See 1 more Smart Citation

Ecological processes dominate the ¹³C land disequilibrium in a Rocky Mountain subalpine forest

Bowling

Ballantyne

Miller

et al. 2014

Global Biogeochemical Cycles

View full text Add to dashboard Cite

Fossil fuel combustion has increased atmospheric CO 2 by ≈ 115 μmol mol À1 since 1750 and decreased its carbon isotope composition (δ 13 C) by 1.7-2‰ (the 13 C Suess effect). Because carbon is stored in the terrestrial biosphere for decades and longer, the δ 13 C of CO 2 released by terrestrial ecosystems is expected to differ from the δ 13 C of CO 2 assimilated by land plants during photosynthesis. This isotopic difference between land-atmosphere respiration (δ R ) and photosynthetic assimilation (δ A ) fluxes gives rise to the 13 C land disequilibrium (D). Contemporary understanding suggests that over annual and longer time scales, D is determined primarily by the Suess effect, and thus, D is generally positive (δ R > δ A ). A 7 year record of biosphere-atmosphere carbon exchange was used to evaluate the seasonality of δ A and δ R , and the 13 C land disequilibrium, in a subalpine conifer forest. A novel isotopic mixing model was employed to determine the δ 13 C of net land-atmosphere exchange during day and night and combined with tower-based flux observations to assess δ A and δ R . The disequilibrium varied seasonally and when flux-weighted was opposite in sign than expected from the Suess effect (D = À0.75 ± 0.21‰ or À0.88 ± 0.10‰ depending on method). Seasonality in D appeared to be driven by photosynthetic discrimination (Δ canopy ) responding to environmental factors. Possible explanations for negative D include (1) changes in Δ canopy over decades as CO 2 and temperature have risen, and/or (2) post-photosynthetic fractionation processes leading to sequestration of isotopically enriched carbon in long-lived pools like wood and soil.

show abstract

Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 67%

Ecological processes dominate the ¹³C land disequilibrium in a Rocky Mountain subalpine forest

Bowling

Ballantyne

Miller

et al. 2014

Global Biogeochemical Cycles

View full text Add to dashboard Cite

show abstract

“…Path [2] is refixation of carbon from root respiration. According to Zhu and Cheng (), Amaranthus tricolor root respiration showed a Δ of +7‰. Based on this value and our root biomass 13 C content (Table ), we calculate a δ 13 C value of the respired CO 2 to be around −24‰.…”

Section: Resultsmentioning

confidence: 81%

Changes in size and composition of pigweed (Amaranthus hybridus L.) calcium oxalate crystals under CO₂ starvation conditions

Tooulakou

Nikolopoulos

Ḏotsika

et al. 2018

Physiologia Plantarum

View full text Add to dashboard Cite

The functional role(s) of plant calcium oxalate (CaOx) crystals are still poorly understood. Recently, it was shown that crystals function as dynamic carbon pools whose decomposition could provide CO2 to photosynthesis when stomata are closed (e.g. under drought conditions) and CO2 starvation conditions may be created within the mesophyll. This biochemical process, named as ‘alarm photosynthesis’, can become crucial for plant survival under adverse conditions. Here, we study crystal decomposition under controlled CO2 starvation conditions (either in the shoot or in the root) to obtain a better insight into the process of crystal formation and function. Hydroponically grown pigweed plants were kept in CO2‐free air and/or CO2‐free nutrient medium for 9 days. Crystal volume was monitored daily, and carbon stable isotope composition (δ13C) and Fourier transformation Raman spectra were obtained at the end of the experiment. A considerable reduction in the leaf crystal volume was observed in shoot‐CO2‐starved plants at the end of the experiment. The smallest crystals were isolated from the plants in which carbon was excluded from both the shoot and the root and contained potassium nitrate. Crystal δ13C of CO2‐starved plants was altered in a predicted way. Specifically, it depended on the average calculated isotope fractionation of all carbon fixation processes considered to be contributing in each experimental treatment. The results of the present study confirmed the correlation between CO2 starvation conditions and the CaOx crystal decomposition. Inorganic carbon fixed in the root may represent a major carbon source for CaOx formation.

show abstract

“…where d 13 C root is the d 13 C value of rhizosphere respiration which was calculated based on the d 13 C value of shoot biomass and the 13 C fractionation of root-derived CO 2 relative to shoot biomass (1.1& for sunflower and 1.3& for soybean, Zhu and Cheng, 2011b).…”

Section: Measurements and Calculationsmentioning

confidence: 99%

Impacts of drying–wetting cycles on rhizosphere respiration and soil organic matter decomposition

Zhu

Cheng

2013

Soil Biology and Biochemistry

Self Cite

View full text Add to dashboard Cite

a b s t r a c tDryingewetting cycles influence both soil organic matter (SOM) decomposition and rhizosphere processes. Rhizosphere processes also affect SOM decomposition through rhizosphere priming. However, little is known about how dryingewetting cycles regulate SOM decomposition with rhizosphere priming, because most previous studies incubated root-free soils and omitted the rhizosphere effect. To investigate the effect of dryingewetting cycles on SOM decomposition in the presence of plants, we grew sunflower (Helianthus annuus) and soybean (Glycine max) in a sandy loam soil under the treatments of either constant moisture or 12 dryingewetting cycles, and used a continuous 13 C-labeling method to partition soil respiration into rhizosphere respiration and SOM decomposition. We found that compared to the constantly-moist treatment, the severe dryingewetting cycles in soils planted with sunflower significantly reduced shoot biomass (32%), root biomass (52%), rhizosphere respiration (29%), and SOM decomposition (22%), while the moderate dryingewetting cycles in soils planted with soybean did not significantly affect these variables. Moreover, SOM decomposition rates in the planted treatment subjected to constantly-moist or dryingewetting conditions were significantly higher compared with the constantly-moist unplanted treatment, indicating a positive rhizosphere priming effect under both soil moisture regimes. However, dryingewetting reduced the rhizosphere priming of sunflower (69% versus 33%) likely due to lower plant biomass and rhizodeposition, but produced similar rhizosphere priming of soybean (82% versus 85%). Overall, dryingewetting cycles significantly modulated rhizosphere respiration and SOM decomposition, with the magnitude depending on soil drying intensity and plant growth performance.Published by Elsevier Ltd.

show abstract

13C isotope fractionation during rhizosphere respiration of C3 and C4 plants

Cited by 39 publications

References 45 publications

Ecological processes dominate the ¹³C land disequilibrium in a Rocky Mountain subalpine forest

Ecological processes dominate the ¹³C land disequilibrium in a Rocky Mountain subalpine forest

Changes in size and composition of pigweed (Amaranthus hybridus L.) calcium oxalate crystals under CO₂ starvation conditions

Impacts of drying–wetting cycles on rhizosphere respiration and soil organic matter decomposition

Contact Info

Product

Resources

About

13C isotope fractionation during rhizosphere respiration of C3 and C4 plants

Cited by 39 publications

References 45 publications

Ecological processes dominate the 13C land disequilibrium in a Rocky Mountain subalpine forest

Ecological processes dominate the 13C land disequilibrium in a Rocky Mountain subalpine forest

Changes in size and composition of pigweed (Amaranthus hybridus L.) calcium oxalate crystals under CO2 starvation conditions

Impacts of drying–wetting cycles on rhizosphere respiration and soil organic matter decomposition

Contact Info

Product

Resources

About

Ecological processes dominate the ¹³C land disequilibrium in a Rocky Mountain subalpine forest

Ecological processes dominate the ¹³C land disequilibrium in a Rocky Mountain subalpine forest

Changes in size and composition of pigweed (Amaranthus hybridus L.) calcium oxalate crystals under CO₂ starvation conditions