Experimental evaluation of an efflux–influx model of C exudation by individual apical root segments

Personeni, Emmanuelle; Nguyen, Christophe; Marchal, Patrice; Pagès, Loïc

doi:10.1093/jxb/erm065

Cited by 30 publications

(34 citation statements)

References 37 publications

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“…To represent the growth of fine roots, we proposed a non-linear model and adjusted it to the data presented by Mello et al (1998), Neves (2000), Leles et al (2001), Teixeira et al (2002), Gatto et al (2003) andMaquere (2008). From this point, we estimate the rate at which C and N release processes from roots as an adaptation of the model by 30 Personeni et al (2007) that was based on Farrar et al (2003).…”

Section: Mathematical Model Overviewmentioning

confidence: 99%

“…For instance, parameters used for modelling fine root growth and rhizodeposition were based in several studies, which include Mello et al (1998), Neves (2000), Leles et al (2001), Teixeira et al (2002), Gatto et al (2003), Maquere (2008) and 5 Personeni et al (2007). The remainder parameters used for simulating C and N cycling in the rhizosphere soil (bacteria + fungi) was based mainly in the studies of Schimel and Weintraub (2003), Allison et al (2010) and Drake et al (2013).…”

Section: Parameter Estimationmentioning

confidence: 99%

“…We used equation 7 to describe net rhizodeposition of carbon by the root, using a model proposed by Farrar et al (2003) and optimized and parameterized by Personeni et al (2007). The estimation of rhizodeposition of organic nitrogen was carried out by dividing the carbon value by the C/N ratio of the rhizodeposited material (Ne, µg cm -³) (equation 8).…”

Section: Estimation Of the Rizodeposition Processmentioning

confidence: 99%

“…During release of rhizodeposits, using the model of Personeni et al (2007), it was noted that there were certain simplifications of the process, i.e. after 8 hours deposition of C and N by roots was assumed to be maximized at 7.5 and 0.75 μg cm-³ h -1 , respectively, with no change thereafter.…”

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confidence: 99%

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Modeling rhizosphere carbon and nitrogen cycling in Eucalyptus plantation soil

Valadares¹,

Neves²,

Costa³

et al. 2017

Preprint

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Abstract. Vigorous Eucalyptus plantations produce 105 to 10 6 km ha -1 of fine roots that probably increase carbon (C) and nitrogen (N) cycling in rhizosphere soil. However, the quantitative importance of rhizosphere priming is still unknown for most ecosystems, for instance Eucalyptus plantations. Therefore, the objective of this work was to propose and evaluate a mechanistic model for predicting rhizospheric C and N cycling in Eucalyptus plantations. The potential importance of the priming effect was estimated for a typical Eucalyptus plantation in Brazil. The process-based model (ForPRAN -Forest 15 plantation rhizospheric available nitrogen) predicts the change in rhizosphere C and N cycling resulting from root growth and consists of two modules: (1) fine root growth, and (2) C and N rhizosphere cycling. The model describes a series of soil biological processes: root growth, rhizodeposition, microbial uptake, enzymatic synthesis, depolymerization of soil organic matter, respiration, mineralization, immobilization, microbial death, microbial emigration and immigration, SOM formation.Model performance was satisfactory quantitatively and qualitatively when compared to observed data in the literature. The 20 input variables that most influenced N gain by rhizospheric mineralization were (in order of decreasing importance): root diameter > rhizosphere thickness > soil temperature > clay content. The priming effect in a typical Eucalyptus plantation producing 42 m³/ha/year of wood, with assumed losses of 40 % of the total N mineralized, was estimated to be 24.6 % of plantation N demand (shoot + roots + litter). The rhizosphere cycling model should be considered for adaptation to other forestry and agricultural production models where the inclusion of such processes offer the potential for improved model 25 performance.

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Section: Mathematical Model Overviewmentioning

confidence: 99%

Section: Parameter Estimationmentioning

confidence: 99%

Section: Estimation Of the Rizodeposition Processmentioning

confidence: 99%

mentioning

confidence: 99%

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Modeling rhizosphere carbon and nitrogen cycling in Eucalyptus plantation soil

Valadares¹,

Neves²,

Costa³

et al. 2017

Preprint

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“…Total organic carbon (TOC) is usually determined by wet digestion method (Nelson and Sommers, 1996;Aulakh et al, 2001), or using an analyzer (Dousset et al, 2001;Personeni et al, 2007;Miya and Firestone, 2001). Sometimes, content of nitrogen (Kjeldahl) is measured (Miya and Firestone, 2001;Nardi et al, 2002).…”

Section: Other Types Of Analysismentioning

confidence: 99%

Methods of plant root exudates analysis: a review

Dundek¹,

Holík²,

Rohlík³

et al. 2014

Acta Univ. Agric. Silvic. Mendelianae Brun.

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DUNDEK, P., HOLÍK, L., ROHLÍK, T., VRANOVÁ, V., REJŠEK, K., FORMÁNEK, P.: Methods of plant root exudates analysis: a review. Acta univ. agric. et silvic. Mendel. Brun., 2011, LIX, No. 3, pp. 241-246 The aim of this review is to summarise current knowledge on methods being used to determine individual compounds and properties of water-soluble plant root exudates. These compounds include amino acids, organic acids and simple sugars, as well as polysaccharides, proteins and organic substances. Qualitative composition of water-soluble root exudates and exudation rate are commonly measured with the aim of consequent synthetic preparation of plant root exudates to be supplied to soil to create artifi cial rhizosphere for diff erent experimental purposes. Root exudates collection usually requires consequent fi ltration or centrifugation to remove solids, root detritus and microbial cell debris, and consequent concentration using an evaporator, lyophilizator or ultrafi ltration. Methods used for analysis of total groups of compounds (total proteins and total carbohydrates) and total organic carbon are simple. On the other hand, HPLC or GS/MS are commonly used to analyse individual low molecular weight organic molecules (sugars, organic acids and amino acids) with separation using diff erent columns. Other properties such as pH, conductivity or activity of diff erent enzymes as well as gel electrophoresis of proteins are sometimes assessed. All of these methods are discussed in this work. amino acids, HPLC, GC/MS, organic acids, root exudates, sugars Substances released by healthy and intact roots into the environment are collectively designated as root exudates. These substances aff ect the composition of microbial community in immediate proximity of plant roots and processes taking place in rhizosphere. Many compounds are released by plant roots, including inorganic ions and substances,

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Root exudation rate as functional trait involved in plant nutrient‐use strategy classification

Guyonnet

Cantarel

Simon

et al. 2018

Ecology and Evolution

101

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Plants adopt a variety of life history strategies to succeed in the Earth's diverse environments. Using functional traits which are defined as “morphological, biochemical, physiological, or phonological” characteristics measurable at the individual level, plants are classified according to their species’ adaptative strategies, more than their taxonomy, from fast growing plant species to slower‐growing conservative species. These different strategies probably influence the input and output of carbon (C)‐resources, from the assimilation of carbon by photosynthesis to its release in the rhizosphere soil via root exudation. However, while root exudation was known to mediate plant‐microbe interactions in the rhizosphere, it was not used as functional trait until recently. Here, we assess whether root exudate levels are useful plant functional traits in the classification of plant nutrient‐use strategies and classical trait syndromes? For this purpose, we conducted an experiment with six grass species representing along a gradient of plant resource‐use strategies, from conservative species, characterized by low biomass nitrogen (N) concentrations and a long lifespans, to exploitative species, characterized by high rates of photosynthesis and rapid rates of N acquisition. Leaf and root traits were measured for each grass and root exudate rate for each planted soil sample. Classical trait syndromes in plant ecology were found for leaf and root traits, with negative relationships observed between specific leaf area and leaf dry matter content or between specific root length and root dry matter content. However, a new root trait syndrome was also found with root exudation levels correlating with plant resource‐use strategy patterns, specifically, between root exudation rate and root dry matter content. We therefore propose root exudation rate can be used as a key functional trait in plant ecology studies and plant strategy classification.

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Experimental evaluation of an efflux–influx model of C exudation by individual apical root segments

Cited by 30 publications

References 37 publications

Modeling rhizosphere carbon and nitrogen cycling in Eucalyptus plantation soil

Modeling rhizosphere carbon and nitrogen cycling in Eucalyptus plantation soil

Methods of plant root exudates analysis: a review

Root exudation rate as functional trait involved in plant nutrient‐use strategy classification

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