Allocation of carbon and nitrogen as a function of the internal nitrogen status of a plant: Modelling allocation under non-steady-state situations

Werf, Adrie van der; Enserink, Tessa; Smit, Bert; Booij, R.

doi:10.1007/bf00025014

Cited by 14 publications

(10 citation statements)

References 11 publications

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“…Under these conditions plants are acclimated to a certain exponential addition rate of nitrogen and biomass partitioning as welt as rates of photosynthesis and respiration remain constant with time. Comparison of simulated and measured data indicated that these allocation functions obtained under steady-state conditions are also valid under non-steady-state situations (Van der Werf et al, 1993b). Later it will be shown that the allocation functions used in the model may be explained by the combined effect of cytokinins and sucrose on carbon and nitrogen allocation to shoots and roots in relation to nitrogen supply.…”

Section: Modelling Shoot and Root Growth In Relation To Nitrogen Supplymentioning

confidence: 80%

“…Nitrogen is added at a low exponential rate of 0.0375 day-L For more detailed information on the description of the model, the reader is referred to Van der Weft et al (1993a,b). Allocation of daily assimilated carbon and nitrogen to shoots and roots is described as a function of the organic plant nitrogen concentration (Van der Werf et al, 1993b). These allocation functions were obtained for plants growing under steady-state conditions.…”

Section: Modelling Shoot and Root Growth In Relation To Nitrogen Supplymentioning

confidence: 99%

“…Hilbert (1990), Gleeson (1993), and Thornley (1995); (see Reynolds and Chen (1996) for maj or limitations of the use of this concept). Van der Werf et al (1993b) modelled biomass partitioning between shoots and roots on the basis of a relationship between both carbon and nitrogen allocation to shoots and roots and the internal organic plant nitrogen status. In general all these approaches simulate biomass partitioning to shoots and roots in a satisfactory manner, without incorporation of a realistic physiological allocation model.…”

Section: Introductionmentioning

confidence: 99%

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Carbon allocation to shoots and roots in relation to nitrogen supply is mediated by cytokinins and sucrose: Opinion

1996

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In this paper we firstly show some general responses of biomass partitioning upon nitrogen deprivation. Secondly, these responses are explained in terms of allocation of carbon and nitrogen, photosynthesis and respiration, using a simulation model. Thirdly, we present a hypothesis for the regulation of biomass partitioning to shoots and roots.Shortly after nitrogen deprivation, the relative growth rate (RGR) of the roots generally increases and thereafter decreases, whereas that of the shoot decreases immediately. The increased RGR of the root and decreased RGR of the shoot shortly after a reduction in the nitrogen supply, cause the root weight ratio (root weight per unit plant weight) to increase rapidly.We showed previously that allocation of carbon and nitrogen to shoots and roots can satisfactorily be described as a function of the internal organic plant nitrogen concentration. Using these functions in a simulation model, we analyzed why the relative growth rate of the roots increases shortly after a reduction in nitrogen supply. The model predicts that upon nitrogen deprivation, the plant nitrogen concentration and the rate of photosynthesis per unit plant weight rapidly decrease, and the allocation of recently assimilated carbon and nitrogen to roots rapidly increases. Simulations show that the increased relative growth rate of the root upon nitrogen deprivation is explained by decreased use of carbon for root respiration, due to decreased carbon costs for nitrogen uptake. The stimulation of the relative growth rate of the root is further amplified by the increased allocation of carbon and nitrogen to roots. Using the simple relation between the plant nitrogen concentration and allocation, the model describes plant responses quite realistically.Based on information in the literature and on our own experiments we hypothesize that allocation of carbon is mediated by sucrose and cytokinins. We propose that nitrogen deprivation leads to a reduced cytokinin production, a decreased rate of cytokinin export from the roots to the shoot, and decreased cytokinin concentrations. A reduced cytokinin concentration in the shoot represses cell division in leaves, whereas a low cytokinin concentration in roots neutralizes the inhibitory effect of cytokinins on cell division. A reduced rate of cell division in the leaves leads to a reduced unloading of sucrose from the phloem into the expanding cells. Consequently, the sucrose concentration in the phloem nearby the expanding cells increases, leading to an increase in turgot pressure in the phloem nearby the leaf's division zone. In the roots, cell division continues and no accumulation of sugars occurs in dividing cells, leading to only marginal changes in osmotic potential and turgot pressure in the phloem nearby the root's cell division zone. These changes in turgor pressure in the phloem of roots and sink leaves affect the turgor pressure gradients between source leaf-sink leaf and source leaf -root in such a way that relatively more carbohydrates are exported to...

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Section: Modelling Shoot and Root Growth In Relation To Nitrogen Supplymentioning

confidence: 80%

Section: Modelling Shoot and Root Growth In Relation To Nitrogen Supplymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Carbon allocation to shoots and roots in relation to nitrogen supply is mediated by cytokinins and sucrose: Opinion

1996

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“…Similarly, conditions that decrease the specific activity of the shoot, such as a reduction in light intensity or CO 2 concentration, increase the dry-matter allocation toward the shoots (Wilson 1988;Enoch 1990). In some models root and shoot activity affect dry-matter allocation indirectly as the dry-matter distribution is related to the ratio of the C and N concentrations of the plant (Reynolds and Thornley 1982;Mäkelä 1986) or to the N concentration of the plant (Ågren and Ingestad 1987;Van der Werf et al 1993).…”

Section: Functional Equilibrium Modelsmentioning

confidence: 99%

Concepts of Modelling Carbon Allocation Among Plant Organs

Marcelis¹,

Heuvelink²

2007

Functional-Structural Plant Modelling in Crop Production

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Abstract. The simulation of carbon allocation among plant organs is one of the weakest features of crop growth models. This paper briefly discusses five concepts of modelling carbon partitioning: 1. Descriptive allometry, proposing a predetermined ratio between the (relative) growth rates of plant organs; 2. Functional equilibrium, proposing an equilibrium between root and shoot activity; 3. Canonical modelling, a mathematical approach based on only a qualitative understanding of the allocation process; 4. Sink regulation, proposing allocation to be determined by sink strengths of the different organs; and 5. Transport resistance, calculating carbon transport from source to sink through a resistance and its utilization in the sink organs. These five concepts are ordered in increasing complexity. Pros and cons of the different concepts are discussed. The most appropriate concept will depend on the species studied and the aim of the research.

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“…Agren & Ingestad (1987) presented a similar argument, using a phenomenological model to understand root-shoot ratio in relation to plant-N status. Experimental data of Van Der Werf et a!. (1993a), De Pinheiro Henriques & Marcelis (2000 and De Groot et a!.…”

Section: Introductionmentioning

confidence: 99%

Simulating the partitioning of biomass and nitrogen between roots and shoot in crop and grass plants

Yin

Schapendonk

2004

NJAS: Wageningen Journal of Life Sciences

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Allocation of carbon and nitrogen as a function of the internal nitrogen status of a plant: Modelling allocation under non-steady-state situations

Cited by 14 publications

References 11 publications

Carbon allocation to shoots and roots in relation to nitrogen supply is mediated by cytokinins and sucrose: Opinion

Carbon allocation to shoots and roots in relation to nitrogen supply is mediated by cytokinins and sucrose: Opinion

Concepts of Modelling Carbon Allocation Among Plant Organs

Simulating the partitioning of biomass and nitrogen between roots and shoot in crop and grass plants

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