Abstract
A whole-plant model of C and N metabolism is presented for the juvenile stage. It is aimed at comparing the growth performance of (wild) plant species in a range of environments with respect to irradiance and availability of nitrate (NO3 -) and ammonium (NH4 +). State variables are the structural masses of leaves, stem and root, NO3 - concentrations in root and shoot, non-structural carbohydrate (C) densities in leaves, stem and root and non-structural organic N concentration in the whole plant. Explicit expressions for NO3 - influx, efflux, translocation and assimilation, and for NH4 + uptake and assimilation have been formulated in an accompanying paper. Photosynthetic rate is derived from electron-transport rate which depends on irradiance and chlorophyll concentration on a leaf-area basis. The latter is proportional to non-structural organic N concentration. Photosynthetic N is considered non-structural. Unique features of the model are the use of metabolite signals and the treatment of C allocation and balanced growth. Metabolite signals are dimensionless functions of non-structural compounds (NO3 -, C, organic N) and modify rate variables involved in N uptake and assimilation, C allocation and growth. Carbon allocation is driven by concentration differences of the cytosolic C pools in stem and root and is modified by the N status of the plant such that a high N status increases the apparent size of the shoot. Photosynthate is unloaded into C buffers which degrade at a constant specific rate. The sugar fluxes which arise from these buffers drive the growth rate of stem and root. No parameters are included for maximum specific growth or for activity or strength of sinks. Primary stem growth is proportional to growth of the leaf compartment: leaves arise from stems in a modular fashion. Leaves are autonomous with respect to their C balance. The model is presented as a system of differential equations which is integrated numerically. Parameter values, e.g., for uptake and assimilation capacities and costs of uptake, assimilation, maintenance and growth, are estimated for a grass species, Dactylis glomerata. Juvenile growth is simulated under optimal conditions with respect to irradiance and NO3 - availability and compared with literature data. Diurnal and daily patterns of C utilisation and respiration, expressed as percentages of gross photosynthetic rate, are discussed. The model satisfactorily simulates typical responses to nutrient and light limitation and pruning, such as redirected C allocation, adjusted root and leaf weight ratios and compensatory growth. A sensitivity analysis is included for selected parameters.
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References
Caloin M, El Khodre A and Atry M 1980 Effect of nitrate concentration on the root:shoot ratio in Dactylis glomerata L. and on the kinetics of growth in the vegetative phase. Ann. Bot. 46, 165–173.
Caloin M, Clement B and Herrmann S 1990 Regrowth kinetics of Dactylis glomerata following defoliation. Ann. Bot. 66, 397–405.
Caloin M, Clement B and Herrmann S 1991 Regrowth kinetics of Dactylis glomerata following root excision. Ann. Bot. 68, 435–440.
Evans J R 1989 Photosynthesis and nitrogen relationships in leaves of C3 plants. Oecologia 78, 9–19.
Evans J R 1993a Photosynthetic acclimation and nitrogen partitioning within a lucerne canopy. I. Canopy characteristics. Aust. J. Plant Physiol. 20, 55–67.
Evans J R 1993b Photosynthetic acclimation and nitrogen partitioning within a lucerne canopy. II. Stability through time and comparison with a theoretical optimum. Aust. J. Plant Physiol. 20, 69–82.
Farquhar G D, Von Caemmerer S and Berry J A 1980 A biochemical model of photosynthetic CO2 assimilation in leaves of C3 species. Planta 49, 78–90.
Farrar J F 1989 The carbon balance of fast-growing and slowgrowing species. In Causes and Consequences of Variation in Growth Rate and Productivity of Higher Plants. Eds H Lambers, M L Cambridge, H Konings and T L Pons. pp 241–256. SPB Academic Publishing, The Hague.
Farrar J F 1992 The whole plant: carbon partitioning during development. In Carbon Partitioning Within and Between Species. Eds C J Pollock, J F Farrar and A J Gordon. pp 163–179. BIOS Scientific Publishers, Oxford.
Farrar J F 1996a Sinks - integral parts of a whole plant. J. Exp. Bot. 47, s1273-s1279.
Farrar J F 1996b Regulation of root weight ratio is mediated by sucrose: opinion. Plant Soil 185, 13–19.
Farrar J F, Minchin P E H. and Thorpe M R 1995 Carbon import into barley roots: effects of sugars and relation to cell expansion. J. Exp. Bot. 46, 1859–1865.
Foyer C H, Valadier M H and Ferrario S 1995 Co-regulation of nitrogen and carbon assimilation in leaves. In Environment and Plant Metabolism. Ed. N Smirnoff. pp 17–33. BIOS Scientific Publishers, Oxford.
Hunt R and Cornelissen J H C 1997 Components of relative growth rate and their interrelations in 59 temperate plant species. New Phytol. 135, 395–417.
Kooijman S A L M 1993 Dynamic Energy Budgets in Biological Systems. Cambridge University Press, Cambridge.
Kooijman S A LM 1998 The synthesizing unit as model for the stoichiometric fusion and branching of metabolite fluxes. Biophys. Chem. 73, 179–188.
Kruger N J 1997 Carbohydrate synthesis and degradation. In Plant Metabolism. Eds D T Dennis, D H Turpin, D D Lefebvre and D B Layzell. pp 83–104. Addison Wesley Longman, Harlow.
Lambers H, Atkin OK and Scheurwater I 1996 Respiratory patterns in roots in relation to their functioning. In Plant Roots: The Hidden Half. Eds Y Waisel, A Eshel and U Kafkaki. pp 323–362. Marcel Decker, New York.
Lambers H, Chapin III F S and Pons T L 1998 Plant Physiological Ecology. Springer-Verlag, New York.
Lappartient A G, Vidmar J J, Leustek T, Glass A D M and Touraine B 1999 Inter-organ signaling in plants: regulation of ATP sulfurylase and sulfate transporter genes expression in roots mediated by phloem-translocated compound. Plant J. 18, 89–95.
Lee R B 1993 Control of net uptake of nutrients by regulation of influx in barley plants recovering from nutrient deficiency. Ann. Bot. 72, 223–230.
McIntyre G I 1997 The role of nitrate in the osmotic and nutritional control of plant development. Aust. J. Plant Physiol. 24, 103–118.
Poorter H and Remkes C 1990 Leaf area ratio and net assimilation rate of 24 wild species differing in relative growth rate. Oecologia 83, 553–559.
Poorter H, Remkes C and Lambers H 1990 Carbon and nitrogen economy of 24 wild species differing in relative growth rate. Plant Physiol. 94, 621–627.
Poorter H and Bergkotte M 1992 Chemical composition of 24 wild species differing in relative growth rate. Plant Cell Environ. 15, 221–229.
Poorter H and Villar R 1997 The fate of acquired carbon in plants: chemical composition and construction costs. In Plant Resource Allocation. Eds F A Bazzaz and J Grace. pp 39–72. Academic Press, San Diego.
Press W H, Flannery B P, Teukolsky S A and Vetterling W T 1988 Numerical Recipes in C. The Art of Scientific Computing. Cambridge University Press, Cambridge.
Ryser P 1996 The importance of tissue density for growth and life span of leaves and roots: a comparison of five ecologically contrasting grasses. Funct. Ecol. 10, 717–723.
Ryser P and Lambers H 1995 Root and leaf attributes accounting for the performance of fast-and slow-growing grasses at different nutrient supply. Plant Soil 170, 251–265.
Scheible W-R, Lauerer M, Schulze E-D, Caboche M and Stitt M 1997a Accumulation of nitrate in the shoot acts as a signal to regulate shoot-root allocation in tobacco. Plant J. 11, 671–691.
Scheible W-R, González-Fontes A, Lauerer M, Müller-Röber B, Caboche M and Stitt M 1997b Nitrate acts as a signal to induce organic acid metabolism and repress starch metabolism in tobacco. Plant Cell 9, 783–798.
Smeekens S and Rook F 1997 Sugar sensing and sugar-mediated signal transduction in plants. Plant Physiol. 115, 7–13.
Stitt M 1997 The flux of carbon between the chloroplast and cytoplasm. In Plant Metabolism. Eds D T Dennis, D H Turpin, D D Lefebvre and D B Layzell. pp 382–400. Addison Wesley Longman, Harlow.
Stitt M and Scheible W R 1998 Understanding allocation to shoot and root growth will require molecular information about which 87 compounds act as signals for the plant nutrient status, and how meristem activity and cellular growth are regulated: opinion. Plant Soil 201, 259–263.
Stitt M and Schulze D 1994 Does Rubisco control the rate of photosynthesis and plant growth? An exercise in molecular ecophysiology. Plant Cell Environ. 17, 465–487.
Thornley J H M 1998 Modelling shoot:root relations: the only way forward? Ann. Bot. 81, 165–171.
Thornley J H M and Johnson I R 1990 Plant and Crop Modelling. A Mathematical Approach to Plant and Crop Physiology. Clarendon Press, Oxford. 669 p.
Van der Werf A, Enserink T, Smit B and Booij R 1993a Allocation of carbon and nitrogen as a function of the internal nitrogen status of a plant: modelling allocation under non-steady-state situations. Plant Soil 155/156, 183–186.
Van der Werf A, Visser A J, Schieving F and Lambers H 1993b Evidence for optimal partitioning of biomass for a fast-growing and slow-growing species. Funct. Ecol. 7, 63–74.
Van der Werf A and Nagel O W 1996 Carbon allocation to shoots and roots in relation to nitrogen supply is mediated by cytokinins and sucrose: opinion. Plant Soil 185, 21–32.
Williams J H H and Farrar J F 1990 Control of barley root respiration. Physiol. Plant. 79, 259–266.
Wilson J B 1988 A review of evidence on the control of shoot:root ratio, in relation to models. Ann. Bot. 61, 433–449.
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Bijlsma, R., Lambers, H. A dynamic whole-plant model of integrated metabolism of nitrogen and carbon. 2. Balanced growth driven by C fluxes and regulated by signals from C and N substrate. Plant and Soil 220, 71–87 (2000). https://doi.org/10.1023/A:1004744903556
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DOI: https://doi.org/10.1023/A:1004744903556