A dynamical model of environmental effects on allocation to carbon-based secondary compounds in juvenile trees.
OBJECTIVE
Patterns and variations in concentration of carbon-based secondary compounds in plant tissues have been explained by means of different complementary and, in some cases, contradictory plant defence hypotheses for more than 20 years. These hypotheses are conceptual models which consider environmental impacts on plant internal demands. In the present study, a mathematical model is presented, which converts and integrates the concepts of the 'Growth-Differentiation Balance' hypothesis and the 'Protein Competition' model into a dynamic plant growth model, that was tested with concentration data of polyphenols in leaves of juvenile apple, beech and spruce trees. The modelling approach is part of the plant growth model PLATHO that considers simultaneously different environmental impacts on the most important physiological processes of plants.


METHODS
The modelling approach for plant internal resource allocation is based on a priority scheme assuming that growth processes have priority over allocation to secondary compounds and that growth-related metabolism is more strongly affected by nitrogen deficiency than defence-related secondary metabolism.


RESULTS
It is shown that the model can reproduce the effect of nitrogen fertilization on allocation patterns in apple trees and the effects of elevated CO(2) and competition in juvenile beech and spruce trees. The analysis of model behaviour reveals that large fluctuations in plant internal availability of carbon and nitrogen are possible within a single vegetation period. Furthermore, the model displays a non-linear allocation behaviour to carbon-based secondary compounds.


CONCLUSIONS
The simulation results corroborate the underlying assumptions of the presented modelling approach for resource partitioning between growth-related primary metabolism and defence-related secondary metabolism. Thus, the dynamical modelling approach, which considers variable source and sink strengths of plant internal resources within different phenological growth stages, presents a successful translation of existing concepts into a dynamic mathematical model.
Gayler
S
S
Institute of Soil Ecology, GSF-National Research Center for Environment and Health, D-85764 Neuherberg, Germany. gayler@gsf.de
Grams
T E E
TE
Heller
W
W
Treutter
D
D
Priesack
E
E
D018533:Biomass; D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D003198:Computer Simulation; D029964:Fagus / Q000254:growth & development / Q000378:metabolism; D027845:Malus / Q000254:growth & development / Q000378:metabolism; D008962:Models, Theoretical; D009584:Nitrogen / Q000378:metabolism; D028222:Picea / Q000254:growth & development / Q000378:metabolism; D014197:Trees / Q000254:growth & development* / Q000378:metabolism*
D002245:Carbon Dioxide; D002244:Carbon; D009584:Nitrogen
Plant Biol (Stuttg). 2005 Nov;7(6):640-9
16388467
Science. 1985 Nov 22;230(4728):895-9
17739203
J Exp Bot. 2006;57(2):355-71
16303828
New Phytol. 2005 Jul;167(1):181-96
15948841
Planta. 1981 Dec;153(4):376-87
24276943
Plant Biol (Stuttg). 2006 Jul;8(4):503-14
16906487
Ecology. 2006 Jul;87(7 Suppl):S150-62
16922310
Plant Biol (Stuttg). 2005 Nov;7(6):659-69
16388469
Nature. 2001 Jun 14;411(6839):843-7
11459067
Plant Biol (Stuttg). 2006 Sep;8(5):653-61
16821190
Q Rev Biol. 2003 Mar;78(1):23-55
12661508
Photosynth Res. 1994 Mar;39(3):413-25
24311133
Planta. 1980 Jun;149(1):78-90
24306196
Plant Biol (Stuttg). 2005 Nov;7(6):560-80
16388460
Plant Biol (Stuttg). 2005 Nov;7(6):601-10
16388463