AOBPreview published online on November 27, 2009
Annals of Botany, doi:10.1093/aob/mcp278
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Are the common assimilate pool and trophic relationships appropriate for dealing with the observed plasticity of grapevine development?
1 Montpellier SupAgro, Département Sciences du Végétal, 2 place Viala, F-34060 Montpellier, France
2 Ecole Centrale de Paris – Laboratoire MAS, Grande voie des vignes, F-92 295 Châtenay-Malabry, France
3 INRA Montpellier, UMR759 LEPSE, 2 place Viala, F-34060 Montpellier, France
* For correspondence. E-mail jeremie.lecoeur{at}supagro.inra.fr
Received: 27 August 2009 Returned for revision: 18 September 2009 Accepted: 12 October 2009
Background and Aims: Models based on the consideration of plant development as the result of source–sink relationships between organs suffer from an inherent lack of quantification of the effect of trophic competition on organ growth processes. The ‘common assimilate pool theory’ underlying many such models is highly debatable.
Methods: Six experiments were carried out in a greenhouse and outdoors with two grapevine cultivars and with 12 management systems, resulting in different types of plant architecture. Ten variables were used to quantify the impact of variations in assimilate supply and topological distances between sources and sinks on organogenesis, morphogenesis and biomass growth.
Key Results: A hierarchy of the responses of these processes to variations in assimilate supply was identified. Organ size seemed to be independent of assimilate supply, whereas both organogenesis and biomass growth were affected by variations in assimilate supply. Lower levels of organ biomass growth in response to the depletion of assimilate supplies seemed to be the principal mechanism underlying the plasticity of plant development in different environments. Defoliation or axis ablation resulted in changes in the relationship between growth processes and assimilate supply, highlighting the influence of non-trophic determinants. The findings cast doubt on the relevance of ‘the common assimilate pool theory’ for modelling the development of grapevine.
Conclusions: The results of this study suggest new formalisms for increasing the ability of models to take plant plasticity into account. The combination of an ecophysiological model for morphogenesis taking environmental signals into account and a biomass driven model for organogenesis and biomass allocation taking the topological distances between the sources and the sinks into account appears to be a promising approach. Moreover, in order to simulate the impact of agronomic practices, it will be necessary to take into account the non-trophic determinants of plant development such as hormonal signaletics.
Key words: Biomass growth, branching system, common assimilate pool, morphogenesis, organogenesis, source–sink, grapevine, Vitis vinifera