Résumé
Assimilate storage in vegetative organs is an essential buffer for the source-sink imbalances that inevitably occur in perennial plants. In contrast to temperate trees, little information is available on such storage in tropical perennials, and almost none for coconut (Cocos nucifera). This poster describes the chemical nature, quantity, distribution and seasonal dynamics of carbohydrate reserves in 17-year-old adult coconut plants grown in optimum conditions (Republic of Vanuatu, southern Pacific). Plants contained little starch but large quantities of sucrose were found, mainly located in the trunk. Less sucrose was present in roots and little in leaflets. Large glucose and fructose pools were found in leaves near the apex of the trunk, in fruits and in the terminal portions of large roots. Aggregate soluble and non-soluble sugar pools were about equivalent to 6 months of copra production or 51 days of crop growth. Under our optimum conditions, these pools varied little, particularly in the trunk, but they may be mobilisable under stress conditions. The reserves did not seem to play a role in the regulation of production of fruit (in quantity). The number of fruits produced seemed to be controlled precociously during two stages - at the moment of differentiation of the flowers and at the beginning of growth of the fruit. Thereafter, the growth (in terms of dry biomass production) of fruit did not seem to be limited by the availability of sugars. (Texte intégral)