REGULATION OF N UPTAKE IN YOUNG PEACH TREES IN RELATION TO THE MANAGAMENT OF CARBON AND NITROGEN STORES

To evaluate how far carbohydrates play a role in the regulation of nitrogen uptake and N store management we manipulated (i) the C availability using trunk girdling or CO₂ depletion, and (ii) N storage by applying 5 levels of fertilization in late summer.
N uptake was reduced by both CO₂ privation and girdling, but the C stores were affected only after girdling, which interrupts the photosynthate supply to the root.
CO₂ privation decreased the respiration losses and reduced the CO₂ assimilation.
On a daily basis, the C budget remained balanced.
Girdling induced a starch accumulation in leaves and shoots and a starch depletion in roots and rootstock-trunk.
The N store management was also related to C metabolism.
N accumulated in the shoots from July to leaf fall, when C was assimilated in excess of growth requirements.
The amounts of stored N were strongly correlated to those of the non-structural carbohydrates.
Mobilization occurred in spring, when trees were not autotrophs for C. At that time growth depended on the amount of N provided the previous summer.
These results are synthesized in a model which describes N uptake in relation to store management, growth and C availability.

IV International Symposium on Mineral Nutrition of Deciduous Fruit Crops

M.O. Jordan, L. Gomez, S. Mediene

Prunus persica L., Soluble proteins, Starch, Soluble sugars, Plant growth

https://doi.org/10.17660/ActaHortic.2001.564.5