The objective of this work was to evaluate the effect of nitrogen nutrition on production and partition of dry matter and the change of some leaf sugars concentrations in 'Sunrise solo' papaya plants. The work was carried out in a randomized blocks experimental design with three treatments (levels of NO-3) and five replications, where each plant was considered an experimental unit. Plants were fertilized with different nutritional solutions prepared to present three concentrations of NO-3 (1.0; 3.0; 5.0 mol m-3). The experiment ended sixty-four days after sowing. It was shown that total dry matter production of stem, leaf and roots, as well as the values of leaf area, leaf area/leaf mass ratio, stem mass and specific leaf area were smaller for plants grown under lower nitrogen availability. However, the root/shoot ratio did not show differences among treatments, indicating that there was no adjustment in carbon partition between these plant parts. The concentrations of total soluble sugars (TSS), reducing sugars (RS) and not reducing sugars (NRS) increased with the increase of NO-3 in solution. An opposing trend was noted for starch concentration, higher for plants grown under NO-3 deficiency. The starch/NRS ratio was higher for plants grown under lower NO-3 availability, suggesting that there was a reduction of export levels of assimilates produced.
Carica papaya L.; nitrate; root; sugars; starch
