Passiflora alata clonal plants were submitted to four shading levels (0, 25, 50 and 75%) at 75 days after cutting establishment (DAC). Ten days later, nitrogen (N) was applied at 0, 25, 50, 100 and 200 mg N kg-1 of soil. A significant interaction (p<0.05) was observed between shading levels (SL) and N concentrations for all photosynthetic parameters evaluated at 175 DAC. There was an increase in the net photosynthetic rate with the increase of the SL and the N, up to 146 mg N kg-1 of soil. The transpiration rate showed a quadratic effect for both SL and N, increasing with the rise of SL and N, up to 50% shading and 137 mg N kg-1, respectively. The leaf mesophyll thickness was reduced with SL intensification. The total chlorophyll and chlorophyll a and b content increased with the increase of SL and N. There were no significant differences (p<0.05) in the SLxN interaction, for all growth parameters analyzed. The higher accumulation of total dry biomass was obtained at 69% of shading and 113mg N kg-1, with decline in the highest SL and N levels. The results showed that a moderate shade (50%) combined with an adequate N supply, increase the photosynthetic rate and biomass of the whole plant.
growth; photosynthesis; sweet passion fruit
