FLOWER ABSCISSION IN PEPPER PLANTS GROWN UNDER DIFFERENT REGIMES OF NITROGEN FERTILIZATION AND PHOTOSYNTHETICALLY ACTIVE RADIATION

Abstract

The effect of nitrogen fertilization on flower abscission in pepper was studied under different growth regimes. The pepper plants were irrigated with 4, 9, and 14 meq L⁻¹of nitrate (N4, N9, and N14). The plants were grown in winter under a low level (639 mol m⁻²) of cumulative photosynthetically active radiation (PAR) (L_PAR), and in spring under a high level (1074 mol m⁻²) of cumulative PAR (H_PAR). The number of flowers and flower abscission were higher under H_PAR than under L_PAR. Flower abscission was higher in response to treatment N4, than in response to treatments N9 and N14, while the flower number was significantly lower. Flower abscission was strongly correlated with growth-related parameters as well as with the carbon or nitrogen contents in plants. Neither the sucrose fluxes nor the amino acid fluxes through the flower pedicels were affected by nitrogen supply. The sucrose fluxes were strongly correlated with air temperature.

Keywords:

• amino acids
• Capsicum annuum L.
• C/N ratio
• phloem sap
• sucrose

ACKNOWLEDGMENTS

The author thanks Mikel Anza and Ainhoa Mendizabal for their skilful technical assistance and Dr Christine Francis for correcting the English text.