Abstract
The cultivation of bell pepper demand irrigation practices to guarantee fruit production and quality. The objective of this work was to study the physiological and biochemical changes, as well as the variation in isotopic discrimination of δ13C in bell pepper plants submitted to different irrigation blades. The experimental design was organized in a completely randomized design (CRD) with three treatments (irrigation blades) and five replications. Blade 1 (B1): Ψm = 10 to 15 kPa, blade 2 (B2): Ψm = 34 to 40 kPa and blade 3 (B3): Ψm = 54 to 60 kPa. Four evaluations were performed at 50, 65, 80 and 95 days after transplantation (DAT), measuring Leaf water potential (Ψlw), net CO2 assimilation (A), stomatal conductance (gs), transpiration (E), isotopic discrimination (δ13C/12C), enzyme activity of nitrate reductase (NR), superoxide dismutase (SOD) and catalase (CAT). Finally, fruits were collected to determine productivity. Bell pepper plants with less water availability and, depending on their development, the leaf water potential was more negative, resulting in greater stomatal closure which caused a considerable decrease in the net CO2 assimilation, transpiration, enzyme activity of nitrate reductase and fruit production, and greater activity of antioxidative enzymes. The increase and duration of water restriction in bell pepper plants induced less isotopic discrimination of δ13C.