Ecofisiologia de pimenta biquinho (Capsicum chinense) submetido à concentrações de prolina como atenuante da salinidade

Abstract

Salinity is one of the major challenges in agriculture in arid and semi-arid regions, as it affects plant development processes and the production of various crops. Thus, the use of salinity stress mitigators is extremely important, as it allows for the use of saline water for agricultural purposes. Among these, proline stands out as a potential alternative to mitigate the damage caused by this stress. Therefore, the objective of this study was to evaluate the effect of proline application as a mitigating agent for the harmful effects of salinity stress on the growth, gas exchange, and metabolism of biquinho pepper. The experimental design used was completely randomized in a factorial scheme 4 (electrical conductivities - CEa: 0.5; 1.50; 3.00; 4.5 dS m⁻¹) x 5 (proline concentrations - Pro: 0.0; 4.00; 8.00; 10.0; 12.00 mM), with six repetitions. Growth, gas exchange, chlorophyll index, chlorophyll a fluorescence, fresh and dry mass of leaves, stems and roots, number and mass of fruits, phenolic compounds, reducing sugars and soluble sugars were evaluated. The application of proline was beneficial for pepper plants, increasing leaf weight and fresh root mass. The concentration of 12.0 mM combined with moderate salinity of irrigation water at 1.50 dS m⁻¹ stimulated gas exchange, resulting in higher net photosynthesis and transpiration in pepper plants. There was an increase in weight and fresh mass of roots (41.92 g plant⁻¹) achieved with a proline concentration of 12.0 mM under irrigation with water at 4.50 dS m⁻¹. The application of 12.0 mM of proline shows beneficial potential for biomass accumulation and stimulates gas exchange, resulting in higher net photosynthesis and transpiration in C. chinense plants.