Gas exchange, leaf and root dry mass in Bell Pepper under fertigation with nitrogen and potassium

Abstract

Bell pepper is a vegetable-fruit of great economic importance in Brazil. Crop production demands adequate water supply, nutrients, and light. The objective of this study was to evaluate gas exchange (net photosynthesis, stomatal conductance, transpiration, internal carbon concentration and instantaneous carboxylation efficiency) and dry mass accumulation in leaves and roots under fertigation with nitrogen and potassium. The experiment was conducted in a completely randomized design in a factorial scheme (4 × 4) with four replications and a total of 64 experimental units. Treatments consisted of a combination of four nitrogen doses (0; 73.4; 146.8 and 293.6 kg ha-1 of N) with four doses of potassium (0; 53.3; 106.7 and 213.4 kg ha-1 of K). An infrared gas analyzer (IRGA) coupled with a light source (irradiation of 600 µmol m-2 s-1) was used for the evaluation of gas exchange. There was a significant interactive effect of N and K on net photosynthesis and leaf and root dry mass. Root dry mass was the variable that best expressed this interaction. Physiological variables measured were more responsive to nitrogen fertilization than to K fertilization. The optimum values of stomatal conductance, transpiration, internal carbon concentration and carboxylation efficiency were obtained with the application of nitrogen doses between 147 and 294 kg ha-1.

Morphophysiology of Eggplant Irrigated With Wastewater and Nitrogen and Phosphorus Doses in the Semi-arid Region of Brazil

“…Therefore, reductions in the photosynthetic and transpiration rates, intracellular CO 2 concentration and stomatal conductance in eggplants submitted to greater nitrogen doses were probably by nutritional excess. Lorenzoni et al (2018) found similar results of nitrogen on sweet pepper (Capsicum annuum L.) plants for the above variables. According to Lorenzoni et al (2018), an excess of nitrogen or an imbalance with other nutrients trigger detrimental effects on plant performance, which may be a result of the physiological imbalance.…”

“…Lorenzoni et al (2018) found similar results of nitrogen on sweet pepper (Capsicum annuum L.) plants for the above variables. According to Lorenzoni et al (2018), an excess of nitrogen or an imbalance with other nutrients trigger detrimental effects on plant performance, which may be a result of the physiological imbalance.…”