Preharvest nitrogen application affects quality and antioxidant status of two tomato cultivars

Abstract

Intensive horticultural crop production usually involves challenges from excessive application of fertilizer, mainly nitrogen (N). The effect of N fertilizer on the fruit quality and antioxidant status of two cherry tomato cultivars (Caballero and Victoria) under greenhouse conditions was performed. Nitrogen treatments were applied ranging from conditions comprising deficiency to toxicity (0, 15, 30, 45 and 60 mmol•L-1). Yield, weight, diameter, fruit quality, phenols, flavonoids, lycopene, ascorbic acid and antioxidant capacity were measured at physiological maturity of the fresh tomato fruits. N treatment with 30 mmol•L-1 produced the highest yield, fruit weight, firmness and diameter in both cultivars. However, increasing N from 30 to 60 mmol•L-1 increased the concentration of phenolics, flavonoids, and antioxidant capacity by 50, 125 and 33% in 'Caballero' tomatoes and by 60, 95 and 24% in 'Victoria' tomatoes, respectively. Lycopene content increased with increasing N doses (45 and 60 mmol•L-1) for 'Caballero' tomatoes, while vitamin C decreased as N concentration increased, suggesting that ascorbic acid acts by protecting against oxidative stress in tomato. The present work shows how N fertilization considerably influences yield and quality of tomatoes, as well as nutritional and healthy values.

Opportunities of Reduced Nitrogen Supply for Productivity, Taste, Valuable Compounds and Storage Life of Cocktail Tomato

“…The lack of differences between the index SFR_G of control and Nred fruits ( Table 3) further suggests that the reduced N supply did not enhance chlorophyll breakdown and thus ripening and senescence processes. This is in accordance with other reports on the coloration of tomato fruits showing no effects of reduced N supply [15,41,50,51]. Similar to our findings, no impact of reduced N fertilization of tomato plants was observed on the content of the most important carotenoids in tomato fruits, lycopene, β-carotene and lutein [7,13,15,20,50,52].…”

“…Other studies showed that reductions in the N supply up to one third of the optimal level often had no effect on the vitamin C content of the tomato fruits [2,7,15,20,29,32]. Moreover, other results suggest that the antioxidative capacity of tomato fruits is little affected by the N supply [20,50,51].…”

Quality, Bioactive Compounds, Antioxidant Capacity, and Enzymes of Raspberries at Different Maturity Stages, Effects of Organic vs. Conventional Fertilization

“…In general, the present work showed that raspberries from organic fertilization had higher total phenolic compound concentrations when compared to conventional raspberries by 116% in the pink stage, 61% in the mature stage, and 47% in the over-ripe stage ( p ≤ 0.05), ( Table 5 ). According to Straus et al [ 44 ] and Frías-Moreno et al [ 45 ], a decrease in nitrogen supply enhances the concentration of secondary metabolites such as phenolic compounds in beetroot and tomato. Although the same amount of nitrogen was applied in both fertilization systems (~150 kg/ha) ( Table 1 and Table 2 ), organic fertilization presented a lower concentration of NO 3 in soil when compared to conventional fertilization (19.7 vs. 34.27 kg/ha) ( Table 3 ).…”

Nitrogen Application Can Be Reduced without Affecting Carotenoid Content, Maturation, Shelf Life and Yield of Greenhouse Tomatoes

“…In general, it is assumed that overfertilization of greenhouse tomatoes will provide maximum production, and it has been established as widespread standard practice; however, it has negative environmental effects because it reduces the efficiency of fertilizers [ 50 , 51 ]. Frías-Moreno et al [ 52 ] reported that the yield, weight and diameter of fresh tomato fruits increased as nitrogen supply increased up to an optimum nitrogen level (30 mmol∙L −1 ) beyond which growth attributes were reduced. According to a previous study [ 39 ], although an increase in nitrogen dose up to a certain level enhances yield, excessive nitrogen has an overall negative effect.…”