The effect of mineral nutrition on the biochemical composition of Venyaminovskoe apple cultivar fruits

Abstract

The results of a five-year study of the mineral fertilizers' effect on the chemical composition of Venyaminovskoe apple cultivar fruits are presented. It is shown that the use of soil and foliar application of nitrogen and potash fertilizers did not have a significant effect on the content of soluble solids, sugars, titrated acids, ascorbic acid, and phenolic compounds in fruits. It was established that the most significant factor affecting the chemical composition of fruits are the weather conditions of the growing season. At the same time, the content of ascorbic acid significantly exceeding the control over an average of five experimental years was found in the option with the introduction of nitrogen and potash fertilizers into the soil at a dose of N60K80 together with foliar top dressing. There is a tendency of increasing accumulation of leucoanthocyanins in fruits over the years. In 2021, there was a significant decrease in catechins with the use of mineral fertilizers at a dose of N60K80, as well as in the following options: without soil and minimal (N30K40) fertilization against the background of top dressing.

Apple Antioxidant Properties as an Effect of N Dose and Rate—Mycorrhization Involvement: A Long-Term Study

“…Similar results were found in five-year studies [ 57 ], where the use of soil and foliar application of nitrogen and potassium fertilizers did not have a strong effect on the concentration of ascorbic acid and phenolic compounds in the apple fruits. It was found that under high N nutrition in apple trees, shoot growth was enhanced and the activity of phenylalanine ammonia lyase, a key enzyme involved in flavonoid biosynthesis, seemed to be downregulated, resulting in a generally decreased flavonoid accumulation [ 20 , 61 ].…”

“…In turn, Li et al [ 55 ] demonstrated that solar radiation influenced ascorbic acid only in the apple peel, while Bui et al [ 56 ] indicated that a higher accumulation of phenolics and ascorbate took place in the sun-exposed part of peel as compared to the shaded part. Significant differences in apple antioxidant content were obtained in five-year study and the weather conditions was indicated as the most significant factor [ 57 ].…”

“…On the other hand, maintaining higher concentrations of antioxidants can be an effective strategy for plants to mitigate the harmful effects of ROS [ 38 ]. Taking into account other long term studies on the influence of various factors regarding the antioxidant metabolism, simultaneously ignoring the tissue type which is the most impacting factor [ 41 ], the year (soil and weather variables) frequently override other factors, including agro-technical approaches [ 3 , 4 , 40 , 41 , 57 ]. However, the type, strength and duration of the environmental stress factor can finally determine the change direction i.e., up- or down- regulation of antioxidant machinery.…”

“…Moreover, it seems necessary to test the fertilization range together with their impact on pro-healthy compound metabolism to find an optimal quantity and quality yield point with respect to particular species/cultivar [ 4 ]. On the other hand the response to N fertilization may also be positive or neutral [ 49 , 57 , 63 ].…”