The aim of the research was to determine selected biochemical and physical characteristics and yielding of fruits in apple varieties (Malus domestica Borkh) such as Gala Schniga, Beni Shogun (Fuji) and Ligol, M.9 rootstock growing in the Wielkopolska region, Poland. high-performance liquid chromatography (HPLC) analysis revealed differences both in the profile and contents of soluble sugars and other metabolites detected in fruits of the tested apple varieties. The highest total saccharide content was found in fruits of cv. Gala Schniga, while leaves and shoots of this variety showed the lowest contents. Electron paramagnetic resonance (EPR) spectroscopy revealed the lowest contents of semiquinone radicals in apple fruits and the highest in leaves of apple trees. All organs of Schniga Gala apple trees were characterized by the highest levels of these radicals. Besides, gas chromatography-mass spectrometry (GC-MS) analysis of abscisic acid (ABA) revealed the highest levels of this molecule in shoots of apple trees, especially the Beni Shogun variety, while in fruits the levels were the lowest. Ligol fruits had the highest content of ABA. The percentage of injury observed after a low-temperature treatment and estimated on the basis of electrolyte leakage, was shown to be the lowest in fruits of the Beni Shogun variety. In turn, the lowest average yield of apple fruits was recorded for the Ligol and Fuji varieties, with the highest in the case of the Gala Schniga variety. At the same time, a significant variability in the average weight of fruits was observed; the highest average mass of fruits was recorded for the Ligol variety, while it was lowest for Gala Schniga. Additionally, firmness evaluation of the fruits revealed that the firmest fruits were harvested from Gala apple trees, before the Beni Shogun and Ligol varieties. A significant variability was recorded in the red blush on fruit surfaces of the tested varieties, with Ligol fruits having the weakest blush. Altogether, these results indicate that fruits of the analyzed apple varieties differed both in terms of their biochemical composition and physical characteristics.

The article describes an experiment conducted on maiden apple trees of selected cultivars growing in a nursery. The aim of the study was to investigate how the foliar application of four biostimulants (Aminoplant 0.4%, Biamino Plant 0.2%, Bispeed 0.2% and Fylloton 0.4%) and two fertilisers (Basfoliar 6-12-6 and Basfoliar 12-4-6+S both at a concentration of 0.5%) affected the growth of the trees cultivated with the mineral fertilisation reduced by half. The plants were sprayed with the preparations and fertilisers four times at three-week intervals, between late May and late July. Selected parameters of the plants’ physiological processes were also assessed: net photosynthetic rate (Pn), transpiration rate (E), stomatal conductance (C) and intracellular CO₂ (I). The foliar application of all the biostimulants and fertilisers significantly improved the growth of the maiden apple trees. The lowest values of the plant growth parameters were noted in the control combination, which was treated with a full dose of mineral fertiliser. The foliar spraying of the apple trees particularly improved the total length and number of side shoots and the fresh weight of maiden apple trees. The apple tree cultivars differed in their growth parameters, and the influence of individual foliar treatments was not conclusive. The foliar application of selected preparations intensified the leaf transpiration coefficient and the internal concentration of carbon dioxide, but it did not increase the net photosynthesis intensity or stomatal conductance.

The technology of producing fruits containing an increased amount of elements essential for the health of the human body, including silicon, has become very important in recent years. Due to the popularity of apple tree cultivation in Europe, appropriate research has been undertaken. The aim of the experiment was to determine the advisability of foliar silicon nutrition in apple tree cultivation. Apple cultivars ‘Gala Schniga’, ‘Ligol’ and ‘Topaz’ were studied and treated with three different doses of silicon (100, 200, 300 mg SiO₂·L⁻¹). The treatments were performed five times during tree growth in the third year of cultivation from early June to late July. Foliar application of silicon did not improve the evaluated tree growth parameters. It significantly influenced, in the highest analysed concentration, a better fruit yield (12%), a higher yield coefficient, depending on the concentration, from 16 to 18%, a better fruit quality (weight and size) and a more extensive red blush. The considered cultivars differed in the growth and yield of trees in the third year of cultivation. ‘Topaz’ grew strongest and ‘Ligol’ yielded the best. The highest yield coefficient was found for the Topaz’ cultivar. The fruit of ‘Topaz’ had the biggest blush and ‘Gala Schniga’ the biggest sugar content. Macro- and micro-nutrient nutritional status of trees were no better, except for iron and copper in leaves, and at some concentrations of applied silicon also zinc and copper in fruit.

Cultivation of sweet cherry trees is growing in popularity in Poland thus there is an increasing demand for good quality nursery material. The growth of maiden sweet cherry trees of ‘Vanda’ depending on three rootstocks was compared within three years of the nursery experiment. Also the nutritional status as well as photosynthetic activity of maiden trees after the use of four foliar preparations were in the scope of interest. On the basis of the size of the trunk diameter and weight of maiden sweet cherry tree fresh mass as well as on the basis of dry mass of leaves, the strongest vigor of growth was observed on Colt rootstock, contrary to the vigor on GiSeLa 5 rootstock, in which it was the weakest. Maidens produced on Colt rootstock formed more lateral shoots in comparison to other rootstocks. After foliar fertilization, maiden sweet cherry trees growing on Colt rootstock did not show better parameters of growth, except for Maxi Grow Excel preparation that caused better results of growth. The influence of preparations used on the content of macro and microelements was differentiated. A positive effect of all preparations was noted as far as gas exchange parameters were concerned, especially in the case of Maxi Grow Excel.

The experiment compared the use of a dose of mineral fertilisation reduced by half in a nursery, which was replaced by foliar treatment with biostimulants and fertilisers. The control combination was a full dose of mineral fertilisation without foliar treatments. The half dose of mineral fertiliser applied into the soil decreased its acidity and salinity. At the same time, it decreased the soil content of macro- and micronutrients, except for calcium and iron. In most cases the simultaneous foliar application of the four biostimulants tested in our experiment reduced the content of macronutrients in the leaves of maiden apple trees, except for calcium. On the other hand, it increased the iron (28.2% average) and manganese (24.8% average) levels in the leaves but reduced the levels of zinc (11.8% average) and copper (25% average). The foliar application of two fertilisers increased the leaf contents of phosphorus (12% average) and calcium (9.3% average). One of the fertilisers also increased the leaf contents of potassium, magnesium, and micronutrients.