The aim of the present work was to assess the physiological state of plants and photosynthetic apparatus activity in lettuce (Lactuca sativa L.) by non-invasive methods (leaf diffuse reflectance spectroscopy and chlorophyll fluorescence) under the deficiency of one of the macronutrients (nitrogen, phosphorus, or potassium). Our experiments assessed the deficiency of each of the macronutrients relative to plants vegetating under optimal nutrition. The used methods showed that the deficiency of macronutrients causes changes in the optical characteristics of lettuce plants (cvs. ‘Vitaminnyi’ and ‘Kokarda’), including a decrease in the chlorophyll content (57% and 51%) and a change in metabolism, which leads to a decrease in the efficiency of light energy conversion in photochemical processes of photosynthesis and an increase in the dissipation of excess light energy (19% and 10%). Linear regression equations, describing the relationship between net productivity and spectral characteristics of diffuse leaf reflectance with high accuracy, have been obtained. Changes in all studied indicators of the physiological state of plants under the influence of macronutrient deficiency are more pronounced at the early stages of development than in later periods, when the first symptoms of aging appear (decrease in ChlRI). The observed differences between lettuce cultivars and their response to nitrogen, phosphorus, or potassium deficiency are non-specific and mainly represent quantitative variation. The method for assessing the spectral characteristics of diffuse reflection of leaves seems to be the most promising for monitoring the physiological status of plants and early detection of nitrogen, phosphorus, or potassium deficiency.

The article presents the results of biochemical and QTL (Quantitative Trait Loci) analysis of dry matter content, nutrient and biologically active compounds: sugars, ascorbic acid, chlorophylls a and b, anthocyanins and carotenoids in populations of doubled haploid lines of leaf, root crops, and oilseeds of the Brassica rapa L. species grown in optimal light culture conditions, but with different photoperiod durations. The purpose of this study was to evaluate the effect of the photoperiod on the transition to bolting and the accumulation of biologically active substances, as well as how the localization and identification of chromosomal loci determined the content of certain phytochemicals. The influence of the length of daylight hours on the content of components of the biochemical composition was assessed. It was shown that growing under conditions of a 16 h photoperiod increased the content of dry matter, sugars, vitamin C, and anthocyanins. On the contrary, the content of photosynthetic pigments was higher under the conditions of a 12 h photoperiod. Valuable lines that can be sources of biologically active compounds were revealed. Based on the results of the obtained data, 102 QTLs were mapped, which determine the manifestation of the studied biochemical quality traits in the B. rapa doubled haploid lines under conditions of short and long daylight hours. Molecular markers genetically linked to the selected QTLs were determined. It was revealed that the identified loci controlling all the studied biochemical traits were mainly in the fifth, sixth, seventh, and ninth linkage groups, which correlated with the data obtained in the field and greenhouse. Most of the identified loci controlled several studied traits simultaneously. The identified QTLs and identified molecular markers are of interest for further study of the genetic control of the economically valuable traits determined by them and for the implementation of marker-assisted selection in B. rapa. The data obtained can be used in genetic and breeding work, including for the obtaining of new genotypes, lines and cultivars with a valuable biochemical composition, adapted for cultivation under specific photoperiodic conditions.

The review presents the current state of the science for stevia (Stevia rebaudiana Bertony), its biochemical composition, therapeutic properties and using in the food industry. Interest in this plant, a source of natural low-calorie sweeteners, is associated with increased consumption of dietary sweeteners, caused by an increase in the number of patients with diabetes, metabolic syndrome, and with many negative effects from the use of synthetic sweeteners. Diterpene glycosides from stevia have a high sweetness (50-350 times sweeter than sucrose), low calorie content, safe for human health. In addition to them, a number of biologically valuable compounds (mineral elements, vitamins, proteins, amino acids, oligosugars, fiber, polyphenols) were found in the leaves of stevia. High antioxidant properties of stevia leaf extracts has been shown, which allows them to be used in the food industry in the production of functional products. Numerous data have been obtained on the various therapeutic properties of stevia. It has been revealed that regular use of stevia glycosides reduces blood glucose and cholesterol levels, promotes cell regeneration, inhibits the growth of tumor cells and strengthens blood vessels. Components from stevia leaves have a choleretic, diuretic effect, normalize blood pressure, prevent diseases of the gastrointestinal tract, and have a beneficial effect on kidney function. Stevia extracts also have antibacterial, antiviral, anti-inflammatory and immunomodulatory effects. The safety and stability of stevia sweet glycosides in an acidic environment and at high temperatures allows them to be widely used in the production of products such as diet drinks, teas, sauces, marinades, seafood, ice cream, yogurts, pastries, culinary products and sweets.

This paper presents the results of breeding and genetic studies of Raphanus sativus L. under the controlled conditions of the biopoligon of the Agrophysical Research Institute (St. Petersburg, Russia). The aim of this study was to create new R. sativus forms for controlled environments with artificial lightning (CEAL). An original technique for accelerated transgressive plant breeding was used. It is based on the methodology for predicting transgressions by economically valuable plant traits when evaluating breeding traits under controlled conditions. Using it in a short period of time (4–5 years) greatly increases productive accessions of small radish and radish adapted to light culture, and a set of valuable characteristics (resistance to bolting, glabrous leaves, compact leaf rosette) were obtained. The yield of roots of new forms was 4.30–4.98 kg/m² (small radish) and 5.46–7.66 kg/m² (radish) for the growing period. Transgression by root mass was observed in plants of three new forms and amounted to 40.7–63.0% in small radish and 40.3% in radish. The breeding of new genotypes of R. sativus is aimed at expanding the range of crops cultivated in plant factories, and ultimately, at a better and more balanced nutrition for the population.