Artificial light culture of plants in modern artificial climate facilities (review)

Intense light culture of plants as a process of plant growing under artificial light emerged in the 19th century (F.H. Besthorn, 2013; J. Kleszcz et al., 2020). In Russia, scientific research in the field of plants light culture began to actively develop in the first half of the 20th century (V.M. Lehman, 1976; A.M. Globus, 2007; E.I. Ermakov, 2009; I.G. Tarakanov et al., 2022). Currently, the study of various aspects of growing plants under controlled environmental conditions is carried out in a number of leading scientific institutions of the Russian Federation and the Republic of Belarus, as well as by research teams from Europe, Asia, the USA, Canada and Australia. Significant interest in this area of plant cultivation is confirmed by the sharply increased number of publications on this topic in recent years (A. Dsouza et al., 2023). Light culture is implemented in modern artificial climate facilities (controlled environment agriculture, CEA), that are usually equipped with multi-level systems for growing plants and lighting sources, and serving as an alternative to traditional agricultural production (T. Kozai et al., 2020). Such facilities (plant factories, vertical farms, city farms, phytotech complexes) are used to produce vegetables in densely populated urban areas and regions with extreme weather conditions, that is, in locations where they have a number of advantages over traditional agriculture (N. Didenko et al., 2021; D.L. Friedrich, 2021; G.G. Panova et al., 2023). The main advantages of artificial climate facilities include the possibility of year-round production regardless of the season and weather conditions; high quality, and closeness to the consumer. Many researchers also note a higher yield of marketable products per 1 m2 due to the use of multi-level growing systems, as well as resource savings due to the applying of modern hydroponic and aeroponic growing technologies and closed cycles (C.E. Wong et al., 2020; N. Engler et al., 2021; K. Al-Kodmany, 2024). The choice of plants for production in the CEA is determined primarily by profitability; therefore, currently there are mainly fast-growing crops with a compact habit (leafy vegetables, spicy and aromatic plants, microgreens). At the same time, there is a need to expand the range of products and breed new varieties intended for controlled growing conditions (K.M. Folta, 2019; M. SharathKumar, 2020; C.E. Wong et al., 2020; A. Dsouza et al., 2023). The main object of research in CEA is now the light environment, since most important processes in plants depend on it: photosynthesis, growth and morphogenesis, biochemical composition, accumulation of valuable metabolites, and, ultimately, optimization of cultivation technologies, resource use efficiency and production profitability (A. Dsouza et al., 2023). This article considers the role of the spectral composition of light, intensity and uniformity of irradiation, photoperiod in the plant growth and metabolism, after that, it assesses the influence of each of such components on the yield and quality of plant products. It is shown that by varying the spectral composition of light, it is possible to control the plant architectonics, and regulate the accumulation of primary and secondary metabolites (G.C. Modarelli et al., 2022; K. Zhang et al., 2023; K. Rosniza et al., 2023). The genetically determined differences in the requirements of a number of crops for the composition of the light environment are reflected, including a discussion of the possibility of the existence of varietal specificity in the reaction of accessions within a crop to the formed growing conditions. The technologies and crops applied in CEA are also discussed; the latest results in the field of breeding program for the light conditions are briefly reflected, and prospects for further research are indicated.