Multispectral phyto-irradiator

Abstract

FIELD: closed-type plant growing.SUBSTANCE: invention can be used for growing plants, including microgreens, in phytotrons and growboxes. The multispectral phyto-irradiator comprises from 1 to M groups of LEDs (1), from 1 to M main drivers (2), from 1 to M temperature sensors (3), a port controller (6), a memory unit (7) and a central controller (8), the first outputs of which are connected to the inputs of the corresponding main drivers (2). The first input of the port controller is bidirectional and is the input-output of the device, with M>N, where N is the number of monochrome components in the spectrum of the multispectral phyto-irradiator. In addition, a local bus (9), from 1 to M keys (4) and from 1 to M additional drivers (5) are introduced into it, in which the set current value is more than twice the set current value in the main drivers (2) and the outputs of which are connected to the second inputs of the corresponding keys (4), the outputs of which are connected to the inputs of the corresponding groups of LEDs (1). The outputs of the main drivers (2) are connected to the first inputs of the corresponding keys (4), the control inputs of which are connected to the corresponding control outputs of the central controller (8), the second outputs of which are connected to the inputs of the corresponding additional drivers (5). The information inputs and outputs of the memory unit (7), central controller (8), port controller (6) and temperature sensors (3) are connected to the local bus (9).EFFECT: expansion of the functional capabilities of the multispectral phyto-irradiator by growing plants with an increased content of antioxidant compounds, as well as the expansion of its scope of application by its use in individual phytotrons and growboxes.1 cl, 3 dwg

Description

[0001] The invention relates to closed-type plant growing and can be used for growing plants (including microgreens) in phytotrons and growboxes.

[0002] A multispectral phyto-irradiator is known [1 - Russian Federation Patent No. 2719773, IPC: A01G 9 / 20 Method for creating an optimal light environment for plants grown in closed soil and a LED lighting system implementing this method (variants)], containing N groups of LEDs and N drivers for controlling the intensity of LED radiation, implemented on the basis of controlled current sources.

[0003] The disadvantages of the multispectral phyto-irradiator [1] are as follows.

[0004] Firstly, the multispectral phyto-irradiator [1] has low reliability because it contains N LED groups, where N exactly corresponds to the number of monochrome components of the optimal spectrum. This design obviously results in low reliability of the multispectral phyto-irradiator in terms of coping with possible LED group failures, since with this design, one group of corresponding LEDs is responsible for each monochrome component of the photon flux in the spectrum, without any duplication. Thus, the failure of one LED group (e.g., red) leads to the disappearance of the corresponding monochrome component in the spectrum of the multispectral phyto-irradiator (e.g., red).Despite the possible presence of natural sunlight, this may be unacceptable if, during this phase of ontogenesis, the plant requires a deliberate increase in photon irradiance (illumination) in this particular range of wavelengths (for example, red light).

[0005] Secondly, the known multispectral phyto-irradiator [1] is unable to operate autonomously without an external data collection and control platform, which includes a computer. This limits the scope of application of the known LED phyto-irradiator, making it unsuitable for widespread use in home phytotrons and growboxes.

[0006] Here and further in the description text, the tested term “photon flux”, measured in μmol / s, will be used along with the term “light intensity”, which reveals its physical meaning, and the tested term “photon irradiance”, measured in μmol / (s⋅m 2), will be used along with the term "illumination" that reveals its physical meaning [2 - GOST 58461-2019 "Illumination of plants in protected ground structures. Terms and definitions"]. At the same time, we note that, in accordance with GOST R 58461-2019 [2], ultraviolet radiation A (UV-A) is radiation in the wavelength range from 315 nm to 400 nm; photosynthetically active radiation (PAR) is radiation in the range from 400 nm to 700 nm; the "blue" region of PAR (blue light) is radiation in the wavelength range from 400 nm to 500 nm; the "green" region of PAR (green light) is radiation in the range from 500 nm to 600 nm; the "red" region of PAR (red light) is radiation in the range from 600 nm to 700 nm; Far red light is radiation in the range from 700 nm to 800 nm.

[0007] Also known is a multispectral phyto-irradiator [3 - Russian Federation Patent No. 2804620, IPC: A01G 9 / 26 System for forming a light environment for plants grown in closed ground], containing M groups of light-emitting diodes, M drivers for controlling the intensity of light-emitting diodes implemented on the basis of controlled current sources, M current meters, K port controllers, a central controller and a memory unit, the first outputs of the K port controllers are connected to the corresponding inputs of the central controller, the input of which is connected to the output of the memory unit, the input of which is connected to the output of the central controller, the first outputs of which are connected to the inputs of the corresponding drivers for controlling the intensity of light-emitting diodes, the outputs of which are connected to the inputs of the corresponding current meters, the first outputs of which are connected to the inputs of the corresponding groups of light-emitting diodes, the second outputs of the current meters are connected to the inputs of the central controller.

[0008] The well-known multispectral phyto-irradiator [3] features high-precision reproduction of the optimal spectrum, since it contains a greater number of LED groups, M, than the number of emitted monochrome components, N, in the total spectrum. This minimizes the possibility of the complete disappearance of any of the monochrome components in the total spectrum in the event of failure of one of the LED groups. Furthermore, unlike its analogue [1], the well-known multispectral phyto-irradiator [3], thanks to its built-in central controller and memory unit, is capable of autonomous operation, requiring no external computer. This makes it suitable for widespread use in home phytotrons and growboxes.

[0009] However, the known multispectral phyto-irradiator [3] has inherent shortcomings, which include its low reliability and limited functional capabilities. The low reliability of the known multispectral phyto-irradiator [3] is due to the lack of technical means for promptly measuring the temperature of each of the M groups of LEDs during operation for the purpose of possible redistribution of radiation intensity tasks (in the event of overheating of a certain group of LEDs) to other groups of LEDs of the same wavelength. Moreover, such a capability for the timely detection and counteraction of overheating of groups of LEDs, as will be shown below, is a necessary condition for the implementation of a mode of enhanced biosynthesis of antioxidant compounds important for humans, such as carotenoids and anthocyanins, in cultivated plants.Accordingly, the impossibility of ensuring the cultivation of plants with an increased content of AOC determines the limited functionality of the known multispectral phyto-irradiator [3].

[0010] The closest in technical essence to the claimed multispectral phyto-irradiator is the multispectral phyto-irradiator selected as a prototype [4 - Russian Federation Patent No. 2831187, IPC: A01G 9 / 20, A01G 9 / 26, A01G 7 / 04 Multispectral phyto-irradiator], containing from 1 to M groups of light-emitting diodes, from 1 to M drivers implemented on the basis of controlled current sources for controlling the intensity of radiation of the groups of light-emitting diodes, from 1 to M current meters, four port controllers, a central controller, from 1 to M temperature sensors, a switch, an analog-to-digital converter, a clock generator, a binary counter and a memory unit, the first outputs of the four port controllers are connected to the corresponding inputs of the central controller, the input of which is connected to the output of the memory unit, the input of which is connected to the output of the central controller, the first outputs of which are connected to the inputs of the corresponding drivers for controlling the intensity of radiation of LED groups,the outputs of which are connected to the inputs of the corresponding current meters, the first outputs of which are connected to the inputs of the corresponding groups of LEDs, the second outputs of the current meters are connected to the inputs of the central controller, the first outputs of all four port controllers and the first four inputs of the central controller are bidirectional, the second input of each of the four port controllers is bidirectional and is an input-output of the device, the outputs of the temperature sensors are connected to the information inputs of the switch, the output of which is connected to the input of the analog-to-digital converter, the output of which is connected to the input of the central controller, the control output of which is connected to the control input of the switch, the output of the binary counter is connected to the input of the central controller, the output of the clock generator is connected to the clock inputs of the central controller, the memory unit, the binary counter, the analog-to-digital converter and all four port controllers,in this case M > N, where N is the number of monochrome components in the spectrum of the multispectral phyto-irradiator.

[0011] The multispectral phyto-irradiator prototype [4] can implement various algorithms of photon irradiance (illumination) changing over time and wavelength range.

[0012] The disadvantages of the prototype device [4] are its limited functionality and scope of application.

[0013] The limited functionality of the prototype device [4] is due to its inability to implement a stressful light radiation mode for the purpose of enhanced biosynthesis of AOS in grown plants, that is, the inability to grow plants with an increased AOS content.

[0014] The prototype device's inability to implement stress light emission mode is determined by the following. Stress light emission, as will be demonstrated below, is only possible with excessive photon irradiance (illumination) of plants, which must be at least twice the photon irradiance (illumination) level used for their normal cultivation. Only at photon irradiance (illumination) levels more than twice the normal level for plants does the plant photosynthetic apparatus (PAP) fail to cope with the incoming photon flow, which causes stress in the plant. The photon flow, in turn, is generated by LED clusters with corresponding drivers included in the prototype device.Because the cost of multispectral phyto-irradiators is always kept to the lowest possible level, multispectral phyto-irradiators do not include "sleeping" LED groups with their own drivers (especially not in double the number of the main ones), which are not used in the main mode and are activated only in stress mode to generate additional photon irradiance. In principle, existing LED groups could be used to generate stress light emission, provided they operate in pulsed mode with a peak current more than twice the maximum current of the LED groups during normal continuous operation. However, the prototype device lacks the necessary technical means to implement this operating mode.

[0015] In particular, as will be shown below, the drivers present in the prototype device provide long-term (hours and days) operation of LED groups with currents not exceeding the maximum continuous current of the LEDs specified in the passport (for practical reasons, the technological reserve is from 80% to 90% of the maximum continuous current) and, accordingly, fundamentally cannot provide the operating mode of LED groups with a doubled value of photon flux, that is, with a doubled value of current.

[0016] Thus, the inability to implement the stress light emission mode determines the narrow functionality of the prototype device [4].

[0017] The limited scope of application of the prototype device [4] is determined by the following factors. The presence of four port controllers in the multispectral phyto-irradiator prototype, each connected to a central controller, allows for the connection of multispectral phyto-irradiators into a network of arbitrary topology, which is important for large industrial greenhouses with complex architectures. Furthermore, a clock generator, binary counter, and 1 to M current meters ensure the ability to maintain a preset lighting program for long periods (over several months, without rebooting) during plant cultivation.

[0018] However, such hardware redundancy (four port controllers, a clock generator, a binary counter, and 1 to M current meters) makes the multispectral phyto-irradiator prototype [4] extremely expensive, labor-intensive to set up, and difficult to operate when applied to the task of growing plants (including microgreens) in individual phytotrons and growboxes for daily consumption. Thus, the second drawback of the multispectral phyto-irradiator prototype [4] is its narrow scope of application, due to the impracticality of its use in individual phytotrons and growboxes (primarily for growing microgreens).

[0019] The technical problem that the proposed invention is aimed at solving is the cultivation of plants with an increased content of AOS (carotenoids and anthocyanins) using a multispectral phyto-irradiator in individual phytotrons and growboxes (primarily for growing microgreens).

[0020] To solve the technical problem, a multispectral phyto-irradiator is proposed, containing from 1 to M groups of LEDs, from 1 to M main drivers, from 1 to M temperature sensors, a port controller, a memory unit and a central controller, the first outputs of which are connected to the inputs of the corresponding main drivers, the first input of the port controller is bidirectional and is the input-output of the device, while M> N, where N is the number of monochrome components in the spectrum of the multispectral phyto-irradiator.

[0021] According to the invention, a local bus, from 1 to M keys and from 1 to M additional drivers are introduced into it, the outputs of which are connected to the second inputs of the corresponding keys, the outputs of which are connected to the inputs of the corresponding groups of LEDs, the outputs of the main drivers are connected to the first inputs of the corresponding keys, the control inputs of which are connected to the corresponding control outputs of the central controller, the second outputs of which are connected to the inputs of the corresponding additional drivers, the information inputs and outputs of the memory unit, the central controller, the port controller and the temperature sensors are connected to the local bus.

[0022] The combination of distinctive features and properties of the proposed multispectral phyto-irradiator are not known from the literature, therefore it meets the criteria of novelty and inventive step.

[0023] The technical result of the invention is the expansion of the functional capabilities of the multispectral phyto-irradiator due to the cultivation of plants with an increased content of AOS, as well as the expansion of its field of application due to the possibility of its use in individual phytotrons and growboxes (primarily for the cultivation of microgreens).

[0024] The multispectral phyto-irradiator is illustrated in Fig. 1, Fig. 2 and Fig. 3.

[0025] Figure 1 shows the structural diagram of a multispectral phyto-irradiator.

[0026] Figure 2 shows the principle of regulating the photon flux using pulse-width modulation (PWM). Figure 2 illustrates the fact that, regardless of the required average photon flux, the LED group 1 is controlled by the corresponding main driver 2 with a current that has the maximum possible value.

[0027] Fig. 3 shows the relationship between the photon irradiance levels (and the relationship between the corresponding photon flux levels) in two operating modes of the multispectral phyto-irradiator.

[0028] The multispectral phyto-irradiator contains (Fig. 1): from 1 to M groups of LEDs 1, from 1 to M main drivers 2, from 1 to M temperature sensors 3, from 1 to M keys 4, from 1 to M additional drivers 5, a port controller 6, a memory unit 7, a central controller 8 and a local bus 9, where M > N, where N is the number of monochrome components in the spectrum of the multispectral phyto-irradiator.

[0029] The first outputs of the central controller 8 are connected to the inputs of the corresponding main drivers 2, the first input of the port controller 6 is bidirectional and is the input-output of the device, the outputs of the additional drivers 5 are connected to the second inputs of the corresponding keys 4, the outputs of which are connected to the inputs of the corresponding groups of LEDs 1, the outputs of the main drivers 2 are connected to the first inputs of the corresponding keys 4, the control inputs of which are connected to the corresponding control outputs of the central controller 8, the second outputs of which are connected to the inputs of the corresponding additional drivers 5, the information inputs-outputs of the memory unit 7, the central controller 8, the port controller 6 and the temperature sensors 3 are connected to the local bus 9.

[0030] The main drivers 2 and additional drivers 5 are based on controlled current sources and use the traditional control method for LED light sources using pulse-width modulation (PWM).

[0031] Temperature sensors 3 are digital, transmitting the measured temperature in the form of a code via local bus 9 to the central controller 8. Structurally, all M temperature sensors 3 in the housing of the multispectral phyto-irradiator are located next to the corresponding M groups of LEDs 1 so that each of the temperature sensors 3 measures the temperature of the corresponding group of LEDs 1.

[0032] Local Bus 9 is an asynchronous address and data bus. Local Bus 9 can implement 1-Wire, SPI, I2C, and other protocols.

[0033] Keys 4, based on signals from the control outputs of the central controller 8, can transmit signals from their first or second inputs to their output, or provide a zero signal at their output.

[0034] The multispectral phyto-irradiator can operate in two modes: the normal plant growing mode and the stress light mode, which provides enhanced biosynthesis and accumulation of AOS in plants.

[0035] We'll begin our discussion of the multispectral phyto-irradiator's operation with the standard plant cultivation mode. In this mode, operating scenarios—that is, photon irradiance (illuminance) parameters or corresponding photon flux (light intensity) values ​​for each wavelength range—are loaded into memory unit 7 via port controller 6, from where they are transmitted to central controller 8 via local bus 9. Data can be loaded via port controller 6 via various interfaces, such as a USB interface from an external flash drive. This same interface can be used to read information about the actual state of LED groups 1 during previous operating scenarios, including the temperature of LED groups 1 during operation, allowing for optimization of subsequent operating scenarios.

[0036] The central controller 8 sets the operating mode of the main drivers 2 through its first outputs. In this operating mode, the keys 4 are in such a position that the signals from the outputs of the main drivers 2 through the first inputs of the keys 4 are fed to the inputs of the corresponding groups of LEDs 1, which determines the value of their photon flux (light intensity).

[0037] If the plant lighting scenarios assume changes in the values ​​of their photon irradiance over time, the required current values ​​of photon irradiance are sent via local bus 9 from memory unit 7 to central controller 8, which sets new values ​​of photon flux (light intensity) of the corresponding groups of LEDs 1 according to the algorithm described above. For example, to simulate the spectrum of natural solar radiation changing during the day, central controller 8 should change the value of the total photon irradiance and the ratio between the spectral components in the same way as described in the work [5 - Parkhomenko N.G., Kosogor A.A., Degtyarev S.V., Knyazkin D.G., Myasoedov E.A. Conceptual approaches to substantiating the composition of the spectrum of LED phyto-irradiators / / Greenhouses of Russia, 2024, No. 3, pp. 26-31].

[0038] Temperature sensors 3, located in the housing of the multispectral phyto-irradiator next to the corresponding groups of LEDs 1, measure the temperature of the corresponding group of LEDs 1 and transmit the measurement results via the local bus 9 to the central controller 8. At the same time, unlike the prototype [4], temperature sensors 3 do not measure the temperature continuously, but only after receiving a corresponding request via the local bus 9 from the central controller 8. This allows for maximizing the energy efficiency of the device, which is important for home and office applications.

[0039] It should also be noted that, unlike the prototype, port controller 6 and memory unit 7 do not use signals from the clock generator, but interact with the central controller 8 (using the built-in clock generator) via local bus 9 in asynchronous mode, which also increases the energy efficiency of the device. Furthermore, in comparison with the prototype [4], the clock generator and binary counter, which were required in the prototype [4] to ensure operation during multi-month continuous experiments, where reboots (restarts) of the device are unacceptable, have been excluded from the multispectral phyto-irradiator circuit. This also simplifies the device, increases its energy efficiency and, accordingly, ensures an expansion of its scope of application due to operation in home and office conditions.

[0040] Let's consider the stressful light radiation regime, which ensures enhanced biosynthesis and accumulation of AOS in plants.

[0041] To achieve elevated levels of AOCs, such as carotenoids and anthocyanins, in cultivated plants, the proposed multispectral phyto-irradiator utilizes a specific procedure for light activation (induction) of dosed stress in the plant photosynthetic apparatus while simultaneously minimizing photodamage (burns) to the outer leaf tissues. This procedure for inducing stressful light exposure to plants has conflicting requirements. On the one hand, such a procedure must occur quickly enough to minimize the likelihood of photodamage to plants. On the other hand, such a procedure must increase the AOC content in the plant within an acceptable waiting time before harvesting. Therefore, it is necessary to use higher photon flux levels (compared to the standard mode), which maximize the risk of photodamage to plants.Finally, the feasibility of implementing such a procedure in a multispectral phyto-irradiator should not lead to excessive complexity or increased cost. This means that it should be performed using the same components used in the primary mode (with possible additional components). It is known that the main cost of a multispectral phyto-irradiator comes from the LED arrays with heat sinks. In the best multispectral phyto-irradiators, the LED arrays provide a photon flux ranging from the lower limit of UVA radiation to the upper limit of far-red light (i.e., from 315 nm to 800 nm), with redundancy for each LED array.Considering that the circuit designs of multispectral phyto-irradiators for home and office use are carefully optimized based on the “efficiency / cost” criterion, the LED groups of such multispectral phyto-irradiators do not contain “reserves” that are not used in normal mode and can therefore be used in the stress light emission mode.

[0042] Thus, the non-trivial task is to implement a stress light emission mode (which leads to a rapid increase in the AOC content in grown plants) without using additional LED groups.

[0043] As previously mentioned, the main drivers 2, which utilize PWM modulation, are used to control the photon flux (luminescence intensity) of LED groups 1. PWM modulation involves controlling LED group 1 by varying the PWM pulse duration (Fig. 2) while maintaining a constant set current, which is close to the maximum current permitted by the LED manufacturer.

[0044] Let's consider the principle of PWM modulation shown in Fig. 2. The diagrams on the left side of Fig. 2 correspond to the case of hypothetical analog control of the photon flux (light intensity). It is clear from the diagrams on the left half of Fig. 2 that the photon flux value numerically corresponds to the current through the LEDs (up to a coefficient). For example, 10%, 50%, or 90% of the photon flux are provided, respectively, by 10%, 50%, or 90% of the current through the LEDs.

[0045] The diagrams on the right side of Fig. 2 correspond to the case of controlling the photon flux (light intensity) using PWM modulation. The same time-averaged photon flux (light intensity) values ​​as in the left diagrams (10%, 50%, or 90%) are obtained in this case as a result of a different control method, which is fundamentally pulse-based, namely, a corresponding change in the duration of the control pulse (which corresponds to a photon flux of 100%) over a time interval called the PWM period. In the diagrams on the right side of Fig. 2, these durations occupy 10%, 50%, or 90% of the PWM period duration, respectively. It is important to note that, regardless of the average photon flux value (10%, 50%, or 90%), the LED current with the maximum possible (for this case) value of 100% is used to achieve it.

[0046] Thus, despite the short duration of stressful light exposure, the use of the main drivers 2 for the implementation of the stressful light emission mode is impossible (since it will not lead to an excessive, excess flow of photons), which predetermines a non-trivial solution, which consists in the short-term connection of additional drivers 5 (Fig. 1) with an increased set current.

[0047] Due to the absence of additional drivers 5 in the prototype device [4], it is unable to operate under stressful light conditions and, consequently, does not enhance the biosynthesis of AOS, i.e., carotenoids and anthocyanins. This is due to the fact that carotenoids and anthocyanins are formed especially actively in plants under various stress conditions, and most effectively under light stress associated with excessive photon irradiation.

[0048] Let us provide a theoretical justification for the procedure implemented in the claimed device for initiating enhanced biosynthesis of carotenoids and anthocyanins through dosed light stress.

[0049] During their life, plants experience various types of abiotic (factors of the inanimate environment) and biotic (factors of the living environment) stress [6 - Lichtenthaler N.K. The Stress Concept in Plants: An Introduction / / Annals New York Academy of Sciences, 1998, Volume 851, pp.187-198], [7 - Plant and Stress. Lecture Course / Ekaterinburg: Ural State University, 2008, 267 p], [8 - Zagoskina N.V., Nazarenko L.V. Reactive Oxygen Forms and the Antioxidant System of Plants / / Bulletin of Moscow State Pedagogical Univ. Series: Natural Sciences, 2016, No. 2, pp. 9-23].

[0050] Abiotic stressors are divided into physical and chemical. Physical stressors include: high and low light; high and low temperatures; mechanical stress; moisture deficiency or excess; and elevated radiation levels. Among chemical factors that can cause stress, the most common are: salts and xenobiotics (gases, pesticides, industrial waste, heavy metals).

[0051] Biotic stressors are typically represented by pathogens: fungi, bacteria, viruses, etc.

[0052] It should be especially noted that regardless of the cause of stress, the most dangerous processes for the plant’s life are activated, associated with reactive oxygen species (ROS) [7], [8], [9 - Poleskaya O.G. Plant cell and reactive oxygen species, Moscow: KDU, 2007, 139 p.].

[0053] The term ROS refers to oxygen species with extremely high reactivity that can oxidize virtually all classes of biological molecules - proteins, membrane lipids, DNA molecules, etc. ROS include singlet oxygen 1 O2, hydroxyl radical HO*, superoxide anion radical O2 - hydroperoxide radical HO2 * hydrogen peroxide H2O2. In normally functioning cells, the ROS content is maintained at a low level, since special enzymatic systems are busy eliminating them [7], [8], [9]. Under any stressful conditions, the ROS content in cells begins to increase rapidly, turning into oxidative stress.

[0054] In particular, singlet oxygen molecules 1O2 can trigger apoptosis processes, i.e. programmed cell death [10 - Vargas F. Et al. Photoinduced Apoptosis by Photosensitizer Drugs - in: Frontiers in Cell Apoptosis Research / edited by Erlich SR, New York, Nova Biomedical Books, 2007, 228 p.], [11 - Martusevich AA Molecular and cellular mechanisms of action of singlet oxygen on biosystems / / Modern technologies in medicine, 2012, No. 2, pp. 128-134].

[0055] The hydroxyl radical HO is considered a very strong oxidizing agent. * This radical is incapable of intracellular migration, as it immediately reacts with biological molecules. It not only initiates membrane destruction and protein degradation by interacting with the residues of many amino acids, but also disrupts carbohydrate bridges between nucleotides, breaking DNA and RNA chains. It is believed that such processes may be factors in natural mutagenesis [7].

[0056] The damaging effect of active oxygen species in plants is counteracted by the antioxidant defense system. In the work [12 - Pradedova E.V. Classification of the antioxidant defense system as a basis for rational organization of experimental studies of oxidative stress in plants / / Plant Physiology, 2011, Vol. 58, No. 2, pp. 177-185] it was shown that all antioxidant compounds can be divided into compounds of indirect (mediated) action and compounds of direct (targeted) action

[12] . Antioxidant compounds of indirect action are capable of reducing the consequences of free radical oxidation at the plant level as a whole, but are ineffective at the cellular level

[12] .Naturally, direct-acting antioxidant compounds appear to be more effective, among which are polyenes (substances with several unsaturated bonds that are easily oxidized, binding ROS and thereby protecting other biomolecules from oxidation) and proton donors (that is, substances with a mobile hydrogen atom that can intercept free radicals)

[12] .

[0057] Polyenes include carotenoids and retinoids.

[0058] Proton donors include phenols (flavonoids, tocopherols, phenol and naphthol derivatives, catechins, etc.), nitrogen-containing heterocyclic substances (including melatonin), and thiols.

[0059] The classes of these compounds are extremely extensive (for example, more than 6,500 varieties of flavonoids alone are currently known). Therefore, when describing the claimed device, typical compounds will include carotenoids (as substances with several unsaturated bonds) and anthocyanins (as proton donors). However, the essence of the proposed device and its scope of application are not limited to carotenoids and anthocyanins, but include any antioxidant compounds found in plants. Therefore, whenever carotenoids and anthocyanins (as the most important antioxidant compounds) are mentioned throughout the description of the claimed invention, antioxidant compounds should be understood in the broad sense of the term.

[0060] The antioxidant properties of carotenoids and anthocyanins in plants are described in many sources, for example [13 - Maslova TG et al. Functions of carotenoids in the leaves of higher plants (Review) / / Journal of General Biology, 2020, Vol. 81, No. 4, pp. 297-310], [14 - Demmig-Adams B. et al. Linking the xanthophyll cycle with thermal energy dissipation / / Photosynthesis Research, 2003, No. 76, pp. 73-80], [15 - Demmig-Adams B. et al. In vivo functions of carotenoid in higer plants / / The FASEB Journal, 1996, Volume 10, Issue 4, pp. 403-412], [16 - Cappellini F. et al. Anthocyanins: From Mechanisms of Regulation in Plants to Health Benefits in Foods / / Frontiers in Plant Science, 2021, Volume 12, October], [17 - Sarma AD et al. Anthocyanin-DNA copigmentation complex: mutual protection against oxidative damage / / Phytochemistry, 1999, No. 52, pp.1313 - 1318], [18 - Lorenc-Kukula K. et al.Ectopic Expression of Anthocyanin 5-O-Glucosyltransferase in Potato Tuber Causes Increased Resistance to Bacteria / / Journal of Agricultural and Food Chemistry, 2004, December, Volume 53, Issue 2, pp.272-281], [19 - Gould KS, Lister C. Flavonoid functions in plants - in: Flavonoids: chemistry, biochemistry and applications, Boca Raton, CRC Press LLC, 2006, pp.397-441], [20 - Makarevich AM et al. Functions and properties of anthocyanins in plant materials / / Proceedings of BSU, 2010, Volume 4, Issue 2, pp. 1-11], [21 - Jaakola L. et al. Activation of flavonoid biosynthesis by solar radiation in bilberry (Vaccinium myrtillus L.) leaves / / Planta, 2004, Volume 218, pp.721 - 728], [22 - Neill SO et al. Antioxidant activities of red versus green leaves in Elatostema rugosum / / Plant, Cell and Environment, 2002, Vol.25, No. 4, pp.539 - 547], etc.

[0061] At the same time, from the point of view of carotenoids and anthocyanins as substances found in the human diet, the following can be noted.

[0062] Carotenoids are natural organic pigments colored red, orange, or yellow. Based on their chemical composition, carotenoids can be divided into two large groups: carotenes (including beta-carotene and lycopene) and xanthophylls (including lutein and zeaxanthin). Carotenoids function as antioxidants in the human body. Carotenoids are provitamins A, metabolic precursors of vitamin A; beta-carotene is the most important of them. Both vitamin A and beta-carotene, being powerful antioxidants, are used in the prevention and treatment of cancer, in particular, by preventing tumor recurrence after surgery. Both vitamin A and beta-carotene protect brain cell membranes from the destructive effects of free radicals, with beta-carotene neutralizing the most dangerous types of free radicals: oxygen radicals and polyunsaturated acid radicals.The antioxidant action of beta-carotene plays an important role in the prevention of heart and arterial diseases, it has a protective effect in patients with angina, and also increases the level of “good” cholesterol (HDL) in the blood.

[0063] Another carotenoid, lycopene, protects against atherosclerosis by preventing oxidation and accumulation of low-density cholesterol on artery walls. It is also the most potent carotenoid in terms of cancer protection, particularly against breast, endometrial, and prostate cancer [23 - Massaretto IL Recovering Tomato Landraces to Simultaneously Improve Fruit Yield and Nutritional Quality Against Salt Stress / / Frontiers in Plant Science, 2018, November, vol. 9]. Lycopene also helps strengthen bones, protect against atherosclerosis and cardiovascular disease, kidney disease, and helps maintain skin elasticity and strong hair.

[0064] Lutein and zeaxanthin are the main carotenoids that protect the eyes: they help prevent cataracts and reduce the risk of macular degeneration (the most important organ of vision), which is the cause of blindness in one in three cases.

[0065] Carotenoids themselves are non-toxic, and their formation into vitamin A is enzymatically limited. Therefore, when consuming foods containing carotenoids, an overdose of vitamin A does not occur, and therefore the upper tolerable intake level has not been established [24 - Nilova L.P., Potoroko I.Yu. Carotenoids in plant food systems / / Bulletin of the South Ural State University, series "Food and Biotechnology", 2021, Vol. 9, No. 4, pp. 54-69].

[0066] Anthocyanins are plant polyphenolic compounds important for humans. The following types of biological activity have been proven for anthocyanins: anticarcinogenic properties; protection against cardiovascular diseases; reduction of capillary fragility and permeability; anti-inflammatory effect; antimicrobial activity; improved visual acuity and restoration of rhodopsin [25 - Pisarev D.I. et al. Biological activity of plant polyphenols. Prospects for the use of anthocyanins in medical practice. Scientific news. Series "Medicine. Pharmacy", 2012, No. 10, Issue 18 / 2, pp. 17-24].

[0067] The work [26 - Koldayev V.M., Kropotov A.V. Anthocyanins in Practical Medicine / / Pacific Medical Journal, 2021, No. 3, pp. 24-28] notes that the medical effects of anthocyanins are mainly associated with the inactivation of free radicals due to their antioxidant properties, as well as their ability to modulate intracellular mitochondrial antioxidant systems. In addition, anthocyanins activate tumor suppressor genes, induce apoptosis of cancer cells, restore genomic DNA and increase its stability

[26] .

[0068] Anthocyanins also help to reduce inflammatory reactions in the intestines when consuming excess fats and carbohydrates, as well as for the treatment and prevention of diabetes [27 - Chehri A. Phytochemical and pharmacological anti-diabetic properties of bilberries (Vaccinium myrtillus), recommendations for future studies / / Primary Care Diabetes, 2022, vol. 16, iss. 1, pp.27 - 33].

[0069] Thus, from a medical point of view, the common properties of carotenoids and anthocyanins are their antioxidant properties, which can be used to prevent cancer. The prospects of using carotenoids to create drugs with antioxidant, antimutagenic, and anticarcinogenic properties are discussed in the work of employees of the Research Institute of Experimental Diagnostics and Therapy of Tumors [28 - Shashkina M.Ya. et al. Carotenoids as a basis for creating therapeutic and prophylactic agents / / Russian Biotherapeutic Journal, 2009, Vol. 8, No. 4, pp. 91-97]. Carotenoids and anthocyanins are not formed in the human body, so a person satisfies 100% of his or her need for these compounds through plant foods

[28] . At the same time, a low level of carotenoids in food and human blood plasma is an indicator of cancer risk [29 - Jeong NH et al. Plasma carotenoids, retinal and tocopherol levels and risk of ovarian cancer / / Acta Obsest Ginecol. Scand., 2009, Volume 88, pp.457 - 462]. Some aspects of the use of anthocyanins in medicinal plants are discussed in the work [30 - Maslennikov P.V. et al. Content of anthocyanin and carotenoid pigments in medicinal plants / / Electronic journal "Vestnik MGOU", www.evestnik-mgou.ru, 2013, No. 1, pp. 1-14].

[0070] So, as shown above, carotenoids and anthocyanins have pronounced antioxidant properties in both plants and the human body. Moreover, increasing the carotenoid and anthocyanin content in plants ensures a longer shelf life of the harvested crop.

[0071] Enhanced and targeted production of carotenoids and anthocyanins in plants can be induced by one of the biotic or abiotic stressors discussed previously. The challenge is to select a stressor that satisfies partially conflicting requirements. On the one hand, such a stressor must be sufficiently effective to ensure that its effect (in the form of increased carotenoid and anthocyanin content) manifests itself within the shortest possible time. The duration of such exposure should be significantly shorter than the standard plant growth period. On the other hand, the stressor must be of such a physical nature that its effect can be easily reversed (deactivated).Finally, the technical support for stress impact must allow its implementation not only in large greenhouses and agro-industrial production facilities, but also in significantly smaller formats, right down to individual home phytotrons and growboxes.

[0072] Due to the long activation time and practically unpredictable deactivation time, it is not advisable to use abiotic stressors associated with water (including excess water or lack of water), chemicals, etc., as well as any types of biotic stressors (fungi, bacteria, insects, weeds, etc.) in the claimed multispectral phyto-irradiator.

[0073] Of all the possible stressors for use in the proposed multispectral phyto-irradiator, one was selected that can be quickly activated and deactivated, even in small form factors (such as phytotrons and growboxes): light stress. A measured application of light stress leads to increased levels of antioxidant compounds (carotenoids and anthocyanins) in the plant being grown. Moreover, the short duration of this stress exposure has virtually no effect on the production cycles of plant products.

[0074] The operation of the proposed multispectral phyto-irradiator in the stress light mode, which ensures enhanced biosynthesis and accumulation of AOS in plants (upon activation of dosed stress in the photosynthetic apparatus of the grown plants), will be considered using the example of growing microgreens, although it should be kept in mind that the algorithms and logic of interaction of the elements included in the multispectral phyto-irradiator used in the proposed multispectral phyto-irradiator remain unchanged when growing any plants in protected or closed soil conditions.

[0075] We will also consider growing microgreens in the most common, everyday conditions of a home, office, small cafe, kindergarten, etc. Microgreens of any crop are extremely unpretentious and develop to a state where they can be eaten, even with minimal light and a suboptimal light composition. For example, there is data on the development of microgreens in low-light conditions of about 100 μmol / (cm) 2 ) [31 - Olonin I.Yu. Justification of the parameters and operating modes of the lighting system when growing microgreens without natural light / / Bulletin of the Nizhny Novgorod State Agrotechnical University, 2024, No. 1, pp. 91 - 102].

[0076] In accordance with the recommendations of seed producers (sellers), microgreen seeds are soaked (with the exception of seeds of certain plant species) and placed in trays on a special substrate, which can be peat media, coconut substrate, jute fiber, cotton fibers, basalt and linen mats and other materials [32 - How to grow microgreens: recommendations for vegetable growers / / https: / / www.gavrishprof.ru / info / publications].

[0077] When germinating seeds, standard blackout periods recommended by seed producers are used. For example, for watercress, this period can be 2-3 days, for peas and mustard, it can be 3-4 days, and for Swiss chard and coriander, it can be 5-6 days [33 - Blackout: Which microgreen seeds need darkening during planting and for how long / / https: / / www.growmicro.ru / blog]. After germination, microgreens reach the cotyledon stage, where cotyledons are the first pair of embryonic leaves emerging from the seed. At this stage, the plant receives nutrition from the stored energy of the seeds. Cotyledons are usually thick and fleshy and serve as the initial source of nutrients for seed germination and plant development.

[0078] After the initial dark period (blackout), the trays with microgreens sprouts are placed under the claimed multispectral phyto-irradiator. In this case, after completing the cotyledon stage, the microgreens enter the true leaf stage. True leaves are the second set of leaves to develop, demonstrating the characteristics of the mature leaves of the plant. At this stage, the flavor, texture, and color of the microgreens begin to appear. Typically, the true leaf stage lasts from 7 to 14 days, depending on the variety and the desired level of maturity [34 - Burak L.Ch., Karbanovich V.I. Antioxidant activity of microgreens, potential for use. Review of the subject field / / Scientific Review, 2023, No. 4, pp. 58-70]. Determining the optimal harvest time is crucial for microgreens to achieve maximum flavor and nutrient content.The ideal time to harvest microgreens is when they have fully developed their first true leaves, but have not yet reached full maturity. Waiting too long to harvest can cause the leaves to become tougher and the flavor to deteriorate

[34] .

[0079] On average, it can be considered that the consumption of microgreens as food occurs approximately from the 7th to the 21st day of its cultivation [35 - Shakleina M.N. et al. Assessment of the content of vitamins in microgreens of several types of cultivated plants / / Chemistry of plant raw materials, 2022, No. 2, pp. 165-172].

[0080] Thus, it should be considered that microgreens are consumed during their formation stage, before reaching full maturity, followed by growth. During this time period (approximately from day 7 to day 21 of cultivation), the photosynthetic apparatus in microgreens is not yet fully developed and is still developing, making it possible to use this circumstance as a specific factor for increasing the AOC content of microgreens.

[0081] As is clear from the above, the AOC content level in microgreens can be significantly increased when exposed to various stress factors

[34] . This is confirmed by a study that showed that exposure to stress factors increased the AOC content level in mung bean and lentil microgreens [36 - Priti et al. Diversity in Phytochemical Composition, Antioxidant Capacities, and Nutrient Contents Among Mungbean and Lentil Microgreens When Grown at Plain-Altitude Region (Delhi) and High-Altitude Region (Leh-Ladakh), India / / Frontiers in Plant Science, 2021, Volume 12, July, article 710812].

[0082] Similar conclusions about the increase in the level of AOC content as a result of stress factors were made in studies devoted to increasing the antioxidant activity of basil and beet microgreens [37 - Brazaityte A. et al. Effect of supplemental UV-A irradiation in solid-state lighting on the growth and phytochemical content of microgreens / / International Agrophysics, 2015, No. 29, pp. 13 - 22], as well as lentil microgreens [38 - Swieca M. et al. Elicitation and precursor feeding as tools for the improvement of the phenolic content and antioxidant activity of lentil sprouts / / Food Chemistry, 2014, Volume 161, pp. 288 - 295], [39 - Swieca M. et al. Antioxidant potential of fresh and stored lentil sprouts affected by elicitation with temperature stresses / / International Journal of Food Science & Technology, Volume 49, Issue 8, pp.1781 - 1961].

[0083] During the microgreen stage of plant development, the most sensitive (i.e., responsive to stress) of all plant functional mechanisms is the developing photosynthetic apparatus, which is determined by the rapid rate of photon-electron reactions. The actual interaction of photons and electrons occurs within picoseconds.

[0084] According to this, in order to quickly and guarantee the introduction of the photosynthetic apparatus of microgreens into a state of stress, it is necessary to perform a sudden increase in the photon irradiation of the plant to the level significantly exceeding the level of photon irradiation of microgreens which ensures its normal, ordinary growth. Naturally, such a level should be selected taking into account the individual characteristics of the crops being grown. It is known that microgreen growth is ensured by photon irradiance values from 100 μmol / (s⋅m 2)

[31] up to values ​​of the order of 1000 μmol / (s⋅m 2 )

[36] . In accordance with the specified range of values most recommended stress values should be selected based on more than double the excess that is, in the approximate range exceeding values ​​from 200 μmol / (s⋅m 2 ) up to 2000 µmol / (s⋅m 2 ).

[0085] Some of the consumers of microgreens grown using the proposed multispectral irradiator are office and industrial workers. Based on a typical mealtime of 40 to 60 minutes, the recommended exposure time for microgreens under stress light before consumption is approximately 30 minutes.

[0086] According to this, well before the expected time of microgreen consumption (time At, which is selected to be approximately 30 minutes), the consumer enters information into port controller 6 that the microgreens should be ready for consumption (cutting) within time Δt. Accordingly, central controller 8 switches to stress light mode, which ensures enhanced biosynthesis and accumulation of AOS in the plants.

[0087] During the time Δt, the following processes occur in the multispectral phyto-irradiator. The central controller 8, using signals at its control outputs, switches 4 into a state where signals from their second inputs are fed to their outputs. Thus, in this mode, LED groups 1 are connected to the outputs of additional drivers 5, rather than to the outputs of the main drivers 2 (as occurs in normal plant cultivation mode).

[0088] In each of the wavelength ranges used, the additional drivers 5 have the fundamental difference from the main drivers 2 in that the current value set in the additional drivers 5 is more than twice the current value set in the main drivers 2. This allows, when using the additional drivers 5, to obtain a photon flux (light intensity) from the corresponding groups of LEDs 1, the value of which is more than twice the value of the photon flux (light intensity) obtained from the same groups of LEDs 1 when using the main drivers 2.

[0089] Let's explain this in more detail. Let's assume that the current value set in the 2 main drivers is approximately 80% to 90% of the maximum rated forward current. Maximum rated forward current value Specified in the technical documentation for LEDs, the current determines the forward current through the LED. The manufacturer guarantees the specified luminous parameters of the light source, i.e., its long-term, trouble-free operation. For practical reasons (ensuring trouble-free, continuous operation of LEDs for hours and days), the actual current in the main drivers 2, as already mentioned, is set within 80% to 90% of the maximum rated forward current.

[0090] In additional 5 drivers, the current value is set to be equal to the peak forward current value Peak forward current value It is also indicated in the technical documentation for LEDs and determines the maximum (limit) current that the LED crystal can withstand for a short time, that is, in pulse mode.

[0091] As an example, we provide the corresponding data on current values for the GT-3535 series LEDs from GMKJ (China) [40 - www.szgmled.com]. For the blue GT-3535P420-1CC0-GM45M LED with a wavelength of 420 nm, the value is 700 mA, the value is 1400 mA. For the GT-3535P380-1CC0-GM45M UV-A LED with a wavelength of 380 nm, the value is 700 mA, the value is 1400 mA. It is clear that the value exceeds the value

[0092] For Cree XLamp LEDs from Cree (USA), it was experimentally established that with a pulsating current with a frequency of 1 kHz and a fill factor of 50%, the value of the peak forward current can be safely set at 200% of the maximum rated forward current . For pulsating current and duty cycle less than 10%, the peak forward current value is can be safely set at 300% of the maximum rated forward current [41 - Skripnichenko A. Pulse power supply of Cree XLamp LEDs with increased current / / Semiconductor lighting technology, 2011, No. 1, pp. 16-19].

[0093] Similar data confirming the possibility of safely (without LED failure) obtaining high values ​​of peak photon fluxes (light intensities) in pulsed LED operating modes are given in [42 - LEDs. LED Microsensor NT Catalog], [43 - Savkova T.N. et al. Study of energy and optical characteristics of high-power LEDs under pulsed excitation / / Bulletin of P.O. Sukhoi State Technical University, 2015, No. 3, pp. 78-85].

[0094] According to this, the main driver 2 is designed so that it can output a maximum current value of 80% to 90% of the maximum rated forward current value continuous mode for hours and days. Additional driver 5 is designed so that it is capable of delivering a maximum current value of approximately 200% to 300% of the maximum rated forward current. in pulsed mode for tens of minutes. Based on this, it can be concluded that the maximum instantaneous photon flux (in pulsed mode) emitted by LED group 1 when operating from additional driver 5 is more than two to three times greater than the maximum photon flux (in continuous mode) emitted by the same LED group 1 when operating from primary driver 2.

[0095] The relationship between the photon irradiance levels (and the corresponding photon flux levels) in two operating modes of the multispectral phyto-irradiator can be estimated from Fig. 3. Fig. 3 shows the dependence of the photon flux level (light intensity) on time for a certain group of LEDs 1 (Fig. 1), for example, blue light. Let us assume that in the normal plant growing mode, the main driver 2 controlling this group of LEDs 1 produces its maximum possible current, which is 80% of the maximum rated forward current this group of LEDs 1, where - a parameter specified in the technical documentation for LEDs and determined by the design and manufacturing technology of the LEDs. This current value through LED groups 1 corresponds to a certain photon flux level (e.g., 80 μmol / s) and the corresponding photon irradiance level of the plants. in this range of wavelengths (for example, blue light).

[0096] At the moment of time Based on signals from central controller 8, the multispectral phyto-irradiator switches to stress light emission mode as described above. Now, the additional driver 5 controlling LED group 1 outputs a current that, in pulses, equals 300% of the maximum rated forward current. of this group of LEDs 1. This value of current through the group of LEDs 1 corresponds to a certain level of photon flux (for example, 300 μmol / s) and the corresponding level of photon irradiance of plants in pulses of light in this range of wavelengths (for example, blue light).

[0097] Based on this, the level of photon irradiation of plants during light pulses in the stress light radiation mode (highlighted in Fig. 3 by shading) more than three times exceeds the level of photon irradiation of plants during the normal plant growing regime, which provides a stressful light effect on the PSA of plants, which causes increased AOS biosynthesis in plants as a response.

[0098] The stress light emission mode continues for the set time interval Δt. During this time interval Δt, additional drivers 5 (Fig. 1) and switches 4, in response to signals from the central controller 8, provide a pulsed mode of operation of LED groups 1 as shown in Fig. 3. The duration of light pulses in this mode can be selected from 1 ms to 100 μs. Despite the presence of a local bus 9 (Fig. 1) in the multispectral phyto-irradiator, control of switches 4, main drivers 2 and additional drivers 5 from the central controller 8 occurs via dedicated communication lines, which insures against unpredictable delays in command execution, since such delays are unacceptable when switching the operating modes of LED groups 1 and the operating modes of the entire multispectral phyto-irradiator.

[0099] The current temperature of LED group 1 is measured by temperature sensors 3 and transmitted via local bus 9 to the central controller 8. Taking into account the possible overheating of LED group 1 in pulse mode, if the current temperature of a certain LED group 1 approaches an unacceptably high value, the central controller 8, via the corresponding additional driver 5, can reduce the maximum pulse current of this LED group 1, which even in this case remains greater than the current of this LED group in the normal plant growing mode. In this case, reducing the pulse current passing through LED group 1 from the maximum value (providing a photon flux of 300 μmol / s) by 1.5 times will still maintain the stress value of the photon flux (about 200 μmol / s), but will effectively reduce the temperature of LED group 1.

[0100] The fact that, in the stress light mode, pulses of darkness are present in the generated light environment alongside pulses of photon flux and corresponding pulses of photon irradiance does not affect the effectiveness of the stress light mode. The fact is that in plants, the interaction of photons and electrons occurs within a few picoseconds, so even a single light pulse (Fig. 3) lasting several hundred microseconds is more than a million times longer than the time interval during which the plant's photosynthetic apparatus receives an excess photon flux and concludes that light stress is occurring.

[0101] In the event that in a particular embodiment the main drivers 2 and the additional drivers 5 change the value of the photon flux of the corresponding groups of LEDs 1 with some variations in relation to the PWM algorithm shown in Fig. 2, this does not cancel the main principle of the claimed device, namely: the main drivers 2 set the constant operating mode of the groups of LEDs 1; the additional drivers 5 set the pulsed operating mode of the groups of LEDs 1 over the time interval At with a current more than twice exceeding the current in the constant operating mode; the choice between the drivers (main or additional) and the implementation of the pulsed operating mode occurs using the keys 4 according to the signals from the controller 8.

[0102] At the end of the time interval At (in our example, 30 minutes after the time ) the tray with microgreens is removed from under the LED emitter, and the microgreens are ready to be cut and eaten.

[0103] The same procedure applies when growing plants other than microgreens. It is advisable to follow the following recommendations: Photon irradiance of grown plants under stressful light conditions must be at least twice the photon irradiance level at which normal plant cultivation occurs. For example, for microgreens, photon irradiance in stress irradiation mode cannot be less than 200 μmol / (m⋅s) 2 ) (which corresponds to a twofold excess of the minimum photon irradiance permissible for normal development), and cannot be more than 2000 μmol / (m⋅s) (since this will lead to thermal damage to the leaves of microgreens and the loss of their marketable appearance).

[0104] For microgreens, the time interval value Δt is chosen as a compromise solution between the acceptable time for preparing microgreens for food (under conditions of a short break, etc.) and the time at which the antioxidant activity of microgreens increases to a sufficient level. Naturally, the larger the value chosen the smaller the time interval Δt should be chosen.

[0105] The spectral composition of the light used to stress the plant plays a significant role in stressful light irradiation. For example, microgreens, unlike many other plant products, are subject to strict requirements regarding their appearance, as they are often not only a food component but also serve an aesthetic function, serving as a decoration for dishes. Therefore, microgreens cannot tolerate a faded appearance, wilted and lifeless leaves, leaf burn, etc. Therefore, the light used to stress microgreens is subject to conflicting requirements: on the one hand, such light must be sufficiently intense to achieve a guaranteed result (i.e., stressing the microgreens) within a relatively short time before consumption.On the other hand, this light radiation should minimally alter the microgreens' typical, attractive appearance, such as their vibrant color and firm leaves. Similar requirements apply not only to microgreens but to other plants as well.

[0106] This contradiction can be resolved as follows. It is known that the ability of plant leaves to absorb light depends very significantly on the wavelength of the incident light. For a number of plants, the corresponding dependencies are given in [44 - McCree KJ The action spectrum, absorptance and quantum yield of photosynthesis in crop plants / / Agricultural Meteorology, 1971, Vol. 9, pp. 191-216], [45 - Liu J., Iersel MW Photosythetic Physiology of Blue, Green, and Red Light: Light Intensity Effects and Underlying Mechanisms / / Frontiers in Plant Science, 2021, Volume 12, March]. From the analysis of the dependence of the degree of light absorption in a plant leaf over the wavelength range, it follows that stressful light radiation should have limitations on the flux of photons (intensity) with wavelengths in a certain part of the range in the vicinity of a wavelength of 550 nm.Excessive photon flux in this wavelength range (around 550 nm) will generate excess energy (dissipated as heat) in the deep structures of leaves, where heat exchange with the external environment is naturally impaired. This will lead to leaf damage in the form of burns, with a corresponding loss of flavor and marketability.

[0107] The situation with the inadmissibility of an excess flow of photons in the green part of the spectrum for the task of increasing the antioxidant activity of grown microgreens is also determined by the following factor. It is known that the main part of photoprotective chemical compounds is located in the surface structures of the leaf, which are most susceptible to the influence of unfavorable factors [46 - Solovchenko A.E., Merzlyak M.N. Screening of visible and UV radiation as a mechanism of photoprotection in plants / / Plant Physiology, 2008, Vol. 55, No. 6, pp. 803 - 822]. Accordingly, stress-inducing light radiation should cause the corresponding reactions (synthesis of antioxidant compounds) precisely in the surface, and not in the deep structures of the leaf, and therefore this light radiation should not contain an excess flow of photons in the green light region.

[0108] Based on the dependence of the absorption capacity of plant leaves on the wavelength of incident light

[44] ,

[45] , it can be assumed that light with wavelengths in the range from 510 nm to 590 nm can be used to create stress-inducing radiation only under the condition that the values ​​of photon irradiance (or, accordingly, photon flux) are not very high.

[0109] It is advisable to use the spectral composition of natural solar radiation on a cloudless afternoon on June 22—the summer solstice in mid-latitude Russia—as the base spectrum for creating stress conditions for microgreens. A detailed description of this spectrum and the relationships between the intensities of its components by wavelength is provided in [5]. It should be noted that the spectrum of this radiation (noon on June 22) is the most uncomfortable for plants, therefore, its use in the proposed multispectral phyto-irradiator will require a minimum application time, which will allow for rapid stressful conditions for microgreens while minimizing the risk of leaf burns.

[0110] Taking into account the above considerations, the stress-inducing light radiation with the most optimized spectral composition may contain spectral components (by wavelength) in the following proportions of photon irradiance (or, accordingly, photon flux): ultraviolet radiation UVA from 315 nm to 400 nm - from 2% to 13%; blue light from 400 nm to 500 nm - from 25% to 70%, green light from 500 nm to 510 nm - from 7% to 15%, green light from 590 nm to 600 nm - from 7% to 18%, red light from 600 nm to 700 nm - from 30% to 65%; far red light from 700 nm to 710 nm - from 10% to 25%.

[0111] Naturally, the specific composition of spectral components should be set so that the sum of the percentages of spectral components of all wavelength ranges is 100%.

[0112] For the practical implementation of the above spectrum, it is possible not to activate the group of green LEDs when generating stress radiation, if you select for use in a multispectral phyto-irradiator a group of blue LEDs and a group of red LEDs such that their non-zero levels of photon flux in the green light region create the required minimum photon flux (light intensity) in the region from 510 nm to 590 nm.

[0113] The ratios between the spectral components in the stress-inducing radiation spectrum shall be established in accordance with the above percentage ratios between the different components by wavelength, and the numerical sum of the percentages of the different components shall be 100%. The best composition of light radiation (optimal composition) is found for each plant species separately, including modeling using the Kubelka-Munk theory, which describes the propagation of light of different wavelengths in a plant leaf, taking into account its pigment composition [47 - Kusuma P., Bugbee B. Improving the Predictive Value of Phytochrome Photoequilibrium: Consideration of Spectral Distirtion Within a Leaf / / Frontiers in Plant Science, 2021, Volume 12, May], [48 - Kokhanovsky A.A. Physical interpretation and accuracy of the Kubelka-Munk theory / / Journal of Physics D: Applied Physics, 2007, Volume 40, March, pp.2210-2216], [49 - Vogelmann T.C.Light within the plant, in Photomorphogenesis in Plants, eds RE Kendrick and GHM Kronenberg, Netherlands: Springer, 1994, pp.491-535], [50 - Kazarinova-Fukshansky N. et al. Distortion of action spectrum in photomorphogenesis by light gradients within the plant tissue / / Photochemistry and Photobiology, 1985, Volume 41, Issue 6, May, pp.689 - 702], [51 - Holmes MG, Fukshansky L. Phytochrome photoequilibria in green leaves under polychromatic radiation: a theoretical approach / / Plant, Cell & Environment, 1979, Volume 2, Issue 1, March, pp.59 - 65].

[0114] The authors of the proposed device for optimizing the spectrum parameters in the stress light radiation mode used the programs "Heliotrope-SFC" and "Heliotrope-KIU", which allow for the assessment of the energy load of the plant's photosynthetic apparatus, taking into account the variability of the main spectrum parameters of the multispectral phyto-irradiator of the "Demeter" type.

[0115] The use of radiation with spectra calculated using the Heliotrope-SFC and Heliotrope-KIU programs made it possible to obtain an increase in the AOC content in the grown arugula and mustard microgreens in the manufactured sample of the multispectral phyto-irradiator, which is at least 1.5 times higher than the same indicator in traditional cultivation.

[0116] Thus, the claimed multispectral phyto-irradiator has expanded functionality due to the possibility of growing plants with an increased content of AOS, as well as an expanded scope of application due to the possibility of its use in individual phytotrons and growboxes (primarily for growing microgreens).

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