Light source for cultivating plants and method for cultivating plants

Abstract

The present invention relates to a light source for cultivating plants and a method for cultivating plants. The method for cultivating plants according to one embodiment of the present invention includes a step of planting germinated plant seeds and a step of cultivating the plants, which includes subjecting the plants to a light treatment. In the plant cultivating step, a main light treatment in which main light is provided to the plants and a dark treatment in which the provision of main light to the plants is stopped may be repeated. The main light may have at least two peak wavelengths in the visible light wavelength range. In addition, the light intensity of the main light may be 92 PPFD (μmol / m 2 / s) and less than 198 PPFD.

Description

[Technical field]

[0001] The present invention relates to a light source for cultivating plants and a method for cultivating plants. [Background technology]

[0002] Plants use light energy to synthesize organic matter from carbon dioxide and water through photosynthesis. Plants use the chemical energy of the organic matter obtained through photosynthesis as nutrients for growth and other purposes.

[0003] One of the most problematic physiological disorders in the cultivation of leafy and fruit vegetables is tip burn, a phenomenon in which the leaf tissue of the plant mysteriously dies. When tip burn occurs, the leaf margins of the plant collapse or turn brown, and eventually the leaves die.

[0004] In order to reduce the occurrence of tip burn in plants, methods for controlling the plant cultivation environment, such as nutrient solution concentration and temperature, have been mainly studied.

[0005] However, temperature control requires a lot of cost and energy because the temperature must be controlled throughout the space in which the plants are grown, and nutrient solution concentration control requires equipment for analyzing each ion in the nutrient solution.

[0006] As described above, both the temperature control method and the nutrient solution concentration control method require a lot of cost, and it can be said that there is still a lack of a practical solution for reducing the occurrence of tip burn.

[0007] The information disclosed in this Background is intended to provide an understanding of the background of the inventive concept only and may include information that does not constitute prior art. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a light source for cultivating plants and a method for cultivating plants that can minimize the occurrence of tip burn in plants.

[0009] Another object of the present invention is to provide a light source for cultivating plants and a method for cultivating plants that can increase the content of functional substances in plants while minimizing the occurrence of tip burn. [Means for solving the problem]

[0010] According to one embodiment of the present invention, there is provided a method for cultivating a plant, the method including planting a germinated seed of the plant and cultivating the plant, the method including subjecting the plant to a light treatment.

[0011] In the stage where the plant is cultivated, a main light treatment in which main light is provided to the plant and a dark treatment in which the light treatment to the plant is interrupted may be repeatedly performed.

[0012] The main light may have at least two peak wavelengths in the visible light wavelength band. The amount of light of the main light may be 92 PPFD (μmol / m 2 / s) but less than 198 PPFD.

[0013] For example, the plant may be lettuce.

[0014] The primary light may have a first peak wavelength and a second peak wavelength, and the luminous intensity of the first peak wavelength may be equal to the luminous intensity of the second peak wavelength.

[0015] The first peak wavelength may be included in a red light wavelength band, and the second peak wavelength may be included in a blue light wavelength band.

[0016] During the stage in which the plant is cultivated, the time period during which the main light treatment is carried out may be 16 hours per day, and the time period during which the dark treatment is carried out may be 8 hours per day.

[0017] The step of cultivating the plant may further include providing the plant with supplemental light in the ultraviolet wavelength range.

[0018] The step of providing supplementary light may be performed during the final main light processing.

[0019] In the step of providing auxiliary light, an auxiliary light treatment in which auxiliary light is provided to the plant and an auxiliary light blocking treatment in which auxiliary light is not provided to the plant may be repeatedly performed.

[0020] In the step of processing the fill light, the fill light processing and the fill light blocking may each be performed for one hour.

[0021] The auxiliary light may have a third peak wavelength that is included in the UVB wavelength band.

[0022] The luminous intensity of the third peak wavelength may be less than the luminous intensity of the peak wavelength of the visible light wavelength band.

[0023] According to another embodiment of the present invention, the optical fiber has at least two peak wavelengths in the visible light wavelength range and is 92 PPFD (μmol / m 2 The present invention provides a light source for plant cultivation, the light source including a main light source that emits main light toward a plant at an amount of light greater than 1000 nm / s and less than 198 PPFD.

[0024] The main light source can repeatedly perform a main light treatment in which the main light is provided to the plant, and a dark treatment in which the provision of the main light to the plant is stopped.

[0025] For example, the plant may be lettuce.

[0026] The primary light may have a first peak wavelength and a second peak wavelength, and the luminous intensity of the first peak wavelength may be equal to the luminous intensity of the second peak wavelength.

[0027] The first peak wavelength may be included in a red light wavelength band, and the second peak wavelength may be included in a blue light wavelength band.

[0028] The time period during which the primary light source performs the primary light treatment may be 16 hours per day, and the time period during which the primary light source performs the dark treatment may be 8 hours per day.

[0029] The light source for plant cultivation may further include an auxiliary light source that emits auxiliary light in the ultraviolet wavelength range to the plant.

[0030] The auxiliary light may be ultraviolet light having a third peak wavelength included in the UVB wavelength band.

[0031] The luminous intensity of the third peak wavelength may be less than the luminous intensity of the peak wavelength of the visible light wavelength band.

[0032] The auxiliary light source can emit the auxiliary light during the final main light processing of the main light source.

[0033] The supplemental light source can repeatedly perform a supplemental light treatment in which supplemental light is provided to the plant, and a supplemental light blocking treatment in which supplemental light is not provided to the plant.

[0034] The auxiliary light source can perform the auxiliary light processing and the auxiliary light blocking for one hour each. Effect of the Invention

[0035] The light source for cultivating a plant and the method for cultivating a plant according to the embodiment of the present invention can provide light in the visible light wavelength band to the plant when cultivating the plant, thereby minimizing the occurrence of chip burn.

[0036] In addition, the light source for cultivating plants and the method for cultivating plants according to the embodiments of the present invention can provide light in the ultraviolet wavelength band during any period during which light in the visible light wavelength band is provided to the plant, thereby minimizing the occurrence of tip burn and increasing the content of functional materials in the plant.

[0037] The accompanying drawings, which are included to provide a further understanding of the invention, and which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the detailed description, serve to explain the concepts of the invention. [Brief description of the drawings]

[0038] [Figure 1] FIG. 1 shows the light spectrum of the main light source used in Experiment 1. [Diagram 2] FIG. 1 shows the light spectrum of the main light source used in Experiment 1. [Diagram 3] FIG. 1 shows the light spectrum of the main light source used in Experiment 1. [Figure 4] FIG. 1 shows the light spectrum of the main light source used in Experiment 1. [Figure 5a] This is a photograph of some of the lettuce included in each experimental group in Experiment 1 to compare the growth of each experimental group. [Figure 5b] This is a photograph of some of the lettuce included in each experimental group in Experiment 1 to compare the growth of each experimental group. [Figure 5c] This is a photograph of some of the lettuce included in each experimental group in Experiment 1 to compare the growth of each experimental group. [Figure 5d] This is a photograph of some of the lettuce included in each experimental group in Experiment 1 to compare the growth of each experimental group. [Figure 6] 1 is a graph showing the average number of leaves of each lettuce included in each experimental group in Experiment 1. [Figure 7] 1 is a graph showing the average live weight of each experimental group in Experiment 1. [Figure 8] 1 is a graph showing the chlorophyll content in each experimental group in Experiment 1. [Figure 9] 1 is a graph showing the anthocyanin content in each experimental group in Experiment 1. [Figure 10] 1 is a graph showing the flavonol content in each experimental group in Experiment 1. [Figure 11a]FIG. 1 shows the number of individuals that developed tip burn in each experimental group in Experiment 1. [Figure 11b] FIG. 1 shows the number of individuals that developed tip burn in each experimental group in Experiment 1. [Figure 11c] FIG. 1 shows the number of individuals that developed tip burn in each experimental group in Experiment 1. [Figure 11d] FIG. 1 shows the number of individuals that developed tip burn in each experimental group in Experiment 1. [Figure 12] FIG. 13 shows the spectrum of the mixed light of the main light and the fill light used in Experiment 2. [Figure 13] 1 is a graph showing the chlorophyll content in experiment 2. [Figure 14] 1 is a graph showing the flavonol content in Experiment 2. [Figure 15] 1 is a graph showing the anthocyanin content in Experiment 2. [Figure 16] This figure shows the spectrum of a primary light source that emits visible light of 198 PPFD or more. [Figure 17] FIG. 13 is a diagram showing the spectrum of light obtained by mixing main light of 198 PPFD or more and auxiliary light having a peak P3 in the wavelength range of 280 nm to 290 nm. [Figure 18] FIG. 13 is a diagram showing the spectrum of light obtained by mixing main light of 198 PPFD or more and auxiliary light having a peak P4 in the wavelength range of 305 nm to 315 nm. [Figure 19] 13 is a diagram showing the spectrum of light obtained by mixing main light of 198 PPFD or more, auxiliary light having a peak P3 in the wavelength range of 280 nm to 290 nm, and auxiliary light having a peak P4 in the wavelength range of 305 nm to 315 nm. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of various embodiments or implementations of the present invention. As used herein, the terms "embodiment" and "implementation" are interchangeable terms that refer to non-limiting examples of devices or methods that use one or more of the inventive concepts disclosed herein. However, it will be apparent that the various embodiments may be practiced without these specific details, or with one or more equivalent arrangements. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the various embodiments. Additionally, the various embodiments may differ from one another, but are not necessarily exclusive. For example, the specific shapes, configurations, and characteristics of the embodiments may be used or embodied in other embodiments without departing from the scope of the inventive concepts.

[0040] Unless otherwise indicated, it should be understood that the illustrated embodiments provide illustrative features of varying detail in some of the ways in which the inventive concept may be practically embodied, and thus, unless otherwise indicated, the features, components, modules, layers, films, panels, regions and / or aspects, etc. (hereinafter individually or collectively referred to as "elements") of the various embodiments may be combined, separated, interchanged and / or rearranged in different ways without departing from the scope of the inventive concept.

[0041] The use of cross-hatching and / or shading in the accompanying drawings is generally provided to clarify boundaries between adjacent elements. Thus, the presence of cross-hatching or shading as well as the elements do not imply or indicate any preference or requirement for specific materials, material quantities, dimensions, proportions, commonalities between the illustrated elements, and / or any other characteristics, attributes, quantities, etc., unless expressly stated. Also, in the accompanying drawings, the size and relative size of elements may be exaggerated for clarity and / or illustrative purposes. When the embodiments may be embodied in different forms, certain steps may be performed in a different order than described. For example, two consecutively described steps may be performed substantially simultaneously or in the reverse order of the described order. Also, the same reference numerals refer to the same elements.

[0042] When an element, such as a layer, is referred to as being "on", "connected to" or "bonded to" another element or layer, the element may be directly on, connected to or bonded to the other element or layer, or there may be intervening elements or layers. However, when an element or layer is referred to as being "directly on", "connected to" or "bonded directly to" another element or layer, there is no intervening element or layer. For this reason, the term "connected" can refer to a physical, electrical and / or fluidic connection with or without an intervening element. Also, the D1-axis, D2-axis and D3-axis are not limited to the three axes of a Cartesian coordinate system, such as the x-, y- and z-axes, but may be interpreted in a broader sense. For example, the D1-axis, D2-axis and D3-axis may be perpendicular to each other, or may indicate different directions that are not perpendicular to each other. For purposes of the present invention, "one or more of X, Y, and Z" and "one or more selected from the group consisting of X, Y, and Z" may be interpreted as X alone, Y alone, Z alone, or any combination of two or more of X, Y, and Z, such as, for example, XYZ, XYY, YZ, and ZZ. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0043] Terms such as "first" and "second" may be used herein to describe various types of elements, but these elements should not be limited by these terms. These terms are used to distinguish one element from another. Thus, a first element discussed below may be named a second element without departing from the teachings of the present invention.

[0044] Spatially relative terms such as "below," "below," "lower," "on," "upper," "upper," "higher," "side" (e.g., as in "sidewall"), and the like, may be used herein for descriptive purposes and to describe the relationship of one element to other elements depicted in the figures. Spatially relative terms are intended to include different orientations of the device during use, operation, and / or manufacture in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as "below" another element or feature may be oriented "above" the other element or feature. Thus, the exemplary term "below" can include both above and below orientations. Also, the device may be oriented differently (e.g., rotated 90 degrees or oriented in other orientations), and thus the spatially relative predicates used herein may be interpreted accordingly.

[0045] The terminology used herein is for the purpose of describing particular embodiments and is not limiting. The singular form used herein includes the plural form unless the context clearly dictates otherwise. Additionally, the terms "comprise" and / or "include" used herein specify the presence of a referenced feature, integer, step, operation, element, component, and / or group thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Additionally, the terms "substantially," "about," and other similar terms used herein are used as terms of approximation, not terms of degree, and thus are used to account for inherent deviations in measured, calculated, and / or provided values ​​that may be recognized by those of ordinary skill in the art.

[0046] Various embodiments are described below with reference to cross-sectional and / or exploded illustrations that are schematic illustrations of idealized embodiments and / or intermediate structures. As such, variations from the shapes of the illustrations may be expected as a result, for example, of manufacturing techniques and / or tolerances. As such, the embodiments disclosed herein should not be construed as necessarily limited to the shape of the particular illustrated region, but should be construed to include, for example, deviations in shape that arise due to manufacturing. In this manner, the regions illustrated in the drawings may be schematic in nature and the shapes of the regions may not reflect the actual shape of the region of a device, and as such, are not necessarily intended to be in a limiting sense.

[0047] As is conventional in the art, some embodiments may be illustrated and described in the accompanying drawings in terms of functional blocks, units, and / or modules. Those skilled in the art will appreciate that each such block, unit, and / or module may be physically embodied by electronic (or optical) circuits, such as logic circuits, discrete components, microprocessors, wiring circuits, memory elements, wiring connections, etc., formed using semiconductor-based fabrication techniques or other fabrication techniques. When the blocks, units, and / or modules are embodied by a microprocessor or other similar hardware, they may be programmed and controlled using software (e.g., microcode) to perform various functions discussed herein, and may be selectively driven by firmware and / or software. Each block, unit, and / or module may also be embodied by dedicated hardware, or as a combination of dedicated hardware for performing some functions and processors (e.g., one or more programmed processors and associated circuitry) for performing other functions. Each block, unit, and / or module of some embodiments may also be physically separated into two or more interacting and separate blocks, units, and / or modules without departing from the scope of the present invention. Furthermore, the blocks, units and / or modules of some of the embodiments may be physically combined into more complex blocks, units and / or modules without departing from the concept of the present invention.

[0048] Unless otherwise defined, all terms used herein (including technical or scientific terms) have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted in an ideal or overly formal manner unless expressly defined herein.

[0049] A plant cultivation light source and a plant cultivation method that can minimize tip burn of plants will be described with reference to drawings and experiments.

[0050] The plant used in the experiments of the present invention is sunny lettuce.

[0051] Disinfected seeds of sunny lettuce were sown on a cultivation sponge and grown using only purified water. After sowing, the seeds were grown in the dark for 3 days and then grown under 69.8 PPFD (μmol / m 2 The seeds were grown and germinated under weak light conditions with a light intensity of 100000 / s. The germinated seeds were planted in a deep flow technique (DFT) cultivation system in which nutrient solution was circulated and supplied, and cultivated for 20 days. The nutrient solution was a diluted Hoagland nutrient solution with an acidity (pH) of 5.5 to 6.5 and an EC of 1.2 mS / cm to 1.3 mS / cm.

[0052] During the 20-day cultivation period, the lettuce was cultivated in an environment with a temperature of 22±1°C and a humidity of 70±5%. Furthermore, during the cultivation period, the lettuce was provided with a dark treatment period of 8 hours and a light treatment period of 16 hours per day. The light treatment is to provide light to the plant, and the dark treatment is to block the light provided to the plant. In this experiment, the main light source that provides light to the plant during the light treatment period may be a light source consisting of an LED. Furthermore, the main light emitted from the main light source and provided to the lettuce is visible light in which red light, white light, and blue light are mixed in a ratio of 11:4:3.

[0053] Experiment 1

[0054] Experiment 1 was an experiment to confirm the effect of the amount of visible light used in growing lettuce on the growth of lettuce, the content of functional substances, and the occurrence of tip burn.

[0055] In experiment 1, multiple lettuce groups were provided with different light exposure environments during the cultivation period in a flooded hydroponic system. That is, the amount of visible light used during the 16-hour light treatment period per day was set differently for each of the multiple lettuce groups. Each of the multiple lettuce groups contained 30 lettuce plants.

[0056] After harvesting the lettuce groups grown under different light intensities, the number of leaves, the number of tipburns, the fresh weight, the chlorophyll content, and the content of functional substances were measured for each group.

[0057] Experimental group 1 was the lettuce group grown at 92 PPFD light, experimental group 2 was the lettuce group grown at 152 PPFD light, experimental group 3 was the lettuce group grown at 198 PPFD light, and experimental group 4 was the lettuce group grown at 268 PPFD light.

[0058] 1 to 4 are diagrams showing the light spectrum of the main light source used in Experiment 1.

[0059] Figure 1 shows the optical spectrum of primary light emitted from a primary light source with an amount of light of 92 PPFD. Figure 2 shows the optical spectrum of primary light emitted from a primary light source with an amount of light of 152 PPFD. Figure 3 shows the optical spectrum of primary light emitted from a primary light source with an amount of light of 198 PPFD. Figure 4 shows the optical spectrum of primary light emitted from a primary light source with an amount of light of 268 PPFD.

[0060] 1 to 4, the primary light emitted from the primary light source has a first peak wavelength P1 at a wavelength of about 450 nm and a second peak wavelength P2 at a wavelength of about 650 nm. The first peak wavelength P1 and the second peak wavelength P2 have the same luminous intensity. That is, in the primary light emitted from the primary light source, the luminous intensity of the red light and the blue light is the same.

[0061] 5 to 11 are diagrams showing the results of Experiment 1.

[0062] Figures 5a to 5d are photographs of some of the lettuce plants in each experimental group for comparing the growth of each experimental group. Figure 6 shows the average number of leaves of each lettuce plant in each experimental group. Figure 7 shows the average fresh weight of each experimental group.

[0063] 5a to 5d, it can be seen that the leaves get larger from experimental group 1 to experimental group 4. It can also be seen that the number of tip burns T increases from experimental group 1 to experimental group 4. In other words, it can be seen that the lettuce grows larger as the amount of light increases, but the occurrence of tip burns also increases.

[0064] Referring to Figure 6, the average number of leaves is 16.60 for experimental group 1, 19.10 for experimental group 2, 21.53 for experimental group 3, and 22.27 for experimental group 4. In other words, the number of leaves tends to increase as the amount of light increases. However, while experimental groups 1, 2, and 3 show significant differences with each other, experimental groups 3 and 4 do not show significant differences with each other.

[0065] Referring to Figure 7, the average fresh weight is 22.83g for experimental group 1, 30.68g for experimental group 2, 32.95g for experimental group 3, and 39.30g for experimental group 4. In other words, the average fresh weight tends to increase as the light intensity increases. However, while experimental group 1 and experimental group 2 show a significant difference, experimental group 2, experimental group 3, and experimental group 4 do not show a significant difference.

[0066] 6 and 7, there is a common significant increase in leaf number and fresh weight between experimental group 1 and experimental group 2. In other words, in order to significantly improve lettuce growth, the amount of light must exceed 92 PPFD.

[0067] Figure 8 shows the chlorophyll content in each experimental group. Figures 9 and 10 show the functional substance content in each experimental group. In detail, Figure 9 shows the anthocyanin content in each experimental group. Also, Figure 10 shows the flavonol content in each experimental group.

[0068] Referring to Figure 8, the chlorophyll content in experimental group 1 was 14.69 mg / m 2 and 16.17 mg / m for experimental group 2. 2and 16.73 mg / m for experimental group 3. 2 and 17.51 ​​mg / m for experimental group 4. 2 In the case of chlorophyll content, experimental group 1 and experimental group 2 show a significant difference from each other, but experimental group 2, experimental group 3, and experimental group 4 do not show a significant difference from each other. In other words, the amount of light must exceed 92 PPFD for a significant increase in the photosynthetic efficiency of lettuce.

[0069] Referring to Figure 9, the anthocyanin content (unit) was 0.28 for experimental group 1, 0.27 for experimental group 2, 0.26 for experimental group 3, and 0.28 for experimental group 4. In other words, the anthocyanin content did not show any significant change even when the light intensity was changed.

[0070] Referring to FIG. 10, the flavonol content (unit) is 0.27 for experimental group 1, 0.28 for experimental group 2, 0.28 for experimental group 3, and 0.38 for experimental group 4. It can be seen that the flavonol content does not change significantly in experimental group 1, experimental group 2, and experimental group 3, but increases in experimental group 4. In other words, it can be seen that there is no significant change in the amount of light between 92 PPFD and 198 PPFD, but at 268 PPFD, it increases significantly compared to 198 PPFD.

[0071] 11a to 11d show the number of individuals with tip burn in each experimental group.

[0072] 11a to 11d, the number of individuals I with tip burn among the 30 lettuce plants included in each experimental group was 2 in experimental group 1, 4 in experimental group 2, 9 in experimental group 3, and 23 in experimental group 4. Here, in experimental groups 1 and 2, one tip burn occurred in each individual with tip burn. However, in experimental group 3, 1 to 6 tip burns were found per individual, and in experimental group 4, 1 to 7 tip burns were found per individual.

[0073] 5 to 11, a light intensity of more than 92 PPFD is required to improve lettuce growth. Also, a light intensity of 92 PPFD or more is required to maintain the content of functional substances, and in particular, a light intensity of more than 198 PPFD is required to increase the content of flavonol. Also, a light intensity of less than 198 PPFD is required to minimize the occurrence of tip burn.

[0074] Therefore, when the amount of light for growing lettuce is greater than 92 PPFD and less than 198 PPFD, lettuce growth, maintenance of functional substance content, and minimization of tip burn can all be satisfied.

[0075] Experiment 2

[0076] Experiment 2 was conducted to confirm the effect of supplementary light source on the growth of lettuce and the change in the content of functional substances during lettuce cultivation.

[0077] In experiment 2, the main light source is a light source that emits visible light, which is the main light irradiated on lettuce for 16 hours per day in a flooded hydroponic cultivation system. The main light source emits an amount of visible light that takes into consideration the growth of lettuce, the content of functional substances, and minimization of the occurrence of tip burn in experiment 1. That is, in experiment 2, the amount of light from the main light source is 125 PPFD, which is greater than the amount of light from 92 PPFD and less than the amount of light from 198 PPFD.

[0078] The primary light emitted from the primary light source has peak wavelengths in the red light wavelength band and the blue light wavelength band, respectively. The detailed spectrum of the primary light emitted from the primary light source can be referred to in FIG.

[0079] The supplemental light source in Experiment 2 was a light source that emitted ultraviolet rays in the UVB wavelength band. The supplemental light source provided ultraviolet rays, which is supplemental light, to the lettuce during the final light treatment period just before the lettuce was harvested. At this time, supplemental light treatment and supplemental light blocking were repeated to prevent the lettuce from being damaged by continuous exposure to the supplemental ultraviolet light. Here, supplemental light treatment refers to providing supplemental light to the lettuce, and supplemental light blocking refers to not providing supplemental light to the lettuce.

[0080] In experiment 2, the auxiliary light source was turned on and off for one hour each. In other words, the lettuce was irradiated with UV light for one hour and then turned off for one hour. The cumulative total amount of UV light irradiated to the lettuce was 4.03 kJ / m 2 It is.

[0081] Figure 12 is a diagram showing the spectrum of the mixed light of the primary light and the auxiliary light used in Experiment 2. Referring to Figure 12, the mixed light of the primary light and the auxiliary light has a first peak wavelength P1 at about 450 nm, a second peak wavelength P2 at about 650 nm, and a third peak wavelength P3 at a wavelength of 290 nm to 320 nm, which is the UVB wavelength band. At this time, the third peak wavelength P3 has a smaller luminous intensity than the first peak wavelength P1 and the second peak wavelength P2.

[0082] In experiment 2, the fresh weight, chlorophyll content, flavonol content, and anthocyanin content of lettuce plants were compared with and without supplemental light during the cultivation period in a submerged hydroponic system.

[0083] The control group was a lettuce group that was light-treated with the main light source during the growing period.

[0084] The experimental group was a lettuce group that was subjected to light treatment with a main light source and a supplementary light source during the cultivation period.

[0085] The experimental results showed that there was no significant difference in fresh weight between the control group and the experimental group. In other words, it is evident that the ultraviolet wavelength band and ultraviolet irradiation amount in Experiment 2 do not inhibit the growth of lettuce.

[0086] 13 to 15 are diagrams showing the experimental results of Experiment 2 with respect to the content of the functional material.

[0087] Figure 13 is a graph showing the chlorophyll content, Figure 14 is a graph showing the flavonol content, and Figure 15 is a graph showing the anthocyanin content.

[0088] Referring to Figure 13, the chlorophyll content in the control group was 17.11 mg / m 2 and 19.81 mg / m for the experimental group. 2 That is, the chlorophyll content in the experimental group increased by 15.8% compared to the control group.

[0089] Referring to Figure 14, the flavonol content (unit) was 0.30 in the control group and 0.47 in the experimental group, i.e., the flavonol content was increased by 56.7% in the experimental group compared to the control group.

[0090] 15, the anthocyanin content (unit) was 0.25 in the control group and 0.30 in the experimental group, i.e., the anthocyanin content was increased by 20.0% in the experimental group compared to the control group.

[0091] Through experiment 2, it was found that ultraviolet light in the UVB wavelength range can increase the content of functional substances in lettuce without reducing its growth.

[0092] Through experiments 1 and 2, it was confirmed that when growing lettuce, using a light source that emits visible light and ultraviolet rays in the UVB wavelength range with an intensity of more than 92 PPFD and less than 198 PPFD increases the content of functional substances without reducing growth, while minimizing the occurrence of tip burn.

[0093] Experiment 3

[0094] In hydroponic cultivation, the roots of plants can receive nutrients quickly through water. If the main light of 198 PPFD or more is provided to the plants, the plants' growth rate increases rapidly due to the fast supply of nutrients and the high main light supply, but the supply of trace elements and other elements necessary for growth is not smooth, which can cause chip burn.

[0095] In the case of sunlight, the light intensity is 198 PPFD or more, so if you use sunlight for hydroponic cultivation, chip burn will occur on the plants.

[0096] Ultraviolet rays act as a stress factor for plants and can suppress plant growth.

[0097] When plants are exposed to visible light of 198 PPFD or more, additional exposure to UVB can suppress excessive plant growth and the chip burn phenomenon that occurs when the plant experiences a rapid increase in growth rate.

[0098] Therefore, in experiment 3, primary light with a light intensity of 198 PPFD or more was provided to the plants while additionally providing UVB as supplemental light.

[0099] When visible light of 198 PPFD or more causes the plant's growth rate to increase dramatically, it is possible to prevent the occurrence of tip burn by providing ultraviolet light at a level that does not damage the plant and regulating the plant's growth rate.

[0100] The light source for plant cultivation in Experiment 3 can include a main light source that emits main light, which is visible light of 198 PPFD or more, and an auxiliary light source that emits auxiliary light, which is UVB.

[0101] Figure 16 shows the spectrum of a primary light source that emits visible light of 198 PPFD or more.

[0102] Referring to FIG. 16, the primary light emitted from the primary light source has a first peak wavelength P1 at a wavelength of about 450 nm and a second peak wavelength P2 at a wavelength of about 650 nm.

[0103] The supplemental light source can provide supplemental light to the plant that is UVB with a peak in the range of 280 nm to 290 nm or a peak in the range of 305 nm to 315 nm.

[0104] For example, a light source for plant cultivation can irradiate a plant with supplementary light of one wavelength band while the plant is being irradiated with main light.

[0105] At this time, the spectrum of light irradiated to the plant is as shown in FIGS.

[0106] FIG. 17 shows the spectrum of light that is a mixture of main light of 198 PPFD or more and auxiliary light having a peak P3 at a wavelength of 280 nm to 290 nm.

[0107] FIG. 18 shows the spectrum of light that is a mixture of main light of 198 PPFD or more and auxiliary light having a peak P4 at a wavelength of 305 nm to 315 nm.

[0108] In addition, the light source for plant cultivation can irradiate the plant with a mixture of light of different wavelength bands while the main light is irradiated to the plant.

[0109] FIG. 19 shows the spectrum of light that is a mixture of main light of 198 PPFD or more, auxiliary light having a peak P3 in the wavelength range of 280 nm to 290 nm, and auxiliary light having a peak P4 in the wavelength range of 305 nm to 315 nm.

[0110] The supplemental light source can also irradiate the plant with supplemental light of different wavelength bands at the same time.

[0111] Alternatively, the supplemental light source can irradiate the plant with supplemental light in the order from light of a high wavelength band to light of a low wavelength band.

[0112] The lower the wavelength of light, the higher the potential energy. The higher the potential energy of light shining on a plant, the higher the risk of damage to the plant.

[0113] Therefore, damage to the plant can be minimized by first irradiating the plant with light having low potential energy to allow the plant to become resistant to the light, and then irradiating the plant with light having high potential energy.

[0114] Therefore, the supplemental light source can irradiate the plant with UVB in the higher wavelength band and then with UVB in the lower wavelength band.

[0115] Thus, through experiment 3, it was found that by using UVB as supplemental light in a hydroponic cultivation system using sunlight, it is possible to improve functional materials while minimizing the occurrence of tip burn and reduced growth.

[0116] While specific embodiments and examples have been described herein, other embodiments and variations will be apparent from such description, and the inventive concept is therefore not limited to such embodiments, but is to be understood as limited to the broader scope of the appended claims and various modifications and equivalent arrangements that will become apparent to those skilled in the art.

Claims

1. The germinated plant seeds are planted; and a step of cultivating the plant by repeatedly performing a main light treatment in which main light is provided to the plant and a dark treatment in which the main light treatment to the plant is interrupted; Including, the primary light has a first peak wavelength and a second peak wavelength in a visible light wavelength band, The amount of light of the main light is 92 PPFD (μmol / m ２ / s) and less than 198 PPFD; The step of cultivating the plant further includes providing the plant with supplemental light in an ultraviolet wavelength range; the auxiliary light is ultraviolet light having a third peak wavelength included in a wavelength range of 280 nm to 290 nm and a fourth peak wavelength included in a wavelength range of 305 nm to 315 nm, the luminous intensity of the third peak wavelength and the fourth peak wavelength is less than the luminous intensity of the first peak wavelength and the second peak wavelength; The plant is lettuce.

2. A plant cultivation method as described in claim 1, wherein the luminous intensity of the first peak wavelength is the same as the luminous intensity of the second peak wavelength.

3. The plant cultivation method according to claim 2 , wherein the first peak wavelength is included in a red light wavelength band, and the second peak wavelength is included in a blue light wavelength band.

4. 2. The plant cultivation method according to claim 1, wherein, in the stage of cultivating the plant, the time period during which the main light treatment is performed is 16 hours per day, and the time period during which the dark treatment is performed is 8 hours per day.

5. The plant cultivation method according to claim 1 , wherein the step of providing supplementary light is performed during the last main light treatment.

6. The plant cultivation method according to claim 1 , wherein, in the step of providing the auxiliary light, a supplementary light treatment in which the auxiliary light is provided to the plant and a supplementary light blocking treatment in which the auxiliary light is not provided to the plant are repeatedly performed.

7. 7. The plant cultivation method according to claim 6, wherein, in the step of providing the supplementary light, the supplementary light treatment and the supplementary light blocking are each performed for one hour.

8. It has a first peak wavelength and a second peak wavelength in the visible light wavelength band, and has a PPFD of 92 (μmol / m ２ / s) and emitting a main light toward the plant with a light amount of main light that is greater than 198 PPFD; an auxiliary light source that emits auxiliary light, the auxiliary light being ultraviolet light having a third peak wavelength included in a wavelength range of 280 nm to 290 nm and a fourth peak wavelength included in a wavelength range of 305 nm to 315 nm, the luminous intensities of the third peak wavelength and the fourth peak wavelength being smaller than the luminous intensities of the first peak wavelength and the second peak wavelength; Including, The main light source repeatedly performs a main light process of providing the main light to the plant and a dark process of interrupting the provision of the main light to the plant, The light source for growing plants, wherein the plant is lettuce.

9. A light source for plant cultivation as described in claim 8, wherein the luminous intensity of the first peak wavelength is the same as the luminous intensity of the second peak wavelength.

10. The light source for plant cultivation according to claim 9 , wherein the first peak wavelength is included in a red light wavelength band, and the second peak wavelength is included in a blue light wavelength band.

11. 9. The light source for plant cultivation according to claim 8, wherein the time during which the main light treatment of the main light source is performed is 16 hours per day, and the time during which the dark treatment is performed is 8 hours per day.

12. The light source for cultivating plants according to claim 8 , wherein the supplementary light source emits the supplementary light while the main light source is performing a final main light treatment.

13. The light source for cultivating a plant according to claim 8 , wherein the supplemental light source repeatedly performs a supplemental light treatment in which supplemental light is provided to the plant and a supplemental light blocking treatment in which supplemental light is not provided to the plant.

14. The light source for cultivating a plant according to claim 13 , wherein the auxiliary light source performs the auxiliary light treatment and the auxiliary light blocking for one hour each.

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