JP2021045049A - Plant cultivation method and plant cultivation system - Google Patents

Abstract

To provide a plant cultivation method and a plant cultivation system for increasing a functional component contained in a plant.SOLUTION: A plant cultivation system comprises: a supply part for supplying liquid to roots of a plant having an edible part; and an irradiation part for irradiating the plant with artificial light, and raises a plant. The supply part supplies liquid with reduced nitrate nitrogen in a nitrate reduction period (4 to 6 days for example) immediately before cropping the plant. The irradiation part continuously irradiates the plant with artificial light in which the intensity of light in a blue wavelength region is stronger than light in a wavelength region of other colors and which entirely has a wavelength region of visible light to show white color, in a light treatment period P3 immediately before cropping the plant.SELECTED DRAWING: Figure 7

Description

The present invention relates to a plant cultivation method and a plant cultivation system for cultivating a plant having an edible portion such as vegetables.

In recent years, lutein has been accumulated in high concentrations in the macula of the human retina together with chitosanfil, and as a functional ingredient useful for protecting the retina from oxidative damage caused by ultraviolet rays and blue light, and for preventing age-related macular degeneration and cataracts. Attention is being paid. Spinach contains more of this lutein than other leafy vegetables.

Lutein is one of the carotenoids that are the constituent pigments of the photosynthetic system. This carotenoid is incorporated into the Large Hadron Collider (LHC) in the photosystem and is involved in the absorption and transfer of light energy. The size and pigment balance of the LHC change under the influence of the growing environment, especially the light environment. It has been reported that the carotenoid content of carotenoids is increased by blue light as a protective action of the photosynthetic control system corresponding to strong light (see, for example, Non-Patent Document 1). This document describes that carotenoids and polyphenols increase by irradiating with light having a light wavelength of 450 nm (blue).

"Importance of Light in Plant Factory Spectrum (Light Wavelength)", Innoplex February 10, 2018, [online], [Search on July 15, 1991], Internet <URL: http: //innoplex.jp/2018/02/10/plantfactory-lighting/>

Lutein is induced and produced by irradiation with blue light or UV light. However, when irradiated with these lights, morphological abnormalities of plants may occur. Therefore, a method for increasing the strengthening component such as lutein by a method other than irradiation with blue light or UV light has been desired.

The plant cultivation method for solving the above problems is a plant cultivation method for growing a plant having an edible portion by irradiating artificial light while supplying a liquid, and in the light treatment period immediately before the harvest of the plant. By continuously irradiating the plant with white artificial light having a light intensity in the blue wavelength region stronger than that in the wavelength region of other colors and having an overall wavelength region of visible light, the plant is continuously irradiated with light. Grow the plant.

The plant cultivation method that solves the above problems is a plant cultivation method in which a plant having an edible portion is grown while supplying a liquid, and nitrate nitrogen of the plant is added during the nitric acid reduction period immediately before the harvest of the plant. The plant is grown by performing a nitric acid reduction treatment to reduce it.

A plant cultivation system that solves the above problems is a system for cultivating the plant, comprising a supply unit that supplies a liquid to the plant having an edible portion and an irradiation unit that irradiates the plant with artificial light. After growing the plant using the culture solution, the supply unit supplies the plant with a liquid that reduces the nitrate nitrogen of the plant during the nitrate reduction period immediately before the harvest of the plant, and the irradiation unit supplies the plant. In the light treatment period immediately before the harvest of the plant, the white artificial light having a stronger light intensity in the blue wavelength region than the light in the wavelength region of other colors and having an overall visible wavelength region was produced. Irradiate the plant continuously.

According to the present invention, it is possible to increase the functional components contained in the plant.

Explanatory drawing explaining the plant cultivation method in Example 1. FIG. Explanatory drawing which shows the spectral distribution of artificial light used in Example 1. FIG. The figure which compares the lutein content by the plant cultivation method in Example 1 with the lutein content of spinach grown by using other artificial light. The figure which compared the lutein content and nitrate nitrogen content by the plant cultivation method in Example 1 with other spinach. Explanatory drawing explaining the plant cultivation method in Example 2. FIG. The figure which shows the lutein content and the nitrate nitrogen content with respect to the number of days which performed the nitric acid reduction treatment in Example 2. FIG. Explanatory drawing explaining the plant cultivation method in Example 3. FIG. It is a figure which compares the value of spinach cultivated by the plant cultivation method in Example 3 with other spinach, (a) is a lutein content, (b) is a nitrate nitrogen content, (c) is a living body weight. .. The figure which shows the result of the taste evaluation in an embodiment.

Hereinafter, a method for cultivating vegetables having an edible portion will be described with reference to FIGS. 1 to 9. In this embodiment, it is assumed that spinach with increased lutein (enhanced component) is cultivated. In this embodiment, the following three methods are used as examples.

(1) A method of cultivating spinach by changing the conditions of artificial light immediately before harvesting (hereinafter referred to as "WB light cultivation method").
(2) Immediately before harvesting, a method of cultivating by executing a nitric acid reduction treatment for reducing nitrate nitrogen (hereinafter referred to as "nitric acid reduction cultivation method").
(3) A method of cultivating by performing both (1) and (2) (hereinafter referred to as "WB photonitric acid reduction cultivation method").

In each example, the culture broth used was set to EC ^{1.44 × 100 mSm -1} and NO _3- N 560 ppm using a nutrient solution-blended fertilizer manufactured by Kaneyama Green Tech. Here, as the nutrient solution compound fertilizer manufactured by Kaneyama Green Tech, the product name "Kaneyama A1", the product name "Kaneyama M5", and the product name "calcium nitrate" are mixed in a composition suitable for spinach cultivation. To use. In addition, the spinach to be cultivated uses a variety called late-drawing summer sky.

(Example 1)
First, (1) the WB light cultivation method will be described with reference to FIGS. 1 to 4.
As shown in FIG. 1, in the growth period P2 of the growth period P1 from planting to harvest, excluding the treatment period immediately before harvesting, the planted spinach is hydroponically grown until it becomes almost harvestable. Grow. In this example, the growth period P1 is 17 to 19 days, and the treatment period is a 48-hour light treatment period P3. Therefore, the growth period P2 is 15 to 17 days.

In this growth period P2, artificial light using a white LED having a color temperature of "5000 K" is irradiated for 16 hours, and then turned off for 8 hours. In this way, spinach is grown by repeating the growth period P2 with 16 hours in the light period and 8 hours in the dark period as one cycle (1 day). In this case, the above-mentioned culture solution is supplied to spinach for cultivation.

As shown in FIG. 2, a white LED having a color temperature of “5000K” outputs artificial light having a wavelength characteristic of photon flux density (PFD) indicated by a dashed line. This light contains more wavelength components of the far-infrared region FR than ordinary white light.

Then, as shown in FIG. 1, the wavelength of the artificial light to irradiate the plant is changed at the end of the growth period P2 and the start of the light treatment period P3 immediately before harvesting. In this light processing period P3, artificial light of a white LED having a color temperature of "6500K" is continuously irradiated.

As shown in FIG. 2, a white LED having a color temperature of “6500K” outputs artificial light having a wavelength characteristic of a photon flux density shown by a solid line. This light contains a large amount of blue wavelength components (components having a wavelength of 450 to 470 nm), and evenly contains each component of visible light (495 to 650 nm) of other colors.
Then, after the light treatment period P3 is completed, spinach is harvested.

The cultivation method in this example is based on the following findings.
FIG. 3 shows the content of lutein contained in the "WB light cultivation method" of this example and spinach of the comparative example. The lutein contents of Comparative Examples 1 and 2 are spinach grown in the same manner as in this example during the growth period P2 (until immediately before the light treatment period P3), respectively. Then, the spinach of Comparative Example 1 was continuously irradiated with blue light during the light treatment period P3 to grow, and the spinach of Comparative Example 2 brightened the light output from the white LED having a color temperature of "5000 K" during the light treatment period P3. The plants were cultivated by repeating the 16-hour period and the dark period of 8 hours until the time of harvest. Further, Comparative Example 3 is the lutein content of spinach cultivated and marketed in an alley near the cultivated area.

FIG. 4 shows the content of lutein and the content of nitrate nitrogen contained in spinach cultivated by the WB light cultivation method. Here, in Comparative Example 4, similarly to Comparative Example 2, the value of spinach grown by repeating 16 hours in the light period and 8 hours in the dark period until the time of harvest with artificial light output by a white LED having a color temperature of “5000 K”. Is shown. Since the plants of Comparative Example 4 and Comparative Example 2 were grown at different growth times, the lutein content was slightly different even under the same light irradiation conditions.

As shown in FIG. 4, in the cultivation method according to this example, the content of lutein contained in spinach was higher than that in the cultivation method of Comparative Example 4, which exceeded the target value of 10 (mg / 100 gFW). Further, in the cultivation method according to this example, the content of nitrate nitrogen (mg / kg FW) contained in spinach was lower than that in the cultivation method of Comparative Example 4.
Further, when the light treatment period P3 is longer than 48 hours, the leaves of spinach gradually wither and the spinach becomes weak.

According to this embodiment, the following effects can be obtained.
(1-1) In this embodiment, in the light treatment period P3 immediately before harvesting, a plant is grown by continuously irradiating artificial light of a white LED having a color temperature of "6500K". As a result, the lutein content can be increased as compared with spinach grown by irradiating blue light during the light treatment period P3 and spinach grown by repeating the cycle of the light period and the dark period until the time of harvest. Furthermore, the content of nitrate nitrogen can be reduced as compared with spinach grown by repeating the cycle of the light period and the dark period until the time of harvest.
In addition, the artificial light of a white LED having a color temperature of "6500K" has a strong blue light component and also contains light of other wavelengths in a well-balanced manner, so that morphological abnormalities of plants are unlikely to occur. Further, the burden on the eyes of the operator can be reduced.

(Example 2)
Next, the (2) nitric acid reduction cultivation method of this example will be described with reference to FIGS. 5 and 6.
As shown in FIG. 5, also in this example, in the growth period P2, as in Example 1, artificial light using a white LED having a color temperature of “5000K” was used for 16 hours in the light period and 8 hours in the dark period. Repeatedly, the above-mentioned culture solution is supplied to grow spinach. In this example, since the nitric acid reduction period P4 of 4 to 6 days is used as the treatment period, the growth period P2 is 11 to 15 days.

Then, in the nitric acid reduction period P4 immediately before the scheduled harvest, the nitric acid reduction treatment for reducing the nitrate nitrogen of the plant is executed. Specifically, at the start of the nitric acid reduction period P4, the culture solution supplied to the plant is stopped, and water containing no nitric acid is supplied to the plant. Then, in the nitric acid reduction period P4, water is supplied to the plant. In this case, the plant is repeatedly grown with artificial light using a white LED having a color temperature of "5000 K" for 16 hours in the light period and 8 hours in the dark period.

Then, after the nitric acid reduction period P4 is completed, harvesting is performed.
The cultivation method in this example is based on the following findings that the lutein content of spinach was increased by performing a nitric acid reduction treatment for reducing nitrate nitrogen.

FIG. 6 shows the dependence of the nitric acid reduction period P4 after switching water from the culture solution to the liquid supplied to the plant with respect to the lutein content and the nitrate nitrogen content. As shown in this figure, the lutein content of spinach having a nitric acid reduction period P4 of "4 days" was higher than that of spinach grown by repeating the cycle of the light period and the dark period without performing the nitric acid reduction treatment. In addition, spinach having a nitric acid reduction period P4 of "6 days" had a lower lutein content than spinach having a nitric acid reduction period P4 of "4 days". In addition, the nitrate nitrogen of spinach whose nitric acid reduction period P4 is "4 days" is significantly reduced. Further, spinach having a nitric acid reduction period P4 of "6 days" was smaller than the nitrate nitrogen content of spinach having a nitric acid reduction period P4 of "4 days", but the amount of decrease was small.

According to this embodiment, the following effects can be obtained.
(2-1) In this example, spinach is cultivated by supplying water instead of the culture solution in the nitric acid reduction period P4 immediately before harvesting. As a result, the lutein content can be increased as compared with spinach grown by repeating the cycle of the light period and the dark period.
(2-2) In this embodiment, nitric acid nitrogen can be significantly reduced by providing the nitric acid reduction period P4 of 4 to 6 days.

(Example 3)
Next, (3) WB photonitric acid reduction cultivation method of this example will be described with reference to FIGS. 7 to 9.

As shown in FIG. 7, also in this example, in the growth period P2, as in the above Examples 1 and 2, artificial light using a white LED having a color temperature of “5000K” was used for 16 hours in the light period and 16 hours in the dark period. Repeat for 8 hours to feed the culture solution to grow spinach.

Then, as in Example 2, at the start of the nitric acid reduction period P4 immediately before the scheduled harvest, the culture solution supplied to the plant is stopped and the supply of water to the plant is started. In the subsequent nitric acid reduction period P4, water is supplied to the plants. Here, "4 days" is used as the nitric acid reduction period P4.

After that, at the start of the light treatment period P3 immediately before the scheduled harvest (48 hours before the scheduled harvest), as in Example 1, the artificial light irradiating the plant is radiated with a white LED having a color temperature of "6500K". Change to the artificial light used. Then, in this light processing period P3, artificial light using a white LED having a color temperature of "6500K" is continuously irradiated.
Then, after 48 hours of continuous irradiation using a white LED having a color temperature of "6500K" is completed, harvesting is performed.

The cultivation method in this example is based on the following findings.
8 (a), (b) and (c) show the lutein content, nitrate nitrogen content and bioweight of spinach cultivated by the WB photonitrate reduction cultivation method of this example. In FIG. 8, the artificial light output by the white LED having a color temperature of “5000 K” is compared with spinach grown repeatedly in the light period of 16 hours and the dark period of 8 hours.

As shown in FIG. 8 (a), the content of lutein contained in spinach according to this example was 14% higher than that of spinach grown by repeating the cycle of the light period and the dark period.
Further, as shown in FIG. 8B, the nitric acid content of the spinach according to this example was 81% lower than that of the spinach grown by repeating the cycle of the light period and the dark period.

As shown in FIG. 8 (c), the body weight of spinach according to this example was reduced by 16% as compared with spinach grown by repeating the cycle of the light period and the dark period.
In addition, FIG. 9 shows the results of the taste test of spinach grown in the cultivation method of each example in this embodiment. Compared with spinach grown by repeating the cycle of the light period and the dark period, the spinach grown by the WB light cultivation method of Example 1 and the 4-day nitric acid reduction cultivation method of Example 2 was easier to eat. In addition, the spinach grown by the WB photonitrate reduction cultivation method of Example 3 was slightly sweet and had a good taste.

According to this embodiment, the following effects can be obtained.
(3-1) In this example, water is supplied instead of the culture solution in the nitrate reduction period P4 immediately before harvesting, and artificial light of a white LED having a color temperature of "6500K" is emitted in the light treatment period P3 immediately before harvesting. The spinach is grown by continuous irradiation. As a result, the lutein content can be increased and the nitrate nitrogen content can be reduced as compared with spinach grown by repeating the cycle of the light period and the dark period until the time of harvest. In addition, the spinach grown by the cultivation method of this example did not increase the amount of lutein more than the spinach of Example 1 and the spinach of Example 2, but the taste could be improved. In addition, morphological abnormalities of plants are unlikely to occur, and the burden on the eyes of the operator can be reduced.

This embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
-In each of the above examples, spinach was grown by repeating one cycle of 16 hours in the light period and 8 hours in the dark period using artificial light having a color temperature of "5000 K" while supplying a culture solution during the growth period P2. .. The cultivation method in the growth period P2 is not limited to this. The time of the dark period or the light period, the time of one cycle, or the like may be changed, or other artificial light may be used. Further, it may be changed according to the type of plant to be cultivated.

-In Examples 1 and 3, artificial light of a white LED having a color temperature of "6500K" was continuously irradiated for 48 hours in the light treatment period P3 immediately before harvesting. The artificial light emitted during the light processing period P3 is not limited to the artificial light output by the white LED having a color temperature of "6500K", and the intensity of the light in the blue wavelength region is stronger than the light in the wavelength region of other colors. , And white artificial light having a wavelength region of visible light as a whole may be used. For example, by adding another illumination to the illumination used in the growth period P2, the intensity of the light in the blue wavelength region is stronger than the light in the wavelength region of the other color, and the visible light wavelength region is increased. The plant may be irradiated with the white artificial light that is possessed as a whole.

-In Examples 2 and 3, water is supplied instead of the culture solution in the nitric acid reduction treatment. The treatment for reducing the nitrate nitrogen of spinach is not limited to this. For example, a nitrate-reducing treatment may be performed by supplying a culture solution from which nitrate ions have been removed.

-The cultivation method of each of the above examples was applied to spinach having lutein as a functional vegetable. The applicable functional plants are not limited to spinach. For example, it can be applied to plants containing functional components in a normal state and having an edible portion, such as leafy vegetables such as lettuce and cabbage. Further, the component to be increased in vegetables is not limited to lutein, and other nutritional components such as vitamins may be used.

FR ... Far infrared region, P1 ... Growth period, P2 ... Growth period, P3 ... Light treatment period, P4 ... Nitric acid reduction period.

Claims (6)

It is a plant cultivation method for growing a plant having an edible portion by irradiating artificial light while supplying a liquid.
During the light treatment period immediately before the harvest of the plant, white artificial light having a light intensity in the blue wavelength region stronger than that in the wavelength region of other colors and having an overall visible wavelength region was produced. A plant cultivation method characterized in that the plant is grown by continuously irradiating the plant. The plant cultivation method according to claim 1, wherein the light treatment period is a time during which the plant does not weaken. The plant cultivation method according to claim 1 or 2, wherein the plant is grown by performing a nitric acid reduction treatment for reducing nitrate nitrogen of the plant during the nitric acid reduction period immediately before harvesting the plant. It is a plant cultivation method for growing a plant having an edible portion while supplying a liquid.
A plant cultivation method characterized in that a nitric acid reduction treatment for reducing nitrate nitrogen of the plant is executed to grow the plant during the nitric acid reduction period immediately before the harvest of the plant. The nitric acid reduction treatment is a treatment of supplying water to the plant in place of the culture solution supplied to the plant before the nitric acid reduction period.
The plant cultivation method according to claim 3 or 4, wherein the nitric acid reduction period is 4 days or more and 6 days or less. A system for cultivating a plant having a supply unit for supplying a liquid to a plant having an edible portion and an irradiation unit for irradiating the plant with artificial light.
After growing the plant using the culture solution, the supply unit supplies the plant with a liquid that reduces nitrate nitrogen of the plant during the nitric acid reduction period immediately before harvesting the plant.
In the light treatment period immediately before the harvest of the plant, the irradiated portion is white in which the intensity of light in the blue wavelength region is stronger than that in the wavelength region of other colors and the entire visible light wavelength region is provided. A plant cultivation system characterized by continuously irradiating the plant with artificial light.

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