WO2024181116A1 - Plant life prolongation method and plant life prolongation apparatus - Google Patents

Abstract

The present invention provides a plant life prolongation method and apparatus with which the condition of a plant can be maintained simply with ease. In this life prolongation method, a leaf blade of a plant is irradiated with light having a 200-240 nm wavelength range. In order to achieve such a life prolongation method, this plant life prolongation apparatus includes a light source capable of emitting light having a 200-240 nm wavelength range.

Description

Method for treating plants to extend their life span and device for treating plants to extend their life span

This disclosure relates to a method for treating plants to extend their lifespan and an apparatus for treating plants to extend their lifespan.

Plants produce the organic substances they need through photosynthesis, a process that converts light energy into chemical energy. Photosynthesis requires water, which is introduced through the plant's roots.
A plant whose roots have been cut off will eventually die, but in order to maintain the condition of the plant for as long as possible, a method is known in which the stem is placed in a vase filled with water, etc. In order to maintain the condition of the plant even further, a method is also known in which water containing a life-extending agent is used (Patent Document 1).

JP 2010-138076 A

Considering the distribution route of plants to the end consumer, it is complicated and difficult to maintain the condition of plants in a desirable state by using water containing a life-extending agent. In addition, the application of the life-extending agent is accompanied by difficulties during transportation.
In order to solve the above-mentioned problems, the plant longevity treatment method of the present disclosure aims to provide a plant longevity treatment method capable of easily maintaining the state of the plant for a long time. Also, the plant longevity treatment device of the present disclosure aims to provide a plant longevity treatment device capable of easily maintaining the state of the plant.

The method for extending the lifespan of a plant according to one embodiment of the present disclosure irradiates the leaf blade of the plant with light having a wavelength in the range of 200 nm to 240 nm.

A plant longevity treatment device according to another aspect of the present disclosure includes a light source capable of emitting light with a wavelength in the range of 200 nm or more and 240 nm or less.
The above-mentioned plant longevity treatment method and plant longevity treatment device according to the present disclosure do not list all of the features of the present disclosure. Also, subcombinations of these features may be inventions.

The plant longevity treatment method and plant longevity treatment device disclosed herein make it possible to easily maintain the condition of the plant.

1 is a block diagram showing a first configuration example of a plant longevity treatment device according to an embodiment of the present invention; FIG. 2 is a block diagram showing a second configuration example of the plant longevity treatment device of the present embodiment. FIG. 11 is a block diagram showing a third configuration example of the plant longevity treatment device of the present embodiment. FIG. 11 is a block diagram showing a fourth configuration example of the plant longevity treatment device of the present embodiment. Photographs showing leaf blades before and after irradiation treatment in Experiment 1. Photographs showing the results of observing changes in the condition of the front and back of the leaf blade in Experiment 2. Photographs showing the state of the leaf blade before the start of irradiation and the front and back of the leaf blade 36 hours after irradiation in Experiment 2. Photographs (side views) showing the results of daily follow-up observations of subjects in Experiment 3. Photographs (top view) showing the results of daily follow-up observations of the subjects in Experiment 3. 13 is a graph showing the observation results in Experiment 4.

Below, the present disclosure will be explained through embodiments of the invention, but the following embodiments do not limit the invention as claimed. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

1. First Embodiment Hereinafter, a life extension treatment device 100 according to a first embodiment of the present disclosure will be described with reference to FIGS.

(1.1) Configuration of plant longevity treatment device: First example Fig. 1 is a block diagram showing the configuration of a plant longevity treatment device 100A, which is a first example of the plant longevity treatment device 100 of this embodiment. The plant longevity treatment device 100A includes a light source 110. Fig. 1 shows a leaf blade 300 of a plant to be irradiated with light from the plant longevity treatment device 100. The leaf blade 300 has a back surface 310 and a front surface 320.
The light source 110 of the plant longevity treatment device 100A will be described in detail below.

<Light source>
The light source 110 is a light source capable of emitting light having a wavelength in the range of 200 nm to 240 nm. The light having a wavelength in the range of 200 nm to 240 nm may be light including all wavelengths in the range, or may be light including a part of the wavelengths in the range. From the viewpoint of efficient processing, the light source 110 may emit light having a central wavelength of 190 nm to 230 nm.

Examples of the light source 110 include a high-pressure mercury lamp, an excimer lamp, a deep ultraviolet LED (Light Emitting Diode), a deep ultraviolet LD (Laser Diode), etc. From the viewpoint of environmental impact, the light source 110 may preferably be an excimer lamp, a deep ultraviolet LED, a deep ultraviolet LD, etc. Examples of the excimer lamp include ArF, KrBr, and KrCl excimer lamps.
An example of a deep ultraviolet LED is an element in which a light emitting layer is formed of Al _x Ga _1-x N (0≦x≦1).

It may be preferable that the light source 110 does not include light with a wavelength of 250 nm or more and 300 nm or less. In order not to emit light with a wavelength of 250 nm or more, the light source 110 may be configured to have an optical element with a transmittance of 20% or less for light with a wavelength of 250 nm, for example. The transmittance of the optical element for light with a wavelength of 250 nm may preferably be 15% or less, and more preferably 10% or less.

A "light source that does not include light with a wavelength of 250 nm or more and 300 nm or less" means that, when the intensity of the central wavelength of the light emitted by light source 110 is taken as 1, the relative intensity of light in the wavelength range of 250 nm or more and 300 nm or less is 0.1 or less. In other words, when the intensity of the central wavelength of the light emitted by light source 110 is taken as 1, light source 110 preferably emits light having a relative intensity of 0.1 or less in the wavelength range of 250 nm or more and 300 nm or less, more preferably 0.01 or less, and even more preferably 0.001 or less.
From the viewpoint of improving the irradiation efficiency and the uniformity of the irradiation, the light source 110 may have a plurality of exit surfaces. There is no particular limitation on the means for providing a plurality of exit surfaces, but a plurality of light source units may be disposed, or one light source unit may have a plurality of independent exit surfaces.

2 is a block diagram showing the configuration of a plant longevity treatment device 100B, which is a second example of the plant longevity treatment device 100 of this embodiment. The plant longevity treatment device 100B includes a light source 110, a recognition unit 120, a distance measurement unit 130, and a light source control unit 140.
Hereinafter, a detailed description will be given of each component of the plant longevity treatment device 100B, except for the light source 110. Note that the light source 110 of the plant longevity treatment device 100B has the same configuration as the light source 110 described in the first example, and therefore a description thereof will be omitted.

<Recognition section>
The recognition unit 120 is capable of recognizing the state of the recognition target in the irradiation area of the light emitted from the light source 110 (also referred to as the field of view of the light source 110). Specific examples of the recognition unit 120 include a leaf blade recognition unit capable of recognizing whether or not a leaf blade of a plant is present, a plant recognition unit capable of recognizing the type of plant, and a flower recognition unit that recognizes whether or not a flower part of a plant is present. Although the specific configuration of each is not particularly limited, the recognition unit 120 may include an imaging unit that captures an image in response to some kind of energy (heat, light, electromagnetic waves, etc.).

The recognition unit 120 may control the operation of the light source 110 according to the recognition result in the recognition unit 120. As an example, the recognition unit 120 may control the start of the light emission operation of the light source 110 and the stop of the light emission operation of the light source 110.
The control of the light source 110 may be realized by directly transmitting a control signal from the recognition unit 120 to the light source 110. Alternatively, a control unit (not shown) that receives information on the recognition result from the recognition unit 120 may control the light source 110.

(Leaf blade recognition unit)
The recognition unit 120 of the plant longevity treatment device of this embodiment may include a leaf blade recognition unit capable of recognizing whether or not a leaf blade of a plant is present in an area irradiated with light from the light source 110. The recognition unit 120 may control the operation of the light source 110 according to the recognition result of the leaf blade recognition unit as to the presence/absence of a leaf blade of a plant.
The leaf blade recognition unit may further be capable of recognizing the front and back surfaces of the leaf blade.

(Plant Recognition Division)
The recognition unit 120 of the plant longevity treatment device of this embodiment may include a plant recognition unit that recognizes the type of plant. The recognition unit 120 may control the operation of the light source 110 according to the recognition result of the plant type by the plant recognition unit. For example, the recognition unit 120 may control the intensity or time of the light to be irradiated according to the type of plant, or control the cumulative amount of light to be irradiated.

(Flower Recognition Department)
The recognition unit 120 of the plant longevity treatment device of this embodiment may include a flower recognition unit capable of recognizing the flower part of the plant. From the viewpoint of reducing adverse effects on the plant, when the recognition unit 120 recognizes the flower part, the recognition unit 120 may control the light source 110 to stop emitting light or to reduce the driving power of the light source 110, or may control the irradiation position and irradiation angle of the light from the light source 110 to reduce the energy of the light irradiated to the flower or the entire plant.
In the following, an example will be described in which the recognition unit 120 is the leaf blade recognition unit 121. Note that in FIG.

<Distance measuring section>
The distance measuring unit 130 can measure the distance to the irradiation target of the light emitted from the light source 110. The distance measuring unit 130 may constantly measure the distance to the irradiation target of the light from the light source 110, or may measure the distance to the irradiation target depending on the presence/absence of a leaf blade of a plant recognized by the leaf blade recognition unit 121. When the distance measuring unit 130 measures the distance to the irradiation target depending on the presence/absence of a leaf blade of a plant, it may be preferable because the distance to the leaf blade of the plant can be treated as information.

<Light source control unit>
The light source control unit 140 is capable of controlling the operation of the light source 110. As an example, the light source control unit 140 is capable of controlling the operation of the light source 110 by controlling the supply of power to the light source 110, etc.
The light source control unit 140 may control the operation of the light source 110 in accordance with information from the leaf blade recognition unit 121. The light source control unit 140 may also control the operation of the light source 110 in accordance with the distance to the irradiation target measured by the distance measurement unit 130. As an example, the light source control unit 140 may control the irradiation time and illuminance in accordance with the distance to the irradiation target.
As another example, the light source control unit 140 may control the light source 110 to be driven in response to the leaf blade recognition unit 121 recognizing that the light is being irradiated to the underside of a leaf blade of a plant.

3 is a block diagram showing the configuration of a plant longevity treatment device 100C which is a third example of the plant longevity treatment device 100 of this embodiment. The plant longevity treatment device 100C includes a light source 110, a recognition unit 120, a distance measurement unit 130, a light source control unit 140, a storage unit 150, and a calculation unit 160.
Hereinafter, a detailed description will be given of each of the memory unit 150, the calculation unit 160, and the light source control unit 140 of the plant longevity treatment device 100B. Note that each of the units other than the memory unit 150, the calculation unit 160, and the light source control unit 140 of the plant longevity treatment device 100B will be omitted because they have the same configuration as the light source 110 described in the first example and the recognition unit 120 and the distance measurement unit 130 described in the second example.

<Memory Unit>
The storage unit 150 stores operation information of the light source 110. The operation information of the light source 110 may include information on the operation time, the applied power during operation, and the power consumption of the plant longevity treatment device 100 as information equivalent to the applied power. The operation information may also include information on the energy of light emitted with respect to the applied power to the light source 110.

The storage unit 150 may be capable of communicating with the distance measurement unit. This allows the storage unit 150 to store the distance to the measurement object. In addition, by combining this with information on the presence/absence of the leaf blade of the plant from the leaf blade recognition unit 121, the distance to the measurement object can be stored as the distance to the leaf blade of the plant.
The means by which the memory unit 150 stores information on the light source 110, the distance to the measurement object, and the distance to the leaf blade of the plant is not particularly limited, but may be a configuration in which the distance measuring unit 130, which can communicate with the leaf blade recognition unit 121, and the memory unit 150 can communicate with each other. Also, the memory unit 150 may be configured to be able to communicate with each of the leaf blade recognition unit 121 and the distance measuring unit 130, or the memory unit 150 may be configured to be able to communicate with the light source control unit 140, which can communicate with each of the leaf blade recognition unit 121 and the distance measuring unit 130, and the memory unit 150.

The memory unit 150 may be provided as a physical part of the plant longevity treatment device 100 (e.g., a memory element), or may be provided as a device that is physically separated from the plant longevity treatment device 100 and can be connected to the plant longevity treatment device 100 via wireless communication or the like (e.g., a memory device of a server).

<Calculation section>
The calculation unit 160 is capable of calculating the integrated amount of light irradiated onto the leaf blade of the plant by inputting the operation information of the light source 110 and the distance to the leaf blade of the plant. As described above, the operation information of the light source 110 may include the operation time of the light source 110, the power applied to the light source 110, and the like.
The calculation unit 160 may be provided independently, or may be provided as a part of the light source control unit 140 .
The calculation unit 160 may be provided as a physical part of the plant longevity treatment device 100 (e.g., an analog IC or digital IC), or it may be provided as a part that is physically separated from the plant longevity treatment device 100 and can be connected to the plant longevity treatment device 100 via wireless communication or the like (e.g., a calculation processing unit of a server).

<Light source control unit>
The light source control unit 140 is capable of controlling the operation of the light source 110 in accordance with the integrated amount of light irradiated onto the leaf blade of the plant calculated by the calculation unit 160 .
It is preferable that the light source control unit 140 controls the operation of the light source 110 so that the light emitted by the light source 110 is irradiated with an integrated dose of (10 x central wavelength of ultraviolet light [nm] - 2190) mJ/cm ² or more. In a plant irradiated with light from the light source 110 with such an integrated dose, the stomata are less likely to open even if the leaf blade is exposed to sunlight, and the plant has a longer lifespan. It is more preferable that the light source control unit 140 controls the operation of the light source 110 so that the light emitted by the light source 110 is irradiated with an integrated dose of 1 mJ/cm ² or more. It is more preferable that the light source control unit 140 controls the operation of the light source 110 so that the light emitted by the light source 110 is irradiated with 400 mJ/cm ² or less. If the integrated dose is 400 mJ/cm ² or less, it is possible to prolong the time until the plant withers without causing damage to the leaf blade due to the light irradiated to the leaf blade.

4 is a block diagram showing the configuration of a plant longevity treatment device 100D, which is a fourth example of the plant longevity treatment device 100 of this embodiment. The plant longevity treatment device 100D includes a light source 110, a recognition unit 120, a distance measurement unit 130, a light source control unit 140, a memory unit 150, a calculation unit 160, and an irradiation position control unit 170.
The irradiation position control unit 170 of the plant longevity treatment device 100D will be described in detail below. Note that the components other than the irradiation position control unit 170 of the plant longevity treatment device 100D have the same configuration as the light source 110 described in the first example, the recognition unit 120, the distance measurement unit 130, and the light source control unit 140 described in the second example, and the storage unit 150 and the calculation unit 160 described in the third example, and therefore the description thereof will be omitted.

<Irradiation position control unit>
The irradiation position control unit 170 can control the relative positional relationship between the light source 110 and the irradiation target by changing the position and angle of the light source 110. As an example, the irradiation position control unit 170 may be a wheel that can move on an object, or a propeller that can float in space. As another form, the irradiation position control unit 170 may be a mechanism that changes the spatial irradiation angle of the light source 110.
By providing the irradiation position control unit 170, even if it is not possible to irradiate the entire desired area with light from the light source 110 by irradiating the entire area with light only once, it is possible to irradiate the next part of the target by moving the light source 110 after irradiating one part of the target, or to irradiate the entire area of the target by continuously moving the light source 110.
The irradiation position control section 170 may operate in accordance with the integrated irradiation amount of light calculated by the calculation section 160 .

(1.5) Configuration of life extension treatment device: Other examples <Plant transport section>
The plant longevity treatment device 100 (100A to 100D) of the present embodiment may further include a plant transport unit capable of transporting a plant to be irradiated. The plant transport unit is not particularly limited, but may be capable of changing the relative position of the plant with respect to the light source 110 while holding the plant.

<Radiation prevention part>
The plant longevity treatment device 100 (100A to 100D) of this embodiment may further include an irradiation prevention part that prevents irradiation of the flower part of the plant. The irradiation prevention part may have a low transmittance of light in the wavelength range of 200 nm or more and 240 nm or less. The transmittance of the irradiation prevention part is not particularly limited, but is preferably 10% or less, and more preferably 5% or less, for example. The irradiation prevention part may be physically connected to the plant longevity treatment device 100 or may be separated therefrom.

(1.6) Plant Life Extension Treatment Method The plant life extension treatment method of this embodiment will be described.
The method for extending the lifespan of a plant according to the present embodiment includes an irradiation step of irradiating the leaf blade of the plant with light having a wavelength in the range of 200 nm to 240 nm. By irradiating the leaf blade of the plant with light having a wavelength in the range of 200 nm to 240 nm, it is possible to extend the time until the plant withers.
The mechanism by which the plant lifespan extension treatment method of the present embodiment extends the time until the plant withers is unclear, but the present inventors speculate that the light acts on the stomata in the leaf blade, suppressing excessive transpiration, thereby extending the time until the plant withers.
The plant longevity treatment method of this embodiment can be realized by the plant longevity treatment device 100 (100A to 100D, etc.) of this embodiment described above.

The description of the life extension treatment method of this embodiment will be continued below.
From the viewpoint of efficient treatment, the central wavelength of the light may be 190 nm or more and 230 nm or less. Moreover, from the viewpoint of suppressing damage to the plant to be irradiated with the light, it is preferable that the light irradiated to the plant does not include light with a wavelength of 250 nm or more and 300 nm or less.
When irradiating the leaf blade with light, the cumulative dose of light irradiated to the leaf blade is preferably (10 x central wavelength of ultraviolet light [nm] - 2190) mJ/ ^cm2 or more. This makes it difficult for the stomata to open even when the plant irradiated with light is exposed to sunlight, and the plant has a longer lifespan. Specifically, the cumulative dose of light irradiated to the leaf blade may be 1 mJ/ ^cm2 or more. If the cumulative dose is 1 mJ/ ^cm2 or more, it is possible to extend the time until the plant withers compared to when light is not irradiated to the leaf blade.
In addition, the cumulative dose of light irradiated to the leaf blade is preferably 400 mJ/ ^cm2 or less. If the cumulative dose is 400 mJ/ ^cm2 or less, it is possible to extend the time until the plant withers without causing damage to the leaf blade due to the light irradiated to the leaf blade.

When irradiating the leaf blade with light, the underside of the leaf blade may be irradiated with light. Since there was no significant difference in the effect of extending the time until withering when light was irradiated to the front and underside of the leaf blade compared to when light was irradiated only to the underside of the leaf blade, it is understood that irradiating light only to the underside is preferable. In addition, it is preferable for the leaf blade to have stomata. By irradiating the side of the leaf blade that has stomata with light, the plant's lifespan will be further extended. This is thought to be because transpiration through the stomata is suppressed when light is irradiated to the stomata.

The plant to be irradiated with light may be a flowering plant. A flowering plant is a plant that blooms with flowers. Flowering plants are ornamental plants, and it is highly desirable to extend the time it takes for them to wither. For this reason, it is preferable to apply the life extension treatment method of the present embodiment to flowering plants.
The plant to be irradiated with light may be a cut flower. For example, according to the "Training Text for Improving the Shelf Life of Cut Flowers, 2013 Innovative Agricultural Technology Training Course," 80% of consumers desire a viewing period of 7 days for gerberas, an example of flowers, but less than 20% actually have a shelf life of more than 7 days, and it is understood that conventional technology does not satisfy consumer needs. Similarly, according to the "Training Text for Improving the Shelf Life of Cut Flowers, 2013 Innovative Agricultural Technology Training Course," it is said that it usually takes about 3 days from harvest to deliver flowers to consumers, and if transfer between markets occurs, it takes another 2 days. That is, it is understood that in order to guarantee the 7-day viewing period desired by consumers, a shelf life of 10 to 12 days from harvest is desired. For this reason, it is preferable to apply the life-extending treatment method of this embodiment to cut flowers.

[Experiment 1: Accumulative irradiation amount study]
Example 1
Leaf blades excised from a rose (cultivar: Ilias) were prepared.
Next, a light source was prepared that had a KrCl excimer lamp that emitted ultraviolet light with a central wavelength of 222 nm and an emission intensity of 1% or more of the emission intensity of the central wavelength in the wavelength range of 200 nm to 235 nm. The light source had an optical filter on the ultraviolet light emission surface that had a transmittance (incident angle 0 degrees) of 17% for light with a wavelength of 235 nm and a transmittance (incident angle 0 degrees) of 3% for light with a wavelength of 240 nm. In addition, the emission intensity of the light source with a wavelength of 250 nm to 300 nm was 1% or less of the emission intensity of the central wavelength.
The leaf blade was placed with the underside facing the light source at a distance of 5 cm from the light source's emission surface, and was irradiated with ultraviolet light at an irradiation dose of 2.5 mW/ ^cm2 until the cumulative irradiation dose reached 44.6 mJ/ ^cm2 , thereby obtaining the treated leaf blade of Example 1.

Example 2
The treated leaf blade of Example 2 was obtained by irradiating with ultraviolet light in the same manner as in Example 1, except that the cumulative irradiation dose was 446 mJ/ ^cm2 .

<Reference Example 1>
An untreated leaf blade of a Reference Example was obtained in the same manner as in Example 1, except that the ultraviolet light irradiation treatment was not carried out.

The leaf blades of Examples 1 and 2 and Reference Example 1 are shown in Fig. 5. The upper row is a photograph of the entire leaf blade, and the lower row is an enlarged photograph of the vicinity of the center of the leaf blade.
The leaf blade of Example 1 was not significantly different from the leaf blade of Reference Example 1.
Discoloration of the irradiated portion was observed in the leaf blade of Example 2 compared to the leaf blade of Reference Example 1. Specifically, discoloration of the leaf blade and the veins within the leaf blade was observed.

[Experiment 2: Comparison of sunburn on front and back]
Example 3
Leaf blades excised from a rose (cultivar: Ilias) were prepared.
The same light source as in Example 1 was prepared, and a leaf blade was placed 5 cm away from the light source with the back side facing the light source, and irradiated with ultraviolet light at an irradiation dose of 2.5 mW/ ^cm2 until the cumulative irradiation dose reached 37.5 mJ/ ^cm2 . Next, the surface of the same leaf blade was also irradiated with ultraviolet light at an cumulative irradiation dose of 37.5 mJ/ ^cm2 (irradiation dose 2.5 mW/ ^cm2 ) to obtain the treated leaf blade of Example 3.

<Comparative Example 1>
An untreated leaf blade of Comparative Example 1 was obtained in the same manner as in Example 3, except that the ultraviolet light irradiation treatment was not carried out.

The treated leaf blade of Example 3 and the untreated leaf blade of Comparative Example 1 were placed in a room at a temperature of about 25° C., and the changes in the condition of the front and back of the leaf blade were observed every 6 hours from before the start of irradiation (0 hours) until 36 hours after irradiation, and the results are shown in Figure 6. In addition, the condition of the front and back of the leaf blade before the start of irradiation (0 hours) and 36 hours after irradiation are shown in Figure 7.
6 and 7, in the leaf blade of Comparative Example 1, which was not irradiated with ultraviolet light, discoloration of the leaf outline began after 24 hours, and in addition to discoloration of the outline, shrinkage of the entire leaf blade was observed after 36 hours. On the other hand, in the leaf blade of Example 3, which was treated with ultraviolet light, neither discoloration of the outline nor shrinkage of the leaf blade was observed even after 36 hours.

[Experiment 3: Comparison of changes in the shape of cut flowers]
Example 4
Roses (variety name: All 4 Love) were prepared.
The same light source as in Example 1 was prepared, and ultraviolet light was irradiated onto the front and back of the prepared rose leaf blade in the same manner as in Example 3 to obtain a treated leaf blade of Example 4.

Example 5
The ultraviolet light irradiation treatment was carried out in the same manner as in Example 4, except that the ultraviolet light irradiation treatment was carried out only on the back surface of the leaf blade, to obtain the treated leaf blade of Example 5.

Example 6
The ultraviolet light irradiation treatment was carried out in the same manner as in Example 5, except that a light source not equipped with an optical filter was used, to obtain the treated leaf blade of Example 6.

<Comparative Example 2>
An untreated leaf blade of Comparative Example 2 was obtained in the same manner as in Example 4, except that the ultraviolet light irradiation treatment was not carried out.

The roses whose leaves had been irradiated in Examples 4 to 6 and the roses whose leaves had not been irradiated in Comparative Example 2 were placed in a room at a room temperature of about 25°C with the lower 9 cm of the stems submerged in water, and daily observations were made, focusing on the condition of the flowers. The observation results are shown in Figures 8 (side view) and 9 (top view).

8 and 9, in the rose of Comparative Example 2, which was not irradiated with ultraviolet light, some of the petals began to wither and gradually turned downward on the fifth day, and by the ninth day, all the petals had turned downward. In contrast, in the roses of Examples 4 to 6, which were irradiated with ultraviolet light, the petals did not wither and did not turn downward even on the fifth day. This shows that the longevity of plants was achieved by irradiating them with light having a central wavelength of 190 nm or more and 230 nm or less.
Furthermore, the rose of Example 6, which was irradiated using a light source without a filter, experienced wilting of the petals on the seventh day, whereas the roses of Examples 4 and 5, which were irradiated using a light source with a filter, still did not wither or wilt. This shows that it is possible to suppress unnecessary damage to plants and achieve even longer lifespans by irradiating them with light of wavelengths less than 240 nm, from which light of wavelengths of 240 nm or more has been removed using a filter.
Furthermore, the roses of Examples 4 and 5 did not wither and remained in good condition even after 12 days had passed. This shows that the longevity of plants can be achieved by irradiating at least the backside of the leaf blade with light having a central wavelength of 190 nm or more and 230 nm or less.

[Experiment 4: Comparison of stomatal opening when exposed to sunlight]
Example 7
Leaf blades excised from a rose (variety: All 4 Love) were prepared.
Next, an ultraviolet LED light source with a central wavelength of 227 nm was prepared.
The leaf blade was placed with the back side facing the light source as close as possible to the light source emission surface, and was irradiated with ultraviolet light at an irradiation dose of 0.91 mW/ ^cm2 until the cumulative irradiation dose reached 83 mJ/ ^cm2 , to obtain the treated leaf blade of Example 7. All of the above irradiations were performed in a dark place.

Example 8
The ultraviolet light irradiation treatment was carried out in the same manner as in Example 7, except that the ultraviolet light was irradiated until the cumulative irradiation amount reached 100 mJ/ ^cm2 , to obtain the treated leaf blade of Example 8.

<Example 9>
The ultraviolet light irradiation treatment was carried out in the same manner as in Example 7, except that the ultraviolet light was irradiated until the cumulative irradiation amount reached 300 mJ/ ^cm2 , to obtain the treated leaf blade of Example 8.

Example 10
The ultraviolet light irradiation treatment was carried out in the same manner as in Example 7, except that the ultraviolet light was irradiated until the cumulative irradiation amount reached 500 mJ/ ^cm2 , to obtain the treated leaf blade of Example 8.

Example 11
The ultraviolet light irradiation treatment was carried out in the same manner as in Example 7, except that the ultraviolet light was irradiated until the cumulative irradiation amount reached 1000 mJ/ ^cm2 , to obtain the treated leaf blade of Example 8.

Example 12
The ultraviolet light irradiation treatment was performed in the same manner as in Example 7, except that the central wavelength of the ultraviolet LED was 238 nm, the ultraviolet light irradiation dose was 1.94 mW/ ^cm2 , and ultraviolet light was irradiated until the cumulative irradiation dose reached 200 mJ/ ^cm2 , thereby obtaining the treated leaf blade of Example 12.

Example 13
The ultraviolet light irradiation treatment was carried out in the same manner as in Example 12, except that the ultraviolet light was irradiated until the cumulative irradiation amount reached 300 mJ/ ^cm2 , to obtain the treated leaf blade of Example 13.

<Example 14>
The ultraviolet light irradiation treatment was carried out in the same manner as in Example 12, except that the ultraviolet light was irradiated until the cumulative irradiation amount reached 400 mJ/ ^cm2 , to obtain the treated leaf blade of Example 14.

Example 15
The ultraviolet light irradiation treatment was carried out in the same manner as in Example 12, except that the ultraviolet light was irradiated until the cumulative irradiation amount reached 500 mJ/ ^cm2 , to obtain the treated leaf blade of Example 15.

<Example 16>
The ultraviolet light irradiation treatment was carried out in the same manner as in Example 12, except that the ultraviolet light was irradiated until the cumulative irradiation amount reached 1000 mJ/ ^cm2 , to obtain the treated leaf blade of Example 16.

<Comparative Example 3>
The leaf blade of Comparative Example 3 was obtained in the same manner as in Example 7, except that ultraviolet light was not irradiated.

<Comparative Example 4>
The ultraviolet light irradiation treatment was carried out in the same manner as in Example 7, except that the ultraviolet light was irradiated until the cumulative irradiation amount reached 50 mJ/ ^cm2 , and the treated leaf blade of Comparative Example 4 was obtained.

<Comparative Example 5>
The ultraviolet light irradiation treatment was carried out in the same manner as in Example 7, except that the ultraviolet light was irradiated until the cumulative irradiation amount reached 67 mJ/ ^cm2 , and the treated leaf blade of Comparative Example 4 was obtained.

<Comparative Example 6>
The ultraviolet light irradiation treatment was carried out in the same manner as in Example 12, except that the ultraviolet light was irradiated until the cumulative irradiation amount reached 50 mJ/ ^cm2 , and the treated leaf blade of Comparative Example 6 was obtained.

<Comparative Example 7>
The ultraviolet light irradiation treatment was carried out in the same manner as in Example 12, except that the ultraviolet light was irradiated until the cumulative irradiation amount reached 100 mJ/ ^cm2 , and the treated leaf blade of Comparative Example 7 was obtained.

The roses of Examples 7 to 16 and Comparative Examples 4 to 7, in which the leaf blades were irradiated, and the rose of Comparative Example 3, in which the leaf blades were not irradiated, were exposed to sunlight, and then the stomata on the surface were observed. The results of opening and closing of stomata were shown in Table 1 below. FIG. 10 shows the relationship between the central wavelength of ultraviolet light and the cumulative dose of irradiation for each of the Examples and Comparative Examples (Examples 7 to 16 and Comparative Examples 4 to 7) other than Comparative Example 3, in which ultraviolet light irradiation was not performed. The straight line L in FIG. 10 indicates the cumulative dose of irradiation (10×central wavelength of ultraviolet light [nm]−2190) mJ/ ^cm2 .

From the results shown in Table 1 and Figure 10, it was confirmed that the stomata of the leaf blade can be closed by irradiating the leaf blade with ultraviolet light at an integrated dose of (10 x central wavelength of ultraviolet light [nm] - 2190) mJ/cm2 or ^more . Similarly, it was confirmed that the stomata of the leaf blade of Comparative Example 3, which was not irradiated with ultraviolet light, opened when exposed to sunlight.
From this, it was confirmed that the integrated dose of ultraviolet light in the present disclosure is preferably (10 x central wavelength of ultraviolet light [nm] - 2190) mJ/ ^cm2 or more.

The present disclosure has been described above using embodiments, but the technical scope of the present disclosure is not limited to the scope described in the above embodiments. It will be clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that forms incorporating such modifications or improvements can also be included in the technical scope of the present disclosure.

The order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before" or "prior to," and it should be noted that the processes can be performed in any order, unless the output of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is explained using "first," "next," etc. for convenience, it does not mean that it is necessary to perform the processes in that order.

110 Light source 120 Recognition unit 130 Distance measurement unit 140 Light source control unit 150 Storage unit 160 Calculation unit 170 Irradiation position control unit 300 Plant leaf blade 310 Back surface of leaf blade 320 Front surface of leaf blade

Claims (32)

A method for extending the lifespan of a plant, comprising irradiating the leaf blade of the plant with light having a wavelength in the range of 200 nm or more and 240 nm or less. 2. The method for treating a plant to extend its lifespan according to claim 1, wherein the central wavelength of the light is 190 nm or more and 230 nm or less. 2. The method for treating a plant to extend its lifespan according to claim 1, wherein the light irradiated to the leaf blade does not include light with a wavelength of 250 nm or more and 300 nm or less. The method for treating a plant to extend its lifespan according to claim 2, wherein an integrated irradiation amount when the light is irradiated to the leaf blade is (10 x the central wavelength (nm) - 2190) mJ/cm2 or ^more . 2. The method for treating a plant to extend its lifespan according to claim 1, wherein an integrated dose of the light applied to the leaf blade is 1 mJ/cm2 ^or more and 400 mJ/cm2 or ^less . 2. The method for treating a plant to extend its lifespan according to claim 1, wherein the light is irradiated onto a back side of the leaf blade when the light is irradiated onto the leaf blade. 2. The method for treating a plant to extend its lifespan according to claim 1, wherein the light is irradiated onto the plant which is a flowering plant. 2. The method for treating a plant to extend its lifespan according to claim 1, wherein the light is irradiated onto the plant which is a cut flower. 2. The method for treating a plant to extend its lifespan according to claim 1, wherein the light is irradiated onto the leaf blade having stomata. The method for treating a plant to extend its lifespan according to claim 1 , wherein the light is emitted from an LED. The method for treating a plant to extend its lifespan according to claim 1 , wherein the light is irradiated onto the leaf blade using a plurality of light sources that emit the light. The method for treating a plant to extend its lifespan according to claim 1 , wherein the light is irradiated onto a plurality of the leaf blades. A plant longevity treatment device equipped with a light source capable of emitting light having a wavelength in the range of 200 nm or more and 240 nm or less. The plant longevity treatment device according to claim 13, wherein the central wavelength of the light emitted from the light source is 190 nm or more and 230 nm or less. The plant longevity treatment device according to claim 13 , further comprising an optical member having a transmittance of 20% or less for the light having a wavelength of 240 nm. The plant longevity treatment device according to claim 13 , further comprising a recognition unit that recognizes a state of an irradiated area of the light emitted from the light source. The plant longevity treatment device according to claim 16 , wherein the recognition unit includes a leaf blade recognition unit capable of recognizing a leaf blade of the plant. Further comprising a distance measuring unit for measuring a distance to an irradiation target of the light emitted from the light source.
The plant longevity treatment device according to claim 16. Further comprising a light source control unit for controlling the operation of the light source.
The plant longevity treatment device according to claim 13. A light source control unit capable of communicating with the leaf blade recognition unit and controlling the operation of the light source is further provided.
The plant longevity treatment device according to claim 17. Further comprising a storage unit for storing operation information of the light source.
The plant longevity treatment device according to claim 13. A storage unit capable of communicating with the distance measuring unit and storing operation information of the light source and the distance measured by the distance measuring unit.
The plant longevity treatment device according to claim 18. The light source may further include a calculation unit that receives the operation information of the light source and the distance and calculates an integrated irradiance of the light on the leaf blade of the plant from the operation information and the distance.
The plant longevity treatment device according to claim 22. Further, a light source control unit controls an operation of the light source in accordance with the integrated irradiation amount calculated by the calculation unit.
The plant longevity treatment device according to claim 23. The plant longevity treatment device according to claim ²⁴ , wherein the light source control unit controls the light source so that an integrated irradiance of the light on the leaf blade of the plant is equal to or greater than (10 × central wavelength of the light (nm) − 2190) mJ/cm2. Further comprising an irradiation position control unit capable of changing an irradiation position of the light emitted from the light source.
The plant longevity treatment device according to claim 13. The plant longevity treatment device of claim 23, further comprising an irradiation position control unit capable of changing the direction in which the light source faces in accordance with the accumulated irradiation amount calculated by the calculation unit, thereby changing the irradiation position of the light emitted from the light source. The light source has a plurality of light exit surfaces from which the light is emitted.
The plant longevity treatment device according to claim 13. Further comprising a plant transport unit,
The plant longevity treatment device according to claim 13. The leaf blade recognition unit includes a plant recognition unit capable of recognizing the type of the plant.
The plant longevity treatment device according to claim 17. The leaf blade recognition unit includes a flower recognition unit capable of recognizing a flower part of the plant.
The plant longevity treatment device according to claim 17. Further comprising an irradiation prevention part that prevents the light from being irradiated onto a flower part of the plant.
The plant longevity treatment device according to claim 13.

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