JP2020054287A - Method for inhibiting plant growth and illumination device for inhibiting plant growth - Google Patents

Abstract

To provide a method for inhibiting plant growth and an illumination device for inhibiting plant growth that can inhibit the growth of plants without using a chemical substance.SOLUTION: A light period treatment for making a plant synthesize NADPand a dark period treatment for making a plant decompose NADPare performed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a plant growth suppressing method and a plant growth suppressing lighting device. More specifically, the present invention relates to a technique for suppressing plant growth suitable for use in managing and controlling plant growth / growth using, for example, artificial light.

  Conventionally, a method of irradiating a plant with light generated from an artificial light source to promote the growth / growth of the plant has been known (for example, Patent Document 1).

JP 2013-153666 A

  On the other hand, a method utilizing light generated from an artificial light source to suppress plant growth / growth has not been established at least as a practical method.

  For example, use technologies to control plant growth / growth, especially chemicals, to create and maintain good landscapes with low grass green spaces, maintain slopes, and prevent reputational damage caused by the use of herbicides and herbicides. A technique that suppresses the growth / growth of plants without using them is useful.

  Therefore, an object of the present invention is to provide a plant growth suppression method and a plant growth suppression lighting device that can suppress plant growth / growth without using a chemical substance.

In order to achieve the object, the method for suppressing plant growth according to the present invention is configured such that a light period treatment for synthesizing NADP ⁺ in a plant and a dark period treatment for decomposing NADP ⁺ are performed.

  In the method for suppressing plant growth according to the present invention, a light period treatment of 0.5 minutes or more and 30 minutes or less and a dark period treatment of 20 minutes or more and 120 minutes or less may be performed.

  In the method for suppressing plant growth according to the present invention, the light period treatment and the dark period treatment may be performed outdoors at night.

The illumination device for plant growth inhibiting according to the present invention includes an illumination condition for irradiating light to the plant in order to synthesize the NADP ⁺ into plants not irradiated with light to plants in order to decompose the NADP ⁺ It is controlled to be in a hibernation state.

  The lighting device for suppressing plant growth according to the present invention has a lighting state of not less than 0.5 minutes and not more than 30 minutes for irradiating the plant, and a halt state of not less than 20 minutes and not more than 120 minutes for not irradiating the plant. May be controlled.

  According to these plant growth suppressing methods and plant growth suppressing lighting devices, plant growth / growth is suppressed by controlling light irradiation, so that plant growth / growth is suppressed without using chemical substances. .

  According to the plant growth suppressing method and the plant growth suppressing lighting device, the growth / growth of the plant can be suppressed by light irradiation for a relatively short time, so that the management / control of the plant growth / growth can be performed at a low cost. Is performed.

Further, the method for suppressing plant growth of the present invention may be arranged such that the photosynthetic photon flux density of light applied to the plant in the light period treatment is 10 to 50 μmolm ⁻² s ⁻¹ , In the lighting device for suppressing plant growth described above, the photosynthetic photon flux density of light may be 10 to 50 μmolm ⁻² s ⁻¹ . In these cases, the growth / growth of the plant is suppressed by the irradiation of weak light.

Further, in the method for suppressing plant growth of the present invention, the intensity of light applied to the plant in the light period treatment may be at least an intensity at which NADP ⁺ can be synthesized in the plant. In the lighting device for suppressing plant growth of the present invention, the light intensity may be at least an intensity at which NADP ⁺ can be synthesized in the plant. In these cases, the growth / growth of the plant is suppressed by irradiation of the minimum necessary weak light.

  According to the plant growth suppressing method and the plant growth suppressing lighting device of the present invention, plant growth / growth can be suppressed without using a chemical substance. And versatility can be improved.

  According to the plant growth suppressing method and the plant growth suppressing lighting device of the present invention, the growth / growth of the plant can be managed and controlled at low cost. It is possible to improve the usefulness and versatility of the device.

  The plant growth suppressing method and the plant growth suppressing lighting device of the present invention can suppress plant growth / growth by irradiating weak light when the light intensity is in a predetermined range or degree. Therefore, it is possible to improve usefulness and versatility as a method for suppressing plant growth / growth.

It is a figure which shows the comparative example of Example 1, and the state of the aspect of growth / growth for every light-dark pattern. It is a figure which shows the transition of the leaf area for every comparative example of Example 1, and a light-dark pattern. It is a figure which shows the comparative example of Example 1, and the individual biomass for every light-dark pattern. It is a figure which shows the comparative example of Example 2, and the increase rate of the leaf area for every light-dark pattern. FIG. 10 is a diagram showing changes in the amount of NADP ^{+ and the} amount of NADPH over time from the start of light irradiation in Example 3. It is a figure which shows each transition of the amount of NADP ^{+ and the} amount of NADPH with time progress from the end of light irradiation of Example 4. It is a figure which shows the total amount of NADP ⁺ and NADPH according to the intensity of the irradiation light of Example 5. It is a figure which shows the total amount of NADP ⁺ and NADPH according to the light irradiation time length of Example 6.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  Hereinafter, an example of an embodiment of a plant growth suppressing method and a plant growth suppressing lighting device according to the present invention will be described.

In the method for suppressing plant growth of the present embodiment, a light period treatment for synthesizing NADP ⁺ in a plant and a dark period treatment for decomposing NADP ⁺ are performed.

  In the plant growth suppressing method of the present embodiment, in particular, a light period treatment of 0.5 minutes or more and 30 minutes or less and a dark period treatment of 20 minutes or more and 120 minutes or less are performed.

The illumination device for plant growth inhibition of this embodiment (simply referred to as "illumination device") includes an illumination condition for irradiating light to the plant in order to synthesize the NADP ⁺ into plants, to decompose the NADP ⁺ For this reason, the plant is controlled to be in a rest state in which light is not irradiated to the plant.

  The illumination device for plant growth suppression of the present embodiment is, in particular, an illumination state of 0.5 minutes or more and 30 minutes or less for irradiating plants, and a lighting state of 20 minutes or more and 120 minutes or less for not irradiating plants It is controlled to be in a hibernation state.

  The lighting device includes a light emitting unit that emits (in other words, emits and emits) light for irradiating a plant, and a control unit that controls the light emitting unit.

  It is conceivable that the lighting device is arranged above the plant. However, the lighting device may be arranged at a position that can irradiate light to the plant to be grown and controlled, and may be arranged at the side of the plant. It may be arranged on the side.

  The light emitting unit of the lighting device includes a light source that emits light, and is configured to emit / emit monochromatic light or mixed color light.

  The light emitting portion of the lighting device may be provided with one unit or a plurality of units as a group of mechanisms for emitting / emitting light. Further, each light emitting section may be configured to have one light source, or may be configured to have a plurality of light sources.

  The light emitting portion of the lighting device may be specifically configured to have, for example, one or a plurality of semiconductor light emitting elements such as a light emitting diode (as a light source) or a laser diode, a fluorescent lamp, a fluorescent lamp, or a metal halide lamp. . The light emitting portion of the lighting device may be configured as a device including a plurality of types of light sources.

  The control unit of the lighting device controls the light emitting unit, and controls the light emitting unit such that a process of emitting light and a process of suspending the emission of light are performed according to a predetermined cycle.

  Regarding the lighting device, a state in which a process of emitting light (that is, a state of irradiating light) is referred to as an “illumination state”, and a state of performing a process of suspending the emission of light (that is, a state of emitting light). The state in which irradiation is not performed) is called a “rest state”. That is, the lighting device is controlled by the control unit so as to be in a lighting state or a hibernation state.

  While the lighting device is not emitting light, the plant is not irradiated with any light including light other than the light emitted from the lighting device as well as the light emitted from the lighting device (that is, , Light-shielded state) is secured and maintained. For example, not only is the plant not irradiated with artificial light from the lighting device, but also with other artificial light or natural light.

  Regarding plants, a state where some light is irradiated is called a “light state”, and a state where no light is irradiated is called a “dark state”.

  Putting the plant in the light state is called "light period processing", and putting the plant in the dark state is called "dark period processing".

The dark state in the present invention refers to a state in which light that can reach a plant is blocked to such an extent that a plant to be grown and controlled does not or hardly synthesizes NADP ⁺ . Therefore, the dark state in the present invention is not only a state in which all light that can reach the plant is blocked and the plant is completely dark (in other words, a completely shaded state for the plant), but also a state in which the plant has NADP ⁺ This includes the state where plants are placed in an environment where light is irradiated to such an extent that synthesis is not performed or hardly performed.

  The control unit of the lighting device executes a process of outputting a command to emit light to the light emitting unit or outputs a command to suspend emission of light in accordance with a predetermined control command stored in the control unit. Execute processing.

  The control unit of the lighting device may be configured by, for example, a combination of a CPU (Central Processing Unit) and a nonvolatile storage device, or controls a power supply device and on / off of the power supply device. It may be configured by a combination with a digital timer.

  The wavelength of the light emitted from the light emitting portion of the lighting device is not limited to a specific peak wavelength or wavelength range. For example, white light may be emitted from the light emitting unit, or red light (specifically, light having a peak wavelength in the range of approximately 600 to 700 nm) or blue light (specifically, (A light having a peak wavelength in the range of approximately 400 to 500 nm) may be emitted, or mixed color light having a plurality of peak wavelengths may be emitted.

The intensity (in other words, the amount of light) of the light emitted from the light emitting unit of the lighting device is not limited to a specific level. The light intensity at the time of the light period treatment is specifically set, for example, to any value in the range of about 5 to 1000 μmolm ⁻² s ⁻¹ in photosynthetic photon flux density, for example only. Can be considered.

  The wavelength and intensity of the light emitted from the light emitting unit of the lighting device may be kept constant during the light period processing, or may be changed during the light period processing.

  In the present embodiment, by switching between a lighting state in which the lighting device irradiates light and a halt state in which the lighting device pauses light irradiation, a light state in which the plant is irradiated with light is performed. The light period treatment and the dark period treatment in which the plants are not irradiated with light are performed alternately and continuously, that is, light irradiation is performed in a mode having a light / dark cycle.

  For example, turning on / off a lighting device (in other words, switching between a lighting state and a dormant state) in an environment where a plant to be grown and controlled is housed in a plant growth chamber, a container, or the like, and external light can be blocked. By performing (operation), the lighting device is turned on, the light from the lighting device is irradiated, and the light period process is performed, and the lighting device is turned off and the external light is shut off to perform the dark period process.

  Alternatively, for plants that grow outdoors and plants that are placed outdoors, the lighting device is turned on and off at night (in other words, a switching operation between a lighting state and a resting state) to perform lighting. The device is turned on, light is emitted by the lighting device, and light period processing is performed, and the lighting device is turned off and dark period processing is performed in a natural environment state in which natural light is sufficiently suppressed.

  The form of the lighting device is not limited to a specific form and form, and an appropriate form and form is appropriately determined in consideration of the situation of the growing area of the plant to be managed and controlled and its surroundings. Selected. Examples of the lighting device include various forms and types such as a stationary type, a fixed type, and a movable type.

  The lighting device may be, for example, a mode (installation type) provided in a facility (for example, a plant growth chamber or a container) in which a plant is housed, or in a zone where a plant is growing or in the zone. It may be installed in an adjacent place (fixed type), or may be installed in a small unmanned aerial vehicle (UAV: Unmanned Aerial Vehicle; also called "drone") (mobile type).

  Since short-time light irradiation is sufficient for the light period processing, it is also possible to use a small unmanned aerial vehicle as the lighting device. In this case, the present invention flexibly responds to the situation and size of the target area It can also be implemented as a mechanism that can be implemented as a remote automatic operation.

  Alternatively, the lighting device may be configured to be equipped with a solar cell and installed outdoors to store electricity during the day and perform illumination at night. In this case, the present invention can be realized as a mechanism that can make the lighting device self-supporting and greatly reduce ordinary labor.

The light treatment in the present invention is a process in which NADP ⁺ is synthesized in a plant by irradiating the plant with light. Therefore, the light treatment is performed at least for the time necessary for the synthesis of NADP ^{+ in} the plant. For this reason, the time length of the light period treatment should be set to an appropriate time length after considering the time length in which NADP ⁺ can be synthesized according to the type and type of the plant to be managed and controlled. It is set appropriately.

  The time length per light period process is specifically set, for example, to any value in a range of about 0.5 to 30 minutes as a general example. It is preferably set to any value in a range of about 20 minutes, more preferably set to any value in a range of about 0.5 to 15 minutes, and more preferably set to a value of 0.5 to 10 minutes. It is even more preferable to set the value to any value in the range of about minutes, and it is particularly preferable to set the value to any value in the range of about 0.5 to 4 minutes.

  A time length of 0.5 to 2 minutes per light period treatment is sufficient, and in particular, the viewpoint of saving energy used for light irradiation (and reducing the cost for light irradiation). Is preferred.

On the other hand, the dark period treatment in the present invention is a process in which NADP ⁺ synthesized in the light period treatment is decomposed by sufficiently suppressing the light irradiated to the plant. Thus, the dark phase treatment is performed for at least the time required for the degradation of NADP ^{+ in} the plant. For this reason, the time length of the dark period treatment is set to an appropriate time length, taking into account the time length in which NADP ⁺ can be decomposed in accordance with the type and type of the plant to be managed and controlled. It is set appropriately.

  Specifically, for example, the length of time per one dark period process is set to about 20 minutes or more, and preferably to about 30 minutes or more as a general example.

  For example, for plants housed in equipment that can block external light, such as a plant growth chamber or a container, the equipment is closed and a light-shielded state is realized to perform dark period processing.

  Alternatively, for plants growing outdoors or placed outdoors, a state in which the light period treatment is not performed at night (that is, a state in which the plants are not irradiated with light) corresponds to the dark period treatment. I do. If necessary, it is considered that the light period processing is started at a time when the time length from the end of the light period processing to the sunrise can be secured for 20 to 30 minutes or more.

  The light / dark cycle process is performed as a set of procedures in which the light period process is performed first and the dark period process is subsequently performed. That is, as the light-dark cycle processing, the light period processing and the dark period processing are continuously performed in this order.

  The light-period processing and the dark-period processing may be performed one time continuously (that is, the light-dark cycle processing is performed only once), or may be performed repeatedly and continuously alternately a plurality of times. (That is, the light-dark cycle processing is repeatedly performed a plurality of times).

  When the light-dark cycle processing is repeatedly performed a plurality of times, the wavelength and intensity (in other words, the light amount) of the light emitted from the light emitting unit of the lighting device in the light-period processing of each light-dark cycle processing are all light-dark cycles. The processing may be the same, or may be different for each light / dark cycle processing.

  Further, when the light-dark cycle processing is repeatedly performed a plurality of times, the time length of the light-period processing and the time length of the dark-period processing in each light-dark cycle processing may be the same in all the light-dark cycle processing, or Alternatively, the time length may be varied within the above-described time length range for each light / dark cycle process.

  The length of time when the light-dark cycle processing is repeated a plurality of times is not limited to a specific length of time, and the degree of suppression of growth / growth required for plants to be controlled and controlled for growth / The time length is appropriately set to an appropriate time length of 24 hours a day depending on the feasibility.

  As a possibility of the light-dark cycle processing, for example, when plants growing outdoors or plants placed outdoors are subject to growth management and control, the light period processing and the dark period processing are alternately and continuously performed. The time period that can be repeated may be limited to nighttime (that is, from sunset to sunrise) without special facilities. In this case, in other words, the length of time during which the light-dark cycle processing is performed ranges from about 10 hours (specifically, in summer) to about 14 hours (specifically, winter). Become. When the light-dark cycle processing is performed only once during the night, the maximum length of the dark period processing is about 10 to 14 hours.

  Further, when the present invention is applied to a plant housed in a facility that can block external light such as a plant growth chamber or a container, for example, it is necessary not to weaken the plant more than necessary. In such a case, the light period process and the dark period process may be performed at night during the day, and natural light may be applied to the plants during the day. In such a case, specifically, for example, as an example, natural light may be applied to the plant for about 6 to 16 hours out of 24 hours a day. That is, the length of time during which the light-dark cycle processing is performed is about 8 to 18 hours.

  The light-dark cycle process can be performed as an operation that starts at an arbitrary timing and ends at an arbitrary timing immediately after the seeds germinate or the seedlings are planted. The present invention can be applied irrespective of the growth stage of the plant subject to growth management and control, that is, regardless of whether it is the initial stage of growth or whether the growth has already progressed.

  The period length when the light-dark cycle processing is repeated a plurality of times is not limited to a specific number of days, but depends on the period during which growth / growth is required to be suppressed for plants to be controlled and controlled. It is set appropriately to an appropriate number of days.

  Cultivated plants targeted by the plant growth suppressing method and the plant growth suppressing lighting device according to the present invention (in other words, cultivated plants to which the present invention can be applied) are not limited to plants of a specific kind or type. For example, the present invention is applicable regardless of whether it is a plant that blooms, whether it is a plant that produces fruit, and whether it is a leafy vegetable, a flower, or a tree.

  In addition, the cultivation mode of the plant (in other words, the plant cultivation mode to which the present invention can be applied) targeted by the plant growth suppressing method and the plant growth suppressing lighting device according to the present invention is a specific type of cultivating mode. It is not limited, and may be any of, for example, hydroponics, soil cultivation, nutrient cultivation, and medium cultivation.

  According to the plant growth suppression method and the plant growth suppression lighting device configured as described above, the growth / growth of the plant is suppressed by controlling the light irradiation. / Growth can be suppressed. For this reason, it is possible to improve the usefulness and versatility as a method of suppressing plant growth / growth. Further, since the growth / growth of the plant can be suppressed by light irradiation for a relatively short time, the management / control of the growth / growth of the plant can be performed at low cost. For this reason, it is possible to improve the usefulness and versatility as a method of suppressing plant growth / growth.

  Although the above-described embodiment is an example of a preferred embodiment when carrying out the present invention, the embodiment of the present invention is not limited to the above-described embodiment, and the present invention is not limited thereto without departing from the gist of the present invention. The invention can be implemented in various modifications.

  For example, in the above-described embodiment, the light period processing is realized by emitting light from the light emitting unit of the lighting device. However, the method of realizing the light period processing is limited to a mode in which the lighting device is used. Instead, natural light (for example, sunlight) may be used. In this case, for example, a plant to be subjected to growth management and control is accommodated in a plant growth chamber or a container having an opening provided with an openable / closable door or shutter, and natural light is generated by opening the door or shutter. Is adopted to realize the light period processing, and the doors and shutters are closed to shut off natural light to realize the dark period processing (in this case, the plant to be subjected to growth management / control is controlled). When it is necessary not to weaken unnecessarily, light processing and dark processing are performed at night during the day, and the doors and shutters are opened during the day to take in natural light. To give the plant natural light.) That is, the plant growth control method according to the present invention can be carried out without using lighting equipment, in other words, using natural light (sunlight) instead of artificial light.

  Embodiments of the method for suppressing plant growth and the lighting device for suppressing plant growth according to the present invention, in which the effect of suppressing the growth / growth of a plant, will be described with reference to FIGS. 1 to 3.

  In the present example, Arabidopsis seeds were sown on the moist culture soil to raise seedlings. Seven days after sowing, the seedlings were collected and subjected to a cultivation experiment.

  Three types of light-dark cycle patterns were set for the combination of the light period processing time length and the dark period processing time length. The patterns of the three types of light-dark cycles were light-dark patterns <A>, <B>, and <C>, respectively.

  The contents of each of the three types of light / dark patterns <A> to <C> were set as follows. In the following, "daytime" refers to approximately 14 hours from sunrise to sunset, and "nighttime" refers to approximately 10 hours from sunset to sunrise.

Light / dark pattern <A>
A light-dark cycle process in which light is irradiated in the daytime as a state corresponding to the natural environment, and a light-period process for 1 minute and a dark-period process for 20 minutes are alternately performed in the nighttime. Is repeated a plurality of times (specifically, 30 times).

Light / dark pattern <B>
In the daytime, light is irradiated as a state corresponding to the natural environment, and in the nighttime, a light-period cycle process in which a light-period process in which light is radiated for 1 minute and a dark-period process in which light irradiation is suspended for 59 minutes is performed alternately and continuously. Is repeated a plurality of times (specifically, 10 times).

Light / dark pattern <C>
In the daytime, light is irradiated as a state corresponding to the natural environment, and at night, a light-dark cycle process in which a light-period process for 10 minutes where light is irradiated and a dark-period process for 50 minutes when light irradiation is stopped are performed alternately and continuously. Is repeated a plurality of times (specifically, 10 times).

  Further, as a <Comparative Example> for substantiating the effect of suppressing the growth / growth of the plant by the method for suppressing plant growth according to the present invention, light is irradiated in the daytime in a state corresponding to the natural environment, and light / dark cycle processing is performed at night. An experimental group was set up that was not administered (ie, the dark state was maintained throughout the night).

  An experimental group consisting of six samples (six seedlings) was constructed for each of the light-dark patterns <A> to <C> and <Comparative Example>, and all the experimental groups were simultaneously accommodated in a growth box and subjected to a cultivation test. .

  The growth box used in this example had a structure capable of blocking external light, and the internal temperature was maintained at 23 ° C. during the experiment.

The light irradiating the plants constituting the experimental groups of the light and dark patterns <A> to <C> in the growth box is white light, and the light intensity (in other words, the amount of light) is the daylight intensity of the photosynthetic photon flux. The light irradiated during the time zone was set at about 100 μmolm ⁻² s ⁻¹ , and the light irradiated during the night light period treatment was set at about 100 μmolm ⁻² s ⁻¹ .

<Experimental results>
Cultivation experiments were performed in accordance with the above-described conditions and specifications, and the results shown in FIG. 1 were obtained on the 7th day of the experiment, for the <Comparative Example> and the state of the mode of growth / growth for each of the light and dark patterns <A> to <C>. Was. Note that all the experimental groups were photographed under the same conditions so that the apparent sizes could be compared.

  From the results shown in FIG. 1, all of the light-dark patterns <A> to <C> subjected to the light-dark cycle processing according to the present invention have stems and stalks better than the <Comparative Example> not subjected to the light-dark cycle processing. The expansion of the leaves was small, and it was confirmed that the light / dark cycle treatment according to the present invention suppressed the growth / growth of the plants.

In addition, regarding the state of the growth / growth phase of each of the <Comparative Example> and the light / dark patterns <A> to <C>, the daily change of the leaf area (unit: cm ² ) from the third day to the seventh day of the experiment. The result shown in FIG. 2 was obtained. The measured value of the leaf area shown in FIG. 2 is the average value of the total of the leaf areas of each seedling of six samples constituting each experimental group.

  From the results shown in FIG. 2, all of the light-dark patterns <A> to <C> subjected to the light-dark cycle processing according to the present invention have a larger leaf area than the comparative example not subjected to the light-dark cycle processing. Was small, and it was confirmed that the growth / growth of the plant was suppressed by performing the light-dark cycle treatment according to the present invention. Specifically, the degree of increase in the leaf area with the passage of time in all of the light-dark patterns <A> to <C> is slower than that in the <Comparative Example>, and the light-dark cycle processing according to the present invention is It was confirmed that the application continuously greatly slowed down the growth / growth of the plant.

  In addition, regarding the state of the growth / growth body for each of the <Comparative Example> and the light / dark patterns <A> to <C>, the individual biomass (specifically, fresh weight) on the 7th day of the experiment (unit: mgFW) The result shown in FIG. 3 was obtained. The measured value of the individual biomass shown in FIG. 3 is the average value of the biomass of each seedling of six samples constituting each experimental group.

  From the results shown in FIG. 3, all of the light-dark patterns <A> to <C> subjected to the light-dark cycle processing according to the present invention were placed in a natural environment and not subjected to the light-dark cycle processing. Example>, the value of the individual biomass was smaller, and it was confirmed that the growth / growth of the plant was suppressed by performing the light-dark cycle treatment according to the present invention.

  In addition, from the results shown in FIGS. 1 and 2, it was confirmed that when the present invention was applied, the plants were only suppressed in their growth / growth, and did not cause abnormal morphology or wither.

  From the results of this example, light-dark cycle processing in which light irradiation for about 1 to 10 minutes and light-shielding for about 20 to 59 minutes are performed alternately and continuously is compared with the case where the light-dark cycle processing is not performed. It was shown that the growth / growth was significantly suppressed from half to about one third (based on individual biomass, 7 days). From the results shown in this example, it is clear that the plant growth suppressing method according to the present invention and the plant growth suppressing lighting device according to the present invention used when performing the method are effective in suppressing plant growth / growth. Was confirmed.

  Another embodiment of the method for suppressing plant growth / growth of a plant growth suppressing method and a plant growth suppressing lighting device according to the present invention will be described with reference to FIG.

  In the present example, Arabidopsis seeds were sown on the moist culture soil to raise seedlings. Seven days after sowing, the seedlings were collected and subjected to a cultivation experiment.

  Two types of light-dark cycle patterns were set for the combination of the light period processing time length and the dark period processing time length. The patterns of the two types of light-dark cycles were light-dark patterns <D> and <E>, respectively.

  The contents of each of the two types of light-dark patterns <D> and <E> were set as follows. In the following, "daytime" refers to approximately 14 hours from sunrise to sunset, and "nighttime" refers to approximately 10 hours from sunset to sunrise.

Light / dark pattern <D>
In the daytime, light is irradiated as a state corresponding to the natural environment, and in the nighttime, a light-period cycle process in which a light-period process in which light is radiated for 1 minute and a dark-period process in which light irradiation is suspended for 59 minutes is performed alternately and continuously. Is repeated a plurality of times (specifically, 10 times).

Light / dark pattern <E>
In the daytime, light is irradiated as a state corresponding to the natural environment, and in the nighttime, a light period process in which light processing is performed for 1 minute and a light period process in which light irradiation is suspended for 119 minutes are alternately and continuously performed. Is repeated a plurality of times (specifically, five times).

  Further, as a <Comparative Example> for substantiating the effect of suppressing the growth / growth of the plant by the method for suppressing plant growth according to the present invention, light is irradiated in the daytime in a state corresponding to the natural environment, and light / dark cycle processing is performed at night. An experimental group was set up that was not administered (ie, the dark state was maintained throughout the night).

  An experimental group consisting of six samples (six seedlings) was constructed for each of the light and dark patterns <D> and <E> and <Comparative Example>, and all the experimental groups were simultaneously accommodated in a growth box and subjected to a cultivation test. .

  The growth box used in this example had a structure capable of blocking external light, and the internal temperature was maintained at 23 ° C. during the experiment.

The light irradiating the plants constituting the experimental groups of the light and dark patterns <D> and <E> in the growth box is white light, and the light intensity (in other words, the amount of light) is the daylight intensity of the photosynthetic photon flux. The light irradiated during the time zone was set at about 100 μmolm ⁻² s ⁻¹ , and the light irradiated during the night light period treatment was set at about 100 μmolm ⁻² s ⁻¹ .

<Experimental results>
Cultivation experiments were carried out in accordance with the above conditions and specifications, and the leaf area (unit: cm ^{2) on the} 7th day of the experiment was determined with respect to the <Comparative Example> and the state of the growth / growth phase for each of the light and dark patterns <D> and <E>. 4), the results shown in FIG. 4 were obtained for the rate of increase (unit:%) from the beginning of the experiment. The measured value of the leaf area based on the increase rate shown in FIG. 4 is the average value of the total of the leaf areas for each seedling of six samples constituting each experimental group.

  From the results shown in FIG. 4, both the light-dark patterns <D> and <E> subjected to the light-dark cycle processing according to the present invention have a larger leaf area than the <Comparative Example> not subjected to the light-dark cycle processing. It was confirmed that the growth / growth of the plant was suppressed by performing the light-dark cycle treatment according to the present invention with a small increase rate.

  In addition, when this invention was applied, it was confirmed as a state of appearance that only the growth / growth of the plant was suppressed, and no abnormal morphology occurred or died.

  According to the results of this example, the light / dark cycle processing in which light irradiation for about 1 minute and light shielding for about 59 to 119 minutes are alternately and continuously performed is compared with the case where the light / dark cycle processing is not performed. It was shown that the growth was significantly suppressed from half to about one quarter (based on the increase rate of leaf area, 7 days). From the results shown in this example, it is clear that the plant growth suppressing method according to the present invention and the plant growth suppressing lighting device according to the present invention used when performing the method are effective in suppressing plant growth / growth. Was confirmed.

  Embodiments of the method for suppressing plant growth and the lighting device for suppressing plant growth according to the present invention, in which a mechanism for suppressing plant growth / growth and a condition required for the present invention are studied, will be described with reference to FIG. I do.

  In the present invention, the mechanism of suppressing plant growth / growth is to produce a remarkable plant growth / growth inhibitory effect by influencing the photosynthetic mechanism of the plant by combining light irradiation and shading. It is considered that there is.

In plant photosynthesis, NADP ⁺ and NADPH, which are coenzymes involved in the oxidation-reduction reaction of a living body, play a role as an electron mediator.

  Specifically, the carbon fixation reaction that takes in carbon dioxide from the air and converts it into organic matter (that is, contributes to plant growth / growth) occurs in a part called stroma in the chloroplast, and the calvin cycle (or calvin cycle)・ Benson circuit). In the Calvin cycle, NADPH plays a role as a reducing agent, and a photochemical reaction using light energy plays a role in supplying NADPH to the Calvin cycle.

NADPH is produced by passing electrons released when water is oxidized to produce oxygen to NADP ⁺ (ie, NADP ⁺ acts as an electron acceptor). Further, NADP ⁺ is synthesized after being irradiated with light, that is, at an initial stage of photosynthesis, and when electrons are not received because photosynthesis is not performed without irradiation of light, it is decomposed after a certain time elapses.

In view of the above, the mechanism of suppressing plant growth / growth in the present invention is to irradiate light to synthesize NADP ⁺ and generate NADPH to use energy for the plant, By stopping light irradiation before being used for growth, synthesis of NADP ⁺ and generation of NADPH (in other words, preparation of photosynthesis) wastes energy and does not use NADPH for growth / growth. As a result, it was thought that the mechanism was to suppress plant growth / growth.

Additional likened also based, in the present embodiment, in order to verify the synthesis and generation realities of NADP ⁺ and NADPH, investigated the relationship between the total length of time and NADP ⁺ and NADPH for irradiating light to the plant Was.

  In the present example, Arabidopsis seeds were sown on the moist culture soil to raise seedlings. Seven days after sowing, the seedlings were collected and subjected to a cultivation experiment.

In this example, the plant was irradiated with white light having a photosynthetic photon flux density of 100 μmolm ⁻² s ⁻¹ .

<Experimental results>
For the experimental body, NADP in the leaves at the start of the experiment (in other words, immediately before the start of light irradiation: 0 minutes) and at the lapse of 0.5, 1, 2, and 4 minutes from the start of light irradiation, respectively. ^{The +} amount (symbol in the figure) and the NADPH amount (symbol in the figure) were measured, and the results shown in FIG. 5 were obtained.

  From the results shown in FIG. 5, it was confirmed that the amount of NADPH in the plant began to increase by irradiating light for at least about 0.5 minutes.

From the results shown in FIG. 5, it was found that NADPH continued to increase and NADP ⁺ did not change for at least about 4 minutes after the start of light irradiation. Here, when a plant is irradiated with light, NADP ⁺ is converted to NADPH within several microseconds to several milliseconds, so that “NADP ⁺ does not change (that is, does not decrease)” and “NADPH increases”. This phenomenon means that "NADP ⁺ is synthesized and the total amount of NADP ⁺ and NADPH is increased". That is, from the results shown in FIG. 5, it is necessary to irradiate the plants with light for 0.5 minutes or more in order to increase (in other words, synthesize) NADP ⁺ in the plants, in other words, 0.5 minutes or more. It has been confirmed that NADP ⁺ can be increased (in other words, synthesized) by light irradiation.

  The results of this example showed that irradiation with light for approximately 0.5 minutes or longer can prepare plants for photosynthesis and consume energy. From the results shown in this example, it was confirmed that the mechanism according to the present invention, in which the plant was prepared for photosynthesis by short-time light irradiation and energy was consumed to suppress plant growth / growth, was confirmed.

  FIG. 6 shows another embodiment in which the mechanism for suppressing plant growth / growth and the conditions required for the present invention are examined using the plant growth suppressing method and the plant growth suppressing lighting device according to the present invention. Will be explained.

In consideration of the viewpoint described in Example 3 above, in this example, in order to verify the actual state of degradation of NADP ⁺ and NADPH, the time length after the irradiation of the plant with light and the total amount of NADP ⁺ and NADPH were determined. The relationship between was examined.

  In the present example, Arabidopsis seeds were sown on the moist culture soil to raise seedlings. Seven days after sowing, the seedlings were collected and subjected to a cultivation experiment.

In this example, first, a plant was irradiated with white light having a photosynthetic photon flux density of 100 μmolm ⁻² s ⁻¹ for 30 minutes. Thereafter, the light irradiation was stopped and the light was shielded, and the plants were maintained in a dark state.

<Experimental results>
With respect to the experimental body, NADP ⁺ in the leaves at the end of light irradiation (in other words, immediately before turning off: 0 minutes) and at 1, 15, 30, and 60 minutes after the end of light irradiation (FIG. The symbol ● in the figure and NADPH (the symbol ○ in the figure) were measured, and the results shown in FIG. 6 were obtained.

From the results shown in FIG. 6, it was confirmed that the amount of NADP ^{+ in} the plant began to decrease by blocking light for at least about 20 minutes.

From the results shown in FIG. 6 and by comparing with the results shown in FIG. 5 of the third embodiment described above, the degree of decrease in the amount of NADP ⁺ and NADPH due to shading is increased by the increase in the amount of NADP ⁺ and NADPH due to light irradiation. It was evident that it was slower than the degree of Here, if the plant is not irradiated with light, NADPH is converted to NADP ⁺ within several microseconds to several milliseconds, so that NADPH is almost at the basal level in the measurement one minute after the end of light irradiation. On the other hand, it was confirmed that NADP ⁺ hardly decreased in the measurement 15 minutes after the end of the light irradiation, but started to decrease in the measurement 30 minutes later, and reached the basal level in about 60 to 120 minutes. From these facts, it was considered that light shielding for about 20 minutes or more was necessary to reduce (in other words, decompose) NADP ⁺ .

The results of this example showed that NADP ⁺ and NADPH once synthesized and produced in plants can be decomposed by shading for about 20 minutes or more. From the results shown in this example, the plant is prepared for photosynthesis by irradiating light for a short time to consume energy, and then the light is shielded from light to dissipate the preparation for photosynthesis and consequently waste energy to produce a plant. The accuracy of the mechanism according to the present invention of suppressing growth / growth was confirmed.

  Referring to FIG. 7, an embodiment in which conditions required for the plant growth suppressing method and the plant growth suppressing lighting device according to the present invention are examined will be described.

In this embodiment, in order to verify the synthesis and generation realities of NADP ⁺ and NADPH, it was examined the relationship between the total amount of the intensity of light and NADP ⁺ and NADPH for irradiating the plant.

  In the present example, Arabidopsis seeds were sown on the moist culture soil to raise seedlings. Seven days after sowing, the seedlings were collected and subjected to a cultivation experiment.

In this example, the experimental body irradiated with white light whose photosynthetic photon flux density was set to 10 μmolm ⁻² s ⁻¹ and the white light whose photosynthetic photon flux density was set to 50 μmolm ⁻² s ⁻¹ The irradiated body was prepared.

<Experimental results>
For each experimental body, per fresh weight (unit: g) of the leaf at the start of the experiment (in other words, immediately before the start of light irradiation) and at the lapse of 5, 10, and 30 minutes from the start of light irradiation, respectively. The total amount (unit: nmol) of NADP ⁺ and NADPH was measured, and the results shown in FIG. 7 were obtained.

From the results shown in FIG. 7, it was confirmed that irradiation of light having a photosynthetic photon flux density of at least about 10 μmolm ⁻² s ⁻¹ started increasing the total amount of NADP ⁺ and NADPH in plants.

From the results shown in FIG. 7, it was confirmed that the total amount of NADP ⁺ and NADPH rapidly increased until about 5 minutes from the start of light irradiation. In addition, when weak light having a photosynthetic photon flux density of about 10 μmolm ⁻² s ⁻¹ is irradiated, it is confirmed that the total amount of NADP ⁺ and NADPH continues to increase for at least about 30 minutes after the start of light irradiation. Was done.

The results of this example showed that the synthesis of NADP ⁺ and the generation of NADPH were induced even by irradiation with weak light having a photosynthetic photon flux density of about 10 μmolm ⁻² s ⁻¹ . From the results shown in this example, in the plant growth suppression method and the plant growth suppression lighting device according to the present invention, the light period treatment is performed even when the photosynthetic photon flux density is about 10 μmolm ⁻² s ⁻¹ light irradiation. It was confirmed that the effect of suppressing plant growth / growth could be exerted.

  With respect to the method for suppressing plant growth and the lighting device for suppressing plant growth according to the present invention, still another embodiment in which conditions required for the present invention are examined will be described with reference to FIG.

In this embodiment, in order to verify the synthesis and generation realities of NADP ⁺ and NADPH, the relationship between the total length of time and NADP ⁺ and NADPH for irradiating light it was investigated against plant.

  In the present example, Arabidopsis seeds were sown on the moist culture soil to raise seedlings. Seven days after sowing, the seedlings were collected and subjected to a cultivation experiment.

  In the present embodiment, each of the experimental bodies in which the time length of light irradiation was set to 0 minute (that is, always in a dark state), 0.5 minutes, 1 minute, 2 minutes, and 4 minutes was prepared.

In this example, the plant was irradiated with white light having a photosynthetic photon flux density of 10 μmolm ⁻² s ⁻¹ .

<Experimental results>
For each experimental body, the total amount of NADP ⁺ and NADPH per fresh weight of leaves (unit: g) at the start of the experiment (in other words, immediately before the start of light irradiation: 0 minutes) and at the lapse of 10 minutes from the start of the experiment (units) : Nmol), and the result shown in FIG. 8 was obtained. Note that the time point of 10 minutes after the start of the experiment is, specifically, for an experimental body that is irradiated with light for 0.5 minutes, for example, the light irradiation is started at the same time as the start of the experiment and 0.5 minutes after the start of the experiment. The light irradiation ends later, and this is 9.5 minutes after the light irradiation ends.

From the results shown in FIG. 8, it was confirmed that the total amount of NADP ⁺ and NADPH started to increase in plants by irradiating light for at least about 0.5 minutes.

From the results of this example, it was confirmed that the synthesis of NADP ⁺ and the generation of NADPH were induced even by light irradiation for a short time of about 0.5 minutes. From the results shown in this example, in the method for suppressing plant growth and the lighting device for suppressing plant growth according to the present invention, the effect of suppressing plant growth / growth can be exerted even when the light period treatment is about 0.5 minute. I understood that.

  INDUSTRIAL APPLICABILITY The plant growth suppressing method and the plant growth suppressing lighting device according to the present invention can favorably perform plant growth management and control through plant growth / growth suppression. The utility value is high in fields such as cultivation (specifically, for example, adjustment of flowering time and shipping time of flowers).

Claims (9)

A plant growth suppressing method, wherein a light period treatment for synthesizing NADP ⁺ in a plant and a dark period treatment for decomposing NADP ⁺ are performed.   A plant growth suppressing method, wherein a light period treatment of 0.5 minutes or more and 30 minutes or less and a dark period treatment of 20 minutes or more and 120 minutes or less are performed.   The method according to claim 1 or 2, wherein the light period treatment and the dark period treatment are performed in the field at night. The method according to claim 1 or 2, wherein the photosynthetic photon flux density of the light applied to the plant in the light period treatment is 10 to 50 µmolm ^-2 s ^-1 . 3. The method according to claim 1, wherein the intensity of light applied to the plant in the light period treatment is at least an intensity at which NADP ⁺ can be synthesized in the plant. It is controlled to an illumination state of irradiating the plant with light to cause the plant to synthesize NADP ⁺ , and a dormant state of not irradiating the plant with light to decompose the NADP ^+. Lighting equipment for plant growth suppression.   A plant growth characterized by being controlled to an illumination state of irradiating the plant with light of 0.5 to 30 minutes and a resting state of not irradiating the plant with light of 20 to 120 minutes. Lighting device for suppression. The plant growth suppression lighting device according to claim 6 or 7, wherein the photosynthetic photon flux density of the light is 10 to 50 µmolm ^-2 s ^-1 . 8. The lighting device for plant growth suppression according to claim 6, wherein the intensity of the light is at least an intensity at which NADP ⁺ can be synthesized in the plant.