JP2008228689A - Method for acclimating plant to low light - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for acclimating plants to low light enabling plants to be kept in good condition even under the low light. <P>SOLUTION: The method for acclimating plants to low light comprises illuminating the plants with light emitted from an artificial light source indoors to acclimate the plants to low light; wherein blue light having the light intensity of ≤300μmolm-2s-1PPFD is shone, or red light having the light intensity of ≤100μmolm-2s-1PPFD is shone. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cultivation method that satisfactorily induces weak light acclimation of a plant and maintains the state of the plant well even under low light, which is preferably used as a cultivation method for indoor garden plants.

  Usually, the living environment of a person does not satisfy the light conditions enough for the growth of the plant, so when cultivating houseplants etc. indoors, the plant adapts to the environment where it is placed and adapts to low light. Arise. In such a weak light acclimation reaction, it is generally observed that the chlorophyll content per chloroplast increases while the chloroplast content per mesophyll cell decreases as the light compensation point decreases. For example, when the light acclimation reaction proceeds with a decrease in the light compensation point in Benjamin gum, the chloroplast content per mesophyll cell is halved, while the chlorophyll content per chloroplast is up to about 3.6 times To increase. These weak light acclimation reactions proceed relatively quickly and are almost completed in 4 weeks after moving under low light (Non-patent Document 1).

However, for example, when a plant is cultivated indoors using an artificial light source that is generally used as indoor lighting, such as a fluorescent lamp, it is not always easy to acclimatize to weak light, and if the acclimatization is delayed, it may increase or fallen leaves To do.
Journal of Horticultural Society Vol. 67, separate volume 2, page 380

  When such a phenomenon occurs, the value of the foliage plant decreases, so a method for cultivating the foliage plant in a good condition even under low light indoors is demanded.

  This invention is made | formed in view of this problem, Comprising: It provides the cultivation method which keeps the state of a plant favorable under low light as the main desired subject.

  That is, the weak light acclimation method according to the present invention is a method of cultivating a plant by irradiating light emitted from an artificial light source indoors, and irradiating blue light with an intensity of 300 μmol-2s-1 PPFD or less, Or it irradiates with red light with the intensity | strength of 100 micromolm-2s-1PPFD or less, It is characterized by the above-mentioned. In the present invention, “blue light” is light having a wavelength of about 470 nm ± 15 nm, and “red light” is light having a wavelength of about 660 nm ± 15 nm. Moreover, blue light and red light are each irradiated alone.

  The artificial light source used in the present invention is not particularly limited as long as it can irradiate blue or red light. Among them, the LED is mixed with bright line spectrum and other radiations in the ultraviolet and infrared regions seen in other light sources. It is possible to irradiate monochromatic light with a small spectrum half-width without using a filter, and it is possible to select a light emission color almost freely, and it is relatively inexpensive, and luminous efficiency compared to other light sources. It is suitable for use because it has good problems such as long life and few problems related to thermal radiation.

  In this invention, the intensity | strength of the light irradiated to a plant is adjusted to 300 micromol-2s-1PPFD or less in the case of blue light, and is adjusted to 100 micromol-2s-1PPFD or less in the case of red light. In general, the intensity of indoor light is one-hundred to one-hundredth of the intensity of light in a greenhouse for production of horticultural plants (approximately 1000 μmol-2s-1PPFD). By using light, acclimation to weak light can be well induced, and although the number of chloroplasts per cell decreases, the chlorophyll content per chloroplast can be increased to compensate for this. The number of newly developed leaves and their chlorophyll content can be maintained at a high level.

  That is, when the main purpose is to favorably induce weak light acclimation of existing leaves, it is preferable to irradiate blue light or red light with an intensity of 100 μmolm-2s-1 PPFD or less, and to emit blue light or red light. Irradiation with an intensity of 10 μmolm-2s-1 PPFD or less is more preferable.

  In addition, when the main purpose is to induce the establishment of newly developed leaves and their weak light acclimation, it is preferable to irradiate blue light with an intensity of 100 to 300 μmol-2s-1PPFD, When the main purpose is to induce the weak light acclimation of the newly developed leaves together with the leaves, it is preferable to irradiate the red light with an intensity of 100 μmolm-2s-1 PPFD or less, and the red light to 10 μmolm-2s- Irradiation with an intensity of 1 PPFD or less is more preferable.

  Although it does not specifically limit as a plant to which the method which concerns on this invention is applied, Generally this invention is used suitably for garden plants, such as a foliage plant grown indoors. Among these horticultural plants, Akko, Indian rubber tree, Oak rubber tree, Banyan tree, Kobanbodaiju, Shonan gum, Ficus Ultisima, Ficus Wildemaniana, Ficus Umberata, Ficus Sagitta, Ficus Triangularis, Ficus Benjamina (Benjamin) Rubber), Ficus pumila, Ficus petiolaris, French rubber tree, Bengalbodaiju, and other genus foliage plants including the genus Panacea such as breadfruit are preferable, and the genus Fixam such as Benjamin gum is particularly preferable. .

  In order to cultivate plants indoors using the present invention, for example, a light irradiation device including an LED as a light source and a means for adjusting the light intensity is used. Therefore, such a light irradiation apparatus used in the weak light acclimation method according to the present invention is also one aspect of the present invention.

One embodiment of a light irradiation apparatus according to the present invention is illustrated in FIG.
The light irradiation device 1 illustrated in FIG. 1 includes a light emitting unit 2 that emits light, and a power supply unit 3 that supplies power so that the intensity of the light emitted to the light emitting unit 2 can be changed. Is. Furthermore, in order to perform finer control according to the growth state of the plant, it is preferable to include the determination unit 4 and the light intensity setting unit 5.

  Each part will be described in detail. As shown in FIG. 2, the light emitting unit 2 includes a large number of LEDs 21 laid on one surface of a flat substrate 22, and is installed so that light emitted from the LEDs 21 faces a plant. The LED 21 is a blue LED or a red LED, and is, for example, a bullet type.

  The power supply unit 3 supplies power so that the emission intensity can be changed independently for each LED 21. As a specific power supply mode, in the present embodiment, for example, a PWM method is adopted, and by receiving reception or input of an external control signal, a duty ratio in a supply power waveform can be set for each LED 21. It is. And by setting the duty ratio, the light emission intensity for each LED 21 can be changed, and the intensity of the light emitted from the entire light emitting part 2 can be changed.

  The discriminating unit 4 discriminates the growth status of the plant 6 to be cultivated, for example, by an input by an operator.

  The light intensity setting unit 5 generates an external control signal for setting on / off and intensity of the light according to the growth state of the plant 6, and transmits the external control signal to the power supply unit 3. It is. Specifically, for example, an external control corresponding to the growth status of the plant 6 is accessed by accessing the control signal specifying data storage unit D1 storing a pair of an identifier indicating the growth status of the plant 6 and the identifier of the external control signal. The signal is specified and the external control signal is transmitted to the power supply unit 3.

  In the present embodiment, the determination unit 4, the light intensity setting unit 5, the control signal specifying data storage unit D1, and the like are configured using the information processing apparatus 7. As shown in FIG. 3, the information processing apparatus 7 includes a CPU 101, an internal memory 102, an external storage device 103 such as an HDD, a communication interface 104 such as a modem, a display 105, an input means 106 such as a mouse and a keyboard, and the like. Then, by operating the CPU 101 and its peripheral devices according to a program set in a predetermined area such as the internal memory 102 or the external storage device 103, the determination unit 4, the light intensity setting unit 5, the control signal specifying data storage unit D1 Is configured to function as The information processing apparatus 7 may be a general-purpose computer or a dedicated computer.

  The light irradiation apparatus according to the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the light irradiation apparatus.

  For example, if it is not suitable as a space for people to relax when irradiated with red light or blue light, an additional light sensor is provided to turn off when the indoor lighting is turned on by sensing light and the indoor lighting is turned off It can be configured to be turned on, or a human sensor using an infrared sensor, an ultrasonic sensor, a photoelectric sensor, etc. is further provided so that it turns off when a person enters the room and turns on when the person leaves the room. It is preferable to configure this.

  The human sensor using the infrared sensor receives an infrared ray emitted from a temperature higher than the surroundings, such as a human body, and further operates when the object is detected as a person. Further, the ultrasonic sensor type human sensor operates when an object (person) is present in the vicinity of the sensor, which is detected by reflection of ultrasonic waves. Installed at the entrance of the room. In addition, by arranging these human sensors from the plant side toward the entrance of the room, it is possible to reliably capture the entrance / exit of the person and the approach of the person to the plant.

  The photoelectric sensor type human sensor includes a transmission type having a projector and a light receiver, and a diffuse reflection type integrated with a light emitter / receiver, and detection light includes red and infrared. Both work when an object (a person) blocks light and are also installed at the entrance of a room. In addition, by arranging these human sensors from the plant side toward the entrance of the room, it is possible to reliably capture the entrance / exit of the person and the approach of the person to the plant.

  When an infrared sensor is used as the human sensor, there is a possibility that the sensor is turned off and the light source is turned on when a person is not moving. In that case, a timer is provided, and within a certain time after the sensor reacts once Is preferably configured so that the light irradiation device continues to be turned off.

  When a diffuse reflection type photoelectric sensor is used as the human sensor, if the sensor is attached to the plant, when a person approaches the plant, the light emitted from the projector is reflected by the human and the light enters the light receiver. Therefore, as long as there is a person on the plant side, the light irradiation device can be turned off.

  According to the present invention having such a configuration, the acclimation to the low light of the horticultural plant can be favorably induced, and even when cultivated indoors, the state of the horticultural plant is kept good, and its commercial value Can be kept high.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

<Test material>
Benjamin gum (Ficus benjamina) that has been planted and propagated by the conventional method and planted in No. 2 plastic pots is cultivated in a normal greenhouse environment for at least 2 months, and then the plant height is kept constant immediately before the start of the test. Side branches were removed and the lower leaves were adjusted so that there were 9-10 fully expanded leaves.

<Test method>
As an artificial light source, a combination of 4 light sources (white fluorescent lamp, blue LED (peak wavelength 470 nm), green LED (500 nm), red LED (660 nm)) and light intensity 2 (5 or 200 μmolm-2s-1PPFD) A total of 9 wards and 9 greenhouses that continue cultivation in the greenhouse were provided, and 5 individuals were provided for each ward.

  Eight wards that use artificial light sources have shelves built in air-conditioned laboratories, and fluorescent light irradiators (made by MITSUYA MFG. Co., Ltd.) or LED irradiation panels (ISL type, made by CCS) are built in. It was surrounded by an ultrafine foamed light reflector (MCPET, manufactured by Furukawa Electric Co., Ltd.) and the outside was covered with a black shading cloth to prevent light from entering from the outside. Moreover, the ventilation fan was installed in the side of each light source, and the dissipation of the heat which arises from a light source was promoted.

  The number of chloroplasts was measured on the 4th and 14th days after each artificial light transfer. Measurement of the number of chloroplasts was carried out according to a conventional method (for example, the method described in Horticultural Society Vol. 67, volume 2, page 380) by collecting the fully expanded leaves at the top of each strain. . In addition, on the 50th day from the start of the test, SPAD values were measured using SPAD-502 (manufactured by Minolta Co., Ltd.) at two locations in the central portion, avoiding the middle of the top two fully developed leaves. Thereafter, one intermediate individual was left in the same environment, and the other four individuals were returned to the greenhouse environment to continue cultivation in order to evaluate the growth after stress. For one individual left under artificial light on the 100th day from the start of the test, all leaves with a leaf length of 10 mm or more were counted, and the SPAD value was measured again.

<Test results>
The obtained results are shown in Table 1, FIG. 4 and FIG.

* 1: The top two fully developed leaves are measured for each individual.
* 2: Measured value for one individual who continued experimental conditions on the 50th day of treatment.

  As shown in Table 1, the number of chloroplasts per palisade tissue cell decreased rapidly under any artificial light, and 85.5 to 93 on the fourth day after the start of the test, compared to the greenhouse. 1% and 69.8 to 83% on the 14th day, but there was no significant difference between the artificial light source sections even when compared between the light source species and the light intensity.

  On the other hand, the SPAD value differs depending on the light source type and the light intensity. When the SPAD value on the 50th day and the SPAD value on the 100th day for the existing leaves are compared, the blue LED 5 μmolm-2s-1PPFD and red 5 μmolm are compared. In the -2s-1PPFD section, the SPAD value increased. From this, the weak light acclimation of the existing leaves was well induced in the blue LED 5 μmolm-2s-1PPFD section and the red 5 μmolm-2s-1PPFD section. Became clear.

  When the newly developed leaves were examined, the SPAD values were high in the blue LED 200 μmolm-2s-1PPFD section and the red 5 μmolm-2s-1PPFD section, and the number of epiphytic leaves was high in the blue LED 200 μmolm-2s-1PPFD section. From this, blue LED 200μmolm-2s-1PPFD section is suitable for the induction of newly developed leaves and induction of weak light acclimation, and red 5μmolm-2s-1PPFD section is acclimated to newly developed leaves with existing leaves. It was found to be suitable for induction of These results are clear from the photographs shown in FIGS.

  As described above, according to the present invention, it is possible to satisfactorily induce acclimation of light in plants, and it is possible to maintain the state of plants well even under low light. Therefore, it is an extremely suitable method for cultivating indoor horticultural plants.

The typical block diagram which shows the light irradiation apparatus in one Embodiment of this invention. The top view which shows the light irradiation part in the embodiment. The equipment block diagram of the information processing apparatus in the embodiment. The photograph which compares and shows the individual | organism | solid of each light section of the process 50th day (a) and the process 100th day (b). The photograph which compared the individual | organism | solid of red LED200micromol-2s-1PPFD section (a) of a treatment 100 day, and a greenhouse section (b) (The photograph of the 50th day of a greenhouse section is also published for the comparison).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light irradiation apparatus 2 ... Light emission part 21 ... LED
DESCRIPTION OF SYMBOLS 3 ... Electric power supply part 4 ... Discrimination part 5 ... Light intensity setting part 6 ... Plant

Claims (10)

It is a method of irradiating light emitted from an artificial light source indoors to acclimate a plant to light,
Irradiate blue light with an intensity of 300 μmolm-2s-1 PPFD or less, or
A weak light acclimation method characterized by irradiating red light with an intensity of 100 μmolm-2s-1 PPFD or less.   The weak light acclimation method according to claim 1, wherein the artificial light source is an LED.   The weak light acclimation method according to claim 1, wherein the plant is a garden plant.   The weak light acclimation method according to claim 3, wherein the horticultural plant is a mulberry plant.   The weak light acclimation method according to claim 4, wherein the mulberry plant is a plant belonging to the genus Fixus.   6. The weak light acclimation method according to claim 5, wherein the plant belonging to the genus Fixix is benjamin gum (Ficus benjamina).   A light irradiation apparatus used for the weak light acclimation method according to claim 1, 2, 3, 4, 5 or 6.   The light irradiation apparatus according to claim 7, further comprising: a light sensor configured to be turned off when the indoor lighting is turned on and turned on when the indoor lighting is turned off.   The light irradiation apparatus according to claim 7 or 8, further comprising a human sensor, configured to be turned off when a person enters the room and turned on when the person leaves the room.   The light irradiation apparatus according to claim 9, wherein the human sensor is an infrared sensor, an ultrasonic sensor, or a photoelectric sensor.