JP2005192517A - Method for growing plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plant-growing method capable of promoting healthy growth of a plant in good balance by light of LED (light emitting diode). <P>SOLUTION: The plant planted in a pot is irradiated with light in which light of blue-green LED 9 is mixed with light of white LED 10 from nearly upper direction of the plant 12 and irradiated with light of red LED 8 from nearly transverse direction. Each light includes a specific wavelength promoting growth of the plant 12 and the plant 12 can be grown in good balance by supplying energy of these light to the plant 12 from various directions. This plant-growing method further can reduce running costs. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a plant growing method for promoting plant growth by artificial light, and more particularly to a plant growing method such as tissue culture or flower bud growing using an LED (light emitting diode) as a light source of artificial light.

  Conventionally, the light environment for promoting plant growth has been performed by sunlight (natural light). However, sunlight is exposed to the season (long summer hours in summer and short winters), weather (short hours during El Niño), weather, and regions (the Pacific side has long annual sunlight hours, the Sea of Japan The side is short), the location (the sun and the shade, the ground and the basement), the time (day and night), and so on. Therefore, in order to promote the growth of plants in a stable environment that is not affected by such natural conditions or artificial conditions, light in place of sunlight or light that supplements sunlight is required, such as incandescent light bulbs, Fluorescent lamps, mercury lamps, sodium lamps, and the like have been used as artificial light sources.

On the other hand, a plant growing method using LEDs as a light source has attracted attention in recent years for these light sources. The advantage of using LED as a light source for plant growth is
1) The emission spectrum of the LED has a steep characteristic, and there is no useless light that does not contribute to growth by using an LED that emits only light having a wavelength that is important for plant growth. Therefore, the power related to lighting can be saved and the running cost can be reduced.
2) Since the LED generates a relatively small amount of heat when it is turned on, the increase in ambient temperature surrounding the plant is small. Therefore, the power related to temperature management such as cooling can be saved, and the running cost can be reduced.
3) Since the directivity of the LED is strong, it can illuminate only the necessary part, so there is little light that does not contribute spatially to the lighting of the plant. Savings can be made and running costs can be reduced.
Etc.

As an example of plant growth using an LED as a light source, a plurality of kinds of LEDs having different emission wavelengths are arranged in parallel to form an LED assembly, and one or a plurality of LED assemblies are directly above or directly above the plant. It is placed obliquely above, and artificially simulated natural environment is created by controlling irradiation time, irradiation light quantity, irradiation light wavelength, irradiation method (always lighting or pulse lighting), etc., and sunlight reaches directly There are plants in which plants are grown evenly in places where there is no place (see, for example, Patent Document 1).
JP 2001-000044 A

  However, when irradiating the LED light from directly above or obliquely from above the plant, the light emitted from the LED is highly directional, so the leaves below the plant are shaded by the leaves above the LED, and the LED light shines. It becomes difficult to reach. In particular, in plants in which leaves overlap in a complicated manner, the ratio of the area receiving light to the total area of the leaves is greatly reduced, which is a factor that inhibits the growth of the plants. Further, since the amount of light received varies depending on the part of the plant, the whole plant cannot grow in a balanced manner.

  Therefore, the present invention was devised in view of the above problems, and provides a plant growing method in which the growth of plants is promoted in a healthy manner by efficiently irradiating artificial light using an LED as a light source. is there.

  In order to solve the above-mentioned problem, the invention described in claim 1 of the present invention is a plant growing method for promoting plant growth by irradiating a plant with light emitted from the LED using the LED as a light source, Light emitted separately from the blue-green LED and the white LED from approximately the top of the plant is mixed and irradiated, and the light is emitted from the red LED from either or both of approximately the bottom and approximately the lateral direction of the plant. It is characterized by irradiating light.

The invention described in claim 2 of the present invention is characterized in that, in claim 1, the photon flux density received by the plant is 15 to 200 μmol · m ⁻² · s ^−1. .

  The plant growing method of the present invention is arranged in a plurality of directions so as to surround a plant by combining a plurality of types of LEDs that individually emit light having a wavelength that promotes the growth of the plant, and the light emitted from the LEDs is emitted from the plant. Since it was made to irradiate a site | part substantially uniformly, it can be made to grow healthy without biasing a plant.

  For the purpose of growing plants of the same form as plants grown in natural environment with artificial light, by setting the light source of artificial light as an LED and the combination of the light wavelengths of the LED and the direction of light irradiation on the plant It was realized.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 3 (the same parts are given the same reference numerals). In addition, since the Example described below is a suitable specific example of this invention, various technically preferable restrictions are attached | subjected, The range of this invention limits this invention especially in the following description. As long as there is no description of that, it is not restricted to these Examples.

  First, before describing this embodiment, what is generally known about the relationship between plant growth and light will be described. Plants are basically those whose growth is promoted by photosynthesis. In photosynthesis, carbon dioxide and water absorbed by plants are sent to chloroplasts contained in mesophyll cells, and light is captured by chlorophyll. It is already well known that the reaction is assimilated into carbohydrates such as starch and starch and simultaneously releases oxygen. In that case, the plant has a chromoprotein that selectively absorbs the wavelength of light, and this chromoprotein is called phytochrome, and various control reactions are performed, for example, germination, flower bud splitting, flowering. It plays various roles such as leaf formation and growth, internode elongation of pedunculated plants.

  Thus, phytochrome is an important factor acting on plant growth and morphogenesis, and this slight variation may significantly change the shape and growth process of plants. In addition, phytochrome has a characteristic of absorbing red light (wavelength: around 660 nm) and near-infrared light (wavelength: around 730 nm) very sensitively, the former being effective for germination, while the latter is Conversely, germination is inhibited. In addition, the blue light is prominently reflected in the direction of light. In addition, pigments such as chlorophyll also have the property of absorbing light, although the wavelength range is different.

Therefore, the present inventors conducted flowering and growing experiments using torenia tissue culture under LEDs and fluorescent lamps emitting red, green, blue-green, and white, and obtained the following findings.
1) The seedlings cultured with red LED light had thick stems, short internodes, and long leaf lengths. In addition, the number of flowers was the smallest.
2) Seedlings cultured with green LED light showed rapid internode elongation and elongated stems.
3) The seedlings cultured with blue-green LED light had the highest number of blooms.
4) The seedlings cultured with white LED light grew in a balanced manner between nodes, leaf width and leaf length.
5) Seedlings cultured with fluorescent light showed similar growth but not as many as red LEDs, and the number of flowering was the second after red LEDs.
From the above findings, it has been clarified that the light of blue-green LED is effective for flowering of plants, and the light of white LED is effective for balanced growth.

  Then, based on the knowledge mentioned above, the plant cultivation method as shown in the following Examples 1-3 was established. First, FIG. 1 is a perspective view schematically showing Example 1 of the plant growing method of the present invention. The present embodiment is a method of performing tissue culture cultivation with an LED light source. A hormone-free MS (Murashige / Skoog) medium 1 is placed at the bottom of a transparent culture vessel 2 such as a test tube, and the stems and leaves 3 containing growth points cut from a part of the mother of Torenia are used as the medium 1. Plant. Then, the culture vessel 2 is covered with a transparent or translucent plastic stopper 4.

  The light that promotes the growth of the tissue culture uses light emitted from the LEDs 5, 6, and 7 disposed around the culture vessel 2. In that case, in order to grow the growth point of the foliage 3 in the culture vessel 2 in a healthy state, the LEDs 5, 6 and 7 are arranged so as to give light energy to each part of the foliage 3 as evenly as possible. ing. Specifically, LEDs are arranged substantially above, substantially below, and around the culture vessel 2, and light energy is applied to the foliage 3 from substantially above with the LEDs 5 arranged substantially above the culture vessel 2. The lower LED 7 gives light energy from substantially below, and the LED 6 arranged in the periphery gives light energy from substantially the lateral direction (surrounding).

  In addition, the types of LEDs 5, 6, and 7 that give light energy to the foliage 3 were selected by combining LEDs that emit light having a wavelength suitable for the purpose based on the knowledge obtained by the flowering and growing experiment described above. Specifically, a red LED 8 that emits red light is disposed substantially below and around, and a blue-green LED 9 that emits blue-green light and a white LED 10 that emits white light are disposed substantially above. The light emitted from the two types of LEDs was mixed and irradiated. As a result, it has become possible to grow into seedlings that grow in a balanced and healthy manner and become plants with a large number of flowers.

  FIG. 2 is a perspective view schematically showing Example 2 of the plant growing method of the present invention. A present Example is a method of performing the outdoor feature cultivation generally performed with the LED light source. The LEDs 5 and 6 are arranged substantially above and around the pot 11, and the light of the LEDs 5 and 6 is irradiated from the time when the potted plant germinates to promote growth. In the outdoor cultivation, the portion of the plant 12 exposed from the ground does not obtain light energy from substantially below, so that the plant 12 is irradiated with light from substantially above and from substantially the lateral direction (periphery). The structure is such that light energy is given to each part as evenly as possible.

  Further, the types and arrangement of the LEDs 5 and 6 used as the light source are the same arrangement and combination as those in Example 1 except for irradiation from substantially below where the irradiation effect is hardly expected. In other words, a red LED 8 that emits red light is arranged around the potted plant, and a blue-green LED 9 that emits blue-green light and a white LED 10 that emits white light are arranged in a mixed manner above the two types of LEDs. Each light emitted from was mixed and irradiated. With this configuration, plants that have grown in a balanced and healthy manner are able to bloom a corresponding number of flowers.

  FIG. 3 is a perspective view schematically showing Example 3 of the plant growing method of the present invention. The present embodiment is a method of performing hydroponics with an LED light source. In this case, in order to increase the production efficiency, many plants are often planted at close intervals to form a plant group. Therefore, even if light is irradiated from substantially the lateral direction (surrounding), the light does not reach the inner plant, and there is almost no illumination effect, so light energy is given from approximately two directions, substantially above and below. .

  The types and arrangements of the LEDs used as the light source are arranged so that a blue-green LED 9 that emits blue-green light and a white LED 10 that emits white light are mixed and disposed substantially above the plant group 21 and emitted from two types of LEDs. Each light was mixed and irradiated. A red LED 8 that emits red light is disposed substantially below and irradiated. In this case, the plant group 21 is immersed in the hydroponics solution 22, and a waterproofed LED is disposed in the hydroponic solution 22 in order to give light energy to the plant group 21 from substantially below. ing. The LED is waterproofed to ensure electrical safety and durability for long-term use.

  Moreover, various effects are acquired by arrange | positioning a LED light source in the hydroponics solution 22. FIG. First, regarding the growth of plants, it has been mentioned above that LEDs generate relatively little heat when lit, but when a large number of LEDs are arranged closely, the amount of heat generated becomes considerable, and this heat is generated by the hydroponic solution. The temperature of 22 will be raised. For plants, the cold hydroponic solution 22 in winter is a factor that slows the growth reaction and impedes growth promotion, so that the hydroponic solution 22 is heated to a predetermined temperature. The amount of heat required for heating can be reduced by the hydroponic solution 22 heated by the above, energy saving can be achieved, and the running cost can be reduced. Further, the LED has an unfavorable characteristic that the light emission efficiency is deteriorated as the temperature of the LED is increased and the amount of emitted light is reduced, and at the same time, the lifetime is shortened. By disposing the LED 23 having such characteristics in the hydroponic solution 22, the LED 23 is cooled by the hydroponic solution 22, so that a decrease in luminous efficiency and a shortening of the life are avoided, and a long period of time is avoided. It can be maintained as a long-life light source with good luminous efficiency.

As a point common to Examples 1-3 mentioned above, as for the light environment of plant growth, it is desirable that the photon flux density of the whole LED light source is 15-200 micromol * m ^<-2 > * s ^{< -1} >. This is because a remarkable effect by irradiating light is not recognized in other ranges. In addition, since the figures attached to the respective examples are schematic diagrams for explaining the examples, the LEDs depicted in the figures do not indicate the number of LEDs used in the examples as they are. The number of LEDs is adjusted and arranged so that the light environment has an optimum photon flux density.

  Here, the effect by this invention is demonstrated. First, the red LED light that grows the leaf length long, the blue-green LED light that blooms many flowers, and the white LED light that grows the internode, leaf width, and leaf length in a balanced manner. By irradiating the plant with the energy of the combined light, the light environment can be formed only with light of a wavelength useful for healthy growth, so it has a balanced balance that approximates the growth of sunlight. Growth can be realized, and the light characteristics of the LED are steep in the emission spectrum, so there is no useless wavelength component that does not contribute to growth, and the light utilization efficiency is high, so the running cost can be reduced by saving power. .

  Also. By irradiating the LED light not only from one direction above the plant but from almost all directions, most parts of the plant can be irradiated uniformly. In particular, when the leaves are complicated and overlapped, the lower part, which was conventionally behind the upper leaves and was not able to receive light, can now receive light from almost the horizontal direction. It grows in a well-balanced manner because the energy of light is distributed. At the same time, the light from the LED is highly directional and can irradiate the target area of the plant intensively, so there is almost no light that does not contribute to the irradiation of the plant spatially, and the light utilization efficiency is high. The power cost for lighting can be reduced.

  In addition, by adopting such a plant-growing method, it is possible to appreciate plants of the same form as grown under sunlight even in places with poor sunlight indoors or places where sunlight does not reach at all, such as underground. Yes, it can enrich your daily life.

It is the perspective view which showed typically the plant cultivation method concerning Example 1 of this invention. It is the perspective view which showed typically the plant cultivation method concerning Example 2 of this invention. It is the perspective view which showed typically the plant cultivation method concerning Example 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Medium 2 Culture container 3 Stem and leaves 4 Plastic stopper 5 LED
6 LED
7 LED
8 Red LED
9 Blue-green LED
10 White LED
11 Pot 12 Plant 21 Plant group 22 Hydroponics solution 23 LED

Claims (2)

A plant growth method for promoting plant growth by irradiating a plant with light emitted from the LED using an LED as a light source, wherein light emitted individually from a blue-green LED and a white LED is mixed from substantially above the plant. And irradiating light emitted from the red LED from either one or both of a substantially lower side and a substantially horizontal direction of the plant. 2. The plant growing method according to claim 1, wherein the photon flux density received by the plant is 15 to 200 μmol · m ⁻² · s ⁻¹ .

Images