JP2021122254A - Method for controlling thickness and size of leaf of green leaf vegetable - Google Patents

Abstract

To provide a method for controlling a future lettuce (Lactuca sativa) leaf morphology (thickness and size of a leaf) by using the intracellular arrangement of chloroplasts.SOLUTION: Provided is a method for controlling the thickness and size of a leaf, in which a seedling of a green leaf vegetable, for example, lettuce, is irradiated with blue light with different intensities (weak light with 5 μmol m-2S-1 and strong light with 50 μmol m-2S-1) at a predetermined temperature for a certain period of time, and the intracellular arrangement of chloroplasts is adjusted. In addition to the blue light with different intensities, desirably, the seedling is also irradiated with red light with different intensities simultaneously. It is found that when irradiated with blue light (weak light), the area of the leaf is larger than when irradiated with blue light (strong light), and the wet weight of an above-ground biomass also becomes heavier. On the other hand, it is found that when irradiated with blue light (strong light), the thickness of the leaf becomes larger than when irradiated with blue light (weak light). There is no difference between when irradiated with blue light (weak light) and when irradiated with blue light (strong light) in the dry weight of the biomass.SELECTED DRAWING: None

Description

The present invention is characterized in that the seedlings of green leafy vegetables such as lettuce are irradiated with blue light having different intensities at a predetermined temperature for a certain period of time to adjust the arrangement of intracellular chloroplasts. It relates to a method of controlling the size.

The phenomenon in which chloroplasts change their intracellular arrangement and location according to light information (intensity, incident direction, wavelength, etc.) is called chloroplast photo-relocation movement, and is generally called chloroplast photo-relocation movement. Is induced by blue light. Under low light (several W m ^-2 s ^-1 or less), chloroplasts gather on the surface side of the leaf, and under strong light (10 W m ^-2 s ^-1 or more), chloroplasts avoid light. Escape to the cell wall parallel to the light. The former is called an aggregate reaction (weak light reaction), and the latter is called an escape reaction (strong light reaction). The aggregate reaction has the physiological significance of increasing the efficiency of photosynthesis, and the escape reaction has the physiological significance of avoiding photoinjury.

Attempts have been made to control plant size and improve seed yields using chloroplast photolocalization for photosynthesis optimization. In order to optimize photosynthesis, the intracellular arrangement of chloroplasts changes according to environmental conditions such as light and temperature (Non-Patent Documents 1 and 2). For example, under strong light in warm conditions, chloroplasts are localized along the cell wall of the pituitary gland by moving away from the light in a process called escape reaction (Non-Patent Document 2). Similarly, under low light under cold conditions, chloroplasts are localized along the cell wall of the pituitary gland by a process called the cold escape reaction (Non-Patent Documents 3 and 4). The escape reaction and the cold escape reaction may reduce the photodamage of chloroplasts caused by photoinhibition under warm and cold conditions, respectively (Non-Patent Documents 5 and 6). In addition, under low light under warm conditions, chloroplasts localize along the surrounding cell wall by moving towards the light in a process called the aggregation reaction. Physiologically, collective reactions are thought to maximize photosynthesis. This is consistent with a recently experimentally confirmed theory through comparisons between various Arabidopsis mutants in which chloroplasts have been shown to be in abnormal positions (Non-Patent Document 7). However, the effects of these reactions on the growth of wild-type plants in economically important species such as vegetables have not yet been confirmed.

The escape reaction and aggregation reaction of chloroplasts are carried out via blue light (BL) photoreceptor phototropin blue light (BL) receptor phototropin (Non-Patent Documents 8 to 10). Recently, the present inventors have reported that phototropin is a temperature sensor molecule that mediates a cold escape reaction (Non-Patent Document 11). Recently, many plant cultivation methods and cultivation methods using light information (intensity, wavelength, etc.) have been proposed.

For example, a light emitting element having an emission peak wavelength in the range of 380 nm or more and 490 nm, and a red fluorescence that is excited by light from the light emitting element and emits light having at least one emission peak wavelength in the range of 580 nm or more and 680 nm or less. The ratio (R / B) of the photon bundle R of red light (RL) in the range of 620 nm or more and 700 nm or less to the photon bundle B of blue light in the range of 400 nm or more and 490 nm or less is more than 20 and 200 or less. A plant cultivation method capable of promoting the growth of a plant using a light emitting device has been proposed (Patent Document 1).

Further, it is a method of cultivating a plant seedling that promotes growth by irradiating the plant seedling with artificial light, and has a period (A) of continuously irradiating the blue illumination light, and continuously irradiates the blue illumination light. 30 or more and less than 80% of the time during which the planting period (A) is performed is the period (A-1) in which the blue illumination light and the red illumination light are continuously irradiated. A method for cultivating plant seedlings capable of cultivating good seedlings has been proposed (Patent Document 2).

In addition, the seedling raising method is performed by alternately and repeatedly irradiating fruit and vegetable seedlings with artificial light such as red illumination light and blue illumination light. The daily integrated photosynthesis effective photon amount is 10 to 25 mol / m ² · day ^-1 and 4 to 15 mol / m ² · day ^{-1, respectively,} and the total of the irradiation time of the red illumination light and the blue illumination light per day is taken. , 16 to 24 hours, a method for raising fruit seedlings is proposed, which enables inexpensive growth of high-quality fruit seedlings with well-developed roots, homogeneity, good survival, and good growth after planting. (Patent Document 3).

Further, in the plant cultivation method in which the red light irradiation step S1 for irradiating the plant with the red light illumination light and the blue light irradiation step S2 for irradiating the plant with the blue light illumination light are performed, the irradiation time of each step is 3 hours or more 48. Irradiation cycles C1 and C2 consisting of a red light irradiation step and a blue light irradiation step are performed for at least two cycles within a certain period, and either the red light irradiation step or the blue light irradiation step is performed in the irradiation cycle. It is a plant cultivation method that starts the procedure in one step, and a plant cultivation method by artificial light irradiation that is simple, energy efficient, and can obtain a plant cultivation effect such as an excellent growth promoting effect has been proposed. (Patent Document 4).

Further, a step of irradiating the plant with red light by controlling a region for irradiating the plant with sunlight, a light irradiation unit for irradiating the plant with artificial light including red light and / or blue light, and the light irradiation unit. It is possible to irradiate the plant with artificial light and sunlight to promote growth by using a plant cultivation device equipped with a control unit that separately and independently executes the step of irradiating the plant with blue light within a certain period of time. A plant cultivation method capable of obtaining excellent energy efficiency has been proposed (Patent Document 5).

Japanese Unexamined Patent Publication No. 2019-161076 Japanese Unexamined Patent Publication No. 2018-121589 JP-A-2017-169509 Japanese Unexamined Patent Publication No. 2015-142585 Japanese Unexamined Patent Publication No. 2014-166178

Fujii and Kodama, Plant Signaling & Behavior 2018; 13 (3): e1411452. (3 pages); Wada, Plant Sci. 2013; 210: 177-182 Kodama et al., J Plant Res. 2008; 121: 441-8 Ogasawara et al., Plant Cell Environ. 2013; 36: 1520-8. Fujii et al., Proc Natl Acad Sci U S A. 2017; 114: 9206-11 Kasahara et al., Nature 420: 829-832, 2002 Gotoh et al. Plant Physiol 178: 1358-1369, 2018 Jarillo et al. Nature 410: 952-954,2001 Kagawa et al. , Science 16 Mar: Vol. 291, Issue 5511, pp. 2138-2141,2001 Sakai et al ,, Proc Natl Acad Sci USA 98: 6969-6974, 2001 Fujii et al., PNAS first published August 7, 2017 https://doi.org/10.1073/pnas.1704462114 2017

In the collective reaction, the chloroplasts move towards the weak blue light and localize along the surrounding cell wall. In contrast, in the escape reaction, the chloroplasts move away from the intense blue light and localize along the pituitary cell wall. The collective reaction maximizes light capture and the escape reaction reduces light damage. The intracellular placement of chloroplasts is important for optimizing photosynthesis and may share a signal with regulators that determine leaf morphology, another factor affecting photosynthesis. An object of the present invention is to predict the future leaf morphology (leaf thickness and size) of lettuce (Lactuca sativa) using the intracellular arrangement of chloroplasts.

The present inventors have diligently studied to solve the above problems. In many plant species, the chloroplast arrangement changes in response to changes in blue light (BL) intensity and temperature. Under artificial conditions such as plant growth facilities (or plant factories), chloroplast placement will only be affected by BL intensity, as temperatures are usually kept constant. In order to investigate the effect of plant chlorophyll arrangement on vegetables cultivated in a plant factory, the present inventors lettuce (Lactuca) grown under a strong BL that induces an escape reaction at a constant warm temperature. We analyzed the effects of sativa) and lettuce grown under weak BL, which induces aggregate reactions.

That is, when lettuce seedlings were irradiated with blue light of an appropriate intensity to induce a lettuce cell aggregation reaction or escape reaction, and plant growth was observed, the leaves of the leaves responded to the weak blue light that induced the aggregation reaction. We have found that the area increases and the leaf thickness increases in response to the strong blue light that induces the escape reaction, and the present invention has been completed.

The present invention is specified by the following matters.
(1) Controlling leaf thickness and size, which is characterized by irradiating green leafy vegetable seedlings with blue light of different intensities at a predetermined temperature for a certain period of time to adjust the arrangement of intracellular chloroplasts. how to.
(2) The method for controlling the thickness and size of leaves according to (1) above, wherein the green leafy vegetables are lettuce.
(3) The method for controlling the thickness and size of leaves according to (1) or (2) above, wherein the blue light is blue light derived from a blue light emitting diode.
(4) The method for controlling the thickness and size of a leaf according to any one of (1) to (3) above, which comprises simultaneously irradiating red light having different intensities in addition to blue light having different intensities. ..
(5) The method for controlling the thickness and size of leaves according to (4) above, wherein the red light is red light derived from a red light emitting diode.
(6) Controlling the leaf thickness and size according to any one of (1) to (5) above, wherein the blue light having different intensities is 5 or 50 μmol · m ^-2 · S ^-1. how to.
(7) Controlling the leaf thickness and size according to any one of (4) to (6) above, wherein the red light having different intensities is 125 or 250 μmol · m ^-2 · S ^-1. how to.
(8) The method for controlling the thickness and size of a leaf according to any one of (1) to (7) above, wherein the predetermined temperature is 15 to 25 ° C.
(9) The method for controlling the leaf thickness and size according to any one of (1) to (8) above, wherein the fixed period is 14 to 28 days.
(10) The method for controlling the leaf thickness and size according to any one of (1) to (9) above, which comprises adjusting the arrangement of intracellular chloroplasts in a plant factory or a greenhouse.

According to the present invention, the thickness and size of leaves of green leafy vegetables can be adjusted by adjusting the arrangement of intracellular chloroplasts only by changing the intensity of blue light irradiating the seedlings of green leafy vegetables. It becomes possible to control.

FIG. 1A (Top and Bottom) shows the arrangement of chloroplasts in lettuce cells irradiated with BL5 for 3 hours. FIG. 1B (Top and Bottom) shows the arrangement of chloroplasts in lettuce cells irradiated with BL50 for 3 hours. It is a photograph of lettuce cultivated under irradiation conditions of various wavelength combinations. 2A is lettuce irradiated with BL5 and RL125, FIG. 2B is lettuce irradiated with BL50 and RL125, FIG. 2C is lettuce irradiated with BL5 and RL250, and FIG. 2D is lettuce irradiated with BL50 and RL250. The white bar indicates 10 cm. It is a graph of the leaf area when BL5 or BL50 and RL125 are irradiated in combination (FIG. 3A), and when BL5 or BL50 and RL250 are irradiated in combination (FIG. 3B). It is a graph of leaf thickness when BL5 or BL50 and RL125 are irradiated in combination (FIG. 3C), and when BL5 or BL50 and RL250 are irradiated in combination (FIG. 3D). It is a graph of the raw weight (fresh weight) of the above-ground biomass when the BL5 or BL50 and the RL125 are irradiated in combination (FIG. 4A), and when the BL5 or BL50 and the RL250 are irradiated in combination (FIG. 4B). .. It is a graph of the dry weight of the above-ground biomass when the BL5 or BL50 and the RL125 are irradiated in combination (FIG. 4C), and when the BL5 or BL50 and the RL250 are irradiated in combination (FIG. 4D).

The method for controlling the leaf thickness and size of green leafy vegetables of the present invention is to control the leaf thickness and size of green leafy vegetables with blue light having different intensities, for example, 5 μmol · m- ² · S- ¹ blue light and 50 μmol · m. It is characterized in that the arrangement of chloroplasts in cells is adjusted by irradiating with blue light of ^-2 · S- ^{1 at a predetermined temperature for a certain period of time.} As the blue light, blue light derived from a blue light emitting diode can be preferably mentioned, and for example, blue light having a peak in the vicinity of a wavelength of 480 nm and having a wavelength in the wavelength range of 440 to 520 nm can be specifically shown.

As the intensity of different blue light ^{(BL), 4~6μmol · m -2} · S -1, preferably blue light 5μmol ^{· m} -2 ^{· S -1} and (low light), 40~60μmol · m ^{- 2.} S ^-1 , preferably 50 μmol · m ^-2 · S ^-1 , blue light (strong light) can be mentioned. Under blue light (weak light), chloroplasts gather on the surface side of the leaf (aggregate reaction), and under blue light (strong light), chloroplasts avoid light and escape to the cell wall parallel to the light (aggregation reaction). Escape reaction). It was also found that when the blue light (weak light) was irradiated, the leaf area was larger and the raw weight of the above-ground biomass was heavier than when the blue light (strong light) was irradiated. On the other hand, it was found that the leaf thickness was larger when the blue light (strong light) was irradiated than when the blue light (weak light) was irradiated. There was no difference in the dry weight of the biomass between the case of irradiating with blue light (weak light) and the case of irradiating with blue light (strong light).

Further, it is preferable to simultaneously irradiate red light (RL) having different intensities in addition to blue light having different intensities. The blue light contributes to the regulation of chloroplast arrangement, while the red light does not participate in the regulation of chloroplast arrangement and contributes to photosynthesis. As such red light, red light derived from a red light emitting diode can be preferably mentioned, and for example, red light having a peak in the vicinity of a wavelength of 660 nm and having a wavelength in the wavelength range of 620 to 680 nm can be specifically shown.

Examples of the red light having different intensities include 120 to 130 μmol · m ^-2 · S ^-1 , preferably 125 μmol · m ^-2 · S ^-1 red light (weak light) and 240 to 260 μmol · m ^-2 ·. S ^-1 , preferably 250 μmol · m ^-2 · S ^-1 red light (strong light) can be mentioned.

Examples of the above green leafy vegetables include lettuce (Lamiaceae), Shungiku (Lamiaceae), Moroheiya (Brassicaceae), cabbage (Brassicaceae), Hakusai (Brassicaceae), Komatsuna (Brassicaceae), Chingensai (Brassicaceae), Mizuna (Brassicaceae), Luccola (Brassicaceae), Cresson (Brassicaceae), Egoma (Lamiaceae), Basil (Lamiaceae), Labiatae (Lamiaceae), Tsurumurasaki (Brassicaceae), Horensou (Brassicaceae), Nira ( (Brassicaceae) and the like can be mentioned, but lettuce can be preferably exemplified.

The predetermined temperature varies depending on the type of green leafy vegetables, but may be generally 15 to 25 ° C, preferably 20 ° C. The optimum temperature for growth of each green leafy vegetable is illustrated below. Lettuce (15-20 ° C), Shungiku (15-20 ° C), Moroheiya (20-30 ° C), Cabbage (15-20 ° C), Chinese cabbage (18-20 ° C), Komatsuna (15-25 ° C), Bok choy (15-25 ° C) 18-20 ° C), Mizuna (15-20 ° C), Arugula (15-25 ° C), Creson (15-20 ° C), Perilla frutescens (20-25 ° C), Basil (20-25 ° C), Perilla (20-25 ° C) 23 ° C.), Tsurumurasaki (20 to 30 ° C.), Spinach (15 to 20 ° C.), and Garlic chives (15 to 25 ° C.).

The fixed period may be 14 to 28 days, preferably 21 days. If the cultivation period is less than 14 days, the effect of the present invention may not be exhibited, but if it exceeds 28 days, the effect of the present invention may be exhibited.

In this way, green leafy vegetables are cultivated at a predetermined temperature for a certain period of time, but the cultivation is carried out in a plant factory or a greenhouse where the light and temperature can be controlled. Efficiently control the leaf thickness and size of green leafy vegetables by systematically cultivating green leafy vegetables in a closed or semi-closed space where the internal environment is controlled, such as in a plant factory or greenhouse. Can be done. In addition, reflux hydroponics can be advantageously carried out in a plant factory or a greenhouse.

Hereinafter, the present invention will be described with reference to examples, but the technical scope of the present invention is not limited to such examples.

1. 1. Materials and methods 1-1 Plant materials and growth conditions Lettuce (Lactuca sativa) seeds (No. 03503, Tohoku Co., Ltd., Tochigi, Japan) were used. Seeds were planted and cultivated in the soil. Seedlings are in an incubator (IJ101, Yamato Scientific Co., Ltd., Tokyo, Japan) at 20 ° C for 21 days with blue light emitting diodes (LEDs) and red LEDs (ISL-150x150-H4RB, CCS Inc., Kyoto, Japan). Growing up in the light.

1-2 Observation of chloroplast placement determination In an artificial meteorological instrument (LH-240SP, Nippon Medical Instruments Mfg. Co., Ltd., Osaka, Japan) that can switch between temperature and illuminance to observe chloroplasts. , Lettuce seedlings were grown under fluorescent white light for 18 days and then transferred to weak BL ( ^{5 μmolm -2} s ^-1 : BL 5) or strong BL (50 μmol m ^-2 s ^-1 : BL 50). .. In order to clearly observe the mesophyll cells, the detached lettuce leaves were degassed and infiltrated with water. The mesophyll cells were observed using an optical microscope (BX60, Olympus, Tokyo, Japan) under a 100x oil immersion objective lens (UPlanApo, 100 × / 1.35 oil). Images were taken using a digital camera (DP72; Olympus) equipped with cellSens software (Olympus).

To optically control the chloroplast arrangement of lettuce cells, ^{use 5 μmol m-2} s ^{-1 (BL5) as the weak BL and 50 μmol m-2} s ^-1 (BL50) as the strong BL. The growth of lettuce was compared. When lettuce cells were irradiated with BL5 for 3 hours, chloroplasts were localized around the cells at the top of the mesophyll cells and aggregated along the peripheral cell wall at the bottom of the cells (Fig. 1A Bottom). In lettuce cells, BL5-induced chloroplast arrangement is a weak light-induced arrangement in plant species growing in strong sunlight (Higa and Wada, Plant Cell Environ. 2016, 39: 871-82; Ishishita et al. J Plant Res. 2016, 129: 175-87.). When lettuce cells were irradiated with BL50 for 3 hours, chloroplasts escaped from the peripheral position (Fig. 1B). Hereinafter, BL5 will be referred to as a set condition, and BL50 will be referred to as an escape condition. It was confirmed that at 15 and 20 ° C., the chloroplasts aggregated at BL5 and escaped at BL50 and BL500, and at 10 ° C., all of BL5, BL50 and BL500 escaped.

For lettuce, when cultivated longer, since it is necessary to provide sufficient light energy for photosynthesis, red light 125μmol ^-2 s ^-1 (RL125) or 250μmol ^-2 s ^-1 to (RL250), BL5 And BL50, respectively, and lettuce seedlings were cultivated at 20 ° C. for 3 weeks. In BL5 and RL62.5, the hypocotyl became an abnormal morphology.

(result)
As is clear from FIG. 2, lettuce irradiated with BL5 and RL125 (FIG. 2A), lettuce irradiated with BL5 and RL250 (FIG. 2C), lettuce irradiated with BL50 and RL125 (FIG. 2B), and lettuce irradiated with BL50 and RL125 (FIG. 2B). Since the growth seemed to be promoted more than the irradiated lettuce (Fig. 2D), leaf area, thickness, and biomass were measured to quantitatively evaluate the results.

To measure the area of the leaves, lettuce leaves were sandwiched between transparent plastic folders, flattened, and images were taken using a scanner (imageRUNNER ADVANCE C5045, Canon Inc.). From the image, the leaf area was measured by ImageJ, and the average value and standard deviation were calculated. For leaf thickness, a digital caliper (MonotaRO Co., Ltd., Japan) was used to calculate the mean and standard deviation. To measure the biomass, the above-ground biomass of the harvested lettuce was measured as raw weight and then oven-dried at 105 ° C. to measure the dry weight. The mean weight and standard deviation were calculated. The measurement results of the leaf area are shown in FIGS. 3A and 3B. The measurement results of leaf thickness are shown in FIGS. 3C and 3D.

[result]
(Leaf area)
In both cases of irradiation in combination with BL5 or BL50 and RL125 (FIG. 3A) and irradiation in combination with BL5 or BL50 and RL250 (FIG. 3B), the leaf area of BL5 was larger than that of BL50. It was significantly larger.

(Leaf thickness)
In both cases of irradiation in combination with BL5 or BL50 and RL125 (FIG. 3C) and irradiation in combination with BL5 or BL50 and RL250 (FIG. 3D), the leaf thickness was determined by BL50 to BL5. Was significantly larger than. In all panels, the asterisk showed a static and significant difference between the conditions (student's t-test, P <0.01). Bars indicate standard deviation.

The above results indicate that BL5 increases the leaf area and BL50 increases the leaf thickness.

(Measurement of biomass)
In both cases of irradiation in combination with BL5 or BL50 and RL125 (FIG. 4A) and irradiation in combination with BL5 or BL50 and RL250 (FIG. 4B), the raw weight of above-ground biomass is determined by BL5. , It was significantly heavier than BL50. That is, the asterisk shows a significant difference (Student's t-test, P <0.01).

However, regarding the dry weight of biomass, BL5 is used in both cases of irradiation in combination with BL5 or BL50 and RL125 (FIG. 4C) and irradiation in combination with BL5 or BL50 and RL250 (FIG. 4D). And BL50 values were about the same, indicating that the net biomass production was comparable under the set condition (BL5) and the escape condition (BL50). That is, the Student's t-test showed that there was no significant difference between the two samples (P = 0.86 in FIG. 4 (C), P = 0.63 in FIG. 4 (D)). In BL500 and RL250, and BL50 and RL500, there was a large variation (standard deviation) in dry weight (20 ° C.).

Our results show that previous studies using Arabidopsis thaliana with mutations in wild-type plants and chloroplast placement increased leaf area and biomass (fresh and dry weight) under conditions that elicit aggregate reactions. Although the result was different from that of (Non-Patent Document 7), it is considered to be important as a result of comparison only under the light conditions of BL5 and BL50.

Comparing the fresh weights (raw weights) of the plants grown under the two BL conditions, the weights of the plants grown on BL5 were significantly heavier than the weights of the plants grown on BL50 (FIGS. 4A and B).
Considering that the dry weights under the two conditions were equivalent (FIGS. 4C and D), this means that the lettuce grown on BL5 has a high water content. The higher the strength of BL, the greater the degree of stomata opening (Kinoshita et al. Nature 2001, 414: 656-60.). It is expected to decrease.

The leaf morphology was significantly different between the lettuce under the assembly condition (BL5) and the lettuce under the escape condition (BL50), but the dry weights were similar (FIGS. 4C and D). Therefore, the photosynthetic production of plants under the two conditions appears to be similar, suggesting that under BL5, some form of compensatory growth occurs in lettuce compared to BL50 (ie, homeostasis). .. This compensatory growth may be based on various strategies for capturing leaf light during lettuce growth.

These results suggest that chloroplast placement responds to signals that control lettuce leaf morphology. The aggregation reaction functions as a signal to expand the area of the leaf, and the escape reaction functions as a signal to increase the thickness of the leaf. Based on these results, it is possible to predict the future leaf morphology of lettuce under certain conditions by observing the arrangement of chloroplasts, and to adjust the leaf morphology by changing the light conditions. Given that leaf morphology is important for many food crops, such control methods are useful for the cultivation of economically important vegetables and the like.

The present invention capable of controlling the leaf thickness and size of green leafy vegetables is useful in the field of agriculture of growing and growing vegetables.

Claims (10)

A method for controlling the thickness and size of leaves, which comprises irradiating seedlings of green leafy vegetables with blue light having different intensities at a predetermined temperature for a certain period of time to adjust the arrangement of intracellular chloroplasts. The method for controlling the thickness and size of leaves according to claim 1, wherein the green leafy vegetable is lettuce. The method for controlling the thickness and size of a leaf according to claim 1 or 2, wherein the blue light is blue light derived from a blue light emitting diode. The method for controlling the thickness and size of a leaf according to any one of claims 1 to 3, wherein in addition to blue light having different intensities, red light having different intensities is simultaneously irradiated. The method for controlling the thickness and size of a leaf according to claim 4, wherein the red light is red light derived from a red light emitting diode. The method for controlling the thickness and size of leaves according to any one of claims 1 to 5, wherein the blue light having different intensities is 5 or 50 μmol · m- ² · S- ^1. The method for controlling the thickness and size of leaves according to any one of claims 4 to 6, wherein the red light having different intensities is 125 or 250 μmol · m- ² · S- ^1. The method for controlling the thickness and size of a leaf according to any one of claims 1 to 7, wherein the predetermined temperature is 15 to 25 ° C. The method for controlling the thickness and size of a leaf according to any one of claims 1 to 8, wherein the fixed period is 14 to 28 days. The method for controlling leaf thickness and size according to any one of claims 1 to 9, wherein the arrangement of intracellular chloroplasts is regulated in a plant factory or a greenhouse.

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