JP2001045866A - Method for stimulating growth of long-day plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for stimulating the growth of a long-day plant, by which the long-day plant can be cultured in a more much stimulated growth speed than those by conventional methods and in high light energy utilization efficiency without causing flower bud differentiation and bolting. SOLUTION: This method for stimulating the growth of a long-day plant comprises irradiating the long-day plant with light also in night only for an initial culture period ranging from a culture-starting day to <=14 days under conditions comprising an irradiation strength of <2 klx and an irradiation time of <=12 hours, when the long-day plant is cultured under the irradiation of light. An irradiation condition in a daytime in the initial culture period includes an irradiation strength of 15 klx.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for promoting the growth of long-day plants, in which cultivation of long-day plants grows faster and light utilization efficiency is higher than in the past.

[0002]

2. Description of the Related Art Generally, in plants, the longer the light irradiation time, the more photosynthesis is performed, so that the growth is promoted. Cultivation is carried out in the open field or in hydroponics. In both cases, the use of artificial lighting or the like can extend the irradiation time. However, in the case of long-day plants, in general, when the irradiation period of one day is extended, the dark period becomes less than a certain value (about 12 days).
If the time is shorter than the time), bolting and flower bud differentiation occur, and the commercial value is significantly reduced. Therefore, light irradiation for 12 hours in the daytime is generally used.

[0003]

As described above, in the cultivation of long-day plants, it is difficult to promote the growth by changing the light irradiation conditions, especially the irradiation time, and this is a problem to be solved. Further, when artificial lighting is used to extend the irradiation time, cost and energy are required.
Therefore, it was also an issue to use the input (irradiated) light energy as efficiently as possible for plants. In contrast, the present inventors have already extended the light irradiation time, even if the cultivation is extended, by setting the intensity of light at the time of extended nighttime irradiation to an appropriate intensity equal to or less than the daylight intensity. Have found that it is possible to promote growth more than ever and to increase the use efficiency of light energy, and filed an application as Japanese Patent Application No. 10-43416. Although this method allows cultivation with high utilization efficiency of light energy, it seems that there is a need to further improve the problems of bolting and flower bud differentiation.

[0004]

Means for Solving the Problems The present invention for solving the above-mentioned problems is as follows: (1) In cultivating long-day plants by irradiating them with light,
Only during the initial cultivation period within 14 days from the start of cultivation, irradiation is performed at night, and the nighttime irradiation conditions during the initial cultivation period are set to an irradiation intensity of 2 klx.
The method for promoting the growth of long-day plants, wherein the irradiation time is less than 12 hours or less, and (2) the irradiation condition in the daytime of the cultivation initial period is irradiation intensity of 15 klx, wherein (1). (3) When cultivating long-day plants by irradiating them with light, 1
Irradiation conditions for 4 days, irradiation intensity 15klx for 12 hours in the daytime
A method for promoting the growth of long-day plants, characterized in that the irradiation intensity is 1.8 klx for 12 hours at night and irradiation is performed only in the day after 15 days from the start of cultivation. In the present invention, daytime and nighttime are defined as 12 hours each of 24 hours a day.
It is hourly, and the daytime means continuous 12 hours, and the nighttime means the remaining 12 hours. The start of cultivation means that after the seeds are germinated, for example, for one day, the seedlings that have been greened under approximately 5 klx of light are planted in a hydroponic solution.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the cultivation of long-day plants, if the time of irradiating light using artificial lighting is extended not only during the daytime but also at nighttime, the time required for photosynthesis becomes longer, so that growth is promoted. . The present invention relates to a method of irradiating light that is extended even at night. I) The period of irradiating the light extended even at night is limited to within 14 days from the start of cultivation. Is called the initial stage of cultivation), after that, only daytime irradiation and no nighttime irradiation should be performed.
The light intensity of the nighttime irradiation of I) is less than 2 klx and 12 hours or less, and the growth of long-day plants can be promoted without bolting or flower bud differentiation by I) and II). Further, under the conditions of the above I) and II), the growth amount of the plant with respect to the integrated light irradiation amount can be increased, that is, cultivation can be performed with high light energy use efficiency.

[0006] The nighttime irradiation conditions in the early stage of cultivation according to the present invention are such that the light intensity is less than 2 klx, preferably 1.99 to 0.01 klx.
It is. If the amount is less than 0.01 klx, the effect of light irradiation may not be observed in plants which are generally insensitive to light. The irradiation time at night is 12 hours or less, preferably 12 to 10 hours. 12 hours of irradiation at night
If the time is less than the time, the effect is recognized, but the longer the irradiation time, the higher the rate of growth promotion can be made as compared with the case where irradiation is not performed at night.

On the other hand, the daytime irradiation conditions in the present invention are as follows:
Irradiation is preferably performed at a light intensity of 15 klx during the nighttime irradiation at the beginning of cultivation, and thereafter, the maximum is 1 in case of natural light irradiation.
Since it is 00 klx, irradiation may be performed at 15 to 100 klx.

[0008] The specific period of the initial stage of cultivation of the present invention can be set to an appropriate period of 14 days or less depending on the plant to be cultivated under the above-mentioned irradiation conditions, but is preferably 14 days.
Days to 10 days. The effect is recognized if the period for setting the above-mentioned irradiation conditions is 14 days in the early stage of cultivation, but the longer the period (the number of days) for setting is, the higher the rate of growth promotion can be made compared to the case where irradiation is not performed at night. .

For example, when spinach is cultivated according to the present invention, night irradiation is performed only for the first 14 days of cultivation,
Particularly good results were obtained when the irradiation conditions were 15 klx for 12 hours during the day and 1.8 klx for 12 hours at night, and thereafter only irradiation during the day.

[0010] In the cultivation according to the present invention, except that the light irradiation time is increased under specific conditions only at the beginning of cultivation,
Other environmental conditions such as temperature and CO ₂ concentration are the same as those in the related art. Further, since the light irradiation time may be extended by artificial lighting or the like, the present invention can be applied to both open field and hydroponic cultivation.

The long-day plants to which the method of the present invention can be applied include, for example, spinach, dancon, wheat, barley, lettuce, carnation, petunia, hyos and the like.

[0012]

EXAMPLES The present invention will be specifically described below by taking, as an example, the case where spinach is hydroponically grown as a long-day plant.

Example 1 Five spinach seeds for hydroponics were sown on a urethane mat and germinated and raised in a dark place for 4 days. The plants were planted in a light place of about 5 klx for one day, and the obtained seedlings were planted in a hydroponic solution to start cultivation. Hydroponic solution is Otsuka House Fertilizer 2 per 1000 liters
No. 3, No. 5, No. 5, No. 6, and No. 7 (all of which are trade names, manufactured by Otsuka Chemical Co., Ltd.)
50g, 3rd 810g, 5th 50g, 6th 500
g and No. 7 were dissolved in 155 g, respectively.
The pH of the hydroponic solution is 6.0 to 6.5, EC (electric conductivity)
Was controlled to be 2.2 to 2.3 (mS / cm). The temperature was 26 ° C. for 12 hours (9:00 to 21:00) in the daytime and 21 ° C. for 12 hours (21:00 to 9:00) in the night. The light used was a white fluorescent lamp as a light source, and the irradiation intensity during the day was 15 klx over the entire cultivation period.

Under normal cultivation conditions, that is, light is illuminated at 15 klx for 12 hours during the day (9:00 to 21:00), darkened for 12 hours at night (21:00 to 9:00), and All were cultivated as a control under the same conditions.

As the cultivation for examining the growth promoting effect according to the present invention, the same 15 kl as that of the control group was used throughout the cultivation period in the daytime.
x, the light irradiation condition was set to a light intensity of 1.8 klx at night, and the night irradiation period was changed as follows.
Irradiation at night only for 14 days from the start of cultivation (darkness at night as in the control group from day 15): Example 1, irradiation at night only from 15 to 28 days after start of cultivation (14 days from start of cultivation) And darkness during the same night as the control group after the 29th day): Comparative Example 1, and irradiation during the entire cultivation period at night: Comparative Example 2 were set.

Table 1 shows the change over time in the average total length (cm) of spinach cultivated under each cultivation condition, and Table 2 shows the change over time in the average wet weight (g / strain) per spinach. Shown together. The results of Tables 1 and 2 are shown as graphs in FIGS. In the following figures, ▲ indicates Example 1, Δ indicates Comparative Example 1, Δ indicates Comparative Example 2, and ● indicates a control group.

[Table 1]

[0017]

[Table 2]

In each of Example 1 and Comparative Examples 1 and 2 cultivated by irradiating 1.8 klx light at night, both the size and the weight of the above-ground part of one plant were 28 days after the start of cultivation. Normally, the growth amount reached more than the harvest amount (total length of about 20 cm, wet weight of one strain of about 10 g).

However, only 1.8 klx irradiation was carried out at night during the period from the start of cultivation to the 14th day (Example 1), and no bolting or flower bud differentiation occurred. In Example 2, bolting and flower bud differentiation were observed.

On the other hand, in the control section under the condition of darkness at night after irradiating with the same light intensity of 15 klx for 12 hours during the day as in the prior art,
No bolting or flower bud differentiation occurred during the 42-day cultivation period, but it reached about 35 days after the start of cultivation, where the amount of growth reached or exceeded the harvest amount. Therefore, only during the period from the start of cultivation to the 14th day, it is irradiated with 1.8klx at night,
After that, it became clear that the cultivation period could be shortened without irradiation and flower bud differentiation by using only daytime irradiation.

From the results of Tables 1 and 2, the following effects of the present invention are recognized. 1. Since the cultivation period until harvest can be shortened, the number of times of cultivation in the same place can be increased. 2. Since the cultivation period until harvest can be shortened, productivity can be improved. 3. Since it is only necessary to lengthen the light irradiation time to promote growth, it is not necessary to newly introduce or add a special means.

With respect to spinach cultivated under each cultivation condition, paying attention to the integrated light irradiation amount which is a value obtained by multiplying the light irradiation time by the intensity as the input light energy amount, the growth amount obtained with the same integrated light irradiation amount Were compared for the average total length (cm) and the average wet weight per strain (g / strain), respectively, and are shown in Tables 3 and 4. 3 and 4 show the results of Tables 3 and 4 as graphs.

[0023]

[Table 3]

[0024]

[Table 4]

From the results in Tables 3 and 4, 1.8 kl at night was obtained.
In the case of cultivation by irradiating x light (Example 1, Comparative Example 1 and Comparative Example 2), it can be seen that the obtained growth amounts are all larger than the control group. As described above, only during the period from the start of cultivation to the 14th day, when 1.8 klx irradiation was performed at night (Example 1), no bolting or flower bud differentiation occurred. In this case, it can be seen that the growth amount obtained with respect to the input light energy amount increased, and the light use efficiency of the plant was high. Therefore, it has been clarified that the efficiency of using light energy can be increased by irradiating 1.8 klx at night only during the period from the start of cultivation to 14 days after the cultivation without lowering the commercial value.

From the results in Tables 3 and 4, the following effects of the present invention are recognized. 1. Since it is only necessary to lengthen the light irradiation time to promote growth, it is not necessary to newly introduce or add a special means. 2. Since the input light energy is effectively used, energy loss and cost required for lighting can be reduced.

[0027]

According to the present invention, the conventional method, for example, in the daytime 12
Compared to a method that only irradiates light for a short time, the extraction time and flower bud differentiation do not occur, and the input light energy can be efficiently used by the plants, significantly shortening the time until harvesting, thereby improving productivity. It is an excellent cultivation method that can reduce production costs.

[Brief description of the drawings]

FIG. 1 is a graph showing the change over time in the average total length (cm) of each spinach in Example 1, Comparative Examples 1 and 2, and a control group. ◆ indicates Comparative Example 2, and ● indicates a control group.

FIG. 2 is a graph showing the change over time of the average wet weight (g / strain) of each spinach of Example 1, Comparative Examples 1 and 2, and a control plot, similarly to the case of FIG.

FIG. 1 shows the growth of each spinach in Example 1, Comparative Examples 1 and 2, and a control plot, the same integrated light irradiation amount (klx · h).
FIG. 2 is a graph showing the same results as in FIG. 1 by comparing the average total length (cm) with respect to r).

FIG. 2 shows that the growth of each spinach in Example 1, Comparative Examples 1 and 2 and the control group was measured at the same integrated light irradiation amount (klx · h).
FIG. 2 is a graph showing the same results as in FIG. 1 in comparison with the average wet weight (g / strain) with respect to r).

Claims (3)

[Claims] 1. When irradiating a long-day plant with light, cultivation is performed at night only during the initial cultivation period within 14 days from the start of cultivation.
A method for promoting the growth of long-day plants, wherein the irradiation time is less than klx and the irradiation time is 12 hours or less. 2. The method for promoting growth of long-day plants according to claim 1, wherein the irradiation condition in the daytime during the initial period of cultivation is an irradiation intensity of 15 klx. 3. In cultivating a long-day plant by irradiating light, the irradiation conditions for 14 days from the start of cultivation are as follows: irradiation intensity is 15 klx for 12 hours in the day and irradiation intensity is 1.8 for 12 hours in the night.
A method for promoting the growth of long-day plants, characterized in that irradiation is carried out only during the day after the 15th day from the start of cultivation.