Abstract:
The present invention relates to plant growth regulators and processes for regulating plant growth, and more particularly, relates to a technique to regulate the growth of a plant using a substance which is friendly to the global environment. A growth regulator of a plant comprising NaHCO 3  and/or KHCO 3  as a principal active ingredient is provided.

Description:
[0001]     This application is a division of application Ser. No. 10/483,044, filed Jun. 24, 2004, which was §371 of international application PCT/JP02/07018, filed Jul. 10, 2002, both of which are herein incorporated by reference.  
         [0002]     The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawings will be provided by the Office upon request and payment of the necessary fee. 
     
    
     BACKGROUND OF THE INVENTION  
       [0003]     1. Field of the Invention  
         [0004]     The present invention relates to plant growth regulators and processes for regulating plant growth, and more particularly, to a technique to regulate the growth of a plant using a substance which is friendly to the global environment.  
         [0005]     2. Description of the Related Art  
         [0006]     Conventionally, plant hormones, or plant growth stimulators as well as suppressors and e their analogues have been utilized as agents for the growth stimulation or suppression of a plant in the cultivation of a variety of crop plants. Furthermore, phytic acid, choline and their analogues have been also known in addition to the plant hormones. However, these substances are expensive, and thus substances that are low in price upon use have been desired. Additionally, some of the plant hormones have teratogenicity to the human body, therefore, safe substances to the human body have been sought.  
         [0007]     Although various proposals have been made heretofore with regard to the growth stimulators of plants, many of them have been directed to chemically synthesized agents. Thus, processes in which such an agent is diluted and sprayed have been predominantly applied. However, organic farming methods have become popular recently, in which compost or a natural organic fertilizer is used. Also for growth accelerators of a plant, attempts have been made to develop those which exert no influences on soil or environmental aspects.  
       SUMMARY OF THE INVENTION  
       [0008]     An object of the present invention is to provide a process for regulating the growth of a plant while avoiding problems involved in safety of pesticides and their analogues, and taking into account of the global environment. The process employs an entirely novel compound as a regulator.  
         [0009]     First aspect of the invention relates to a growth regulator of a plant comprising NaHCO 3  and/or KHCO 3  as a principal active ingredient. Further, depending on the circumstances, a growth regulator of a plant is provided in which a plant hormone (preferably, auxin) is included as an active ingredient.  
         [0010]     Second aspect of the invention relates to a process for the growth regulation of a plant in which 0.003 to 1% by weight of NaHCO 3  and/or KHCO 3  is included in a germination and nursery bed of the plant. Further, depending on the circumstances, a process for the growth regulation of a plant is provided in which a plant hormone is included at 10 −3  to 10 −7  M.  
         [0011]     As already proposed, the present inventors have developed on dwarfing methods of a plant using sodium bicarbonate (NaHCO 3 ), and have focused attention to the point that sodium bicarbonate is soluble in water, harmless to human and animals, friendly to the global environment, and available at comparatively low cost. Thus, the inventors conducted a variety of investigations, and unexpectedly found that sodium bicarbonate has an action on a plant to regulate the germination and growth of the plant. Accordingly, the inventors achieved the invention through further evolving the previous proposals to provide growth regulators of a plant and processes for the growth regulation of a plant, which are inexpensive and safe to the human body.  
         [0012]     The plant growth regulator used in the invention includes water soluble NaHCO 3  (sodium bicarbonate) and/or KHCO 3  as a principal active ingredient. The invention is further explained hereinafter with a central focus on sodium bicarbonate. Because an aqueous solution of sodium bicarbonate is almost neutral (pH 8.2) even if it is saturated, it hardly affects the soil. Moreover, sodium bicarbonate runs off with rainwater after the treatment to a plant. Accordingly, this substance is friendly to the global environment, and thus needless to add, can be subjected to the treatment without adversely affecting it. Such sodium bicarbonate and its analogues which can be used may be any known one, which may contain impurities, as long as adverse effects are not exerted to the environment with departing from the object of the invention. As a matter of course, combined use with ingredients of a fertilizer such as nitrogen, phosphorus and potassium, as well as other plant growth regulator is allowed. Commercially available sodium bicarbonate which can be used in the invention includes for example, “ARMEX”, trade name by Church &amp; Dwight Co., Inc. Although this article contains a slight amount of Na 2 CO 3 , Ca, Mg, SiO 2  etc., it can be used as a plant growth regulator without any problems even though such impurities coexist. Of course, the sodium bicarbonate of the invention is not limited thereto. Also in respect of KHCO 3 , influences on the global environment are hardly exerted, almost similarly to sodium bicarbonate.  
         [0013]     When the sodium bicarbonate or their analogues of the invention is used by adding to water upon hydroponics, the concentration for the treatment varies depending on the plant type, as a matter of course, however, the concentration for regulating germination and growth after germination will be 0.003 to 1% by weight, and preferably in the range of 0.01 to 0.1% by weight. In other words, the concentration at a higher range functions as a factor to act for inhibiting a plant growth, and the concentration within a predetermined range leads to expectation to the growth acceleration effects on a plant, resulting in greater height, more rapid growth, as well as upsized fruits, and increased number of fruits. The concentration range for use in the germination and growth of the plant is determined ad libitum taking into account that a high concentration is disadvantageous because germination does not occur, and that too low a concentration does not achieve the expected effects. Sodium bicarbonate and KHCO 3  may be used in combination of course, and the ratio of them is appropriately determined depending on the plant to be applied through determining the concentration ad libitum.  
         [0014]     In accordance with the invention, to use a plant hormone in combination with sodium bicarbonate or KHCO 3  is also a preferable means. For example, indole-3-acetate (IAA) that is a plant hormone suppresses the growth at a relatively high concentration, however, it exhibits a growth acceleration action at a lower concentration (approximately 10 −4  to 10 −7  M). Although the system thereof has not been completely elucidated, plants may involve a growth acceleration mechanism which is stimulated by efflux/influx of Na +  or K + , or a mechanism to induce the activation of a growth acceleration hormone.  
         [0015]     Plant hormones which may be used include auxin, for example, 2,4-D (2,4-dichlorophenoxy acetate), IAA (indole-3-acetate), IBA (indole-3-butyrate), NAA (1-naphthalene acetate), 2,4,5-T (2,4,5-trichlorophenoxy acetate), picloram (4-amino-3,5,6-trichloropyridine-2-carboxylate), dicamba (3,6-dichloro-O-anisate), naphthaleneacetamide, 5-chloro-1H-indazol-3-yl ethyl acetate, MCPA (4-chloro-O-tolyloxyacetate), 2,3,6-TBA (2,3,6-trichlorobenzoate), dichloroprop [2-(2,4-dichlorophenoxy)propionate], mecoprop [2-(4-chloro-2-methylphenoxy)propionate], 2,4-DB [4-(2,4-dichlorophenoxy)butyrate], MCPB [4-(4-chloro-O-tolyloxy)butyrate], phenoprop [2-(2,4,5-trichlorophenoxy)propionate] and the like. These may be used alone or in combination of two or more.  
         [0016]     Further, as cytokinin, for example, kinetin (6-furfurylaminopurine), BA (benzyladenine), 4-PU (4-pyridylphenylurea), zeatin [4-hydroxy-3-methyl(E)-2-butenylaminopurine], dihydrozeatin (4-hydroxy-3-methylbutylaminopurine), 2-isopentenyladenine, 2-isopentenyladenosine, transribosylzeatin [6-(4-hydroxy-3-methyl-(E)-2-butenylamino)-9-β-D-ribofuranosylpurine], CPPU [N-(2-chloro-4-pyridyl)-N-phenylurea] and the like are included. These may be used alone or in combination of two or more.  
         [0017]     Other plant hormones include for example, GA (gibberellin), ABA (abscisic acid), brassinosteroid, jasmonic acid, etc.  
         [0018]     Methods of using the sodium bicarbonate and their analogues of the invention is not particularly limited, however, conventional methods for plant growth regulators such as the soil affusion treatment, addition to the hydroponic solution, coating on seeds, treatment to cuttings may be used. Additionally, combined use with other pesticide or fertilizer is also possible, of course. Therefore, dramatic effects as a soil-improving agent are also exerted. As is described below, by blending the sodium bicarbonate ore its analogues in volcanic ash, for example, modification effects for the soil can be also achieved.  
         [0019]     Specific methods for use include a process in which seeds of a plant are immersed in an aqueous sodium bicarbonate solution, followed by seeding in an agricultural field or potting compost to germinate and grow the plant. This process may include a procedure in which the seeds are mixed with a carrier immobilized with sodium bicarbonate, or potting compost containing the same, followed by seeding in an agricultural field or potting compost.  
         [0020]     Although applicable target plants are not particularly limited, included are for example, root vegetables such as radish ( Raphanus sativus ), carrot ( Daucus carota ), burdock ( Arctium lappa ); vegetables such as etiolated seedling, lettuce ( Lactuca sativa ), Chinese cabbage ( Brassica campestris ),  Brassica chinensis  komatsuna, strawberry, melon ( Cucumis melo ); cereal grains such as rice ( Oryza sativa ), wheat ( Triticum aestivum ), maize ( Zea mays ); petal flowers such as chrysanthemum, lily, orchid, rose, pansy, carnation; turfs such as  Zoysia , zoysiagrass, pentograss; beans such as garden pea ( Pisum sativun ), soybean ( Glycine max ), peanut ( Arachis hypogaea ); trees such as Japanese cedar ( Cryptomeria japonica ), Japanese cypress ( Chamaecyparis obtusa ), azalea ( Rhododendron indicum ); fruit trees such as tomato ( Lycopersicon esculentum ), pear ( Pyrus pyrifolia ), grape ( Vitis vinifera ), apple ( Malus domestics ); weeds such as  Veronica persica  Poir, as representatives thereof. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  is a drawing (photograph) illustrating the state of rice seedlings within a dish.  
         [0022]      FIG. 2  is a drawing (photograph) in which the length of a shoot and a root of seedling as shown in  FIG. 1  was compared.  
         [0023]      FIG. 3  is a drawing (photograph) illustrating the state of tomato seedlings within a dish.  
         [0024]      FIG. 4  is a drawing (photograph) in which the length of a shoot and a root of seedling as shown in  FIG. 3  was compared.  
         [0025]      FIG. 5  is a drawing (photograph) illustrating the state of lettuce seedlings within a dish.  
         [0026]      FIG. 6  is a drawing (photograph) in which the length of a shoot and a root of seedling as shown in  FIG. 5  was compared.  
         [0027]      FIG. 7  is a drawing (photograph) illustrating the state of perennial ryegrass in germ within a dish.  
         [0028]      FIG. 8  is a drawing (photograph) in which the length of a shoot and a root of seedling as shown in  FIG. 7  was compared.  
         [0029]      FIG. 9  is a drawing (photograph) in which the length of a shoot and a root of radish seedlings was compared.  
         [0030]      FIG. 10  is a drawing (photograph) in which the length of a shoot and a root of  Veronica persica  Poir seedling for NaHCO 3  as a control was compared.  
         [0031]      FIG. 11  is a drawing (photograph) in which the length of a shoot and a root of tomato seedling for NaHCO 3  as a control was compared.  
         [0032]      FIG. 12  is a drawing (photograph) in which the length of a shoot and a root of tomato seedling upon use of NaHCO 3  and auxin in combination was compared.  
         [0033]      FIG. 13  is another exemplary drawing (photograph) in which the length of a shoot and a root of tomato seedling upon use of NaHCO 3  and auxin in combination was compared.  
         [0034]      FIG. 14  is yet another exemplary drawing (photograph) in which the length of a shoot and a root of tomato seedling upon use of NaHCO 3  and auxin in combination was compared.  
         [0035]      FIG. 15  is a drawing (photograph) in which the length of a stalk and a root of  Veronica persica  Poir in germ upon use of NaHCO 3  and auxin in combination was compared.  
         [0036]      FIG. 16  is another exemplary drawing (photograph) in which the length of a shoot and a root of  Veronica persica  Poir seedling upon use of NaHCO 3  and auxin in combination was compared.  
         [0037]      FIG. 17  is another exemplary drawing (photograph) in which the length of a shoot and a root of lettuce seedling for NaHCO 3  using volcanic ash was compared. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0038]     The present invention is specifically explained below with references to Examples which are made for merely illustrative purpose, and the invention is not limited to these Examples.  
         [0000]     (1) Effect of NaHCO 3    
       Example 1  
     Rice, FIG.  1  and FIG.  2   
       [0039]     The present invention (NaHCO 3 ) was demonstrated using rice. Absorbent cotton was spread on a 4.5 cm dish, and thereto was added 10 ml of a test solution. Seeds (10 seeds) were added thereto, grown at 23° C. for 4 days in the dark, and thereafter cultured at 23° C. for 3 days in the light (about 3000 lux). Each Figure illustrates for NaHCO 3  used as a principal active ingredient showing from the left: control (NaHCO 3  concentration of 0%), 1% (1/10 dilution of a stock solution of an aqueous saturated solution of 10%), 0.3%, 0.1%, 0.03%, 0.01%, and 0.003%.  
         [0040]      FIG. 1  is a drawing illustrating the state of seeds within each of the dishes.  FIG. 2  is a drawing comparing the length of each shoot and the length of each root. The shoots have the length of 5.3±0.3 mm, 3.3±0.3 mm, 7.3±1.5 mm, 13.3±0.9 mm, 15.0±1.0 mm, 10.0±0 mm, 11.0±1.0 mm, respectively. The length of the roots is 10.3±1.8 mm, 0±0 mm, 2.3±0.3 mm, 20.7±2.3 mm, 23.7±0.9 mm, 18.0±9.7 mm, 32.0±9.3 mm, respectively. For reference, the length of the label is 5 mm.  
         [0041]     As is clear from  FIG. 1  and  FIG. 2  as well as the length of each shoot and root, it is revealed that the growth is suppressed when the concentration is high, whilst the growth is accelerated when the concentration is low.  
       Example 2  
     Tomato, FIG.  3  and FIG.  4   
       [0042]     The present invention (NaHCO 3 ) was demonstrated using tomato.  FIG. 3  is a drawing illustrating the state of germination within each of the dishes similarly to  FIG. 1 .  FIG. 4  is a drawing comparing the length of each embryonic axis (shoot) and that of each root similarly to  FIG. 2 .  
         [0043]     The shoots have the length of 22.7±1.5 mm, 0±0 mm, 14.7±0.3 mm, 41.3±1.9 mm, 46.0±1.5 mm, 39.3±1.5 mm, 30.0±1.7 mm, respectively. The length of the roots is 55.0±1.2 mm, 0±0 mm, 1.3±0.3 mm, 29.3±1.8 mm, 60.7±8.1 mm, 26.3±3.7 mm, 17.0±1.5 mm, respectively. For reference, the length of the label is 5 mm.  
         [0044]     As is clear from  FIG. 3  and  FIG. 4  as well as the length of each shoot and root, it is revealed that the growth is suppressed or the germination does not occur when the concentration is high, whilst the growth is accelerated when the concentration is 0.1% or less.  
       Example 3  
     Lettuce, FIG.  5  and FIG.  6   
       [0045]     The present invention (NaHCO 3 ) was demonstrated using lettuce.  FIG. 5  is a drawing illustrating the state of germination within each of the dishes similarly to  FIG. 1 .  FIG. 6  is a drawing comparing the length of each shoot and that of each root similarly to  FIG. 2 .  
         [0046]     The shoots have the length of 17.3±0.3 mm, 0±0 mm, 6.7±0.3 mm, 15.7±0.3 mm, 24.3±0.3 mm, 24.3±0.9 mm, 14.0±0.6 mm, respectively. The length of the roots is 21.3±0.7 mm, 0±0 mm, 3.7±0.3 mm, 11.0±0.6 mm, 14.3±1.9 mm, 21.0±0.6 mm, 18.7±4.7 mm respectively. For reference, the length of the label is 5 mm.  
         [0047]     As is clear from  FIG. 5  and  FIG. 6  as well as the length of each shoot and root, it is revealed that the growth is suppressed or the germination does not occur when the concentration is high, whilst the growth is accelerated when the concentration is low.  
       Example 4  
     Perennial Ryegrass, FIG.  7  and FIG.  8   
       [0048]     The present invention (NaHCO 3 ) was demonstrated using perennial ryegrass.  FIG. 7  is a drawing illustrating the state of seeds within each of the dishes similarly to  FIG. 1 .  FIG. 8  is a drawing comparing the length of each shoot and that of each root similarly to  FIG. 2 .  
         [0049]     The shoots have the length of 25.3±0.9 mm, 0±0 mm, 19.0±0.6 mm, 55.7±0.7 mm, 44.3±1.5 mm, 42.0±0.6 mm, 24.7±0.3 mm, respectively. The length of the roots is 29.7±0.3 mm, 0±0 mm, 4.7±0.3 mm, 28.0±1.5 mm, 26.0±0.6 mm, 27.3±1.5 mm, 25.3±0.9 mm, respectively. For reference, the length of the label is 5 mm.  
         [0050]     As is clear from  FIG. 7  and  FIG. 8  as well as the length of each shoot and root, it is revealed that the growth is suppressed or the germination does not occur when the concentration is high, whilst the growth is accelerated when the concentration is low.  
       Example 5  
     Radish, FIG.  9   
       [0051]     The present invention (NaHCO 3 ) was demonstrated using radish.  FIG. 9  is a drawing comparing the length of each embryonic axis (shoot) and that of each root similarly to  FIG. 2 .  
         [0052]     The shoots have the length of 60.3±1.9 mm, 0±0 mm, 19.3±0.7 mm, 66.7±3.4 mm, 60.0±3.1 mm, 74.0±1.5 mm, 66.3±4.1 mm, respectively. The length of the roots is 33.7±4.2 mm, 0±0 mm, 7.3±1.3 mm, 22.0±1.5 mm, 80.7±5.9 mm, 71.3±1.9 mm, 37.0±1.5 mm, respectively. For reference, the length of the label is 5 mm.  
         [0053]     As is clear from  FIG. 9  as well as the length of each shoot and root, it is revealed that the growth is suppressed or the germination does not occur when the concentration is high, whilst the growth is accelerated when the concentration is low.  
         [0000]     (2) Effect of KHCO 3  and NaHCO 3  Used in Combination  
       Example 6  
       Veronica persica  Poir, FIG.  10   
       [0054]     The present invention (NaHCO 3 +KHCO 3 ) was demonstrated using  Veronica persica  Poir.  FIG. 10  is a drawing illustrating the state of seeds within each of the dishes similarly to  FIG. 1 , and each control is shown. The Figure illustrates for NaHCO 3  used as a principal active ingredient showing from the left: 0%, 10%, 3%, 1%, 0.3%, and 0.1%. In addition, the lengths of each embryonic axis shoots and root are indicated.  
         [0055]     Experiments were conducted with varying concentrations of KHCO 3  for each concentration of NaHCO 3  shown in  FIG. 10 . Although not shown in the Figure, when the concentration of KHCO 3  was varied at 0% of NaHCO 3 , the length of the shoot and root was 0 mm at 1% of KHCO 3  (the germination did not occur), but became 7 mm and 10 mm respectively at 0.1%, which were approximately identical to the values for 0.1% of NaHCO 3 .  
         [0056]     Next, the experiments were conducted with varying concentrations of KHCO 3  (0.1 to 10%) when the concentration of NaHCO 3  was 10%, 3%, 1% and 0.3%. Thus resulting length of the shoot and root was 0 mm (the germination did not occur). Moreover, when similar tests were carried out for 0.1% of NaHCO 3 , the development of the shoot and root was not found at 10 to 1% of KHCO 3  (the germination did not occur), however, at 0.1% of KHCO 3 , the length of the shoot became 10 mm and the length of the root became 18 mm. These results suggest that more remarkable growth was achieved than the control ( FIG. 10 ) for 0.1% of NaHCO 3  (shoot: 8 mm, root: 9 mm) and for 0.1% of KHCO 3  (shoot: 7 mm, root: 10 mm). Accordingly, the effects by combined use of both compounds were demonstrated.  
       Example 7  
     Tomato, FIG.  11   
       [0057]     The present invention (NaHCO 3 +KHCO 3 ) was demonstrated using tomato.  FIG. 11  is a drawing illustrating the state of seeds within each of the dishes similarly to  FIG. 1 , and each control is shown. The Figure illustrates for NaHCO 3  used as a principal active ingredient showing from the left: 0%, 10%, 3%, 1%, 0.3%, and 0.1%. In addition, the lengths of each shoot and root are presented. In addition, it is revealed that the germination does not occur at 10% and 3%.  
         [0058]     Experiments were conducted with varying concentrations of KHCO 3  for each concentration of NaHCO 3  shown in  FIG. 11 . Although not shown in the Figure, when the concentration of KHCO 3  was varied at 0% of NaHCO 3 , the length of the shoot and root was 0 mm at 1% of KHCO 3  (the germination did not occur), became 40 mm and 62 mm respectively at 0.1%, which revealed greater effects than those suggested by the values for 0.1% of NaHCO 3 .  
         [0059]     Next, the experiments were conducted with varying concentrations of KHCO 3  (0.1 to 10%) when the concentration of NaHCO 3  was 10% and 3%. Thus resulting length of the shoot and root was 0 mm (the germination did not occur). Moreover, when similar tests were carried out for 1% of NaHCO 3 , the development of the shoot and root was not found at 10% or 0.1% of KHCO 3 , however, at 1% of KHCO 3 , the length of the shoot became 11 mm and the length of the root became 5 mm. These reveal greater effects than the control ( FIG. 11 ) for 1% of NaHCO 3  (shoot: 5 mm, root: 1 mm). In addition, when KHCO 3  was used at 10% for 0.1% of NaHCO 3 , the development of the shoot and root was 0 mm (the germination did not occur). However, at 1% of KHCO 3 , the length of the shoot was 2 mm, and, at 0.1% of KHCO 3  the length of the shoot was 50 mm and the length of the root was 45 mm. Accordingly, the effects by combined use of both compounds are remarkable.  
         [0000]     (3) Effect of Auxin Used in Combination  
       Example 8  
     Tomato, FIGS.  12  to  14   
       [0060]     The present invention (auxin used in combination) was demonstrated using tomato. Indole-3-acetate (IAA) was used as the auxin. When IAA was used at 10 −4  to 10 −5  M, although not shown in the Figures, the length of each shoot was 20 mm, 23 mm, and the length of each root was 30 mm, 41 mm, respectively. Thus, when the cases of use in combination with NaHCO 3  were examined, as is shown in  FIG. 12 , in the instances of 10% or 3% of NaHCO 3  and 10 −3  to 10 −5  M of IAA were used, any of the length of the shoot and root was 0 mm (the germination did not occur).  FIG. 13  is a photograph illustrating the instances where 1% or 0.3% of NaHCO 3  and 10 −3  to 10 −5  M of IAA were used. Moreover,  FIG. 14  is a photograph illustrating the instances where 0.1% of NaHCO 3  and 10 −3  to 10 −5  M of IAA were used. According to these Figures, it was revealed that when both compounds were used at a predetermined ratio, the root especially became strong. As the foregoing, when NaHCO 3  and IAA were used in combination, the effects of the combined use are prominent, including the inhibition of the growth and the acceleration of the growth of the plant. In particular, it is proven that when NaHCO 3  was used at 0.1%, IAA at the concentration of approximately 10 −4  to 10 −6  M greatly contributes to the growth of the plant.  
       Example 9  
       Veronica persica  Poir, FIGS.  15  to  16   
       [0061]     The present invention (auxin used in combination) was demonstrated using  Veronica persica  Poir. Indole-3-acetate (IAA) was used as the auxin. When IAA was used at 10 −4  to 10 −5  M, although not shown in the Figures, the length of each shoot was 8 mm, 13 mm, and the length of each root was 11 mm, 22 mm, respectively. Thus, when the cases of use in combination with NaHCO 3  were examined, in the instances of 10% or 3% of NaHCO 3  and 10 −3  to 10 −5  M of IAA were used, any of the length of the shoot and root was 0 mm (the germination did not occur).  FIG. 15  is a photograph illustrating the instances where 1% or 0.3% of NaHCO 3  and 10 −3  to 10 −5  M of IAA were used. Moreover,  FIG. 16  is a photograph illustrating the instances where 0.1% of NaHCO 3  and 10 −3  to 10 −5  M of IAA were used. According to these Figures, it is proven that when NaHCO 3  and IAA were used in combination, the effects of the combined use are prominent including the inhibition of the growth and the acceleration of the growth of the plant.  
       Example 10  
     Modification of Volcanic Ash  
       [0062]     NaHCO 3  was blended in volcanic ash (originated in Hokkaido, Chitose), and the germination of lettuce was thereby accelerated. For control 1, absorbent cotton was spread on a 4.5 cm dish, and thereto was added 10 ml of water. Seeds (10 seeds) were added thereto, grown at 23° C. for 4 days in the dark, and thereafter cultured at 23° C. for 3 days in the light (about 3000 lux). The length of the shoot and root was as shown in  FIG. 17 . Control was for water alone, resulting in the length of the shoot and root of 24.1±1.1 mm and 26.9±1.5 mm. Additionally, when the lettuce seeds were seeded to the soil which was prepared by adding water to the volcanic ash (volcanic ash: 100 g and water: 28 g), the length of the shoot and root was 23.7±2.9 mm and 17.1±2.6 mm.  
         [0063]     However, for the soil including the volcanic ash+10% NaHCO 3  (volcanic acid: 100 g and saturated sodium bicarbonate solution: 28 g), the development of the shoot and root was 0 mm. Moreover, for the soil including the volcanic ash+1% NaHCO 3  (volcanic acid: 100 g and 1% NaHCO 3  solution: 28 g), the length of the shoot and root was 26.0±1.5 mm and 5.4±1.1 mm. Further, for the soil including the volcanic ash+0.1% NaHCO 3  (volcanic acid: 100 g and 0.1% NaHCO 3  solution: 28 g), the development of the shoot and root was 33.4±1.1 mm and 21.0±0.8 mm.  
         [0064]     According to these results, adding NaHCO 3  to the soil contributes to the growth of a plant. Thus, the modification of volcanic ash such as whitebait, and red soil was enabled. Of course, it goes without mentioning that modification of soil can be practiced by use of NaHCO 3  alone, and use thereof in combination with KHCO 3 , as well as use in combination with a plant hormone.  
       INDUSTRIAL APPLICABILITY  
       [0065]     The plant growth regulator of the present invention exerts dramatic effects as described herein above, and is readily available. Furthermore, the plant growth regulator of the invention is characterized by not adversely affecting the soil and being friendly to the environment, and thus the usefulness thereof is eminent.