JPH11243798A - Plant husbandry - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for cultivating a plant, capable of obtaining cell seedlings which do not cause over-luxuriant growth even in transplanting to main field when applied to raising of seedlings and making cultivation management easy and simultaneously capable of reducing occurrence of physiological disorder and increasing yield of high-purity or high-quality fruit in comparison with a conventional method when applied to main field culture. SOLUTION: This method for cultivating plants comprises using a cultivating apparatus 1 having pots 2 which are culture media for keeping plants and a mat 3 which is a liquid-retaining body arranged so as to communicate with at least bottom of the pots 2 and equipped with liquid-retaining function for supporting the pots 2. In the cultivation method, water content potential value of liquid fed to the pot 2 and water content potential value of liquid fed to the mat 3 are set so that these values are different at initial stage of cultivation. Thereby, water content potential is gradually lowered in a growing step of the plant and stress can be gradually given to plants. Consequently, when applied to raising of seedlings, reproduction and growth are sufficiently advanced and high-quality cell seedlings which do not cause over-luxuriant growth can be produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plant cultivation method.

[0002]

2. Description of the Related Art In recent years,
In the production of vegetables and flowers, the use of cell seedlings (so-called cell seedlings) is expanding. Raising seedlings using cell seedlings requires a relatively short seedling raising period, eliminates the need to expand the plants during seedling, is suitable for mass production, and is easy to handle in transportation, so that seedlings are produced in an agricultural manner. It is easy to distribute to farmers, and its use has greatly contributed to labor saving in agricultural work.

[0003] However, for example, when cell seedlings are used in tomato cultivation, there is a problem that overgrowth occurs and deformed stems are produced, resulting in a decrease in yield. This is because the differentiation of the first flower of the first flower cluster, like tomato,
In the case of plants that continue to grow foliage while repeating flower bud differentiation and fruit enlargement one after another, in order to continuously harvest the fruits, it is necessary to balance the vegetative growth and reproductive growth with the growth of foliage and flowering and fruiting. Need to be continued, but the first
Until the inflorescence enlargement begins, the vigorous rooting force causes the foliage to grow and tends to vegetatively grow. For this reason, when the cell seedling in a state before the enlargement of the first inflorescence is planted in this field, since the reproductive growth has not been sufficiently achieved, the roots rapidly elongate, whereby the foliage develops and the amount of photosynthesis is reduced. Due to a large increase, the photoproducts translocate to the foliage and roots rather than the undeveloped flower buds, and become more and more inclined to vegetative growth.

[0004] Therefore, in the past, in tomato cultivation, in order to avoid such a problem of the cell seedling, the cultivation farmer generally reared the cell seedling and planted it at the time of flowering of the first and second flower clusters. However, there is a problem that the merits of using cell seedlings are not fully utilized. For this reason, in tomato cultivation, it has been desired to develop a cell seedling that does not overgrow even when planted directly in the main field.

On the other hand, in this field cultivation, the osmotic pressure is changed by adding inorganic salts such as salt to the culture solution at an appropriate time during the growth process, and when water stress is applied, the harvested fruits become high in sugar content. It is known that quality is improved.

[0006] However, the above-mentioned means for imparting water stress is carried out at an appropriate time in the late growth stage, since the quality of the fruit is determined by the environment in the late growth stage. Cultivation. Therefore, when this means is implemented, the growth environment of the plant changes rapidly. For this reason, there is a problem that the plant is not well adapted to a new environment, and a physiological disorder occurs, and assass rot frequently occurs and the growth is significantly stagnated, so that the yield is reduced. That is, conventional water stress applying means that suddenly changes the growth environment of plants in the late growth stage, even if high sugar content or high quality fruit can be produced, has limited the yield. In addition, even if the supply time of a high-concentration culture solution to which inorganic salts are added is too early, since fruit hypertrophy is suppressed, high-concentration culture is performed after the end of fruit hypertrophy corresponding to two to three weeks before the start of harvest. It is said that it is preferable to start the supply of the liquid or the like, and the supply timing must be strictly controlled.

The present invention has been made in view of the above points, and when applied to raising seedlings, it is possible to obtain cell seedlings which do not overgrow even when planted in the main field. Another object of the present invention is to provide a plant cultivation method which can easily control the cultivation, reduce the occurrence of physiological disorders as compared with the conventional method, and increase the yield of high sugar content or high quality fruit.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has arranged, under a medium in which plants are planted, a liquid-retaining liquid that supports the medium and can hold the liquid. Focusing on the fact that if the values of the water potentials of the liquids supplied to both are made different, the water potential of the medium gradually changes under the influence of the water potential of the liquid holding liquid, and water stress can be applied to the plants. The invention has been completed.

That is, a plant cultivation method according to the present invention according to the first aspect of the present invention provides a medium for holding a plant, and a liquid holding medium which is disposed so as to be in liquid junction with at least a bottom portion of the medium and supports the medium. In a plant cultivation method using a cultivation device having a liquid holding device having a function, the value of the water potential of the liquid supplied to the medium and the value of the water potential of the liquid supplied to the liquid holding device are different. It is characterized by cultivation. The plant cultivation method according to the present invention according to claim 2 is the plant cultivation method according to claim 1, wherein the value of the water potential of the liquid supplied to the medium and the water potential of the liquid supplied to the liquid holding liquid. Is set to be different in the early stage of cultivation.
The method for cultivating a plant according to the present invention described in claim 3 is based on claim 1.
Or the plant cultivation method according to 2, wherein the value of the water potential of the liquid supplied to the liquid holding medium is smaller than the value of the water potential of the liquid supplied to the medium. The method for cultivating a plant according to the present invention according to claim 4 is the method for cultivating a plant according to any one of claims 1 to 3, wherein at least one of the medium and the liquid retaining liquid contains a solute. The method is characterized in that the value of the water potential of the liquid supplied to the medium and the liquid holding liquid is changed by adjusting the rate. The plant cultivation method according to the present invention according to claim 5 is the plant cultivation method according to claim 3, wherein the difference between the water potential values of the liquids supplied to the medium and the liquid retaining liquid is 200 to 3000 kPa. It is characterized by being in the range. A plant cultivation method according to a sixth aspect of the present invention is the plant cultivation method according to the fifth aspect, wherein the value of the water potential of the liquid supplied to the medium is −30.
At a pressure of 0 kPa or more, the value of the water potential of the liquid supplied to the liquid holding liquid is in a range of -3000 to -300 kPa. The plant cultivation method according to the present invention according to claim 7 is the plant cultivation method according to claim 3, 5 or 6, wherein the nitrogen component content of the liquid supplied to the medium is within a range desirable for plant growth. The value of the water potential of the liquid supplied to the liquid holding medium is made smaller than the value of the water potential of the liquid supplied to the culture medium while adjusting. The plant cultivation method according to the present invention according to claim 8 is the plant cultivation method according to claim 7, wherein the content of the liquid supplied to the liquid holding liquid is higher than the nitrogen component content of the liquid supplied to the medium. The content of the nitrogen component is low, and the value of the water potential of the liquid supplied to the liquid holding medium is made smaller than the value of the water potential of the liquid supplied to the culture medium by adjusting the content of the solute other than the nitrogen component. It is characterized by the following. The plant cultivation method according to the present invention according to claim 9 is the plant cultivation method according to claim 8, wherein the solute other than the nitrogen component contained in the liquid supplied to the liquid retaining liquid is sodium chloride, Potassium chloride, calcium chloride, magnesium chloride, sodium sulfate, potassium sulfate, magnesium sulfate, sodium hydrogen sulfate, potassium hydrogen sulfate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, It is characterized in that it is at least one selected from the group consisting of polyethylene glycol and sodium ligninsulfonate or a mixture of two or more thereof. The plant cultivation method according to the present invention according to claim 10 is the plant cultivation method according to claim 8 or 9, wherein the nitrogen component content of the liquid supplied to the medium is 5 when applied to seedlings. ~
30 mmol kg ^-1 , and when used for field cultivation, it is in the range of 10-60 mmol kg ^-1 , and the nitrogen content of the liquid supplied to the medium is in any case, the nitrogen content of the liquid supplied to the medium. It is characterized by being at most 80% of the component content. The plant cultivation method according to the present invention according to claim 11 is the plant cultivation method according to any one of claims 1 to 10, wherein during the growth period of the plant to be cultivated,
In the case of performing the additional replenishment of the liquid, it is characterized in that the replenishment of the liquid is performed with respect to the medium and the liquid holding liquid having a small water potential value. The plant cultivation method according to the present invention described in claim 12 is the method according to claim 1.
The method for cultivating a plant according to any one of items 1 to 11, wherein the liquid supplied to the medium has a weight of 0.01 to 10 ppm.
Characterized in that 5-aminolevulinic acid is added to give a concentration of The plant cultivation method according to the present invention according to claim 13 is the plant cultivation method according to any one of claims 1 to 12, wherein a root shield sheet is provided between the medium and the liquid retaining liquid. It is characterized in that it is implemented.

[0010]

Next, the present invention will be described in more detail with reference to the embodiments shown in the drawings. In the figure,
Reference numeral 1 denotes a cultivation apparatus used to carry out the plant cultivation method according to the present embodiment, and includes a rock wool pot 2 and a rock wool mat 3 that supports the pot 2. I have. That is, in the present embodiment, the pot 2 corresponds to a medium for holding a plant,
The mat 3 corresponds to the liquid retention.

The pot 2 has a size of about 5 to 10 cm square, depending on the type of plant to be cultivated. Of course, the material is not limited to rock wool, and any material having a certain degree of shape retention may be used. Also, the shape is not limited to a cube or a rectangular parallelepiped,
It may be cylindrical or the like.

The mat 3 may be formed in a shape such as a cube or a rectangular parallelepiped on which the pot 2 can be placed on its upper surface, and may be any as long as it can retain liquid. The mat 3 may be any as long as it can support the pot 2, and its shape is not limited at all. Further, the mat 3 is not necessarily limited to the one on which the pot 2 can be placed. It is necessary to adopt a liquid junction configuration. Here, the “liquid junction” refers to a state in which hydraulic continuity is maintained. In the present embodiment, a rock wool is used, but the present invention is not limited to this. For example, a woven or non-woven fabric of a predetermined thickness capable of retaining liquid, or sand or vermiculite having a small particle size, or a container having a drain hole whose drainage amount and drainage speed are adjusted to be within a predetermined range, and the like are described above. It can be used as a liquid retaining liquid instead of the mat 3.

In the cultivation apparatus 1, between the pot 2 and the mat 3, a root shielding sheet 4 that allows liquid such as water to pass but prevents passage of plant roots, for example, a polyester filament is densely woven. The maximum size of the gap is 30μm
Something can be arranged. Thus, there is an advantage that the elongated roots can be prevented from entering the mat 3, and for example, the operation for separating the pot 2 from the mat 3 after raising the seedlings is facilitated. However, as will be described later, the plant cultivation method of the present embodiment is performed by setting the liquid retention, that is, the water potential of the mat 3 to be low at the beginning of cultivation. Even if it is not installed, the penetration of the elongated roots into the mat 3 is limited as compared with the case where a normal cultivation method in which the water potential of the pot 2 and the mat 3 is almost the same is performed. Has a water potential of -10
When the pressure is not more than 00 kPa, there is almost no problem even if the root shielding sheet 4 is not practically provided.

Next, a plant cultivation method according to the present embodiment using the cultivation apparatus 1 having the above-described configuration will be described. That is, in the present embodiment, in the early stage of cultivation, the value of the water potential of the liquid supplied to the pot 2 as the culture medium and the value of the water potential of the liquid supplied to the mat 3 as the liquid holding liquid are changed, and the water potential of the liquid supplied to the pot 2 is changed. Cultivation is carried out with the setting to be high. In the present invention, it is important from the above-mentioned purpose that stress is not gradually applied to the plant but is applied gradually. That is, it is important to carry out such that the water potential of the liquid supplied into the pot 2 where the roots are present gradually decreases from the relationship with the water potential of the liquid supplied to the mat 3 having different values. is there.

In the present invention, at any time during the cultivation period, the pot 2 which is a culture medium and the mat 3 which is
There is a time when the value of the water potential of the liquid supplied to the pot 2 is different, and as a result, the water potential of the liquid supplied to the pot 2 becomes lower at a predetermined growth time,
It suffices if stress can be applied to the plant by this, but as in the present embodiment, in the early stage of cultivation, the value of the water potential of the liquid supplied to the mat 3 which is a liquid retaining liquid is smaller than that of the pot 2. It is appropriate to set them differently from the viewpoint of facilitation of cultivation management.

Here, the term “early cultivation” of a plant refers to a case where the plant cultivation method according to the present embodiment is applied to a seedling raising, and refers to a sowing period when directly sown in a pot 2, and from a germination period. When grown up to about 2 true leaves separately,
It refers to the stage of transplanting such seedlings into pot 2. In addition, when applied to main field cultivation, it refers to the planting period.

Further, the water potential (unit: Pa)
Is the chemical potential of water (liquid) (unit: J / mo)
l) is changed to a partial molar volume of water (liquid) (unit: m ³ / mo).
It is expressed as a thermodynamic quantity divided by l), and is an index of the energy quantity of water (liquid), and is expressed by the following equation. _{Ψ w = μ w -μ o /} V w = RTlna w / V w In the formula, [psi _w is water potential, mu _w is the chemical potential of the water (liquid) of the measurement object, mu _o net at the measurement temperature The chemical potential of water, _Vw is the partial molar volume of water (liquid) of the object to be measured, _aw is the activity of water (liquid) in the object to be measured, R is the gas constant, and T is the absolute temperature.

[0018] and pure water mu _o as the reference, are determined in the zero as defined, water potential is quantitatively represents how much energy chemical potential difference relative to the pure water, substances Because of the melting or the tension between the solid substance and the water molecule, the potential energy decreases, and the water potential is represented by a negative value. In addition, water (liquid) flows from the higher water potential to the lower water potential ("biological environment control",
Vol. 32, no. 4 (1994), Nos. 203-21
Page 7, Review "Biological Measurement and Environmental Regulation" (Author:
Hiroshi Nonami)).

Means for making the water potential value of the liquid supplied to the pot 2 different from that of the liquid supplied to the mat 3 can be adjusted by adjusting the content of the solute contained in at least one of the two. For example, sodium chloride, potassium chloride, calcium chloride, magnesium chloride, sodium sulfate, potassium sulfate, magnesium sulfate, sodium hydrogen sulfate, potassium hydrogen sulfate, and phosphoric acid are added to the liquid (culture liquid) supplied to the mat 3 as a solute. It contains at least one selected from the group consisting of disodium hydrogen, dipotassium hydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, polyethylene glycol and sodium ligninsulfonate, or a mixture of two or more thereof. For example, the value of the water potential of the liquid supplied to the mat 3 can be made smaller than the value of the liquid (culture liquid) supplied to the pot 2. Further, the diluted seawater can be used as a liquid supplied to the mat 3.

The difference between the value of the liquid potential supplied to the pot 2 and the value of the water potential supplied to the mat 3 is 200 to 300.
It is preferably 0 kPa. If there is a difference in this range, the value of the water potential of the liquid supplied to the pot 2 gradually decreases during the cultivation period, and stress can be gradually applied to the plant.

Further, the value of the water potential of the liquid supplied to the pot 2 is preferably -300 kPa or more. Further, the value of the water potential of the liquid supplied to the mat 3 is preferably in the range of -3000 to -200 kPa. If the ratio is out of this range, there is a high possibility that the development of flower buds is delayed or the cotyledon leaves fall earlier.

It should be noted that the resistance of the plant to the water potential, that is, the value of the water potential of the liquid supplied in the pot 2 is smaller (more than -300 kPa).
(A value close to the above), 5-aminolevulinic acid is added to the liquid supplied to the pot 2 in a concentration range of about 0.01 to 10 ppm by weight so that the growth of the plant is not adversely affected. Is preferred. The addition of 5-aminolevulinic acid acts to lower the water potential of the liquid by the amount of the addition, but within the above range, the reduction is negligible. In addition, since 5-aminolevulinic acid becomes a trace amount in about 1 to 2 weeks after being supplied, it is preferable to additionally supply 5-aminolevulinic acid about once every 1 to 3 weeks. Of course, as described later, in a case where the liquid is not additionally supplied to the pot 2,
It is not necessary to additionally supply 5-aminolevulinic acid.
In that case, 5-aminolevulinic acid is also supplied only at the beginning of cultivation, but it is advantageous compared to the case where no 5-aminolevulinic acid is supplied.

In order to produce high quality plants (seedlings), nitrogen is indispensable. Of course, if nitrogen is supplied too much, it is unfavorable because the nutrients grow too much. On the other hand, for the purpose of the present invention, in order to gradually apply stress to the plant, when the plant reaches a predetermined growth stage, it is preferable that the plant is in a state where it cannot absorb much nitrogen. Therefore, it is preferable that the nitrogen component contained in the liquid supplied to the pot 2 decreases not only due to absorption by the plant but also due to the migration accompanying the concentration gradient to the mat 3. Preferably, there is a difference between the nitrogen content of the liquid to be supplied and the nitrogen content of the liquid supplied to the mat 3. In addition, the pot 2 in which the roots of the plant are held, from these facts, the nitrogen component content changes within a proper range for the growth of the plant from the initial stage of cultivation to a predetermined growth stage, and gradually decreases. It is preferred that

Specifically, when the present method is applied to raising seedlings, it is in the range of 5 to 30 mmol kg ^{-1 at} the beginning of cultivation.
It is preferable to set within the range of 〜60 mmol kg ⁻¹ . In any case, the content of the nitrogen component supplied to the liquid holding medium is preferably 80% or less of the content of the nitrogen component of the liquid supplied to the culture medium.

Of course, since nitrogen is also a solute of the liquid to be supplied, the higher the nitrogen content, the smaller the value of the water potential. However, in the present embodiment, other than nitrogen as described above, Is adjusted so that the value of the water potential of the mat 3, which is a liquid retention liquid, is reduced by the solute content.

In the present embodiment, if the liquid to be supplied to the pot 2 and the mat 3 is set as described above and supplied in the early stage of cultivation, then, during the cultivation period, the pot 2 and the mat 3 are supplied.
It is not necessary to additionally supply the liquid to the mat 3.
Since the plant gradually stresses due to the gradual decrease in the value of the water potential of the liquid in the pot 2, when the pot 2 is additionally replenished with the liquid, the stress is gradually applied. The meaning that had been used disappears. Therefore, when additional replenishment of liquid is performed, it is performed only for the mat 3. Since only the mat 3 needs to be performed, the mat 3 is usually arranged in a tray (not shown).
It is only necessary to supply the liquid into the tray without preparing a special liquid supply device, and it is possible to easily perform additional supply of the liquid.

(Example 1) Implementation conditions: Pot size: 75 × 75 × 75 (mm) Maximum liquid holding capacity of the pot: about 400 cm ³ Material of the pot: Rock wool (a polyethylene film is coated on the outer periphery of the side) Pot arrangement: mat (use a root shield sheet) 1. In the case, it is arranged in 5 rows and 2 columns. 2. Mat size: 50 × 150 × 375 (mm) Maximum liquid holding capacity of the mat: about 270 cm ³ per pot ³ Material of the mat: rock wool 3. Root shield sheet: 17 cm x 40 cm (trade name: "Luton S48" manufactured by Seiwa Co., Ltd.) In addition, prepare one with a root shield sheet between the pot and the mat, and one without. Type of liquid: I. Liquid to be supplied to the pot: the following three types Level 1: 10 kg of 50 g each of A-formulated liquid manure and B-formulated liquid manure
Culture solution (nitrogen concentration: 5 mm
olkg ^-1 , EC value: 1.1 mScm ^-1 , water potential value: about -35 kPa) Level 2: 100 g of each of the A-formulated liquid fertilizer and the B-formulated liquid fertilizer for 10 k
g of culture solution diluted with well water (nitrogen concentration: 10
mmol kg ^-1 , EC value: 2.1 mScm ^-1 , water potential value: about -70 kPa) Level 3: 150 g each of A-formulated liquid fertilizer and B-formulated liquid fertilizer for 10 k
g of culture solution diluted with well water (nitrogen concentration: 15
mmol kg ^-1 , EC value: 3.1 mScm ^-1 , water potential value: about -100 kPa) II. Liquid supplied to the mat: calcium chloride ("granular,
"Commercial food additive" manufactured by Central Glass Co., Ltd.) is dissolved in well water to have the following concentration. Level 1: 11.6 g / kg (moisture potential value: about-
500 kPa) Level 2: 22.9 g / kg (water potential value: about-
1000 kPa) Level 3: 44.7 g / kg (water potential value: about −
2000 kPa)

The formulas of the liquid fertilizers of Formula A and Formula B are as shown in the following table. Formulation of Formulation A liquid fertilizer (300 liters finish) Material name Manufacturing company Compounding amount (kg) Compounding fertilizer "SR-A (addition of iron)" Yoneyama Chemical Industry Co., Ltd. 20 Magnesium sulfate fertilizer "16.0 Magnesium sulfate fertilizer""Torii Kasei Kogyo Co., Ltd. 7 Sulphate Kali" 51.0 Sulphate Kari "Ueno Pharmaceutical Co., Ltd. 5 Compound fertilizer" SR-M "Yoneyama Chemical Industry Co., Ltd. 1

B Formulation of liquid fertilizer B (300 liters finish) Raw material name Manufacturer name Compounding amount (kg) Lime nitrate “Calcium nitrate” Yoneyama Chemical Industry Co., Ltd. 20 Calcium chloride “Granular, commercial food additive” Central Glass 1

The water potential was determined as follows. That is, in general, the water potential is determined by the above equation. However, under the conditions of this embodiment,
The pressure potential is 0 because the atmospheric pressure is released, and the pot 2
And the capillary potential of the rock wool constituting the mat 3 is a negligible value because the water content is extremely high when the experimental conditions are set, and the gravitational potential is a negligible value due to the thickness of the pot 2 and the mat 3. is there. Therefore, under the conditions of the present embodiment, it can be considered that the water potential is the same as the osmotic potential. Since the osmotic potential is equal to the amount obtained by adding a negative value to the osmotic pressure, the water potential can be eventually expressed by the following equation. Osmotic pressure Π = νRTWa · φm / 1000 Va where ν is the number of ions generated by dissociation of one solute molecule, R
Is the gas constant, T is the absolute temperature, Wa is the molecular weight of the solvent, Va
Is the partial molar volume of the solvent, φ is the permeability coefficient, and m is the molarity of the solution. The solvent is water at 25 ° C.
a is approximated by the formula quantity of water / (density of water at 25 ° C. × 10 ⁶ ),
And φ is the Chemical Handbook Basic Edition II (Maruzen Revised 2nd Edition, issued on June 20, 1975), pp. 1202-1203, Table 1.
When approximation by a two-point linear interpolation from the numerical value of 0.72 (permeation coefficient of the aqueous electrolyte solution (25 ° C.)) is permitted, the following practical formula is obtained. Osmotic pressure Π = ν × 2.47 × 10 ⁶ × mx × φa + (m−
a) × (φb−φa) / (ba)} where a is a molar value in the nearest numeral table smaller than mmol.
φa is its permeability coefficient, b is the molar value of the nearest number table greater than mmol and φb is its permeability coefficient.

Experimental method: Seeds of tomato (variety: Momotaro (Takii seedling)) were sown in a medium, germinated, and the above-mentioned "I.
Seedlings with two true leaves are transplanted one by one to each of the above pots, and then the above liquid is added to the pot. And a mat. The liquid was supplied immediately after transplantation (early stage of cultivation), and no additional replenishment was performed.

Evaluation: Seedlings were raised for one month, and the growth and quality of the seedlings were evaluated. The evaluation results are shown in FIGS. In addition, each evaluation was performed in relation to the value of the water potential of the liquid supplied to the mat and the nitrogen concentration.

First, in FIG. 2, the live weight of seedlings (FWt
(G)). As is clear from the figure, as the nitrogen concentration (N (mmolkg ^-1 )) increases,
The higher the value of the water potential (WP (kPa)), the higher the living weight. Note that RSS means a root shield sheet, S is a case having a root shield sheet, and D is a case having no root shield sheet. For example, “N5 / S” is the case where the nitrogen concentration is 5 mmol kg ⁻¹ and the root shielding sheet is provided.
FIG. 3 shows the relationship with the dry matter weight (DWt (g)) of the seedling, which also increases as the nitrogen concentration increases and as the value of the water potential increases, similarly to the live weight. I have. FIG. 4 shows the relationship with the growth index. The growth indicator is represented by stem length (cm) x leaf number x stem diameter (mm). It can be seen from this figure that, as in FIGS. 2 and 3, the higher the nitrogen concentration and the higher the value of the water potential, the higher the growth indicator.

In each of the above cases, the same tendency was exhibited irrespective of the presence or absence of the root shield sheet. In addition, the effect of the presence or absence of the root shield sheet on the characteristic values related to the above evaluation was not statistically significant.

On the other hand, the dry matter ratio (DW) shown in FIG.
t (%)) shows a completely opposite tendency. The dry matter ratio is DWt
(%) = Dry matter weight (DWt (g)) / live weight (FWt
(G)). In other words, it is the ratio of the components other than the water content of the plant to the living weight, and the dry matter ratio is usually higher as the seedlings have grown more visually as they grow. However, according to the present embodiment, the lower the nitrogen concentration and the lower the water potential value, the higher the dry matter ratio. This is because the water potential value and the nitrogen concentration in the pot are gradually reduced and stress is applied, so that the content of the plant is enriched in terms of phytonutrientation, despite the reduced seedling size. It indicates that the seedling is a seedling, and it is possible to provide a seedling that is not biased to vegetative growth even if it is planted, that is, does not overgrow even though it is a small-sized cell seedling.

The experimental conditions described above (that is, the number of pots per mat (= number of seedlings) was 10 (1 experimental section), 2 levels with or without root shield sheets, 3 levels with nitrogen concentration,
(3 levels in terms of the water potential).
A total of 180 seedlings were raised in the 18 experimental plots, but none of the seedlings withered during the seedling raising because none of the above experimental conditions were within the preferred range of the present invention.

(Comparative Example 1) The same pot and mat as in the example were used, but a root raising sheet was not provided, and a normal seedling raising method was carried out at the same time as the example. That is, for both the pot and the mat, a culture solution (nitrogen concentration: 10 mmol kg ^-1 , EC value: 2.1 m) was prepared by diluting 100 g of each of the above-mentioned liquid fertilizers A and B with 10 kg each with well water.
Scm ^-1 , water potential value: about -70 kPa) is supplied at the beginning of cultivation (at the time of transplanting seedlings into pots), and thereafter,
The same liquid was additionally supplied to the pot as needed.

The live weight (FWt (g)) of the seedling is 3
6 g, dry weight (DWt (g)) 3.6 g, dry matter rate (D
Wt (%) is 9.9%, Growth Index is 2
700 results were obtained. This result indicates that the seedlings are too large as compared with the examples, and that the seedlings contain much water and are prone to the growth. Therefore, it is necessary to perform an operation such as appropriately expanding the number of plants according to the growth during the raising of the seedlings, and there is also a problem in handling related to the movement of the seedlings when planting in the main field.

(Example 2) Implementation conditions: The liquid supplied to the pot was prepared according to I. Level 2
While fixing to one kind similar to the above, the liquid supply to the mat is adjusted by adjusting the concentration of calcium chloride ("granular, commercial food additive" manufactured by Central Glass Co., Ltd.) to change the water potential as follows. The relationship between the water potential of the liquid supplied to the mat, flower bud development and cotyledon senescence was investigated. The other conditions such as the size, material, and shape of the pot and the mat and the presence or absence of the root shield sheet are exactly the same as those in the first embodiment. The results are shown in Tables 1 and 2.

(Table 1) Water potential Flower bud development degree (kPa) (0 to 10) 0 2.0 -125 3.0 -250 3.2 -500 5.4 -1000 5.8 -2000 5.0- 4000 0.0 Flower bud development degree: 0 means that flower buds cannot be visually confirmed in all strains. In the case of No.:10, a substantial flower bud can be visually confirmed in all strains.

(Table 2) Water potential Degree of cotyledon aging (kPa) (0 to 10) 0 10 -125 10 -250 9.2 -500 4.2 -1000 1.3 -2000 2.8 -4000 10 Cotyledon aging Degree: 0 indicates no cotyledon yellowing or falling in all strains. No. 10 indicates that all the plants have yellowing or falling of cotyledons.

The results of Tables 1 and 2 are shown in the graph of FIG. As is clear from these tables and the graph of FIG. 6, the upper limit of the value of the water potential of the liquid supplied to the mat that is the liquid retaining agent is such that the flower bud development degree and the cotyledon senescence degree gradually increase when the value exceeds −500 kPa. Worsen, -30
The degree of cotyledon senescence tends to rapidly deteriorate from around 0 kPa. In addition, when the lower limit is less than -2000 kPa, both the flower bud development degree and the cotyledon senescence gradually deteriorate again,
When it is less than -3000 kPa, the degree of flower bud development is insufficient, the cotyledon senescence is high, and there is a problem in the quality of seedlings.

(Example 3) Operating conditions: The liquid supplied to the mat was replaced with II. While fixing to one kind similar to level 2, while changing the nitrogen concentration of the liquid supplied to the pot as follows, the relationship between the nitrogen concentration of the liquid supplied to the pot and the flower bud development degree and cotyledon senescence degree Examined. The water potential of the liquid supplied to the pot was adjusted so as to be -300 kPa or more. Other conditions such as the size, material and shape of the pot and the mat, and the presence or absence of the root shield sheet are exactly the same as those in the first embodiment. The results are shown in Tables 3 and 4.

(Table 3) Nitrogen concentration Flower bud development degree (mmol kg ^-1 ) (0 to 10) 10405 2.010 5.8 15 8.3 20 7.2 30 6.0 Flower bud development degree: 0 indicates that flower buds cannot be visually confirmed in all strains. In the case of No.:10, a substantial flower bud can be visually confirmed in all strains.

(Table 4) Nitrogen concentration Cotyledon senescence (mmol kg ^-1 ) (0 to 10) 110 4 10 5 6.3 10 1.7 15 0.8 20 0.9 30 0.8 Cotyledon senescence: 0 means that all the plants have no cotyledon yellowing or falling. No. 10 indicates that all the plants have yellowing or falling of cotyledons.

The results of Tables 3 and 4 are shown in the graph of FIG. As is clear from these tables and the graph of FIG. 7, the nitrogen concentration of the liquid supplied to the pot, which is the medium,
10mmolkg below ^-1 and floral development degree, worse gradually both cotyledons aging degree, from per below the 5Mmolkg ^-1 cotyledons aging degree, flower bud development of both rapidly tends to deteriorate. Although there is no problem in the degree of cotyledon aging, 15 mm
When the amount exceeds ol kg ⁻¹ , the degree of flower bud development gradually decreases. Therefore, it is preferable to set the upper limit to about 30 mmol kg ⁻¹ .

(Example 4) Next, an example in which the plant cultivation method according to the present invention is applied to field cultivation will be described.
FIG. 8 shows the configuration of the cultivation apparatus 10 used in this field cultivation, wherein reference numeral 11 denotes a pot, 12 denotes a mat, 13 denotes a root shield sheet, and 14 denotes a mulching sheet.

Implementation conditions: 1. Seedlings to be planted: tomato seedlings obtained in Example 1 and tomato seedlings obtained in Comparative Example 1. Pot size: 75 × 75 × 75 (mm) Maximum liquid holding capacity of the pot: about 400 cm ³ Material of the pot: Rock wool (a polyethylene film is coated on the side periphery) Pot arrangement: on a mat (root shield sheet) 2. The three seedlings of the above two types are arranged in tandem on separate mats. Feeding to a pot: Culture medium is supplied at a rate of about 300 cm ³ per pot immediately before planting. ^3. Size of mat: 75 × 300 × 900 (mm) Maximum liquid holding capacity of mat: about 6500 cm ³ per pot Material of mat: rock wool 4. Shielding sheet: Product name: "Luton S48" manufactured by Seiwa Co., Ltd. Type of liquid: I. Liquid to be supplied to the pot: A culture solution prepared by diluting 300 g of each of the liquid fertilizers A and B shown in Example 1 with well water so as to be 10 kg (nitrogen concentration: 30 mmol kg ⁻¹ , E
C value: 6.0 mScm ^-1 , water potential value: about -2
00 kPa) II. Liquid supplied to the mat: calcium chloride ("granular,
Commercial Food Additive "Central Glass Co., Ltd.)
Dissolve in well water to a concentration of 1.6 g / kg (water potential value = -500 kPa)

Experimental method: Attraction was entangled with a string hung from a greenhouse structure. Axillary bud removal was performed as needed. Pinching left two leaves that had settled on the first inflorescence, and removed apical buds immediately above them. Pollination was performed. After the liquid was supplied immediately before the above-mentioned planting (early cultivation), no additional replenishment was performed.

Evaluation: The fruits were cultivated for 2 months, and the quality and size of the fruits were evaluated. Table 5 shows the results. The values in the table represent the average value of three tomato seedlings of Example 1 and the average value of three tomato seedlings of Comparative Example 1.

(Table 5) Normal fruit Butt rot fruit Seedling type Number of fruits Average 1 fruit weight (g) Refractive sugar content (%) Number of fruits Seedling of Example 1 3.3 120 9.3 0.33 Comparative example 1 Seedling 3.7 113 8.9 0.67

As is clear from Table 5, when any of the seedlings is used, when the plant cultivation method of the present invention is applied to the field cultivation, high-quality fruits having a refraction sugar content of about 9% can be obtained. At the same time, it can be seen that the occurrence of butt rot fruit is suppressed low.

[0053]

According to the plant cultivation method of the present invention, the water potential is gradually lowered in the growth process of the plant, and the plant can be gradually stressed. Therefore,
When applied to raising seedlings, reproductive growth is sufficiently advanced, and high-quality cell seedlings that do not overgrow even when planted in this field can be produced. In particular, it is possible to produce good-quality cell seedlings even for plants that have conventionally been difficult to use directly in this field even when produced as cell seedlings, for example, tomatoes. In addition, since the stress applied to the plant is not sudden but gradually applied, it hardly withers during the cultivation.

When the plant cultivation method of the present invention is applied to the main field cultivation, the occurrence of butt rot fruits is reduced, and fruits with high sugar content can be produced without reducing the yield.

Further, by applying a configuration in which the nitrogen content is gradually lowered in addition to the water potential being gradually lowered, it is possible to produce high-quality cell seedlings and fruits.

Further, in the plant cultivation method of the present invention, a liquid retaining liquid used for gradually lowering the water potential of the liquid supplied to the medium is separately provided below the medium in which the roots of the plant are prosperous. Because of the configuration, in the early stage of cultivation, if the value of the water potential of the liquid supplied to the culture medium and the liquid supplied to the liquid holding liquid is specified, subsequent cultivation management is almost unnecessary, and the effect of labor saving of cultivation work is also obtained. large.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a cultivation apparatus used in one embodiment of a plant cultivation method of the present invention.

FIG. 2 is a diagram showing the evaluation results of Example 1 of the plant cultivation method of the present invention, and is a diagram showing the live weight of a seedling in relation to a water potential and a nitrogen concentration.

FIG. 3 is a diagram showing evaluation results of Example 1 of the plant cultivation method of the present invention, and is a diagram showing a dry weight of a seedling in relation to a water potential and a nitrogen concentration.

FIG. 4 is a diagram showing evaluation results of Example 1 of the plant cultivation method of the present invention, and is a diagram showing growth indicators of seedlings in relation to a water potential and a nitrogen concentration.

FIG. 5 is a diagram showing evaluation results of Example 1 of the plant cultivation method of the present invention, and is a diagram showing a dry matter ratio of a seedling in relation to a water potential and a nitrogen concentration.

FIG. 6 is a diagram showing evaluation results of Example 2 of the plant cultivation method of the present invention, and is a diagram showing a relationship between a water potential and a flower bud development degree and a cotyledon senescence degree of a seedling.

FIG. 7 is a diagram showing the evaluation results of Example 3 of the plant cultivation method of the present invention, and is a diagram showing the relationship between the nitrogen concentration and the degree of flower bud development and cotyledon senescence of a seedling.

FIG. 8 is a configuration diagram illustrating the outline of a cultivation apparatus used in Example 4 in which the plant cultivation method of the present invention is applied to main field cultivation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cultivation apparatus 2 Pot 3 Mat 4 Root shield sheet 10 Cultivation apparatus 11 Pot 12 Mat 13 Root shield sheet 14 Mulching sheet

Claims (13)

[Claims] 1. A cultivation apparatus having a medium for holding a plant, and a liquid holding liquid provided with a liquid holding function for supporting the medium, which is disposed so as to be in liquid junction with at least a bottom portion of the medium. In the plant cultivation method, the plant is cultivated such that the value of the water potential of the liquid supplied to the culture medium is different from the value of the water potential of the liquid supplied to the liquid holding medium. 2. The method for cultivating a plant according to claim 1, wherein
A plant cultivation method, wherein a value of a water potential of a liquid supplied to the culture medium and a value of a water potential of a liquid supplied to the liquid holding liquid are set to be different at an early stage of cultivation. 3. The plant cultivation method according to claim 1, wherein a value of a water potential of the liquid supplied to the liquid holding medium is smaller than a value of a water potential of the liquid supplied to the culture medium. Characteristic plant cultivation method. 4. The method for cultivating a plant according to any one of claims 1 to 3, wherein the medium and the medium are maintained by adjusting the content of a solute contained in at least one of the medium and the liquid holding medium. A method for cultivating a plant, wherein the value of the water potential of the liquid supplied to the liquid is made different from that of the liquid. 5. The plant cultivation method according to claim 3, wherein
A plant cultivation method, wherein a difference between water potential values of the liquids supplied to the medium and the liquid holding liquid is in a range of 200 to 3000 kPa. 6. The plant cultivation method according to claim 5, wherein
The value of the water potential of the liquid supplied to the medium is-
A plant cultivation method, wherein the value of the water potential of the liquid supplied to the liquid holding liquid is at least 300 kPa, and the value of the water potential is in the range of -3000 to -300 kPa. 7. The method for cultivating a plant according to claim 3, 5 or 6, wherein the nitrogen content of the liquid supplied to the medium is adjusted to a range desired for plant growth, and the liquid is supplied to the liquid holding liquid. A method for cultivating a plant, wherein the value of the water potential of the liquid to be supplied is made smaller than the value of the water potential of the liquid supplied to the culture medium. 8. The method for cultivating a plant according to claim 7, wherein
The nitrogen component content of the liquid supplied to the liquid holding medium is lower than the nitrogen component content rate of the liquid supplied to the medium, and the liquid content supplied to the liquid holding liquid is adjusted by adjusting the content of other solutes other than the nitrogen component. A method for cultivating a plant, wherein the value of the water potential of the liquid to be supplied is made smaller than the value of the water potential of the liquid supplied to the culture medium. 9. The method for cultivating a plant according to claim 8, wherein
Solutes other than the nitrogen component to be contained in the liquid supplied to the liquid holding liquid are sodium chloride, potassium chloride, calcium chloride, magnesium chloride, sodium sulfate, potassium sulfate, magnesium sulfate, sodium hydrogen sulfate, potassium hydrogen sulfate, It is at least one selected from the group consisting of disodium hydrogen phosphate, dipotassium hydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, polyethylene glycol, and sodium lignin sulfonate, or a mixture of two or more thereof. A plant cultivation method comprising: 10. The method for cultivating a plant according to claim 8 or 9, wherein the nitrogen component content of the liquid supplied to the medium is in the range of 5 to 30 mmol kg ⁻¹ when applied to raising seedlings, 10-60mm when used for main field cultivation
olkg ^-1 , and the nitrogen content of the liquid supplied to the medium is 80% or less of the nitrogen content of the liquid supplied to the medium in any case. . 11. The method for cultivating a plant according to any one of claims 1 to 10, wherein when supplementing liquid is performed during a growing period of the plant to be cultivated, the medium and the liquid holding liquid are added. A plant cultivation method characterized in that a liquid having a small water potential value is additionally supplied with a liquid. 12. The method for cultivating a plant according to any one of claims 1 to 11, wherein 5-aminolevulinic acid is added to the liquid supplied to the culture medium so as to have a concentration of 0.01 to 10 ppm by weight. A plant cultivation method characterized by being added. 13. The plant cultivation method according to claim 1, wherein a root shield sheet is disposed between the medium and the liquid retaining liquid. Method.