ZA200402799B

ZA200402799B - Method of producing rooted cutting of arboreous plant.

Info

Publication number: ZA200402799B
Application number: ZA200402799A
Authority: ZA
Inventors: Akihisa Minato; Takayuki Asada
Original assignee: Oji Paper Co
Priority date: 2001-10-02
Filing date: 2004-04-13
Publication date: 2005-04-13
Also published as: WO2003030628A1; BR0206090A; JP2003111521A; CN1498073A; NZ521709A; CN1265698C; AU2002301265B2

Description

- "0. 9004/2799

FIELD OF THE INVENTION

The present invention is related to a method for producing rooted cuttings of arboreous plants. Rooted cuttings refer to seedling in which scions are gathered from a stock tree of an elite plant, and are used on a large scale for the purpose of afforestation and the like. . BACKGROUND OF ART

The technology to increase the yield of plants by distributing water in which carbon dioxide is dissolved over phylloplane of plants is disclosed, for instance, in publications of unexamined Japanese patent application Nos. 61-181311 and 08-84530.

Plants are roughly divided into an arboreous plant that has a ligneous stem (bark) and an herbaceous plant whose above-ground part is flexible but that does not take the ligneous form. At commercial nurseries of the arboreous plant, in general, a seedling nursery plant whose germination originates from a seed and a clonal nursery plant by means of cutting, graft, or cell culture, are known. In particular, the cutting is a most convenient and inexpensive technology for a clonal nursery plant so that a large number of rooted cuttings of Eucalyptus species plants or Acacia species plants for the purpose of large-scale forestation is produced in South America, Europe, Southeast Asia, and South Africa, for instance. :

Prior art in relation to a rooted cutting used for Eucalyptus plant is described in detail in “Eucalypt Domestication and Breeding’ (K.G. Eldridge, J.

Davidson, & C. Harwood, 1993, New York: Oxford University Press Inc., 237-246).

According to this reference, one to four nodes, two to eight leaves are cut out v from a branch of a mother tree, and the leaves are partially removed to prepare a scion. This scion is soaked in a bactericide solution such as Benlate, its base coated with hormone dust such as indolebutyric acid functioning as a rooting accelerator or soaked in a hormone solution, then inserted into a hole provided with a cutting medium. As the cutting medium, bark, sand, sawdust, peat moss, vermiculite, perlite, charcoal, or any mixture of two or more of these materials is used. In general, such a cutting medium is put in a container such as a nursing pot or plug tray.

Any kind of materials that has an appropriate permeability and water retentivity can be used for cutting medium. The balance of the permeability and water retentivity will play a key role for successful rooting of a scion. Further, in order to avoid the putrefaction of the scion, such cutting medium should not include organic matter, but preferably is sterilized. Normally, although ’ fertilization is not required, slow-release granular fertilizer may have been mixed . in a medium, or liquid manure may be added at the time of irrigation. Since an appropriate temperature, high humidity, and circulation of air are required for rooting of scions, techniques such as mist spraying, fogging, covering with a polyethylene sheet, shading, and bottom-heating are applied in combination. The hours of sunshine to bring about better results are approximately 400 per month.

However, even though the cutting method described in the aforementioned publications, which has been highly established, is used, it is often difficult to secure rooting of a scion due to various conditions, such as the weather of the country or the area where such a cutting method is performed. In addition to this, the rooting ability of scions varies depending on the species of the plants. Even if the species has a high rooting ability, rooting a scion may be difficult because of the physiological factors of the mother tree. Further, it is often difficult to secure a rooting even when a mother tree is pruned and its sprouted branch is used as a scion for cutting.

Accordingly, the rooting of scions greatly depends on meteorological factors of the production field, or genetic or physiological factors of the cuttings. Thus, it is difficult to root scions consistently according to a conventional cutting method, which makes it extremely difficult to produce rooted cuttings efficiently.

As a result, in not a few cases, such a production of rooted cuttings has been . abandoned, which results in industrial disadvantage. Therefore, a cutting method that is capable of enhancing the rooting of scions efficiently and consistently has been required. In particular, a technique for efficiently producing rooted cuttings of Eucalyptus species plants and Acacia species plants, which are forested on a large scale, has been required.

Japanese unexamined patent publication No. 2001-186814 discloses a method that comprises steps of “preparing a rooting bed wetted with liquid medium within an incubator, culturing the scions inserted into the medium, and controlling the carbon dioxide gas concentration within the incubator’ and describes that according to this technique, the rooting ability of scions will be 1mproved.

However, in the case of afforestation, even in a test case where the number of nursery stocks is 1,000 — 10,000, it is more than one million in an industrial ’ situation. . It is not easy to isolate such a large amount of cuttings in an incubator or a culture room while keeping the carbon dioxide flowing within the incubator or the culture room.

It is the object of the present invention to provide a method for producing rooted cuttings, which can root cuttings at extremely high probabilities, and applied to a large scale of afforestation, and, in particular, a method for effectively producing rooted cuttings of arboreous plants whose rooting ability is low.

SUMMARY OF THE INVENTION

In order to solve the above problem, the invention employs the following constitution. That is, the first aspect of the invention is a method for producing rooted cuttings of arboreous plants in which scions are inserted in a medium, comprising a step of supplying at least one kind of solution, which is selected from a group composed of carbon dioxide solution, oxygen solution, carbonate ion solution, and hydrogencarbonate ion solution, to the scions inserted in the medium, and accelerating their rooting abilities.

The second aspect of the invention comprises a step of supplying said solution to the above-ground part of the scions by spraying intermittently according to the above first aspect of the invention. ‘ The third aspect of the invention comprises a step of setting spray time of the solution in which such a time is determined by the elapsed time required for the solution adhering to the surface of the leaves of the scions to begin to drop, and setting the interval of each spray in which such an interval is determined by the elapsed time for the solution adhering to the surface of the leaves of the scions to dry according to the above second aspect of the invention.

: The fourth aspect of the invention comprises a step of supplying the solution to the scions in such a manner to irrigate the solution to the medium according to the above first aspect of the invention.

The fifth aspect of the invention is a method for producing rooted cuttings of arboreous plants in which scions are grafted in a medium, a step of supplying at least one kind of solution intermittently, which is selected from a group composed of carbon dioxide solution, carbonate ion solution, and hydrogencarbonate ion ’ solution, to the above-ground part of the scions inserted in the medium, and . irrigating oxygen solution intermittently to the medium.

The sixth aspect of the invention comprises of selecting arboreous plants to gather scions from a group composed of Eucalyptus species plants and Acacia species plants according to any of the above first to fifth aspects of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a situation in which carbon dioxide solution is prepared by using a membrane module and a compressed-carbon dioxide cylinder, for spraying the carbon dioxide solution to the above-ground part of the scions inserted in the medium according to a method of the present invention.

FIG. 2 illustrates a situation in which oxygen solution is prepared by using a membrane module and a compressed oxygen cylinder, and irrigating the oxygen solution to a medium according to a method of the present invention.

BEST MODE TO CARRY OUT THE INVENTION :

As described in the background art, the production of clone seedlings by cuttings is inexpensive and easy so that it is suitable for a large scale of : afforestation. The method of the present invention can be applied to all cuttings gathered from any kind of arboreous plants. The method, of course, can be used ’ for producing rooted cuttings for Eucalyptus species plants and Acacia species plants whose afforestation is widely performed recently.

Eucalyptus species plants include the trees used for papermaking material (pulp wood) such as Eucalyptus camaldulensis, Eucalyptus grandis, Eucalyptus globulus, Eucalyptus nitens, Eucalyptus tereticornis, Eucalyptus urophylia,

Eucalyptus dunnii, cross breeding species whose parent is one of these, and subspecies or varieties thereof. They also include the trees used for gardening, greening, and ornamental purpose such as Eucalyptus gunii, Eucalyptus viminalis, or the like.

More detailed explanations are described in “Environmental Management:

The Role of Eucalyptus and Other Fast Growing Species’ (K.G. Eldridge, M.P.

Crowe & K.M. Old eds., 1995, CSIRO Publishing) and “Eucalyptus Species as greening trees” (T. Ishikawa, 1980, Zorin-Ryokukagijyutu-kenkyusho). : Acacia species plants include the trees used for papermaking material such : as Acacia auriculiformis, Acacia mangium, Acacia mearnsii, Acacia crassicarpa,

Acacia aulacocarpa, Acacia glaucocarpa, cross breeding species whose parent is one of these, and subspecies or varieties thereof. They also include the trees used for gardening, greening, and ornamental purpose such as Acacia baileyana, Acacia dealbata, or the like.

A form of a mother tree for gathering scions can be either pot seedling or open- field-planting seedling, and seedling nursery plants can be either natural tree form or sprouting pruned to be bred. Further, a mother tree for gathering scions can be a seedling, or can be cutting, graft, or a clone seedling in which a parent tree is rejuvenated by a method such as cell culture. Although there is no specific limitation about the age of a mother tree, a younger tree is preferable because of its high rooting ability.

Now, the process to breed a cutting by which a scion is sampled from a mother tree, and inserted in a cutting medium for rooting will follow a method described in detail in “Eucalypt Domestication and Breeding’ (1993, New York:

Oxford University Press Inc.) . A branch which includes one to four nodes and two to eight leaves is cut out from a mother tree, and, in general, the leaves are } partially removed to prepare a scion. This scion is soaked in a bactericide solution such as Benlate, and inserted in a cutting medium filled in a seedling pot, plug tray, or the like.

As the cutting medium, any bark, sand, sawdust, peat moss, vermiculite, perlite, charcoal, or any mixture of two or more of these materials can be used.

Any materials that have an appropriate permeability and water retentivity can be used. In order to prevent cuttings from putrefaction, distribution of bactericide ’ should be performed periodically after cutting.

Rooting accelerating solution of the present invention, which accelerate the rooting by supplying it to cuttings inserted in a medium, can be selected from a group composed of carbon dioxide solution, oxygen solution, carbonate ion solution, and hydrogencarbonate ion solution.

The term “carbon dioxide solution” refers to water in which carbon dioxide of more than 0.52 ppm per one liter of water is dissolved at a temperature of 25°C.

Similarly, the term “oxygen solution” refers to water in which oxygen of 8.4 ppm or i more per one liter of water is dissolved at a temperature of 25°C. ; Namely, the saturation solubility of carbon dioxide at gas partial pressure in air of 25°C is 0.52 ppm, and the saturation solubility of carbon dioxide per one atmospheric pressure is 1491 ppm. The saturation solubility of oxygen at gas partial pressure in air of 25°C is 8.4 ppm, and the saturation solubility of oxygen per one atmospheric pressure is 40 ppm. The aforementioned reference,

JP2001-186814, reveals that the maximum concentration of carbon dioxide in the air is 1500 ppm. Accordingly, if dissolution is performed at saturation concentration in water, the concentration of carbon dioxide in the water can be calculated as 2.25 ppm.

The concentration of carbon dioxide in solution used in the invention is preferably 10 ppm or above, more preferably 1000 ppm or up, further preferably 1500 ppm (as previously mentioned, such a saturation concentration corresponds to one atmospheric pressure) or up, most preferably, exceeds 2000 ppm. The concentration of carbon dioxide dissolved in water to be supplied to plants can be low for raising general plants. However, in order to enhance rooting ability of cuttings revolutionarily, it is particularly effective to have the concentration high as described above. However, as it is difficult to produce carbon dioxide solution whose concentration of carbon dioxide exceeds 10000 ppm, it is practical to use carbon dioxide solution whose concentration is lower than 10000 ppm. ’ The concentration of oxygen in solution used in the present invention needs to be 10 ppm or above, preferably 16 ppm or above, more preferably, 40 ppm or up (as previously mentioned, such a saturation concentration corresponds to one atmospheric pressure).

According to the invention, the term “carbonate ion solution” refers to solution obtained by dissolving water-soluble carbonate in water, and the term

“hydrogencarbonate ion solution” refers to solution obtained by dissolving water-soluble acid carbonate in water. The concentration of carbonate ions or hydrogencarbonate ions of such solutions in water is preferably within the range of the concentration of carbon dioxide as described above when respective ions are converted into carbon dioxide. In other words, the amount of COz2 calculated from the mg value of solute dissolved in water of one liter is preferably within a range of 10 mg — 2000 mg. oo There are no restrictions as to the method of producing carbon dioxide . solution used in the invention.

As a first example of such a method, there is a means in which dry ice is put into contact with water. As a second example, there is another means in which sodium carbonate, ammonium carbonate, potassium carbonate, ammonium hydrogencarbonate, sodium hydrogencarbonate (bicarbonate), potassium hydrogencarbonate, and the like are dissolved to generate carbonate ion and hydrogencarbonate ion, and the pH of water lowered by the action of acid to generate carbon dioxide.

As a third example, there is another means in which carbon dioxide are obtained by burning fossil fuel or the like, from a chemical cylinder filled with carbon dioxide, or by segregating and concentrating the air by using a CO2 separation film, and thus obtained carbon dioxide are blown into water to produce carbon dioxide solution. As a fourth example, there are other means, in which water will be sprayed into a pressure tank filled with COg2 gas, or reversely, carbon dioxide will be supplied to a pressure proof receptacle filled with water. A fifth example represents a means in which a membrane having a number of pores, typically a hollow fiber membrane, is used in such a way that raw water will permeate the hollow section while the carbon dioxide will permeate the outer surface so that the carbon dioxide melts into the raw water which flows through ) the hollow section (as disclosed in JP patent application unexamined publication

No. 2001-293342). According to a sixth example, COz2 gas, which is generated by electrolyzing water by using carbon material on an anode, is dissolved into water ( as disclosed in JP patent application unexamined publication No. H6-154760).

There is no restriction as to the method of producing carbonate ion solution and hydrogencarbonate ion solution used in the invention. For instance, when the pH of water increases by the action of alkali against carbon dioxide solution obtained by any of the above methods, hydrogencarbonated ion water or carbonated ion water can be easily obtained. Otherwise, carbon dioxide can be dissolved in alkali water.

Further, sodium carbonate, ammonium carbonate, potassium carbonate, ammonium hydrogencarbonate, sodium hydrogencarbonate (bicarbonate), potassium hydrogencarbonate, and the like are dissolved to generate carbonate ’ lon solution and hydrogencarbonate ion solution. i Similarly, there is no restriction as to the method of producing oxygen solution used in the present invention. With respect to a first example of the method for producing oxygen solution, there is a means in which a material, such as magnesium peroxide or calcium peroxide, which generates O2 when in contact with water, will be put into contact with water. As a second example, there is another means in which Oz gas is dissolved in water by putting O2 gas in contact with water through a porous film with micro-diameter, or non-porous gas permeable film. Further, according to a third example, Oz gas will be generated by electrolyzing water and thus the obtained Oz will be dissolved.

According to the invention, when at least one solution for accelerating rooting, which is selected from a group composed of carbon dioxide solution, oxygen solution, carbonate ion solution, and hydrogencarbonate ion solution, is sprayed to the above-ground part of cuttings inserted in the medium intermittently, the frequency will vary depending on plants and circumstances.

Thus, no restriction is applied. However, as an example, it can be selected from once every 10 minutes to once a day.

The spray time of the solution for accelerating rooting will be set for the time ] required for the water adhering to the surface of the leaves of cuttings to begin to drop. The interval of spray of each solution is preferably set for the time required ) for the water adhering to the surface of plants to evaporate. The spray time is, in general, within a range of 5 — 180 seconds.

Further, the form of spray of the solution for accelerating rooting is not specifically restricted. However, in general, it is preferable to use a spray member such as a spray nozzle to spray like mist. The average particle size of such a mist is preferably within a range of 10 — 100 micron. Thereby, for example,

carbon dioxide solution can be distributed on the surface of leaves uniformly, and adhered to as fine droplets so that CO2 is dispersed into cuttings due to the concentration gradient, which accelerates the rooting of cuttings.

The amount of the solution for accelerating rooting is not restricted specifically. However, the amount of spray is preferably regulated within a range of 50 to 300 cc / min. per a single spray member.

In order to irrigate, the solution can be supplied to a cutting medium either ‘ continuously or one to several times a day. That is, the medium can be . appropriately wet or the top of the medium can have some water.

A method for producing rooted cuttings according to the invention will be described with reference to the following accompanying figures as a more concrete example in which carbon dioxide solution and oxygen solution are produced by using a membrane process, and supplied to cuttings to root them.

Figure 1 shows one example of the method of the invention in which carbon dioxide is dissolved in raw water to a predetermined concentration, which will be, then, sprayed onto scions intermittently. Figure 1 illustrates a generator of carbon dioxide solution which is composed of raw water tank WT, booster pump P, filter F, membrane module MO, COz2 gas cylinder 1, and control valve SV2 from the upper stream side, and the whole operation of the generator is controlled by a controller which is not shown.

A raw water tank WT is a receptacle for housing raw water that is used to produce carbon dioxide solution. Although there is no specific restriction about the kinds of raw water, the service water is preferably used from the viewpoint of cost.

A booster pump P is used for supplying the above raw water to a membrane module MO. The flow rate and flow velocity will be determined by the discharge ability of this booster pump. In this example, the flow rate to be supplied is 1 to ) 1.5 liters per minute.

A filter F provided at the downstream of the booster pump P is used for removing particulate contained in the raw water discharged from the booster pump P when necessity arises.

A membrane module MO is used as an air charging membrane module for producing carbon dioxide solution by supplying carbon dioxide while allowing the raw water delivered from the upper stream to flow through it. The membrane module MO generates pressure gradients inside or outside of the membrane so that carbon dioxide solution having a predetermined concentration in relation to the raw water can be produced easily.

Further, if a part of the water treated in the membrane module MO is returned to the input side of the booster pump JN, carbon dioxide solution having a predetermined concentration can be produced easily by the circulation of the ’ treated water. . The carbon dioxide solution produced by the apparatus shown in figure 1 has © 10 higher COg2 concentration, in particular, compared to the carbon dioxide solution produced by other methods. For instance, the solubility of CO2 under the atmospheric pressure at temperature of 20°C is approximately 1.78 (g / liter water) and this CO2 concentration is the upper limit under the atmospheric pressure. On the other hand, according to the apparatus shown in figure 1, CO2 can be dissolved to the saturation concentration which corresponds to the gas pressure by applying gas pressure (1.1 to 5.0 kgf / cm?) to the membrane module

MO.

Moreover, the apparatus shown in figure 1 can be applied for producing not only carbon dioxide solution but also oxygen solution so that oxygen solution produced by this apparatus has higher O2 concentration compared to gas concentration dissolved in water under atmospheric pressure. For instance, the solubility of O2 under the atmospheric pressure at temperature of 20°C is approximately 44.3 (mg / liter water) and this O2 concentration is the upper limit under the atmospheric pressure. On the other hand, according to the apparatus shown in figure 1, similar to the above dissolution of COg2, O2 can be dissolved in } service water to the saturation concentration, which corresponds to the gas pressure. ) In figure 1, the outlet of the membrane module MO is connected to a spray 6.

Under normal operation, carbon dioxide solution or oxygen solution passed through the outlet of the membrane module MO is delivered to the spray 6, and sprayed to cuttings of plants through a spray member 61 provided at the spray 6.

The position of the spray 6 in relation to cuttings is not restricted specifically.

The spray can be arranged above the cuttings to spray downwards as shown in figure 1, or it can be arranged below the cuttings to irrigate them as described below.

As described above, according to the apparatus illustrated in figure 1, carbon dioxide solution or oxygen solution dissolved in raw water to a predetermined concentration under pressure can be produced continuously in any desirable amount in an extremely short time, and supplied to cuttings.

In the present invention, the action performed by the above carbon dioxide ’ solution (inclusive hydrogencarbonated ion water and carbonated ion water) to . accelerate the rooting of scions is considered as follows: First, CO2 dissolved in water partially changes into carbonic acid (H2COs), which ionizes to generate hydrogencarbonate ion (HCO3™) and hydrogen ion (H*). When carbon dioxide solution is supplied to scions, the amount of CO2 and hydrogencarbonate ion diffused and taken in the scions increases in a unit of time. Second, the hydrogencarbonate ion infused in cuttings is transformed into CO2 rapidly subject to catalyst of carbon dioxide dehydratase (carbonic anhydrase), which widely exists in plants. Thus, both the concentration of COz2 in chloroplast stroma and the matrix concentration of ribulose-diphosphate carboxylase which is carbon dioxide fixation enzyme becomes high so that photosynthesis is activated and the rooting ability of cuttings can be improved.

In addition, the action performed by the oxygen solution of the invention to accelerate the rooting of scions is considered as follows: First, when oxygen solution is supplied to scions, the concentration of Og is higher compared to that dissolved in water under the partial pressure of oxygen of atmospheric pressure.

Therefore, the concentration gradient is generated between the peripheral and inside of plant cells which constitutes the scions so that Og is diffused and taken . into the scions. Og thus obtained supplied the life energy required by the cuttings.

That is, when electrons of NADH and FADHz2 generated in, for instance, glycolysis, fatty acid oxidation, or citric acid cycle are transferred to O2 through serial electron carriers, APT is produced. The propagation of a reaction that requires the biosynthesis of biopolymer or other energy can be accomplished by conjugating with the hydrolysis of this ATP. The supply of Oz enhances various biosynthesis of biopolymer or other metabolism so that the rooting ability of cuttings can be improved.

As to the photorespiration reaction in leaves of plants, Oz and COg2 are competitive as a matrix ‘with regard to the ribulose-diphosphate carboxylase that 1s carbon dioxide fixation enzyme, and mutually inhibit reactions relating to the other’s matrix. That is, photorespiration increases when a plant receives light under the gaseous conditions of high O2 concentration, which becomes a factor to lower the production due to photorespiration depending on the species of plants.

Therefore, when oxygen solution is sprayed onto cuttings, it is preferable to choose ’ a dark period in which the light is shady, or a method described below in which . oxygen solution is irrigated into cuttings.

Figure 2 illustrates an example of the irrigation method in which gaseous oxygen is dissolved in raw water to a predetermined concentration, and thus obtained oxygen solution is irrigated to a medium of scions intermittently.

Although oxygen solution can be supplied to the above-ground part of the scions, it is preferable to supply oxygen solution from a section located at the base of the scions. In order to perform it, in the example shown in figure 2, oxygen solution is irrigated over a supporting medium so that such an oxygen solution can be absorbed from a section provided at the base of the scions. Namely, a watering apparatus 7 is placed under scions in figure 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While examples of a method for producing rooted cuttings according to the invention has been particularly shown, the invention is not limited by these examples. [Example 1]

An epicornic branch grown and expanded newly after the spring was cut out ] from a mother tree of biennial Eucalyptus globulus, and a stem of a scion was prepared to be approximately 10 cm in length and to have only a pair of leaves by ) removing the lower leaves. The top half of the pair of leaves was removed, and the base of the scion was cut back with a knife. The top of the scion was soaked in a disinfectant solution for 5 seconds, and water up-taken for one day and night.

Then, thus prepared scions were inserted into medium, which was a mixture of an equal amount of vermiculite and peat-moss, pre-moistened by filling in a plug-tray.

MHF (three layer multiple hollow fiber) membrane module (Mitsubishi

Rayon Co., Ltd.) was used as a membrane module MO following the method illustrated in figure 1. Carbon dioxide solution was intermittently sprayed from above cuttings for 60 seconds each time with a 15-minute interval with the amount of sunlight at 0.10 (ly / minute) or above in a greenhouse under natural light. In the meantime, following the method illustrated in figure 2, oxygen solution was irrigated over a medium three times a day with an eight-hour interval for forty-three days for breeding. . The concentration of the carbon dioxide solution was 2100 ppm and concentration of the oxygen solution was 40 ppm. [Comparison example 1]

The example 1 was repeated for forty-three days except for using service water instead of the carbon dioxide solution and oxygen solution.

Table 1 represents the rooting rate (%) of the scions of Eucalyptus globulus after 43-day breeding with respect to the example 1 and comparison example 1.

The rooting rate (%) is based on: (the number of scions rooted within 43 days from the date of cutting) + (the number of sample scions) X 100

Table 1

Example! | 60 | = 44 | 0013 mr [Ft

Example 1

The table 1 demonstrates the proof that the rooting of scions can be accelerated when scions of plants (in this case, Eucalyptus globulus) are bred with - 25 supplying high concentration of carbon dioxide solution and oxygen solution according to the cutting method of the present invention. Similar results have been obtained when a wide range of plants, such as Eucalyptus camaldulensis,

Acacia auriculiformis, Eucalyptus grandis, were used. [Example 2al

A potted seedling of Acacia auriculiformis (biennial, 50 cm in height) bred with cuttage was used as a mother tree. A branch that includes the fifth to ninth leaves from the apex was collected, the lower leaves removed except for a pair of leaves at the ear tip to prepare a scion of approximately 8 cm in length. The top half of the pair of leaves was removed and the base of the scion was cut back with a knife. The top of the scion was soaked in a disinfectant solution for 5 seconds, and water up-taken for one day and night. Then, thus prepared scions were ’ inserted into vermiculite medium that was pre-moistened by filling in a plug-tray. . MHF (three layer multiple hollow fiber) membrane module (Mitsubishi

Rayon Co., Ltd.) was used as a membrane module MO following the method illustrated in figure 1. Carbon dioxide solution was mist-sprayed from above cuttings for 60 seconds each time with a one-hour interval during diurnal period under the irradiation of light (12 hours of diurnal period at 24°C, 12 hours of dark period at 20°C) for forty-eight days for breeding. The concentration of the carbon dioxide solution was 2400 ppm. [Example 2b]

The example 2a was repeated for forty-eight days except for mist-spraying oxygen solution to the upper part of scions instead of the carbon dioxide solution.

The concentration of the oxygen solution was 60 ppm. [Comparison example 2]

The example 2a was repeated for forty-eight days except for using service water instead of the COz2 solution.

Table 2 represents the rooting rate (%) of the scions of Acacia auriculiformis } after 48-day breeding with respect to the examples 2a and 2b, and comparison example 2.

The rooting rate (%) is based on: (the number of scions rooted within 48 days from the date of cutting) + (the number of sample scions) X 100

Table 2

Example?b | Opsolutiom | 80

Example 2

The table 2 demonstrates the proof that the rooting of scions can be accelerated when scions of plants (in this case, Acacia auriculiformis) are bred by intermittently spraying high concentration of carbon dioxide solution and oxygen solution according to the cutting method of the present invention. Similar results have been obtained when a wide range of plants, such as Eucalyptus camaldulensis, Eucalyptus globulus, Eucalyptus grandis, were used.

INDUSTRIAL APPLICABILITY

As explained above, according to the method of the invention for producing rooted cuttings, the rooting rate of scions gathered from arboreous plants can be greatly increased. Therefore, the invention is suitable to produce rooted cuttings of Eucalyptus species plants and Acacia species plants which are widely used for a large scale of afforestation.

Claims

What is claimed is:

~ 1. Amethod for producing rooted cuttings of arboreous plants in which scions are inserted in a medium, comprising a step of supplying at least one kind of solution, which is selected from a group composed of carbon dioxide solution, oxygen solution, carbonate ion solution, and hydrogencarbonate ion solution, to the scions inserted in a medium so as to accelerate their rooting abilities.
2. The method for producing rooted cuttings defined in claim 1, in which said solution is supplied to the above-ground part of the scions by spraying . intermittently.
3. The method for producing rooted cuttings defined in claim 2, in which the spray time of the solution is determined by the elapsed time for the water adhering to the phylloplane of the scions to begin to drop, and the interval between each spray is determined by the elapsed time for the solution adhering to the phylloplane of the scions to evaporate. : 15
4. The method for producing rooted cuttings defined in claim 1, in which the solution 1s supplied to the scions in such a manner to irrigate the solution to the medium.
5. The method for producing rooted cuttings of arboreous plants, in which scions are inserted in a medium in which at least one kind of solution, which is selected from a group composed of carbon dioxide solution, carbonate ion solution, and hydrogencarbonate ion solution, is supplied to the above-ground part of the scions intermitténtly, and oxygen solution is irrigated to the medium. oo

:
6. The method for producing rooted cuttings of arboreous plants defined in claim 1 or 5, in which the arboreous plants for gathering scions are selected from a oo oF group composed of Eucalyptus spcics plants and Acacia species plants. AMENDED SHEET — 25 APRIL 2005