A method for separating roots for root-to-root communication research and application thereof

Abstract

This invention relates to the field of plant root division technology, and more particularly to a root division method for root zone-root zone communication research and its application. The root division method of this invention includes the following steps: (1) Seedling cultivation: germinating seeds are hydroponically cultured to obtain seedlings; (2) Main root pruning of seedlings: when the lateral roots of the seedlings described in step (1) grow to 3-4 cm, the main root is pruned to obtain seedlings with pruned main roots; (3) Double rootstock grafting of seedlings: two seedlings with pruned main roots of the same growth are selected for double rootstock grafting to obtain grafted seedlings; (4) Grafting of grafted seedlings: the roots of the grafted seedlings are completely immersed in the culture solution, with the grafting interface outside the culture solution, and cultured until the grafting interface is completely healed and both rootstock A and rootstock B have grown new roots, to obtain seedlings to be divided; (5) Root division: the seedlings to be divided are transferred to a root division box for root division treatment. The root division method of this invention can more accurately and intuitively reflect the exchange of substances between roots.

Description

Technical Field

[0001] This invention relates to the field of plant root division technology, and in particular to a root division method for root zone-root zone communication research and its application. Background Technology

[0002] The soil on which plants depend for survival is heterogeneous. Different root zones within the same plant can be subjected to different environmental stimuli. These different root zones are interconnected through the taproot or root base, and this natural connection between the root zones, linked by the taproot or root base, may be the structural basis for signal communication and coordinated response to stimuli. Signal exchange between root zones mediated by the taproot or root base, independent of the above-ground parts, is called root-to-root zone communication. Root division is widely used to study plant responses to heterogeneous environments. A suitable root division system for studying root-to-root zone communication should achieve two root division effects: ① preserving the natural connection between the two root groups at the root base; ② creating two independent root groups not connected by the root base. These two effects should be freely convertible without changing other variables. While commonly used root division methods can obtain two root zones that preserve the natural connection or are independent, they cannot achieve both root division effects without changing other variables. Therefore, establishing a scientific root division system is a prerequisite for studying root-to-root zone communication. Summary of the Invention

[0003] The purpose of this invention is to provide a root division method that can preserve the natural connection and independence between root regions, and can be freely transformed without changing other variables. In particular, it relates to a root division method for root region-root region communication research and its application.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a root division method for root region-root region communication research, comprising the following steps:

[0006] (1) Seedling cultivation: Germinated seeds are hydroponically cultured to obtain seedlings;

[0007] (2) Cutting the main root of the seedling: When the lateral roots of the seedling described in step (1) grow to 3-4 cm, cut off the main root to obtain the seedling with the main root cut off.

[0008] (3) Double rootstock grafting of seedlings: Select two seedlings with the same growth and cut taproots for double rootstock grafting to obtain grafted seedlings.

[0009] (4) Cultivation of grafted seedlings: The roots of the grafted seedlings are completely immersed in the culture solution, with the grafting point outside the culture solution, and they are cultivated until the grafting point is completely healed and both rootstock A and rootstock B have grown new roots, thus obtaining seedlings ready for root division.

[0010] (5) Root division: The seedlings to be divided are transferred to the root division box for root division treatment.

[0011] Preferably, the hydroponic temperature in step (1) is 24–26°C;

[0012] The light intensity for hydroponics is 7500–8500 Lx;

[0013] The humidity level for hydroponics is 60-70%.

[0014] The light exposure time for hydroponics is 15–17 h / d.

[0015] Preferably, the seedlings with the main root cut retain 1-2 cm of the main root base.

[0016] Preferably, the method of double rootstock grafting includes the following steps: a seedling with its taproot cut is cut with a 55-70° wedge-shaped incision 1-2 cm below the hypocotyl at the cotyledon node to obtain rootstock A; another seedling with its taproot cut is cut off at the top, leaving only one cotyledon, and a 55-70° wedge-shaped incision is cut 1-2 cm below the hypocotyl at the cotyledon node to obtain rootstock B; the wedge-shaped incisions of rootstock A and rootstock B are joined in parallel to fix the grafting interface and complete the grafting.

[0017] Preferably, the solvent for the culture medium in step (4) is water;

[0018] The culture medium contains the following components at the following concentrations:

[0019] H3BO30.2~0.3mg / L, MnSO4·H2O0.1~0.2mg / L, ZnSO4·7H2O0.01~0.05mg / L, CuSO4·5H2O0.005~0.01mg / L, (NH4)6Mo7O 24 ·4H2O0.001~0.003mg / L, KNO350~52mg / L, MgSO4·7H2O48~50mg / L, KH2PO410~15mg / L, NH4H 2PO450~52mg / L, EDTA-Na23~5mg / L, FeSO4·7H2O2.5~3mg / L, Ca(NO3)2·4H2O115~120mg / L.

[0020] Preferably, the culture temperature in step (4) is 24–26°C;

[0021] The light intensity for cultivation is 7500–8500 Lx; the humidity for cultivation is 60–70%.

[0022] As a preferred method, the root division process in step (5) is as follows: the root system of rootstock A is divided into two root regions, a1 and a2; the root system of rootstock B is divided into two root regions, b1 and b2; the four root regions a1, a2 and b1, b2 are divided into two groups for root division.

[0023] a1 and a2 root zones indicate that the lateral roots newly grown from rootstock A after grafting are equally divided into two root zones;

[0024] b1 and b2 root zones indicate that the lateral roots newly grown from rootstock B after grafting are equally divided into two root zones;

[0025] (a1+a2) / (b1+b2) is an independent root group;

[0026] (a1+b1) / (a2+b2) is the interconnected root group;

[0027] Independent root groups indicate that the root systems of rootstock A and rootstock B are connected at the junction of the hypocotyl, but not by the taproot;

[0028] Interconnected root groups indicate that parts of the root systems of rootstock A and rootstock B are interconnected by the taproot.

[0029] The present invention also provides the application of the aforementioned root division method in the study of plants in heterogeneous environments.

[0030] This invention also provides the application of the aforementioned root division method in the study of root-to-root communication in plants.

[0031] This invention provides a root division method for root-to-root communication research and its application. The method of this invention has the following advantages:

[0032] By combining the taproot division method with the double rootstock grafting method, the plant root system was divided into four root zones. Different combinations of these zones achieved two root division effects: ① preserving the natural connection between the two root groups at their bases; ② creating two independent root groups not connected at their bases. This root division method is suitable for studying the mechanism of coordinated stress response through inter-root zone signal exchange under heterogeneous environmental stimuli, and it innovates the method for studying inter-root zone communication in plant roots.

[0033] The root division method of this invention preserves the natural connections and independence between root zones and allows for free transformation without altering other variables. This method is applicable to the study of the mechanism of coordinated response to stress through root zone signal exchange under heterogeneous environmental stimuli, and innovates a method for studying root-zone communication between different root zones. This is crucial for studying the mechanism of coordinated response of roots on both sides under heterogeneous stress conditions, thus offering significant advantages over grafting or other root division methods. Furthermore, this method can also perform girdling treatment based on existing root division methods, severing / preserving material transfer in the aboveground parts, providing a more accurate and intuitive reflection of the material exchange between root systems. Attached Figure Description

[0034] Figure 1 The image shows the root system of cotton seedlings before and after taproot pruning (left image shows the root system before taproot pruning, right image shows the root system after taproot pruning).

[0035] Figure 2 This is a flowchart of the grafting process using two rootstocks.

[0036] Figure 3 The diagram shows the effect of the root-splitting system for root-region communication research (left diagram shows independent root-splitting, right diagram shows interconnected root-splitting).

[0037] Figure 4 For different root division methods 15 The effect of N on the transit rate in the root interval (A represents a schematic diagram of independent roots, B represents a schematic diagram of interconnected roots, C represents...). 15 (N transport rate in the root region).

[0038] Figure 5 The effect of root-to-root communication on rhizosphere interactions among plants (A represents a schematic diagram of the effect of rhizosphere interactions among cotton seedlings, and B represents the changes in stomatal opening in leaves of plants with rhizosphere interactions and control plants). Detailed Implementation

[0039] This invention provides a root division method for root region-root region communication research, comprising the following steps:

[0040] (1) Seedling cultivation: The germinated seeds are hydroponically cultured to obtain seedlings; (2) Seedling taproot cutting: When the lateral roots of the seedlings described in step (1) grow to 3-4 cm, the taproot is cut off to obtain seedlings with taproot cut off; (3) Seedling double rootstock grafting: Two seedlings with taproot cut off with the same growth are selected and grafted onto two rootstocks to obtain grafted seedlings; (4) Grafted seedling cultivation: The roots of the grafted seedlings are completely immersed in the culture solution, with the grafting point outside the culture solution, and cultivated; Cultivate until the grafting point is completely healed and both rootstock A and rootstock B grow new roots to obtain seedlings to be divided; (5) Root division: The seedlings to be divided are transferred to a root division box for root division treatment.

[0041] In this invention, the hydroponic temperature in step (1) is 24-26°C, preferably 25°C; the light intensity in the hydroponic system is 7500-8500 Lx, preferably 8000 Lx; the humidity in the hydroponic system is 60-70%, preferably 65%; and the light duration in the hydroponic system is 15-17 h / d, preferably 16 h / d.

[0042] In this invention, the timing for cutting off the taproot is preferably when the lateral roots of the seedling reach 3.5cm in length; the seedling with the taproot cut off retains 1-2cm of the taproot base, preferably 1.5cm of the taproot base.

[0043] In this invention, the method of double rootstock grafting includes the following steps: a seedling with its taproot cut is cut with a 55-70° wedge-shaped incision 1-2 cm below the hypocotyl at the cotyledon node to obtain rootstock A; another seedling with its taproot cut is cut off at the top, leaving only one cotyledon, and a 55-70° wedge-shaped incision is cut 1-2 cm below the hypocotyl at the cotyledon node to obtain rootstock B; the wedge-shaped incisions of rootstock A and rootstock B are joined in parallel to fix the grafting interface and complete the grafting.

[0044] In this invention, the solvent of the culture medium in step (4) is water;

[0045] The culture medium contains the following components at the following concentrations:

[0046] H3BO3 0.2~0.3mg / L, preferably 0.25mg / L; MnSO4·H2O 0.1~0.2mg / L, preferably 0.15mg / L; ZnSO4·7H2O 0.01~0.05mg / L, preferably 0.03mg / L; CuSO4·5H2O 0.005~0.01mg / L, preferably 0.075mg / L; (NH4)6Mo7O 24 • 4H2O 0.001~0.003mg / L, preferably 0.002mg / L; KNO3 50~52mg / L, preferably 51mg / L; MgSO4·7H2O 48~50mg / L, preferably 49mg / L; KH2PO4 10~15mg / L, preferably 12.5mg / L; NH4H2PO4 50~52mg / L, preferably 51mg / L; EDTA-Na 23~5mg / L, preferably 4mg / L; FeSO4·7H2O 2.5~3mg / L, preferably 2.75mg / L; Ca(NO3)2·4H2O 115~120mg / L, preferably 117.5mg / L.

[0047] In this invention, the culture temperature in step (4) is 24-26°C, preferably 25°C; the light intensity during culture is 7500-8500 Lx, preferably 8000 Lx; and the humidity during culture is 60-70%, preferably 65%.

[0048] In this invention, the grafted seedlings in step (4) are cultivated in a hydroponic box. The cotyledons of the grafted seedlings are hung on the seedling support ropes on the hydroponic box, ensuring that the roots of the grafted seedlings are completely immersed in the culture solution, and the grafting point does not come into contact with the culture solution. The hydroponic box is 34-36cm long, preferably 35cm; 22-24cm wide, preferably 23cm; and 9-11cm high, preferably 10cm. The seedling support ropes are parallel lines (the distance between the parallel lines is 2-3cm, preferably 2.5cm) set above the hydroponic box, with two lines forming a group. The ropes are required to have a certain strength to support the weight of multiple groups of grafted seedlings.

[0049] In this invention, the root-separating box mentioned in step (5) is the plant root-separating device disclosed in patent ZL202111006280.3, "A Plant Root-Separating Device Based on Germination Paper and a Plant Root-Separating Culture Method". The plant root-separating device includes a culture chamber and a seedling-fixing wall. The plant root-separating device is 14-18cm long, preferably 16cm; 6-10cm wide, preferably 8cm; and 14-18cm high, preferably 16cm. The culture chamber is 6-10cm long, preferably 8cm; 3-5cm wide, preferably 4cm; and 4-6cm high, preferably 5cm. The seedling-fixing wall is 14-18cm long, preferably 16cm; and 14-18cm high, preferably 16cm.

[0050] The root division process described in step (5) is as follows: the root system of rootstock A is divided into two root zones, a1 and a2; the root system of rootstock B is divided into two root zones, b1 and b2; the four root zones a1, a2 and b1, b2 are divided into two groups for root division.

[0051] a1 and a2 root zones indicate that the lateral roots newly grown from rootstock A after grafting are equally divided into two root zones;

[0052] b1 and b2 root zones indicate that the lateral roots newly grown from rootstock B after grafting are equally divided into two root zones;

[0053] (a1+a2) / (b1+b2) is an independent root set (MI);

[0054] (a1+b1) / (a2+b2) is the interconnected root set (MC);

[0055] Independent root groups indicate that the root systems of rootstock A and rootstock B are connected at the junction of the hypocotyl, but not by the taproot;

[0056] Interconnected root groups indicate that parts of the root systems of rootstock A and rootstock B are interconnected by the taproot.

[0057] The present invention also provides the application of the aforementioned root division method in the study of plants in heterogeneous environments.

[0058] This invention also provides the application of the aforementioned root division method in the study of root-to-root communication in plants.

[0059] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0060] The hydroponic box described in this embodiment of the invention is 35cm long, 23cm wide, and 10cm high; the spacing between the parallel lines of the seedling rope is 2.5cm.

[0061] The root-dividing box is the plant root-dividing device disclosed in patent ZL202111006280.3, "A Plant Root-Dividing Device and Plant Root-Dividing Culture Method Based on Germination Paper". The plant root-dividing device includes a culture chamber and a seedling-fixing wall. The plant root-dividing device is 16cm long, 8cm wide, and 16cm high. The culture chamber is 8cm long, 4cm wide, and 5cm high; the seedling-fixing wall is 16cm long and 16cm high.

[0062] Example 1: Cultivation and root division for root-interval communication research in cotton.

[0063] Take cotton seeds in a beaker, soak them in tap water for 7 hours, then transfer them to a damp towel to germinate them. Place them in a 25°C light incubator for 48 hours. Once the radicle has grown to 2.5 cm, transfer them to a hydroponic box for further cultivation. The hydroponic box includes a hydroponic floating plate with small holes. Insert the radicle into the holes to fix the seeds. The diameter of the small holes is 1.5 mm.

[0064] The hydroponic culture was conducted at 25℃, with a light / dark cycle of 16 / 8 h / d, a light intensity of 8000 Lx, and a relative humidity of 75%. After 3 days of cultivation in the hydroponic box, when the cotyledons had unfolded and lateral roots had not yet developed, the best-growing seedlings were selected and transferred to a thick hydroponic floating plate with large holes. Cultivation continued for 4 days. The radicle was wrapped with sponge tape and inserted into the holes to secure the seed (the holes were 20 mm in diameter, and the sponge tape was 15 mm wide and 3 mm thick). When the cotton seedlings' lateral roots reached 3.5 cm in length, the taproot was cut off (leaving 1.5 cm of the taproot base), dividing the seedling's lateral roots into two equal root zones. The root system of the cotton seedlings before and after taproot cutting is shown below. Figure 1As shown. Continue cultivation in the hydroponic box for 7 days until the cotton seedlings with the main root cut off grow a true leaf. At this time, replace the purified water in the hydroponic box with a culture medium. The culture medium, with water as the solvent, contains the following components at the following concentrations: H3BO3 0.286 mg / L, MnSO4·H2O 0.118 mg / L, ZnSO4·7H2O 0.022 mg / L, CuSO4·5H2O 0.008 mg / L, (NH4)6Mo7O 24 ·4H2O0.002mg / L, KNO350.55mg / L, MgSO4·7H2O49.294mg / L, KH2PO413.609mg / L, NH4H2PO4 51.7635mg / L, EDTA-Na23.725mg / L, FeSO4·7H2O2.785mg / L, Ca(NO3)2·4H2O118.075mg / L.

[0065] Once the cotton seedlings with their taproots cut have grown to the point where the first true leaf has fully unfolded (one leaf and one bud), take two similarly grown cotton seedlings (A and B). For seedling A, make a 60° wedge-shaped incision 1.5cm below the hypocotyl at the cotyledon node, obtaining rootstock A. Similarly, make a 60° wedge-shaped incision 1.5cm below the cotyledon node for seedling B, and remove the top, leaving only one cotyledon, obtaining rootstock B. Join the two rootstock incisions parallel to each other using the wedge-shaped incision method, and secure the graft union with a grafting clip to obtain a grafted seedling. At this point, the seedling's root system is divided into four equal parts: a1, a2, b1, and b2. The steps for double rootstock grafting are as follows... Figure 2 As shown.

[0066] The grafted seedlings were cultured in a hydroponic box containing nutrient solution for 7 days to allow the graft union to heal completely and both rootstocks to grow new roots, resulting in seedlings ready for root division. These seedlings were then transferred to a root division box for root division.

[0067] Two root division effects can be achieved by combining the four root zones of cotton seedlings in different ways:

[0068] Independent root division method (MI): (a1+a2) / (b1+b2),

[0069] Interconnected root division method (MC): (a1+b1) / (a2+b2), the result is as follows Figure 3 As shown.

[0070] Figure 3 The results show that the independent root division method makes the root zones of cotton seedlings independent of each other and not connected by the root base; the interconnected root division method retains the root base as the natural connection.

[0071] The cotton used in Example 1 was Agricultural University 601.

[0072] Example 2: The effect of different root division methods of cotton on N 15 The effect of translocation rate in the root region

[0073] Signal transduction between the root zone and the root zone is based on material transport. To demonstrate the existence of material exchange between the root zone and the root zone, the following experiment was designed: Two root division operations (Example 1) were performed on cotton seedlings, namely MI and MC. Both groups of seedlings were subjected to nitrogen starvation treatment, and after 7 days, the seedlings were subjected to non-uniform treatment. 15 N treatment: Apply to one root region 15 N(MI- 15 N and MC- 15 N), the other root region is not processed (MI-0 and MC-0) ( Figure 4 (A and 4B). Nitrogen starvation treatment involves culturing seedlings in a nitrogen-deficient culture medium with water as the solvent, containing the following components at the following concentrations: H3BO3 0.286 mg / L, MnSO4·H2O 0.118 mg / L, ZnSO4·7H2O 0.022 mg / L, CuSO4·5H2O 0.008 mg / L, Na2MoO2 4·4H2O 0.003 mg / L, MgSO4·7H2O 49.294 mg / L, KH2PO4 13.609 mg / L, EDTA-Na 23.725 mg / L, FeSO4·7H2O 2.785 mg / L, and CaCl2 220 mg / L. 15 The nutrient solution used for nitrogen treatment was nitrogen-deficient culture medium with added NH4NO3-. 15 NO3 (10%) 15 The concentration of N reached 324.16 mg / L.

[0074] MI- was determined using mass spectrometry isotope detection. 15 N and MC- 15 N lateral root region 15 The difference in N-direction MI-0 and MC-0 transport rates ( Figure 4 C). The results showed that, 15 When N processes 0h, in each root region 15 N is approximately 0.365% (under natural conditions). 15 (N content); 15 After N treatment for 6 hours, the application of MI and MC root splitting methods 15 N lateral root (MI- 15 N and MC- 15 N), 15 N rose rapidly to 1.576% and 1.685%, with no significant difference between the two; while 15 After N treatment for 6 hours, in the lateral root systems of MI-0 and MC-0 15The N content increased by 0.507% and 0.657% respectively, with a significant difference between the two, indicating that the N transport rate in the two root intervals of the interconnected root segmentation (MC) mode is significantly higher than that of the independent root segmentation mode (MI).

[0075] Example 3: The effect of root zone-to-root zone communication on rhizosphere interactions among cotton seedlings

[0076] When plants are stressed, they transmit signals to neighboring plants through rhizosphere communication, causing changes in the stomatal state of neighboring plants. To investigate whether, under heterogeneous salt stress, the stressed root zone transmits signals to the salt-free lateral root zone via root-to-root communication, and then the salt-free lateral root zone transmits the signals to neighboring plants, an experiment was designed as follows: Two root division operations (Example 1) were performed on cotton seedlings, namely MI and MC. The roots of the cotton seedlings on both sides were placed in culture solutions containing 200 mM NaCl (MI-200 and MC-200) and 0 mM NaCl (MI-0 and MC-0), respectively. Simultaneously, another cotton seedling was placed in the MI-0 and MC-0 culture solutions as rhizosphere interaction plants (MI-a and MC-b). Figure 5 A). The changes in stomatal aperture of leaves in rhizosphere-interacting plants under different root division methods (MI and MC) were measured respectively. Figure 5 B). The results showed that after 0 h of heterogeneous salt stress treatment, there was no significant difference in stomatal opening between MI-a and MC-b leaves; after 6 h of heterogeneous salt stress treatment, the stomatal opening of MC-b leaves decreased rapidly and was significantly lower than that of MI-b; after 12 h of heterogeneous salt stress treatment, the stomatal opening of both MI-a and MC-b leaves decreased, and there was no significant difference between the two, indicating that in the interconnected root splitting method (MC), the rate at which the salt stress signal is transmitted from the high-salt side (MI-200) to the salt-free side (MI-0) is faster than in the independent root splitting method (MI).

[0077] As can be seen from the above embodiments, this invention provides a root division method and its application for studying root-zone communication. By combining the taproot division method and the double rootstock grafting method, the plant root system is divided into four root zones. Different combinations of these root zones can achieve two root division effects: ① preserving the natural connection between the two root groups at their bases; ② creating two independent root groups not connected at their bases. This root division method is suitable for studying the mechanism of plant roots responding to stress through inter-root zone signal exchange under heterogeneous environmental stimuli, and it innovates the method for studying root-zone communication in different plant root zones.

[0078] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A root division method for root-region communication research, characterized in that, Includes the following steps: (1) Seedling cultivation: Germinated seeds are hydroponically cultured to obtain seedlings; (2) Cutting the main root of the seedling: When the lateral roots of the seedling described in step (1) grow to 3-4 cm, cut off the main root to obtain the seedling with the main root cut off. (3) Grafting of seedlings onto two rootstocks: Select two seedlings with the same growth and cut taproots for grafting onto two rootstocks to obtain grafted seedlings; (4) Cultivation of grafted seedlings: The roots of the grafted seedlings are completely immersed in the culture solution, with the grafting point outside the culture solution, and they are cultivated until the grafting point is completely healed and both rootstock A and rootstock B have grown new roots, and seedlings ready for root division are obtained. (5) Root division: The seedlings to be divided are transferred to the root division box for root division treatment; The seedlings with the main root cut off retained 1-2 cm of the main root base; The method of double rootstock grafting includes the following steps: a seedling with its taproot cut is cut with a 55-70° wedge-shaped incision 1-2 cm below the hypocotyl at the cotyledon node to obtain rootstock A; another seedling with its taproot cut is cut off at the top, leaving only one cotyledon, and a 55-70° wedge-shaped incision is cut 1-2 cm below the hypocotyl at the cotyledon node to obtain rootstock B; the wedge-shaped incisions of rootstock A and rootstock B are joined parallel to each other, the grafting interface is fixed, and the grafting is completed; The root division process described in step (5) is as follows: the root system of rootstock A is divided into two root zones, a1 and a2; the root system of rootstock B is divided into two root zones, b1 and b2; the four root zones a1, a2 and b1, b2 are divided into two groups for root division. a1 and a2 root zones indicate that the lateral roots newly grown from rootstock A after grafting are equally divided into two root zones; b1 and b2 root zones indicate that the lateral roots newly grown from rootstock B after grafting are equally divided into two root zones; (a1+a2) / (b1+b2) is an independent root group; (a1+b1) / (a2+b2) is the interconnected root group; Independent root groups indicate that the root systems of rootstock A and rootstock B are connected at the junction of the hypocotyl, but not by the taproot; Interconnected root groups indicate that parts of the root systems of rootstock A and rootstock B are interconnected by the taproot; The seedlings are cotton seedlings.

2. The root division method according to claim 1, characterized in that, The hydroponic temperature in step (1) is 24~26℃; The light intensity for hydroponics is 7500~8500 Lx; The humidity level for hydroponics is 60-70%. The light exposure time for hydroponics is 15-17 hours per day.

3. The root division method according to claim 1, characterized in that, The solvent for the culture medium in step (4) is water; The culture medium contains the following components at the following concentrations: H3BO3 0.2~0.3 mg / L,MnSO4·H2O 0.1~0.2 mg / L,ZnSO4·7H2O 0.01~0.05 mg / L,CuSO4·5H2O 0.005~0.01 mg / L,(NH4)6Mo7O 24 ·4H2O 0.001~0.003 mg / L, KNO3 50~52 mg / L,MgSO4·7H2O 48~50 mg / L,KH2PO4 10~15 mg / L, NH4H2PO4 50~52 mg / L,EDTA-Na2 3~5 mg / L,FeSO4·7H2O 2.5~3 mg / L,Ca(NO3)2·4H2O 115~120 mg / L。 4. The root division method according to claim 1, characterized in that, The culture temperature in step (4) is 24~26°C; The light intensity for cultivation is 7500~8500 Lx; the humidity for cultivation is 60~70%.

5. The application of the root division method according to any one of claims 1 to 4 in the study of plants in heterogeneous environments.

6. The application of the root division method according to any one of claims 1 to 4 in the study of root zone-root zone communication in plants.

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