A method of promoting macadamia rootlet formation and growth

Abstract

The application discloses a method for promoting the formation and growth of macadamia roots. The method comprises the following steps: first, cultivating the macadamia seedlings with a vegetative growth solution A, irrigating each seedling with 200-400 mL of the vegetative growth solution A every 2-3 days, and continuing for 9-10 days; second, cultivating the seedlings with a nutrient mixed solution after the cultivation with the vegetative growth solution A is completed, irrigating each seedling with 300-400 mL of the nutrient mixed solution every 2-3 days, and continuing for 25-30 days; the nutrient mixed solution comprises 40-100 micromoles per liter of naphthalene acetic acid (NAA), 10-40 micromoles per liter of strigolactone, and a vegetative growth solution B; and after the cultivation period of the nutrient mixed solution is completed, the macadamia seedlings can form abundant macadamia roots, which is beneficial to the absorption of the nutrients in the soil by the macadamia. The method combines the vegetative growth solution, the strigolactone and the naphthalene acetic acid in the growth process, promotes the root formation ability of the macadamia, and increases the formation of the macadamia roots.

Description

Technical Field

[0001] This invention belongs to the field of fruit tree planting technology, specifically relating to a method for promoting root formation and growth in macadamia nuts. Background Technology

[0002] Macadamia nuts (Macadamia integrifolia M. Tetraphylla), also known as Hawaiian nuts, are evergreen fruit trees belonging to the genus Macadamia in the family Proteaceae. Native to the subtropical rainforests of Australia, macadamia nuts are highly valued for their rich nutritional content, including fats, proteins, and essential minerals, earning them the nickname "Queen of Nuts." Introduced and trial-cultivated in my country since the late 1990s, they have become a major economic forestry crop in southern regions such as Yunnan, Guangxi, Guizhou, and Guangdong, and are an important source of income for farmers in tropical and subtropical areas.

[0003] The root system is the main organ for plants to absorb nutrients and water, and its early development directly affects the formation of the root system and the absorption and utilization of nutrients throughout the entire growth period. Lateral roots, a special type of root structure in macadamia nuts, possess a strong ability to adapt to nutrient stress and play a crucial role in nutrient absorption and utilization. Therefore, promoting the formation and growth of lateral roots is key to the sustainable production of macadamia nuts. Current technologies for improving macadamia nut rooting capacity mainly involve using single rooting agents or combinations of rooting agents to promote seedling rooting, but they do not focus on the formation and growth of lateral roots, which is crucial for nutrient absorption and utilization, thus hindering the green, efficient, and sustainable development of the macadamia nut industry. Summary of the Invention

[0004] The purpose of this invention is to provide a method for promoting the formation and growth of macadamia roots. By using a combination of nutrient solution, strigolactone and naphthaleneacetic acid during the growth process, the rooting ability of macadamia nuts is promoted, the formation of macadamia roots is increased, and at the same time, the excessive use of various rooting agents is reduced, soil pollution is reduced, and the development of drug resistance in macadamia nuts is slowed down.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A method for promoting root formation and growth in macadamia nuts, characterized by:

[0007] (1) For macadamia seedlings, first use nutrient growth solution A for cultivation. Apply 200-400 mL to each seedling, once every 2-3 days, for 9-10 days.

[0008] (2) After the nutrient growth solution A is completed, the nutrient mixture is used for further cultivation. Each seedling is irrigated with 300-400 mL of nutrient mixture every 2-3 days for 25-30 days.

[0009] The nutrient mixture includes 40-100 μmol / L naphthaleneacetic acid (NAA), 10-40 μmol / L strigolactone, and nutrient growth solution B;

[0010] The nutrient growth solution B comprises: 1500-2000 μmol / L Ca(NO3)2, 50-100 μmol / L KH2PO4, 800-850 μmol / L K2SO4, 80-100 μmol / L KCl, 600-650 μmol / L MgSO4, 1-2 μmol / L MnSO4, 1-2 μmol / L ZnSO4, 0.1-0.2 μmol / L CuSO4, 1-2 μmol / L H3BO3, 0.005-0.01 μmol / L Na2MoO4, and 80-100 μmol / L Fe-EDTA. The solutions are prepared and mixed according to the concentrations of each reagent, and the pH is then adjusted to 5.0-5.5.

[0011] (3) After the nutrient solution culture cycle is completed, macadamia seedlings can form abundant macadamia root system, which is conducive to macadamia nut absorption of nutrients in the soil.

[0012] As a preferred technical solution, the nutrient solution A comprises 1500-2000 μmol / L Ca(NO3)2, 450-500 μmol / L KH2PO4, 600-625 μmol / L K2SO4, 80-100 μmol / L KCl, 600-650 μmol / L MgSO4, 1-2 μmol / L MnSO4, 1-2 μmol / L ZnSO4, 0.1-0.2 μmol / L CuSO4, 1-2 μmol / L H3BO3, 0.005-0.01 μmol / L Na2MoO4, and 80-100 μmol / L Fe-EDTA. The solutions are prepared and mixed according to the concentrations of each reagent, and then the pH is adjusted to 5.0-5.5.

[0013] As a preferred technical solution, the concentration of naphthaleneacetic acid (NAA) is 80 μmol / L.

[0014] As a preferred technical solution, the concentration of the strigolactone is 20 μmol / L.

[0015] As a preferred technical solution, the nutrient growth solution B comprises: 2000 μmol / L Ca(NO3)2, 50 μmol / L KH2PO4, 850 μmol / L K2SO4, 100 μmol / L KCl, 650 μmol / L MgSO4, 1 μmol / L MnSO4, 1 μmol / L ZnSO4, 0.1 μmol / L CuSO4, 1 μmol / L H3BO3, 0.005 μmol / L Na2MoO4, and 100 μmol / L Fe-EDTA. The solutions are prepared and mixed according to the concentrations of each reagent, and then the pH value is adjusted to 5.0–5.5.

[0016] The present invention has the following beneficial effects:

[0017] 1. In this invention, the root system is first cultured in nutrient solution A for a period of time to allow it to fully absorb nutrients. After 10 days of culture, the solution is replaced with a mixture of naphthaleneacetic acid (NAA), strigolactone, and nutrient growth solution B to promote the formation and differentiation of adventitious roots. In this invention, NAA promotes cell division and expansion, inducing the formation of adventitious roots. Strigolactone can be secreted by the plant roots into the rhizosphere, promoting seed germination and root growth; it also stimulates the plant to absorb phosphates and other minerals from the soil, promoting its growth and development, and promoting the absorption of nutrients from nutrient growth solution B. Nutrient growth solution B is rich in various mineral elements required by plants, meeting the root system's nutrient needs. The phosphorus content in nutrient growth solution B is lower than that in nutrient growth solution A, which is more conducive to inducing adventitious root formation under low phosphorus conditions. Since adventitious root formation is related to the plant's phosphorus nutrient absorption, it is a characteristic of macadamia nuts that tolerate low phosphorus. Therefore, this invention promotes the formation of adventitious roots under the mixed solution culture.

[0018] 2. The method of this invention is simple, easy to implement, and effective. This invention uses 800 μmol / L naphthaleneacetic acid (NAA), 20 μmol / L strigolactone, and nutrient growth solution B to spray macadamia seedlings. Within 30 days, the number of roots can reach 124, indicating a very rich root system, which is beneficial for promoting nutrient absorption and accelerating growth. Attached Figure Description

[0019] Figure 1 Bar chart of root number of macadamia seedlings under different strigolactone concentrations;

[0020] Figure 2 Bar chart of root count in macadamia seedlings treated with different concentrations of naphthaleneacetic acid;

[0021] Figure 3 Comparison of root formation in macadamia seedlings treated with different concentrations of naphthaleneacetic acid.

[0022] Figure 4 The image shows the growth status of macadamia seedlings in each group after 30 days of nutrient solution culture. Detailed Implementation

[0023] The present invention will be further described below with reference to embodiments:

[0024] Example

[0025] I. Source of Test Materials

[0026] 1. Experimental variety: The macadamia nut variety is "Guire No. 1". The seedlings are uniformly growing, healthy and disease-free, and were provided by the macadamia nut breeding team of the South Asia Institute of Guangxi Academy of Agricultural Sciences.

[0027] 2. Nutrient growth solution A: 2000 μmol / L Ca(NO3)2, 500 μmol / L KH2PO4, 625 μmol / L K2SO4, 100 μmol / L KCl, 650 μmol / L MgSO4, 1 μmol / L MnSO4, 1 μmol / L ZnSO4, 0.1 μmol / L CuSO4, 1 μmol / L H3BO3, 0.005 μmol / L Na2MoO4, 100 μmol / L Fe-EDTA. Nutrient growth solution A is prepared by mixing the reagents according to their concentrations. The pH of the mixture is adjusted to 5.0–5.5.

[0028] 3. Nutrient growth solution B: 2000 μmol / L Ca(NO3)2, 50 μmol / L KH2PO4, 850 μmol / L K2SO4, 100 μmol / L KCl, 650 μmol / L MgSO4, 1 μmol / L MnSO4, 1 μmol / L ZnSO4, 0.1 μmol / L CuSO4, 1 μmol / L H3BO3, 0.005 μmol / L Na2MoO4, 100 μmol / L Fe-EDTA. Nutrient growth solution B is prepared by mixing the reagents according to their concentrations. The pH of the mixture is adjusted to 5.0–5.5.

[0029] 4. Hormone type:

[0030] ① Auxin (IAA): Naphthaleneacetic acid (NAA), provided by Shanghai Yuanye Biotechnology Co., Ltd.

[0031] ②Strigolactones (SLs): GR24, a synthetic analog of strigolactones, was provided by Shanghai Yuanye Biotechnology Co., Ltd.

[0032] II. The effect of nutrient growth solution on root growth.

[0033] The experiment was conducted in the greenhouse of the Guangxi Subtropical Agricultural Research Institute. Plastic pots (20cm top diameter, 15cm bottom diameter, 22cm height) were used for cultivation. Two treatments were established, with five pots replicated for each treatment, for a total of ten pots. The specific operational steps are as follows:

[0034] (1) Filling the substrate: Take 10 plastic flower pots of the same size with a base, clean them and let them dry; put two layers of newspaper on the bottom of the flower pots to prevent the soil from flowing out; put sterilized quartz sand into the test pots, compact it in layers until it is level with the top of the pot, put the base of the flower pot on the bottom, mark each flower pot and attach a label; moisten the quartz sand in each pot with sterile water and equilibrate for 2 days.

[0035] (2) Sowing: Select 10 healthy macadamia seedlings with uniform growth and no disease, and moisten them with a small amount of sterile water for 2 days.

[0036] (3) Nutrient solution A cultivation: At 5-6 pm, apply 400 mL of nutrient growth solution A to each seedling in each pot, once every 2 days, for 10 consecutive days. During the cultivation period, remove the trays under each pot and pour the nutrient solution back into the original pot to avoid loss of nutrient solution. If dryness occurs 2 cm below the surface sand, water each pot with an equal amount of sterile water.

[0037] (4) Comparative culture: Grouped experiments, watering every 2 days for 30 consecutive days.

[0038] Control group: Each seedling in each pot was irrigated with 400 mL of water.

[0039] Experimental group: 400 mL of nutrient growth solution B was applied to each seedling in each pot.

[0040] During the cultivation period, remove the saucers from under each pot and pour any leaked liquid back into the original pot. If dryness occurs 2cm below the surface sand, water each pot with an equal amount of sterile water. Rotate the pots weekly to avoid the influence of environmental factors on the experiment.

[0041] (5) Root count: After 30 days of cultivation, three seedlings were randomly selected from each treatment. The above-ground parts were cut off from the base, the entire root system was removed, the roots were cleaned with tap water, the number of roots was counted, and the results were recorded in Table 1.

[0042] Table 1. Effects of nutrient solution on root formation in macadamia seedlings

[0043] Plant / plant control group experimental group Number of rows 18.67 20.33

[0044] III. Screening of strigolactone solution concentration

[0045] The experiment was conducted in the greenhouse of the Guangxi Subtropical Agricultural Research Institute. Plastic pots (20cm top diameter, 15cm bottom diameter, 22cm height) were used for cultivation. Five treatments were established, with 12 pots replicated per treatment, for a total of 60 pots. The operational steps are as follows:

[0046] (1) Filling the substrate: Take 60 plastic flower pots of the same size with a base, clean them and let them dry; put two layers of newspaper on the bottom of the flower pots to prevent the soil from flowing out; put sterilized quartz sand into the test pots, compact it in layers until it is level with the top of the pot, put the base of the flower pot on the bottom, mark each flower pot and attach a label; moisten the quartz sand in each pot with sterile water and equilibrate for 2 days.

[0047] (2) Sowing: Select 60 healthy macadamia seedlings with uniform growth and no disease, and moisten them with a small amount of sterile water for 2 days.

[0048] (3) Nutrient solution A cultivation: At 5-6 pm, apply 400 mL of nutrient growth solution A to each seedling in each pot, once every 2 days, for 10 consecutive days. During the cultivation period, remove the trays under each pot and pour the nutrient solution back into the original pot to avoid loss of nutrient solution. If dryness occurs 2 cm below the surface sand, water each pot with an equal amount of sterile water.

[0049] (4) Different treatments: Experiments were conducted according to the five pre-defined treatment groups. Every two days, each seedling in each pot was irrigated with 400 mL of the five different treatment solutions. The details of each treatment solution are as follows:

[0050] ①CK: 0 μmol / L strigolactones (SLs) + nutrient growth solution B;

[0051] ②T1: 5 μmol / L strigolactones (SLs) + nutrient growth solution B;

[0052] ③T2: 10 μmol / L strigolactones (SLs) + nutrient growth solution B;

[0053] ④T3: 20 μmol / L strigolactones (SLs) + nutrient growth solution B;

[0054] ⑤T4: 40 μmol / L strigolactones (SLs) + nutrient growth solution B.

[0055] During cultivation, remove the trays from under each pot and pour the nutrient solution back into the original pot to prevent nutrient loss. If dryness occurs at a depth of 2cm below the surface sand, water each pot with an equal amount of sterile water. Rotate the pots weekly to minimize the impact of environmental factors on the experiment.

[0056] (5) Root Extrusion Statistics: After 30 days of cultivation in each group, 6 seedlings were randomly selected from each treatment. The above-ground parts were cut off from the base, and the entire root system was removed intact. The roots were cleaned with tap water, and the number of extruded roots was counted and recorded in Table 1. A graph showing the number of extruded roots of macadamia seedlings under different concentrations of strigolactone treatment was plotted (e.g., Figure 1 (As shown).

[0057] Table 1. Root formation in macadamia seedlings treated with different concentrations of strigolactone.

[0058] Plant / plant CK T1 T2 T3 T4 Number of rows 20.12 31.22 55.64 92.18 64.45

[0059] Depend on Figure 1 As shown in Table 1, after 30 days of cultivation with a mixture of 5–40 μmol / L strigolactones (SLs) and nutrient growth solution B, the average number of root clusters formed in macadamia seedlings ranged from 31.22 to 92.18 per plant, representing increases of 11.10, 35.52, 72.06, and 44.33 per plant, respectively, compared to the control treatment (20.12 per plant). Specifically, after 30 days of cultivation with a mixture of 20 μmol / L strigolactones and nutrient growth solution B, the average number of root clusters formed in macadamia seedlings was 92.18 per plant, 4.58 times that of the control treatment (20.12 per plant). This indicates that an appropriate amount of strigolactones helps promote root cluster formation with good and stable results, and this formulation is relatively low-cost, environmentally friendly, and safe.

[0060] IV. Screening of Naphthaleneacetic Acid Solution Concentration

[0061] The experiment was conducted in a greenhouse at the Guangxi Subtropical Agricultural Research Institute. Plastic pots (20cm top diameter, 15cm bottom diameter, 22cm height) were used for cultivation. Six treatments were established, with 12 pots replicated for each treatment, for a total of 72 pots. The specific operational steps are as follows:

[0062] 1. Filling the substrate: Take 72 plastic flower pots of the same size with a base, clean them, and let them dry; place two layers of newspaper at the bottom of the flower pots to prevent soil from flowing out; fill the test pots with sterilized quartz sand, compact it in layers until it is level with the top of the pot, place the base plate at the bottom of the flower pot, mark each flower pot and attach a label; thoroughly moisten the quartz sand in each pot with sterile water and allow it to equilibrate for 2 days.

[0063] 2. Sowing: Select 72 healthy macadamia seedlings that are growing uniformly and are free from disease, and moisten them with a small amount of sterile water for 2 days.

[0064] 3. Nutrient Solution A Cultivation: Between 5 and 6 PM, apply 400 mL of nutrient growth solution A to each seedling in each pot, repeating every two days for 10 days. During cultivation, remove the trays from under each pot and pour the nutrient solution back into the original pot to prevent nutrient loss. If dryness occurs at 2 cm below the surface sand, water each pot with an equal amount of sterile water.

[0065] 4. Culture with different mixed solutions: Two days after the completion of nutrient solution A culture, experiments were conducted according to the six pre-defined treatment groups. Every two days, 400 mL of the treatment mixed solution was applied to each seedling in each pot for 30 consecutive days. The details of each mixed solution are as follows:

[0066] ①CK: 0 μmol / L naphthaleneacetic acid (NAA) + 20 μmol / L strigolactone + nutrient growth solution B;

[0067] ②T1: 10 μmol / L naphthaleneacetic acid (NAA) + 20 μmol / L strigolactone + nutrient growth solution B;

[0068] ③T2: 20 μmol / L naphthaleneacetic acid (NAA) + 20 μmol / L strigolactone + nutrient growth solution B;

[0069] ④T3: 40 μmol / L naphthaleneacetic acid (NAA) + 20 μmol / L strigolactone + nutrient growth solution B;

[0070] ⑤T4: 80 μmol / L naphthaleneacetic acid (NAA) + 20 μmol / L strigolactone + nutrient growth solution B;

[0071] ⑥T5: 100μmol / L naphthaleneacetic acid (NAA) + 20μmol / L strigolactone + nutrient growth solution B.

[0072] During cultivation, remove the trays from under each pot and pour the nutrient solution back into the original pot to prevent nutrient loss. If dryness occurs at a depth of 2cm below the surface sand, water each pot with an equal amount of sterile water. Rotate the pots weekly to minimize the impact of environmental factors on the experiment.

[0073] 5. Root Excavation Statistics: After 30 days of cultivation following step (4), 6 seedlings were randomly selected from each treatment. The above-ground parts were cut off from the base, and the entire root system was removed intact. The roots were cleaned with tap water, and the number of excavated roots was counted and recorded in Table 2. A graph showing the number of excavated roots of macadamia seedlings under different concentrations of naphthaleneacetic acid treatment was drawn (e.g., ...). Figure 2 As shown), take photos to record the root sorting results of different treatment groups, such as... Figure 3 As shown.

[0074] Table 2. Root formation in macadamia seedlings under different concentrations of naphthaleneacetic acid treatment.

[0075] Plant / plant CK T1 T2 T3 T4 T5 Number of rows 34.67 45.47 60.67 90.89 124.65 100.52

[0076] From Table 2, Figure 2 and Figure 3 It was found that after 30 days of cultivation in a mixture of 10–100 μmol / L naphthaleneacetic acid (NAA) + 20 μmol / L strigolactone + nutrient growth solution B, the average number of roots formed in macadamia seedlings ranged from 45.47 to 124.65 per plant, representing increases of 10.80, 26.00, 56.22, 89.98, and 65.85 per plant, respectively, compared to the control treatment (34.67 per plant). Specifically, after 30 days of cultivation in a mixture of 80 μmol / L NAA + 20 μmol / L strigolactone + nutrient growth solution B, the average number of roots formed in macadamia seedlings was 124.65 per plant, 3.60 times that of the control treatment (34.67 per plant). Especially... Figure 3 It can be seen that the root system is particularly dense, indicating that an appropriate amount of naphthaleneacetic acid helps to promote root formation.

[0077] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for promoting root formation and growth in macadamia nuts, characterized in that: (1) For macadamia seedlings, first use nutrient growth solution A for cultivation. Apply 200-400 mL to each seedling, once every 2-3 days, for 9-10 days. The nutrient growth solution A comprises 1500-2000 μmol / L Ca(NO3)2, 450-500 μmol / L KH2PO4, 600-625 μmol / L K2SO4, 80-100 μmol / L KCl, 600-650 μmol / L MgSO4, 1-2 μmol / L MnSO4, 1-2 μmol / L ZnSO4, 0.1-0.2 μmol / L CuSO4, 1-2 μmol / L H3BO3, 0.005-0.01 μmol / L Na2MoO4, and 80-100 μmol / L Fe-EDTA. The solutions are prepared and mixed according to the concentrations of each reagent, and the pH is then adjusted to 5.0-5.

5. (2) After the nutrient growth solution A is completed, the seedlings are then cultured with the nutrient mixture. Each seedling is irrigated with 300-400 mL of the nutrient mixture every 2-3 days for 25-30 days. The nutrient mixture comprises 80 μmol / L naphthaleneacetic acid (NAA), 20 μmol / L strigolactone, and nutrient growth solution B; The nutrient growth solution B comprises: 1500-2000 μmol / L Ca(NO3)2, 50-100 μmol / L KH2PO4, 800-850 μmol / L K2SO4, 80-100 μmol / L KCl, 600-650 μmol / L MgSO4, 1-2 μmol / L MnSO4, 1-2 μmol / L ZnSO4, 0.1-0.2 μmol / L CuSO4, 1-2 μmol / L H3BO3, 0.005-0.01 μmol / L Na2MoO4, and 80-100 μmol / L Fe-EDTA. The solutions are prepared and mixed according to the concentrations of each reagent, and the pH is then adjusted to 5.0-5.

5. (3) After the nutrient solution culture cycle is completed, the macadamia seedlings will form abundant macadamia root system, which is conducive to the absorption of nutrients from the soil.

2. The method for promoting root formation and growth of macadamia nuts according to claim 1, characterized in that: The nutrient growth solution B comprises: 2000 μmol / L Ca(NO3)2, 50 μmol / L KH2PO4, 850 μmol / L K2SO4, 100 μmol / L KCl, 650 μmol / L MgSO4, 1 μmol / L MnSO4, 1 μmol / L ZnSO4, 0.1 μmol / L CuSO4, 1 μmol / L H3BO3, 0.005 μmol / L Na2MoO4, and 100 μmol / L Fe-EDTA. The solutions are prepared and mixed according to their respective concentrations, and the pH is then adjusted to 5.0-5.5.

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