Application of sphingomonas cucurbitae SPZ1 and complex microbial inoculant thereof in promoting photosynthetic physiology of peanut plants

Abstract

The invention discloses application of sphingomonas cucurbitae SPZ1 and a complex microbial inoculant thereof in promoting photosynthetic physiology and nitrogen metabolism of peanut plants, and belongs to the technical field of microorganisms. According to the invention, the complex microbial inoculant composed of active bacteria, namely arthrobacter plantarum ARZ1 (Arthrobacter oryzae) and sphingomonas melonis SPZ1 (Sphingomonas melonis), is applied to the field of peanut planting for the first time, and the maximum photochemical efficiency and leaf chlorophyll (SPAD) value of peanut plants are obviously improved through the synergistic effect of the two bacteria in the complex microbial inoculant; particularly, the activity of nitrogen metabolism enzymes (nitrate reductase and glutamine synthetase) of whole peanut leaves can be improved, so that the method can be applied to promoting photosynthetic physiology and nitrogen metabolism of peanut plants.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and specifically relates to an application of Sphingomonas cucurbitae SPZ1 and a composite bacterial agent thereof in promoting photosynthetic physiology and nitrogen metabolism of peanut plants. Background Art

[0002] Nitrogen is an indispensable nutrient in the growth process of peanuts, affecting their growth, development and yield formation. Within the appropriate application range, nitrogen significantly promotes the growth of peanut plants, promotes the good development of lateral branches and root systems, and improves the absorption capacity of the roots and the photosynthetic efficiency of the leaves. At the same time, the effective conversion and utilization of nitrogen can promote the efficient accumulation and transportation of nutrients in the plant, thereby increasing the accumulation of dry matter and increasing peanut yield. However, in the context of intensive agricultural development, excessive nitrogen application may inhibit the nitrogen fixation function of peanut nodules, reduce the utilization rate of nitrogen fertilizer, lead to excessive growth and premature aging of plants, inhibit material transportation and metabolism, and ultimately affect peanut yield and quality.

[0003] Therefore, without increasing the amount of nitrogen fertilizer applied, exploring ways to improve the photosynthetic physiology of peanuts and promote material transport and metabolism has important sustainable development value. Previous studies have mostly improved the photosynthetic physiology and material metabolism of peanuts by improving fertilization methods and optimizing fertilizer characteristics, but to a certain extent have ignored the important role of microorganisms in regulating the growth and physiology of peanuts. Therefore, it is necessary to develop suitable microbial agents to improve the photosynthetic physiology and nitrogen metabolism of peanuts, enhance nitrogen utilization efficiency, and lay the foundation for increasing peanut yields. Summary of the invention

[0004] In view of the deficiencies in the prior art, the object of the present invention is to provide an application of Sphingomonas cucurbitae SPZ1 and a composite bacterial agent thereof in promoting light and physiology and nitrogen metabolism of peanut plants.

[0005] In order to achieve the above-mentioned purpose, the inventors conducted a large number of experiments to explore the effects of different strains on the maximum photochemical efficiency, leaf chlorophyll SPAD value, leaf glutamine synthetase activity and leaf nitrate reductase activity of two peanut varieties, and finally obtained the following technical solutions: a cucurbit sphingomonas (Sphingomonas melonis) SPZ1, whose strain preservation number is CCTCC No: M20241884. A plant arthrobacter (Arthrobacter oryzae) ARZ1, whose strain preservation number is CCTCC No: M20241883. The address of the depository unit is Wuhan University, Wuhan, China

[0006] The plant Arthrobacter ARZ1 (Arthrobacter oryzae) used in the present invention is isolated from the rhizosphere soil of peanuts, has excellent self-nitrogen fixation ability, can survive in the rhizosphere and soil of peanuts, grows well under pH 7.0-9.0 environmental conditions, and survives well under pH 8.0. The strain was identified as plant Arthrobacter ARZ1 (Arthrobacter oryzae) by microbiological characteristics such as morphological characteristics, cultural characteristics, and physiological and biochemical characteristics. The strain has been deposited in the China Center for Type Culture Collection on September 2, 2024, and the deposit number is CCTCCNo: M20241883. The address of the deposit unit is Wuhan University, Wuhan, China

[0007] The cucurbit sphingomonas SPZ1 (Sphingomonas melonis) used in the present invention is also isolated from the rhizosphere soil of peanuts, has excellent self-nitrogen fixation ability, can survive in the rhizosphere and soil of peanuts, grows well under pH 6.0-9.0 environmental conditions, and survives well under pH 8.0. The strain was identified as cucurbit sphingomonas melonis SPZ1 by microbiological characteristics such as morphological characteristics, culture characteristics, and physiological and biochemical characteristics. The strain was deposited in the China Center for Type Culture Collection on September 2, 2024, with the deposit number CCTCCNo: M20241884.

[0008] When the above two strains are used alone or in combination, they have a significant positive promoting effect on the maximum photochemical efficiency, leaf chlorophyll SPAD value, leaf glutamine synthetase activity and leaf nitrate reductase activity of two peanut varieties, Qinghua No. 6 and Qinghua No. 22. Therefore, the present invention also provides the following applications:

[0009] (1) Application of ARZ1 strain or SPZ1 strain in improving light physiology and nitrogen metabolism of peanut plants.

[0010] (2) Application of the composite strain of ARZ1 and SPZ1 in improving the maximum photochemical efficiency of peanut plants during the podding and maturity stages.

[0011] (3) Application of ARZ1 strain or SPZ1 strain or composite strain of ARZ1 and SPZ1 in improving the chlorophyll SPAD value of peanut plants.

[0012] (4) Application of ARZ1 strain or SPZ1 strain or a composite strain of ARZ1 and SPZ1 in increasing the activity of glutamine synthetase in peanut plant leaves.

[0013] (5) Application of ARZ1 strain or SPZ1 strain or a composite strain of ARZ1 and SPZ1 in increasing the nitrate reductase activity in peanut plant leaves.

[0014] In the above application, the ARZ1 strain is Arthrobacter oryzae ARZ1CCTCC No: M20241883, and the SPZ1 strain is Sphingomonas melonis SPZ1CCTCC No: M20241884.

[0015] Further preferably, when the composite strain is used, the ratio of the number of live bacteria of Sphingomonas melonis SPZ1 and Arthrobacter oryzae ARZ1 is 1:(1-2).

[0016] It should be noted that the inventors unexpectedly discovered when screening strains that improve the light and physiological and nitrogen metabolism of peanuts that a composite bacterial solution containing Sphingomonas melonis SPZ1 (Sphingomonas melonis) and Arthrobacter oryzae ARZ1 (Arthrobacter oryzae) has a significant effect on improving the maximum photochemical efficiency of peanut plants, and can significantly increase the leaf chlorophyll SPAD value of peanuts in two growth periods, and can increase the activity of nitrogen metabolic enzymes (glutamine synthetase and nitrate reductase) in the leaves of the whole peanut plant. Based on this discovery, the inventors prepared these two bacteria into a composite bacterial agent by culturing and fermenting.

[0017] The composite bacterial agent can be prepared by the following method: mixing the bacterial solution of Sphingomonas melonis SPZ1 and Arthrobacter oryzae ARZ1 cultured to the logarithmic growth phase, and adding a protective agent to the mixed bacterial solution to adjust the number of viable bacteria to (1.0-2.0)×10 10 cfu / mL, pH 6-9; the protective agent is composed of: 90-120g / L skim milk powder, 25-35mL / L glycerol, 90-120g / L maltodextrin, 120-180g / L lacquer sugar and 8-13g / L L-sodium glutamate.

[0018] The fermentation culture method of Sphingomonas melonis SPZ1 is as follows: Sphingomonas melonis SPZ1 is inoculated into beef extract peptone culture medium at an inoculum amount of 4%-10%, and is cultured at a constant temperature of 25-27°C for 24-72 hours. After centrifugal washing, a mixed solution containing 0.5g / L Yeast Extract, 20g / L Mannitol, 0.2g / L K2HPO4, 0.8g / L KH2PO4, 0.2g / L MgSO4·7H2O, 0.1g / L CaSO4·2H2O, 0.01g / L FeCl3, 0.002g / L Na2MoO4·2H2O, and 15g / L Agar is added to each bacterial precipitate, and the pH is 4. 6-9, and the viable bacterial count of Sphingomonas melonis SPZ1 was adjusted to (1.0-2.0)×10 10 cfu / mL, mix well and pour into culture.

[0019] The fermentation culture method of Arthrobacter oryzae ARZ1 is as follows: oryzae ARZ1 was inoculated into beef extract peptone culture medium at an inoculum rate of 4%-10%, and cultured at a constant temperature of 25-27°C for 24-72 hours. After centrifugation and washing, a mixed solution containing 0.5 g / L Yeast Extract, 20 g / L Mannitol, 0.2 g / L K2HPO4, 0.8 g / L KH2PO4, 0.2 g / L MgSO4﹒7H2O, 0.1 g / L CaSO4﹒2H2O, 0.01 g / L FeCl3, 0.002 g / L Na2MoO4﹒2H2O, and 15 g / L Agar was added to each bacterial precipitate, and the pH was adjusted to 6-9, and the viable bacterial count of Arthrobacter oryzae ARZ1 was adjusted to (1.0-2.0)×10 10 cfu / mL, mix well and pour into culture.

[0020] Still more preferably, the composite strain is prepared to have a total viable count of (1.0-2.0)×10 10 cfu / mL of compound fungal agent; the first application is in the beginning flowering stage of peanuts, the dosage is 2.5-3.5L / 667m 2 The second application is during the peanut pod-setting period, with a dosage of 2.5-3.5L / 667m 2 .

[0021] Still more preferably, if manual application is adopted, the bacterial solution is diluted with clean water and then sprayed on the roots of peanuts using an agricultural sprayer; if drone spraying is used, the bacterial solution is directly diluted with clean water and placed in a medicine barrel and sprayed before rain.

[0022] Still more preferably, when peanuts are planted in a film-covered planting method, sub-film drip irrigation is used for bacterial solution drip irrigation, and the irrigation depth moistens the soil by 8-10 cm.

[0023] Still more preferably, the bacterial solution and the pesticide cannot be used together, and the interval between their use is more than 2 days.

[0024] Compared with the prior art, the active bacteria in the composite bacterial agent involved in the present invention are composed of Arthrobacter oryzae ARZ1 and Sphingomonas melonis SPZ1. The two bacteria in the composite bacterial agent can significantly improve the maximum photochemical efficiency and leaf chlorophyll SPAD value of peanut plants through synergistic action, and can especially improve the activity of nitrogen metabolic enzymes (nitrate reductase and glutamine synthetase) in the leaves of the whole peanut plant, so that it can be used to promote the photosynthetic physiology and nitrogen metabolism of peanut plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 :Plant culture and scanning electron microscopy images of Arthrobacter oryzae ARZ1;

[0026] Figure 2 :Plate culture and scanning electron microscopy images of Sphingomonas melonis SPZ1;

[0027] Figure 3 :Effects of each treatment on the maximum photochemical efficiency of peanut;

[0028] Figure 4 :Effects of each treatment on chlorophyll SPAD in peanut leaves;

[0029] Figure 5 :Effects of different bacterial agents on glutamine synthetase activity in peanut leaves;

[0030] Figure 6 :Effects of different bacterial agents on nitrate reductase activity in peanut leaves;

[0031] Figure 3-Figure 6 Different letters in the text represent significant differences among different treatments in the same group (p<0.05). DETAILED DESCRIPTION

[0032] The above contents of the present invention are further described in detail below by way of examples, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples, and all technologies realized based on the above contents of the present invention belong to the scope of the present invention. In addition, the test methods in the following examples are conventional methods unless otherwise specified.

[0033] Example 1: Screening and Isolation of ARZ1 and SPZ1 Strains

[0034] (1) The process of discovering, screening, isolating and identifying strains. Based on the test of adding root secretions to the intercropping of corn and peanut, the inventors found that the addition of root secretions can improve the maximum photochemical efficiency and nitrogen metabolism enzyme activity of peanut plants, and stimulate the light and physiological and nitrogen metabolism of peanut plants. Therefore, we speculate that the addition of root secretions reassembles the soil microbial community, thereby promoting the light and physiological and nitrogen metabolism of peanuts. On this basis, we prepared the peanut rhizosphere soil samples treated with the above-mentioned root secretion addition into a suspension, applied the bacterial solution to the bacterial culture medium, and isolated and purified the strains. The 16S rRNA sequence of the isolated strains was obtained using high-throughput sequencing technology, and the 16S rRNA sequence was compared with the nr database of NCBI. The sequence cluster analysis was performed by comparing the degree and similarity, and a phylogenetic tree was constructed. The isolated and purified strains were compared with known strains, and a comprehensive analysis was performed in terms of morphology, physiology and biochemistry to determine the bacterial species. In order to further verify the function of the strains, the isolated and purified strains were used to carry out peanut cultivation addition tests.

[0035] (2) Mycological properties of microorganisms. The colonies of Arthrobacter oryzae ARZ1 are white, round, and moist. Figure 1 ), can grow on nitrogen-fixing medium, with a suitable pH of 6-9 and a temperature of 25-27°C. The colonies of Sphingomonas melonis SPZ1 are yellow, round, small, moist and smooth, opaque, with neat edges and no halos ( Figure 2 ), can grow on nitrogen-fixing medium, suitable growth pH is 6-9, temperature is 25-27℃.

[0036] Example 2: Preparation of ARZ1, SPZ1 and composite bacterial agents

[0037] (1) Arthrobacter oryzae ARZ1 was inoculated at a rate of 4% to 10% in a beef extract peptone culture medium (beef extract 3 g / L, peptone 10 g / L, NaCl 5 g / L, agar 15 g / L), pH 7.4-7.6, culture at a constant temperature of 25-27°C for 24-72 hours, and after centrifugation and washing, add a nitrogen-fixing medium containing 0.5 g / L Yeast Extract, 20 g / L Mannitol, 0.2 g / L K2HPO4, 0.8 g / L KH2PO4, 0.2 g / L MgSO4·7H2O, 0.1 g / L CaSO4·2H2O, 0.01 g / L FeCl3, 0.002 g / L Na2MoO4·2H2O, and 15 g / L Agar to the bacterial precipitate, pH 6-9, and adjust the viable count of Arthrobacter oryzae ARZ1 to about 1.0×10 10 cfu / mL, mix well and then pour culture; the specific operation method of pour culture is: dilute the plant Arthrobacter oryzae (Arthrobacter oryzae) ARZ1 suspension and add it to the sterile nitrogen-fixing medium, invert and culture after solidification, a single strain proliferates to form colonies, take a single colony to make a suspension, repeat several times to obtain a pure culture.

[0038] (2) Sphingomonas melonis SPZ1 was inoculated at an inoculum amount of 4% to 10% in a beef extract peptone culture medium (beef extract 3 g / L, peptone 10 g / L, NaCl 5 g / L, agar 15 g / L), and cultured at a constant temperature of 25-27° C. for 24-72 hours. After centrifugation and washing, a mixed solution containing 0.5 g / L Yeast Extract, 20 g / L Mannitol, 0.2 g / L K2HPO4, 0.8 g / L KH2PO4, 0.2 g / L MgSO4·7H2O, 0.1 g / L CaSO4·2H2O, 0.01 g / L FeCl3, 0.002 g / L Na2MoO4·2H2O, and 15 g / L Agar was added to each bacterial precipitate, and the pH was adjusted to 8. 6-9, and the number of viable bacteria of Sphingomonas melonis SPZ1 was adjusted to about 1.0×10 10cfu / mL, mix well and then pour culture; the specific operation method of pour culture is: dilute the Sphingomonas melonis SPZ1 suspension and add it to the sterile nitrogen-fixing medium, invert and culture after solidification, a single strain proliferates to form colonies, take a single colony to make a suspension, repeat several times to obtain a pure culture.

[0039] (3) Prepare a protective agent, the composition of which is: 100 g / L skim milk powder, 30 mL / L glycerol, 100 g / L maltodextrin, 150 g / L lacquer sugar and 10 g / L sodium L-glutamate, pH 6-9.

[0040] (4) Add the protective agent prepared in step (3) to the Arthrobacter ARZ1 bacterial solution obtained in step (1) to adjust the viable bacterial count to about 1.0×10 10 cfu / mL , and obtain ARZ1 bacterial agent The protective agent prepared in step (3) was added to the bacterial solution of Sphingomonas cucurbitae SPZ1 obtained in step (2) to adjust the number of viable bacteria to about 1.0×10 10 cfu / mL , and obtain SPZ1 bacterial agent .

[0041] The bacterial liquid obtained in steps (1) and (2) was mixed at a live bacterial count ratio of 1:(1-2) of Sphingomonas SPZ1:Arthrobacterium plantum ARZ1, and the protective agent prepared in step (3) was added to the mixed bacterial liquid to adjust the total number of effective live bacteria to about 1.0×10 10 cfu / mL , and obtain the composite bacterial agent .

[0042] Example 3: Experiment of ARZ1 inoculant in potted peanut cultivation

[0043] Test type: Pot test

[0044] Experimental location: Qingdao Agricultural University (Qingdao, China)

[0045] Test time: 2023.05-2023.09

[0046] Test crops: Peanuts (varieties: Qinghua No. 6 and Qinghua No. 22)

[0047] Test soil: sterilized soil (soil pH 6.70, organic matter 11.92 g / kg, alkaline nitrogen 99.86 mg / kg, available phosphorus 35.22 mg / kg, available potassium 89.79 mg / kg).

[0048] Experimental groups: CK was the blank control, ARZ1-F and ARZ1-T were treated with plant bacterium ARZ1, and each treatment was repeated 3 times in random blocks.

[0049] Experimental design: PVC pots were used for potting, with an inner diameter of 16 cm and a height of 23.5 cm. The inoculant was added 25 days after peanut sowing (mix the inoculant with 200 ml of water and pour it to the roots of peanuts). After the inoculant was added, samples were taken at the cleavage stage and maturity stage.

[0050] Dosage and method: ARZ1-F was treated with 0.05 mL / pot of the ARZ1 inoculant prepared in Example 2, and ARZ1-T was treated with 0.1 mL / pot of the ARZ1 inoculant prepared in Example 2. The inoculants were diluted to 200 mL respectively and poured to the roots of peanuts. CK was 200 mL of blank aqueous solution.

[0051] Table 1 Maximum photochemical efficiency of plants treated with Arthrobacterium arz1

[0052]

[0053]

[0054] Note: Different letters represent significant differences among different treatments in the same group (p<0.05), the same below.

[0055] From the test results in Table 1, it can be seen that the maximum photochemical efficiency of the Qinghua No. 6 peanut variety at the pod-setting stage was significantly increased by 5.19% compared with CK under ARZ1-T treatment, and the maximum photochemical efficiency at the maturity stage had no significant difference among different treatments; the maximum photochemical efficiency of the Qinghua No. 22 peanut variety at the pod-setting stage was significantly increased by 3.80% and 1.27% compared with CK under ARZ1-F and ARZ1-T treatments, respectively, and the maximum photochemical efficiency at the maturity stage had no significant difference among different treatments. In summary, the treatment of Arthrobacter plantum ARZ1-F or ARZ1-T has a significant effect on improving the maximum photochemical efficiency of peanut plants at the pod-setting stage.

[0056] Example 4: Experiment of SPZ1 fungicide in potted peanut planting

[0057] Test type: Pot test

[0058] Experimental location: Qingdao Agricultural University (Qingdao, China)

[0059] Test time: 2023.05-2023.09

[0060] Test crops: Peanuts (variety: Qinghua No. 6, Qinghua No. 22)

[0061] Test soil: sterilized soil (soil pH 6.70, organic matter 11.92 g / kg, alkaline nitrogen 99.86 mg / kg, available phosphorus 35.22 mg / kg, available potassium 89.79 mg / kg).

[0062] Experimental groups: CK was the blank control, SPZ1-F and SPZ1-T were treated with Sphingomonas cucurbitae SPZ1, each treatment was repeated 3 times and arranged in random blocks.

[0063] Experimental design: PVC pots were used for potting, with an inner diameter of 16 cm and a height of 23.5 cm. The inoculant was added 25 days after peanut sowing (mix the inoculant with 200 ml of water and pour it to the roots of the peanuts). After the inoculant was added, samples were taken from the pod-setting stage and the mature area.

[0064] Dosage and method: SPZ1-F was treated with 0.05 mL / pot of the SPZ1 inoculant prepared in Example 2, and SPZ1-T was treated with 0.1 mL / pot of the SPZ1 inoculant prepared in Example 2. The inoculants were diluted to 200 mL respectively and poured to the roots of peanuts. CK was 200 mL of blank aqueous solution.

[0065] Table 2 Maximum photochemical efficiency of plants treated with Sphingomonas cucurbitae SPZ1

[0066]

[0067]

[0068] From the test results in Table 2, it can be seen that the maximum photochemical efficiency of the Qinghua No. 6 peanut variety at the pod-setting stage was significantly increased by 5.19% under the SPZ1-F treatment compared with CK, and there was no significant difference in the maximum photochemical efficiency at the maturity stage under different treatments; the maximum photochemical efficiency of the Qinghua No. 22 peanut variety at the pod-setting stage was significantly increased by 2.53% under the SPZ1-F treatment compared with CK, and there was no significant difference in the maximum photochemical efficiency at the maturity stage under different treatments. In summary, the plant straw fungus SPZ1-F treatment has a significant effect on improving the maximum photochemical efficiency of peanut plants at the pod-setting stage.

[0069] Example 5: Experiment of composite bacterial agent in field peanut planting

[0070] Test location: Pingdu City, Qingdao City, Shandong Province

[0071] Test time: 2024.05-2024.09

[0072] Test crops: Peanuts (varieties: Qinghua No. 6 and Qinghua No. 22)

[0073] Experimental soil: The soil is mortar black soil (soil pH is 7.06, organic matter is 16.18g / kg, alkaline nitrogen is 77.76mg / kg, available phosphorus is 45.58mg / kg, and available potassium is 78.69mg / kg).

[0074] Test groups:

[0075] CK is a blank aqueous solution control,

[0076] The ARZ1-F group was administered with the ARZ bacterial agent prepared in Example 2 (the total number of viable bacteria was about 1.0×10 10 cfu / mL), the application amount was 1.5L / 667m 2 ;

[0077] The ARZ1-T group was administered with the ARZ bacterial agent prepared in Example 2 (the total number of viable bacteria was about 1.0×10 10 cfu / mL), the application rate is 3L / 667m 2 ;

[0078] The SPZ1-F group was administered with the SPZ1 bacterial agent prepared in Example 2 (the total number of viable bacteria was about 1.0×10 10 cfu / mL), the application amount was 1.5L / 667m 2 ;

[0079] The SPZ1-T group was administered with the SPZ1 bacterial agent prepared in Example 2 (the total number of viable bacteria was about 1.0×10 10 cfu / mL), the application rate is 3L / 667m 2 ;

[0080] The SF+AF group was administered with the composite bacterial agent prepared in Example 2, i.e., Sphingomonas cucurbitae SPZ1 and Arthrobacter plantarum ARZ1 were mixed in a ratio of 1:1 (the total number of viable bacteria was about 1.0×10 10 cfu / mL), the application rate is 3L / 667m 2 ;

[0081] The SF+AT group was treated with the composite bacterial agent prepared in Example 2, i.e., Sphingomonas cucurbitae SPZ1 and Arthrobacter plantarum ARZ1 were mixed in a ratio of 1:2 (the total number of viable bacteria was about 1.5×10 10 cfu / mL), the application rate is 3L / 667m 2 .

[0082] Usage: The first application is at the beginning of flowering of peanuts. Dilute the amount of microbial agent per mu in the above test group mentioned in the above treatment to 15L with clean water, and then use an agricultural sprayer to spray it on the roots of peanuts manually; the second application is at the pod-setting stage of peanuts, and the amount and application method are the same as the first application. It should be noted that microbial agents should not be used together with pesticides, and the use time of the two should be at least 2 days apart.

[0083] Planting management: Peanuts are planted in a ridge-covered manner, with a ridge spacing of 90 cm, 2 rows per ridge, a small row spacing of 35 cm on the ridge, and a hole spacing of 11 cm (2 seeds per hole). 50 kg of compound fertilizer (N-P2O5-K2O: 15-15-15) is applied per mu, and no additional fertilizer is required in the later stage.

[0084] Test results:

[0085] 1) Effect of strains on the maximum photochemical efficiency of peanut

[0086] pass Figure 3 A comparison of the experimental results showed that during the pod-setting period, compared with the CK group, the maximum photochemical efficiency of Qinghua No. 6 under the treatment of the composite strain SF+AT group was significantly increased by 7.70%, and that of Qinghua No. 22 was significantly increased by 6.28%; under the treatment of the composite strain SF+AF group, the maximum photochemical efficiency of Qinghua No. 6 was significantly increased by 7.56%, and that of Qinghua No. 22 was significantly increased by 6.32%.

[0087] At maturity, compared with the CK group, the maximum photochemical efficiency of Qinghua No. 6 was significantly increased by 3.15% and 3.00% under the treatment of composite strain SF+AT group and SF+AF group, and that of Qinghua No. 22 was significantly increased by 1.42% and 1.70%; at the same time, through statistical comparison, in terms of the maximum photochemical efficiency of the two peanut varieties, at two growth periods, the ST+AT and ST+AF treatment groups had significant improvements compared with the SPZ1-F, SPZ1-T, ARZ1-F and ARZ1-T groups.

[0088] 2) Effect on chlorophyll SPAD value of peanut plants

[0089] pass Figure 4 Comparison of the experimental results showed that during the pod-setting period, compared with the CK group, the chlorophyll SPAD value of Qinghua No. 6 under the treatment of the composite strain SF+AT group was significantly increased by 18.22%, and that of Qinghua No. 22 was significantly increased by 18.41%; under the treatment of the composite strain SF+AF group, the chlorophyll SPAD value of Qinghua No. 6 was significantly increased by 20.20%, and that of Qinghua No. 22 was significantly increased by 15.91%.

[0090] At maturity, compared with the CK group, the chlorophyll SPAD value of Qinghua No. 6 was significantly increased by 43.70% and 46.47% under the treatment of composite strain SF+AT group and SF+AF group, and that of Qinghua No. 22 was significantly increased by 7.72% and 8.73%; at the same time, through statistical comparison, in the two growth periods and under the two peanut varieties, the SF+AF treatment group had a significant improvement effect compared with the SPZ1-F, SPZ1-T, ARZ1-T and ARZ1-F groups.

[0091] 3) Effects on glutamine synthetase activity in peanut leaves

[0092] pass Figure 5 A comparison of the experimental results showed that at the podding stage, compared with the CK group, the glutamine synthetase activity of the peanut leaves of Qinghua No. 6 was significantly increased by 25.44% under the treatment of the composite strain SF+AT group, and that of Qinghua No. 22 was significantly increased by 39.47%; under the treatment of the composite strain SF+AF group, the glutamine synthetase activity of the peanut leaves of Qinghua No. 6 was significantly increased by 28.23%, and that of Qinghua No. 22 was significantly increased by 38.37%.

[0093] At maturity, compared with the CK group, the glutamine synthetase activity of the Qinghua No. 6 peanut leaves was significantly increased by 61.07% and 68.97% under the treatment of the composite strain SF+AT group and SF+AF group, and that of the Qinghua No. 22 was significantly increased by 48.80% and 44.03%; at the same time, through statistical comparison, in terms of the leaf glutamine synthetase activity of the two peanut varieties, at two growth periods, the SF+AT and SF+AF treatment groups had a significant improvement effect compared with the SPZ1-F, SPZ1-T, ARZ1-T and ARZ1-F groups.

[0094] 4) Effects on nitrate reductase activity in peanut leaves

[0095] pass Figure 6 The results of the experiment were compared and found that at the pod-setting stage, compared with the CK group, the nitrate reductase activity of the leaves of Qinghua No. 6 peanut significantly increased by 88.86% under the treatment of the composite strain SF+AT group, and that of Qinghua No. 22 significantly increased by 88.58%; under the treatment of the composite strain SF+AF group, the nitrate reductase activity of the leaves of Qinghua No. 6 peanut significantly increased by 64.20%, and that of Qinghua No. 22 significantly increased by 80.87%;

[0096] At maturity, compared with the CK group, the nitrate reductase activity of the leaves of Qinghua No. 6 peanut was significantly increased by 83.35% and 61.63% under the treatment of composite strain SF+AT group and SF+AF group, and that of Qinghua No. 22 was significantly increased by 99.28% and 94.52%; at the same time, through statistical comparison, under the two peanut varieties, at two growth periods, the nitrate reductase activity of the ST+AT and ST+AF treatment groups was significantly improved compared with the SPZ1-F, SPZ1-T, ARZ1-F and ARZ1-T groups.

[0097] In summary, through statistical comparison, in many aspects of light and physiological and nitrogen metabolism indicators of peanut plants, the composite strain SF+AT and SF+AF treatment groups had significant improvements in plant leaf maximum photosynthetic efficiency, leaf chlorophyll SPAD value, leaf nitrate reductase and glutamine synthetase activities. This shows that the composite bacterial agent prepared by Sphingomonas melonis SPZ1 (Sphingomonas melonis) and Arthrobacter oryzae ARZ1 (Arthrobacter oryzae) in a ratio of 1: (1-2) (the total number of effective live bacteria is about 1-2×10 10 cfu / mL), 3L / 667m 2 Applying the amount of peanut at the podding stage and maturity stage can significantly promote the maximum photochemical efficiency, chlorophyll SPAD value, nitrate reductase and glutamine synthetase activity of peanut plant leaves, which is beneficial to improving the light and physiological and nitrogen metabolism of peanut plants.

Claims

1. A Sphingomonas melonis SPZ1, whose strain collection number is CCTCCNo:M20241884.

2. Application of ARZ1 strain or SPZ1 strain in improving the maximum photochemical efficiency of peanut plants during the pod-setting period, wherein the ARZ1 strain is Arthrobacter oryzae ARZ1 CCTCC No: M20241883, and the SPZ1 strain is Sphingomonas melonis SPZ1 CCTCC No: M20241884.

3. Application of a composite strain of ARZ1 and SPZ1 in improving the maximum photochemical efficiency of peanut plants at the pod-setting and maturity stages, wherein the ARZ1 strain is Arthrobacter oryzae ARZ1 CCTCC No: M20241883, and the SPZ1 strain is Sphingomonas melonis SPZ1 CCTCC No. No:M20241884.

4. Application of ARZ1 strain or SPZ1 strain or composite strain of ARZ1 and SPZ1 in improving SPAD value of chlorophyll in peanut leaves, wherein the ARZ1 strain is Arthrobacter oryzae ARZ1 CCTCC No: M20241883, and the SPZ1 strain is Sphingomonas melonis SPZ1 CCTCC No: M20241884.

5. Application of ARZ1 strain or SPZ1 strain or a composite strain of ARZ1 and SPZ1 in improving the activity of glutamine synthetase in leaves of peanut plants, wherein the ARZ1 strain is Arthrobacter oryzae ARZ1CCTCC No: M20241883, and the SPZ1 strain is Sphingomonas melonis SPZ1 CCTCC No: M20241884.

6. Application of ARZ1 strain or SPZ1 strain or a composite strain of ARZ1 and SPZ1 in improving nitrate reductase activity in peanut plant leaves, wherein the ARZ1 strain is Arthrobacter oryzae ARZ1 CCTCC No: M20241883, and the SPZ1 strain is Sphingomonas melonis SPZ1 CCTCC No: M20241884.

7. The use according to any one of claims 3 to 6, characterized in that: When the composite strain is used, the ratio of the number of live bacteria of Sphingomonas melonis SPZ1 and Arthrobacter oryzae ARZ1 is 1:(1-2).

8. The use according to claim 7, characterized in that: The composite strain is made into a total number of viable bacteria (1.0-2.0)×10 10 cfu / mL of bacterial solution; the first application is in the beginning flowering stage of peanuts, the dosage is 2.5-3.5L / 667m 2 The second application is during the peanut pod-setting period, with a dosage of 2.5-3.5L / 667m 2 .

9. The use according to claim 7, characterized in that: If manual application is adopted, the solution will be diluted with clean water and sprayed on the roots of peanuts with an agricultural sprayer; if drone spraying is used, the bacterial solution will be directly diluted with clean water and placed in a medicine barrel and sprayed before rain.

10. The use according to claim 7, characterized in that: When peanuts are planted in a film-covered planting method, the bacterial solution is dripped under the film, and the irrigation depth is 8-10cm to moisten the soil.

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