A method for promoting the growth of metasequoia and improving its salt tolerance

Abstract

The present application discloses a method for promoting the growth of Metasequoia and improving its salt tolerance, wherein a liquid bacterial agent is directly used to perform root irrigation treatment on Metasequoia; the liquid bacterial agent is a liquid bacterial agent containing Bacillus pseudomycoides JYZ‑SD5 and Schizophyllum Be, or a liquid bacterial agent containing only Schizophyllum Be. Through experiments on the growth and salt tolerance of Metasequoia by single or double inoculation of rhizosphere growth-promoting bacteria Bacillus pseudomycoides JYZ‑SD5 and mycorrhizal fungus Schizophyllum Be, it is confirmed that JYZ‑SD5 and Be can promote the growth of Metasequoia and effectively alleviate salt stress, and double inoculation has the best effect. The present application provides a reference basis for using beneficial microorganisms to improve the salt tolerance of woody plants, and provides a potential approach for the bioremediation and utilization of saline-alkali land.

Description

Technical Field

[0001] The present application relates to the technical field of plant growth promotion, and in particular to a method for promoting the growth of Metasequoia glyptostroboides and improving its salt tolerance. Background Art

[0002] Soil salinization is an increasingly serious soil degradation condition currently faced worldwide. Salt stress can induce osmotic stress, oxidative stress and ion toxicity in plants, interfere with the main metabolic processes of plants, and damage the absorption of water and nutrients by the roots (Paul et al., 2014). At present, how to alleviate or reduce the damage caused by salinization to plants has become one of the key challenges for the effective use of plants to restore the growing saline-alkali land.

[0003] The use of beneficial microorganisms, including plant-growth-promoting rhizobacteria (PGPR), ectomycorrhizal fungi (EMF), leguminous rhizobia, etc., to improve plant salt tolerance has become an alternative means to alleviate plant salt stress and repair saline-alkali land (Berg, 2009). PGPR can directly or indirectly promote plant growth, yield and nutrient absorption through a variety of mechanisms, such as regulating plant physiological processes by fixing nitrogen, dissolving phosphorus, producing iron carriers, producing plant hormones, stimulating plant immunity, and increasing the production of osmotic substances and antioxidant enzymes by plants under adverse conditions (Kumar et al., 2018; Goswami et al., 2020). At present, the research on PGPR to alleviate plant salt stress is mainly focused on herbaceous plants, including tomato (Lycopersicon esculentum), rice (Oryza sativa), wheat (Triticum aestivum), potato (Solanum tuberosum), soybean (Glycinemax) and corn (Zea mays) (Abbas et al., 2019; Kumar et al., 2019). Studies have shown that inoculating camellia (Camellia japonica) with Bacillus licheniformis MH48 or inoculating coconut trees (Cocos nucifera) with Serratia marcescens KiSII and Enterobacter sp. RNF 267 under salt stress can promote tree growth and nutrient absorption, and significantly increase their biomass (George et al., 2013; Park et al., 2017). However, there are still few studies on the effects of these PGPR on the salt tolerance of woody plants.

[0004] EMF is considered to be an important component in alleviating plant salt stress. + The redistribution of nutrients, improvement of plant mineral nutrition, and regulation of plant water transport can improve plant tolerance to stress (Guerrero-Galan et al., 2019). Studies have shown that under salt stress, the Na+ mycorrhizal seedlings of black spruce (Piceamariana), shortleaf pine (Pinus banksiana), American elm (Ulmus americana), Chinese pine (Pin. tabulaeformis) and poplar (Populus) inoculated with EMF increased significantly. + The accumulation of K + The uptake capacity is enhanced, thereby alleviating the damage of salt stress to seedlings (Nguyen et al., 2006; Calvo-Polanco et al., 2008; Wang et al., 2011; Ma et al., 2014; Zwiazek et al., 2019).

[0005] Metasequoia glyptostroboides is a relict plant endemic to China and is known as a "living fossil" of plants. It has been widely introduced and planted at home and abroad for its beautiful tree shape, straight trunk and texture, rapid growth, strong adaptability, and excellent autumn leaves. In recent years, Metasequoia has become the main tree species for urban and rural greening. However, with the expansion of Metasequoia planting area, some sites with high soil salinity have a great impact on the survival rate and growth of Metasequoia seedlings. At present, there are few reports on the use of beneficial microorganisms to improve the adaptability of Metasequoia plants to salt stress. Summary of the invention

[0006] In view of the deficiencies in the prior art, the technical problem to be solved by the present application is to provide a method for promoting the growth of Metasequoia and improving its salt tolerance, by promoting the growth of Metasequoia and improving its salt tolerance through the interaction of Bacillus pseudomycoides JYZ-SD5 and Schizophyllum Be.

[0007] In order to solve the above technical problems, the technical solution adopted in this application is:

[0008] A method for improving the salt tolerance of Metasequoia glyptostroboides comprises directly using a liquid bacterial agent to perform root irrigation treatment on Metasequoia glyptostroboides; the liquid bacterial agent is a liquid bacterial agent containing Bacillus paramycoides JYZ-SD5 and Schizophyllum commune Be, or a liquid bacterial agent containing only Schizophyllum commune Be.

[0009] The method for improving the salt tolerance of Metasequoia glyptostroboides comprises the following steps: firstly, inoculating Schizophyllum Be with a liquid bacterial agent and inoculating the roots with an inoculation amount of 50 mL / plant; and then inoculating Bacillus mycoides JYZ-SD5 with a liquid bacterial agent and inoculating the roots with an inoculation amount of 1×10 10 CFU / strain.

[0010] A method for promoting the accumulation of soluble sugar and soluble protein in Metasequoia leaves comprises directly using a liquid bacterial agent to irrigate the roots of Metasequoia; the liquid bacterial agent is a liquid bacterial agent containing Bacillus mycoides JYZ-SD5.

[0011] A method for promoting the increase of proline content in Metasequoia saplings, comprising directly using a liquid microbial agent to perform root irrigation treatment on Metasequoia saplings; the liquid microbial agent is a liquid microbial agent containing Bacillus pseudomycoides JYZ-SD5 and Schizophyllum Be, or a liquid microbial agent containing only Schizophyllum Be.

[0012] A method for reducing the antioxidant enzyme activity of Metasequoia glyptostroboides comprises directly using a liquid bacterial agent to perform root irrigation treatment on Metasequoia glyptostroboides; the liquid bacterial agent is a liquid bacterial agent containing Bacillus mycoides JYZ-SD5 and / or Schizophyllum Be.

[0013] A change in Metasequoia + / K + The method comprises directly using a liquid bacterial agent to perform root irrigation treatment on Metasequoia; the liquid bacterial agent is a liquid bacterial agent containing Bacillus mycoides JYZ-SD5 and / or Schizophyllum Be.

[0014] A method for promoting the growth of metasequoia includes directly using a liquid bacterial agent to perform root irrigation treatment on metasequoia; the liquid bacterial agent is a liquid bacterial agent containing Bacillus mycoides JYZ-SD5 and Schizophyllum Be, or a liquid bacterial agent containing only Schizophyllum Be.

[0015] The method for promoting the growth of Metasequoia glyptostroboides comprises the following steps: firstly, inoculating with Schizophyllum Be, using a liquid bacterial agent for root inoculation, and the inoculation amount is 50 mL / tree; and 10 days later, inoculating with Bacillus mycoides JYZ-SD5, using a liquid bacterial agent for root inoculation, and the inoculation amount is 1×10 10 CFU / strain.

[0016] Beneficial effects: Compared with the prior art, this application tests the growth and salt tolerance of Metasequoia glyptostroboides by single or double inoculation of rhizosphere growth-promoting bacteria Bacillus pseudomycoides JYZ-SD5 and mycorrhizal fungus Schizophyllum Be, and confirms that strains JYZ-SD5 and Be can promote the growth of Metasequoia glyptostroboides and alleviate salt stress, and double inoculation has the best effect. Strains JYZ-SD5 and Be inhibit the loss of water and increase of membrane permeability of Metasequoia glyptostroboides seedlings under salt stress, reduce the accumulation of free radicals and damage to plant cells, increase the content of osmotic regulating substances, and reduce Na + / K + Among them, the JYZ-SD5 strain has a better effect in improving the osmotic regulation ability of Metasequoia, and the Be strain has the best effect in maintaining the ion balance of Metasequoia. The double inoculation is significantly better than the single inoculation treatment in improving water absorption, maintaining cell membrane stability and alleviating oxidative stress in Metasequoia. This application provides a reference for using beneficial microorganisms to improve the salt tolerance of woody plants and provides a potential way for the bioremediation of saline-alkali land. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a graph showing the effects of Bacillus mycoides JYZ-SD5 and Schizophyllum Be on the growth and root morphology of Metasequoia glyptostroboides.

[0018] Figure 2 This is the result of the effect of Bacillus mycoides JYZ-SD5 and Schizophyllum Be on the salt damage degree and relative water content of Metasequoia leaves under salt stress; in the figure, different lowercase letters indicate significant differences at the 0.05 level, the same below;

[0019] Figure 3 This is the result diagram of the effect of Bacillus mycoides JYZ-SD5 and Schizophyllum Be on the osmotic regulating substances of Metasequoia glyptostroboides under salt stress;

[0020] Figure 4 This is the result diagram of the effect of Bacillus mycoides JYZ-SD5 and Schizophyllum Be on the antioxidant capacity of Metasequoia glyptostroboides under salt stress;

[0021] Figure 5 Effects of Bacillus mycoides JYZ-SD5 and Schizophyllum Be on Na in roots, stems and leaves of Metasequoia glyptostroboides under salt stress + / K + Result diagram of the effect of ratio. DETAILED DESCRIPTION

[0022] The present application is further described below in conjunction with specific embodiments.

[0023] The materials used in the following examples are as follows:

[0024] Rhizobacteria: Bacillus paramycoides JYZ-SD5 was isolated from the rhizosphere of poplar trees in Yucheng, Shandong (CN109355228A, CCTCC NO: M2018469); ectomycorrhizal fungi: Schizophyllum commune (hereinafter referred to as Be) was purchased from the Institute of Microbiology, Chinese Academy of Sciences. The above strains were stored in the Forest Pathology Laboratory of Nanjing Forestry University.

[0025] The March-grown Metasequoia potted seedlings were grown, and the medium was the rhizosphere surface soil of the Beidashan forest of Nanjing Forestry University.

[0026] Example 1

[0027] Preparation of liquid inoculum of Schizophyllum Be: inoculate pure culture of Schizophyllum Be into ZPD solid culture medium, place in fungal incubator at 25℃ for 7d; make holes with a cork hole (5mm), take out the mycelium blocks from the plate, culture with ZPD liquid culture medium, place 10 blocks per 1000mL, and culture on a shaker (25℃, 180rpm) for 7d; break the mycelium balls with a blender; take the bacterial solution into a 50mL centrifuge tube, incubate at 25℃, 8000r / min, 10min, discard the supernatant, and wash twice with 10mL of deionized water, 25℃, 8000r / min, 5min; resuspend the bacterial pellet in an equal volume of deionized water, oscillate and mix well for later use.

[0028] Liquid inoculum of Bacillus mycoides JYZ-SD5: shake the strain JYZ-SD5 in liquid LB medium for 12 hours as a seed solution; inoculate the seed solution into the LB medium at an inoculum size of 1%, place it on a shaker for shaking culture (28°C, 200rpm) for 12 hours, and obtain the fermentation liquid of the bacterial strain JYZ-SD5; take the fermentation liquid into a 50mL centrifuge tube, centrifuge at 25°C, 8000r / min, 10min, discard the supernatant, and wash twice by centrifugation with 10mL of deionized water, 25°C, 8000r / min, 5min; resuspend the bacterial pellet in an equal volume of deionized water, oscillate and mix well for later use.

[0029] 1. Treatment with mixed liquid microbial agents: In May 2020, Metasequoia was treated with microbial agents. First, Schizophyllum Be was inoculated, and the inoculation volume was 50 mL per pot. Ten days later, Bacillus mycoides JYZ-SD5 was inoculated, and the inoculation volume was 1×10 10 CFU / strain.

[0030] 2. Treatment of Metasequoia glyptostroboides with liquid inoculum Be alone: ​​Liquid inoculum Be was used for root inoculation with an inoculation volume of 50 mL per pot.

[0031] 3. Treatment of Metasequoia glyptostroboides with Bacillus mycoides JYZ-SD5 liquid inoculant alone: ​​liquid inoculant was used for root inoculation, with an inoculum volume of 1×10 10 CFU / strain.

[0032] 4. Blank (CK) Metasequoia glyptostroboides bacteria treatment method: no bacteria were applied, and the same volume of water was used instead of the bacterial solution.

[0033] 5. Salt stress treatment: The plants were inoculated with bacteria for 60 days (treatments 1, 2, and 3 above) and subjected to salt stress treatment to make the soil salt content reach 0.3%. A total of 5 treatments were set up, namely, non-inoculated control under non-salt stress (CK), non-inoculated control under salt stress (NaCl+CK), single inoculation of JYZ-SD5 under salt stress (NaCl+JYZ-SD5), single inoculation of Be under salt stress (NaCl+Be), and double inoculation of JYZ-SD5+Be under salt stress (NaCl+JYZ-SD5+Be), with 6 replicates for each treatment. The height and ground diameter growth of Metasequoia were measured and recorded before the application of bacteria and before the salt stress treatment; the root system of Metasequoia was scanned and analyzed before salt stress; the appearance of Metasequoia was observed 5 days after salt stress and other related indicators were measured.

[0034] 6. The specific methods for determining relevant indicators are as follows:

[0035] Determination of growth indexes of Metasequoia glyptostroboides: The plant height and new shoot growth of Metasequoia glyptostroboides were measured with a tape measure (cm), and the ground diameter was measured with a vernier caliper (mm). Three replicates were performed.

[0036] Determination of root growth parameters of Metasequoia: Take the Metasequoia seedlings out of the pots, shake off the surface soil, rinse the roots with tap water, dry the surface moisture of the roots with absorbent paper, scan the roots with EPSON.EXPRESSION1680 scanner (EPSON, Japan), and then use Win RHIZO2003b root analysis software to analyze the root length, root surface area, root volume, average root diameter, total root tip number and branch number of Metasequoia root system in each treatment. Three replicates were performed.

[0037] Salt damage degree of Metasequoia: The damage degree of Metasequoia was observed according to the salt damage classification standard of Huo Jianan et al. (2012). The salt damage levels are divided into: Level 1: The leaves of the plant are normal, without yellowing; Level 2: Some leaf tips and leaf edges of the plant turn yellow and dry, and the wilting of leaves accounts for 50% or less of the total; Level 3: Most leaves are scorched, and the wilting of leaves accounts for 50% to 80% of the total; Level 4: The whole plant is yellow, the leaves are withered and fallen, and even the whole plant is dead. Six plants were observed in each treatment.

[0038] Relative moisture content of Metasequoia: Take fresh Metasequoia leaves, measure their weight (Wf), then immerse the leaves in distilled water for 10 hours, take them out and dry the moisture on the leaf surface with absorbent paper, weigh them, immerse the Metasequoia leaves in distilled water for 1 hour, take them out and dry them, weigh them, until the saturated weight of Metasequoia leaves is close, which is the saturated fresh weight of Metasequoia leaves (Wt), then wrap Metasequoia leaves with tin foil and place them in an oven at 85℃ for 10 hours to get the dry biomass of Metasequoia leaves (Wd). Repeat 3 times. The calculation formula is as follows:

[0039] Relative water content (RWC) = (Wf-Wd) / (Wt-Wd)*100% Osmotic regulating substances in Metasequoia glyptostroboides leaves: Soluble sugar content was determined by anthrone colorimetry, soluble protein content was determined by BCA method, and proline content was determined by acid ninhydrin method. The above indicators were determined and calculated according to the kit (Suzhou Keming Biotechnology Co., Ltd.).

[0040] Antioxidant related indicators of Metasequoia leaves: Superoxide dismutase (SOD) activity was determined by nitroblue tetrazolium method, peroxidase (POD) activity was determined by guaiacol colorimetry, catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) activities were determined by ultraviolet absorption method, hydrogen peroxide (H2O2) was determined by titanium sulfate colorimetry, superoxide anion (O 2- The above indicators were measured and calculated according to the kit (Suzhou Keming Biotechnology Co., Ltd.). Electrolyte leakage was measured using a conductivity meter (FE38, Shanghai) (Yang et al., 2016), and malondialdehyde (MDA) content was measured using the thiobarbituric acid method (Li Hesheng, 2000).

[0041] Metasequoia + , K +Content: Collect the roots, stems and leaves of Metasequoia glyptostroboides from each treatment, fix them in an oven at 105℃ for 15min, and dry them at 75℃ to constant weight; grind and pass through a 40-mesh sieve; take 0.1g Metasequoia glyptostroboides tissue in a digestion tube, add 4mL of mixed acid (HNO3:HCIO4=5:1), shake well, put a bent-neck funnel on the bottle mouth, and let it stand overnight; digest on a digestion furnace in a fume hood, keep it in a slightly boiling state at the beginning, release a large amount of brown NO2 gas, and raise the furnace temperature after the brown gas disappears to dehydrate SiO2 until white smoke appears until the white smoke almost disappears and the solution becomes clear; after digestion, wait for the solution to cool, add 4mL of deionized water, filter it into a 25mL volumetric flask with quantitative filter paper, wash the digestion tube with deionized water 3 times and filter it, finally make up to volume with deionized water, shake well, and use it as the test solution. Atomic absorption spectrometer (AA900T, USA) was used to determine the Na in the test solution. + , K + 3 replicates.

[0042] 7. Data Analysis

[0043] Excel 2019, prism cracked and PS software were used to analyze and plot the experimental data. SPSS21.0 software was used for significant difference analysis (Duncan method, P < 0.05). The data in the charts are mean ± standard deviation.

[0044] 8. Results

[0045] 1) Inoculation with strains JYZ-SD5 and Be significantly increased the biomass of Metasequoia seedlings. Compared with the control seedlings, the plant height growth of Metasequoia seedlings inoculated with JYZ-SD5 alone increased by 28.95%, and that of seedlings inoculated with Be alone and with JYZ-SD5+Be increased significantly by 61.65% and 65.47%, respectively (P<0.05). The ground diameter growth of the above three treatments increased significantly by 52.4%, 79.81%, and 63.46%, respectively (P<0.05) (Table 1, Figure 1 A).

[0046] Table 1 Effects of Bacillus mycoides JYZ-SD5 and Schizophyllum Be on the biomass of Metasequoia glyptostroboides

[0047]

[0048]

[0049] Different lowercase letters in the same column indicate significant differences at the 0.05 level. The same below.

[0050] Compared with the control seedlings, single inoculation with JYZ-SD5 increased the root length, root surface area, root volume, average root diameter and number of branches of Metasequoia seedlings, but not significantly. Only the total number of root tips increased significantly by 60.56% (P < 0.05). Single inoculation with Be significantly increased the root length (1.39 times), root surface area (88.15%), total number of root tips (1.11 times) and number of branches (1.2 times) of Metasequoia seedlings (P < 0.05). Double inoculation with JYZ-SD5 and Be significantly increased the root length (1.04 times), root surface area (1.51 times), root volume (2.2 times), total number of root tips (1.88 times) and number of branches (2.31 times) of Metasequoia seedlings (P < 0.05) (Table 2, Figure 1 B). This indicates that the inoculation of strains JYZ-SD5 and Be can promote the growth of seedling roots, and the effect of double inoculation is significantly better than that of single inoculation.

[0051] Table 2 Effects of Bacillus mycoides JYZ-SD5 and Schizophyllum Be on root growth parameters of Metasequoia glyptostroboides

[0052]

[0053] 2) Under salt stress, most of the leaves of the uninoculated Metasequoia turned yellow and wilted, and were severely damaged, showing obvious signs of salt damage; while the damage degree of the leaves of the single-grafted and double-grafted Metasequoia was lower than that of the uninoculated treatment, and the degree of salt damage was significantly reduced ( Figure 2 A). This indicates that inoculation with strain JYZ-SD5 and Be can effectively alleviate the damage of salt stress to plants, and double inoculation has the best effect.

[0054] At the same time, the results showed that compared with CK, the RWC of Metasequoia saplings treated with NaCl+CK was significantly reduced by 68.9% (P<0.05). However, the RWC of Metasequoia saplings treated with NaCl+JYZ-SD5, NaCl+Be, and NaCl+JYZ-SD5+Be was significantly increased by 56.22%, 79.54%, and 100.02% (P<0.05) respectively compared with NaCl+CK ( Figure 2 B). This indicates that salt stress causes severe water loss in Metasequoia glyptostroboides, and inoculation with strains JYZ-SD5 and Be can promote effective water absorption in seedlings under salt stress, with double inoculation achieving the highest result.

[0055] 3) Compared with CK, the soluble sugar and proline of Metasequoia glyptostroboides seedlings treated with NaCl+CK increased significantly by 27.79% and 109.09% (P<0.05), respectively, and the soluble protein increased by 38.71%. Under salt stress, strain JYZ-SD5 and Be inoculation can increase the osmotic regulating substances of Metasequoia glyptostroboides to maintain osmotic balance and improve the tolerance of seedlings to osmotic stress. The soluble sugar, soluble protein and proline of Metasequoia saplings treated with NaCl+JYZ-SD5 were significantly increased by 12.4%, 62.58% and 38.99% (P<0.05), respectively. The soluble sugar, soluble protein and proline of Metasequoia saplings treated with NaCl+Be and NaCl+JYZ-SD5+Be were significantly decreased by 33.49% and 37.71% (P<0.05), respectively. The soluble protein was significantly decreased by 47.08% and 48.67% (P<0.05), respectively. The proline was significantly increased by 122% and 35.64% (P<0.05), respectively. Figure 3 ). This indicates that strain JYZ-SD5 can widely increase the content of various osmotic regulating substances in Metasequoia, while strain Be has a particularly significant effect on the content of proline.

[0056] 4) Compared with CK, the H2O2 content and O 2- The production rates of NaCl+CK and JYZ-SD5 were significantly increased by 1.04 and 1.49 times, respectively (P<0.05). 2- The production rates were significantly reduced by 26.58% and 9% (P < 0.05), NaCl + Be was reduced by 8.91% and 7.77%, and NaCl + JYZ-SD5 + Be was significantly reduced by 15.58% and 26.38% (P < 0.05). Obviously, the effect of double inoculation of JYZ-SD5 and Be on reducing the accumulation of active oxygen in Metasequoia glyptostroboides to alleviate oxidative stress under salt stress was significantly better than that of single inoculation ( Figure 4 A, B).

[0057] 5) Compared with CK, the electrolyte leakage and MDA content of Metasequoia seedlings treated with NaCl+CK increased significantly by 8.55 times and 69.32% (P<0.05), respectively. Compared with NaCl+CK, the MDA content of Metasequoia seedlings treated with NaCl+Be decreased by 8.54%, and NaCl+JYZ-SD5 and NaCl+JYZ-SD5+Be decreased significantly by 15.85% and 53.66%, respectively (P<0.05). The electrolyte leakage of the above three treatments decreased significantly by 18.76%, 22.09% and 30.39%, respectively (P<0.05). This shows that the ability of double inoculation of JYZ-SD5 and Be to maintain the stability of the cell membrane of Metasequoia seedlings under salt stress and reduce the level of membrane lipid peroxidation to alleviate salt stress is significantly better than that of single inoculation treatment ( Figure 4 C, D).

[0058] 6) Compared with CK, the activities of SOD, POD, CAT, APX and GR in the Metasequoia saplings treated with NaCl+CK were significantly increased by 2.84 times, 2.25 times, 1.19 times, 2.94 times and 38.32% respectively (P<0.05). Under salt stress, each inoculation treatment can significantly improve the biological activity of Metasequoia leaves, alleviate the oxidative stress of the plants themselves, and thus reduce the level of antioxidant enzymes in the plants. Compared with NaCl+CK, the SOD activities of Metasequoia glyptostroboides seedlings treated with NaCl+JYZ-SD5, NaCl+Be and NaCl+JYZ-SD5+Be were significantly reduced by 41.76%, 52.14% and 25.37% (P<0.05), the POD activities were significantly reduced by 31.32%, 43.52% and 73.48% (P<0.05), the CAT activities were significantly reduced by 9.61%, 8.76% and 18.13%, the APX activities were significantly reduced by 78.43%, 71.8% and 76.37% (P<0.05), and the GR activities were significantly reduced by 73.63%, 74.63% and 76.67% (P<0.05) ( Figure 4 EI).

[0059] 7) Compared with CK, NaCl+CK treatment had a significant effect on the Na content of roots, stems and leaves of Metasequoia glyptostroboides seedlings. + Compared with NaCl+CK, the NaCl+JYZ-SD5 and NaCl+Be treatments increased the Na + The contents of NaCl+JYZ-SD5+Be treatment were significantly decreased by 10.33% and 10.13% (P<0.05), and increased by 8.68% (P<0.05). + The contents in the roots of JYZ-SD5 and Be decreased by 9.22%, 10.44% and 7.43% respectively (P<0.05), and increased by 71.39%, 15.36% and 41.04% respectively (P<0.05). + Retention in the roots reduces the aboveground Na + The transport of NaCl+JYZ-SD5 in the root + The content is the highest, but the Na content in the aboveground stems and leaves is + There was no significant difference in content between the treatments with NaCl+Be (P<0.05) (Table 3).

[0060] Table 3 Effects of Bacillus mycoides JYZ-SD5 and Schizophyllum Be on Na in roots, stems and leaves of Metasequoia glyptostroboides under salt stress +, K + The influence of content

[0061]

[0062]

[0063] Compared with CK, the K content of roots and leaves of Metasequoia glyptostroboides treated with NaCl+CK was significantly higher than that of CK. + The contents of K in the leaves of Metasequoia glyptostroboides treated with NaCl+JYZ-SD5 were significantly reduced by 57.7% and 15.34% (P<0.05), while those in the stems increased by 7.75%. + The content of K in the stems of the three treatments increased by 4.05%, and the treatments of NaCl+Be and NaCl+JYZ-SD5+Be increased significantly by 22.33% and 16.1%, respectively (P<0.05). + The contents in the roots of Metasequoia glyptostroboides were significantly increased by 12.45%, 17.66% and 12.07% (P < 0.05), and those in the roots were significantly increased by 36.53%, 21.54% and 28.61% (P < 0.05). + The content had the best effect (Table 3).

[0064] Compared with CK, NaCl+CK treatment had a significant effect on the Na content in the roots, stems and leaves of Metasequoia glyptostroboides seedlings. + / K + Compared with NaCl+CK, the NaCl+Be treatment of Metasequoia glyptostroboides significantly increased the Na + / K + The NaCl+JYZ-SD5 and NaCl+JYZ-SD5+Be treatments significantly increased the NaCl+JYZ-SD5 and NaCl+JYZ-SD5+Be treatments by 25.7% and 9.72% (P<0.05). + / K + The contents in the roots, stems and leaves of Metasequoia glyptostroboides were significantly reduced by 23.84%, 19.2% and 17.4% (P < 0.05), and those in the leaves were significantly reduced by 26.58%, 13.8% and 6.41% (P < 0.05). + / K + The effect of the treatment was significantly better than that of NaCl+JYZ-SD5 and NaCl+JYZ-SD5+Be, with significant difference (P<0.05)( Figure 5 ), indicating that single inoculation of Be effectively improved the tolerance of seedlings to ion toxicity.

Claims

1. A method for improving the salt tolerance of Metasequoia glyptostroboides, characterized in that: Directly use liquid bacterial agent to carry out root irrigation treatment on Metasequoia; the liquid bacterial agent is a liquid bacterial agent containing Bacillus mycoides JYZ-SD5 and Schizophyllum Be, or a liquid bacterial agent containing only Schizophyllum Be.

2. The method for improving the salt tolerance of Metasequoia glyptostroboides according to claim 1, characterized in that: The Metasequoia trees were inoculated with Schizophyllum Be first, using a liquid inoculum to irrigate the roots with an inoculation volume of 50 mL / plant. Ten days later, Bacillus mycoides JYZ-SD5 was inoculated, using a liquid inoculum to irrigate the roots with an inoculation volume of 1×10 10 CFU / strain.

3. The method for improving the salt tolerance of Metasequoia glyptostroboides according to claim 1, characterized in that: Directly use liquid bacterial agent to carry out root irrigation treatment on Metasequoia glyptostroboides to promote the accumulation of soluble sugar and soluble protein in Metasequoia glyptostroboides leaves; the liquid bacterial agent is a liquid bacterial agent containing Bacillus pseudomycoides JYZ-SD5.

4. The method for improving the salt tolerance of Metasequoia glyptostroboides according to claim 1, characterized in that: Directly use liquid microbial agent to carry out root irrigation treatment on Metasequoia glyptostroboides to promote the increase of proline content in Metasequoia glyptostroboides seedlings; the liquid microbial agent is a liquid microbial agent containing Bacillus pseudomycoides JYZ-SD5 and Schizophyllum Be, or a liquid microbial agent containing only Schizophyllum Be.

5. The method for improving the salt tolerance of Metasequoia glyptostroboides according to claim 1, characterized in that: Directly use liquid bacterial agent to irrigate the roots of Metasequoia glyptostroboides to reduce the antioxidant enzyme activity of Metasequoia glyptostroboides; the liquid bacterial agent is a liquid bacterial agent containing Bacillus mycoides JYZ-SD5 and / or Schizophyllum Be.

6. A method for promoting the growth of Metasequoia glyptostroboides, characterized in that: Directly use liquid bacterial agent to carry out root irrigation treatment on Metasequoia; the liquid bacterial agent is a liquid bacterial agent containing Bacillus mycoides JYZ-SD5 and Schizophyllum Be, or a liquid bacterial agent containing only Schizophyllum Be.

7. The method for promoting the growth of Metasequoia glyptostroboides according to claim 6, characterized in that: The Metasequoia trees were inoculated with Schizophyllum Be first, using a liquid inoculant to irrigate the roots at a rate of 50 mL / tree. Ten days later, Bacillus mycoides JYZ-SD5 was inoculated, using a liquid inoculant to irrigate the roots at a rate of 1×10 10 CFU / strain.

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