Method for ferulic acid to improve salt tolerance of pyrus betulaefolia cooper with solibacter and application thereof

Abstract

This invention discloses a method and application for improving the salt tolerance of *Pyrus pyrifolia* in conjunction with ferulic acid and *Bacillus lysinensis*, relating to the field of pear tree stress resistance technology. The method involves simultaneously applying ferulic acid and *Bacillus lysinensis* bacterial solution to the roots of *Pyrus pyrifolia* plants. This invention is the first to construct a technical system for synergistically enhancing plant salt tolerance through phenolic acids and functional bacteria, and has determined that 0.01 mM is the optimal ferulic acid concentration for promoting *Bacillus lysinensis* proliferation. Compared with the application of *Bacillus lysinensis* alone, the combined use of ferulic acid and *Bacillus lysinensis* can significantly reduce the sodium content in *Pyrus pyrifolia*. + Content and Na + / K + This invention improves the ratio of SOD, POD, and CAT antioxidant enzyme activities, reduces MDA content, alleviates leaf yellowing and abscission caused by salt stress, and inhibits root growth, while promoting chlorophyll synthesis and root development. The method is green, environmentally friendly, simple to operate, and low in cost, making it suitable for regulating the salt tolerance of *Pyrus pyrifolia* rootstocks in saline-alkali pear orchards, and has broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of pear tree stress resistance technology, and more specifically to a method and application of ferulic acid synergistically with Bacillus subtilis to improve the salt tolerance of Pyrus pyrifolia. Background Technology

[0002] Duli ( Pyrus betulaefolia (This text appears to be a fragmented collection of unrelated phrases and sentences, making a coherent translation impossible. It includes fragments about pear rootstocks, salt tolerance, and salt tolerance in soil, and a lack of context.) + Salt damage can cause ion toxicity, osmotic imbalance, and oxidative stress, leading to symptoms such as leaf yellowing and abscission, decreased photosynthetic efficiency, and inhibited root growth in pear plants. This severely impacts seedling survival rates and early orchard yields. Therefore, green and efficient salt-tolerant regulation technologies are urgently needed to improve the success rate and yield stability of pear orchards in saline-alkali land.

[0003] Rhizosphere growth-promoting bacteria are important biological resources for improving plant resistance to abiotic stresses. They can enhance plant salt tolerance through nitrogen fixation, phosphorus solubilization, secretion of plant hormones, regulation of ion balance, and activation of antioxidant systems. However, in high-salt field environments, inoculating a single functional bacterium often faces problems such as insufficient rhizosphere colonization, low proliferation efficiency, and unstable stress resistance, limiting their practical application. In recent years, constructing a synergistic regulatory system of functional substances and growth-promoting bacteria mediated by root exudate signaling molecules has become a cutting-edge direction for improving plant salt tolerance. This approach can significantly enhance the survival and colonization of functional bacteria in the rhizosphere, amplifying their growth-promoting and stress-resistance effects.

[0004] Ferulic acid is a typical phenolic acid. Previous studies have shown that salt stress can increase ferulic acid secretion in the roots of *Pyrus pyrifolia*, and there is a certain positive correlation between ferulic acid and the abundance of rhizosphere lysinophils. However, no research has yet combined phenolic acids with lysinophils to construct a technical system that synergistically enhances the salt tolerance of *Pyrus pyrifolia*.

[0005] Based on the above situation, a method is provided to synergistically improve the salt tolerance of pear trees with ferulic acid and lysozyme. Enhancing the stress resistance of pear trees in saline-alkali land and promoting green and efficient production in pear orchards in saline-alkali land are problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for improving the salt tolerance of pear includes the following steps: simultaneously applying ferulic acid and lysozyme solution to the roots of the pear plant.

[0008] Furthermore, the ferulic acid is one or more of isoflavonic acid or trans-isoflavonic acid.

[0009] Furthermore, the application concentration of ferulic acid is 0.01 mM.

[0010] Furthermore, the OD of the lysozyme solution 600 The value is 0.6~0.8, and the application method is root irrigation.

[0011] Furthermore, the lysozyme is *Doctonymycosis* (…). Lysobacter dokdonensis It is deposited at the Guangdong Provincial Center for Microbial Culture Collection, with accession number GDMCC NO. 807941, and has the functions of nitrogen fixation, phosphorus solubilization and auxin secretion.

[0012] Furthermore, the combined use of ferulic acid and lysozyme can significantly reduce Na+ in pear. + Content and Na + / K + The ratio increases the activity of SOD, POD, and CAT antioxidant enzymes, reduces MDA content, and alleviates leaf yellowing, abscission, and root growth inhibition under salt stress.

[0013] Furthermore, the method is applicable to the salt tolerance regulation of grafted pear trees with Pyrus pyrifolia rootstock in saline-alkali land pear orchards.

[0014] Application of a method to improve the salt tolerance of pear in the cultivation of pear trees in saline-alkali land.

[0015] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows: 1) The first construction of a synergistic salt tolerance system of phenolic acids and functional bacteria: For the first time both domestically and internationally, ferulic acid has been publicly demonstrated to promote the proliferation of lysozyme. The synergistic effect of ferulic acid and lysozyme in improving the salt tolerance of pear can effectively alleviate leaf yellowing, leaf drop, and root inhibition under salt and alkali stress, increase chlorophyll content, and promote root development. The innovation is prominent and the patentability is strong.

[0016] 2) Screening for the optimal ferulic acid concentration to promote the proliferation of lysozyme: 0.01 mM was determined to be the optimal concentration for promoting the proliferation of lysozyme, which requires a small amount and is low in cost.

[0017] 3) The salt tolerance mechanism is clear: Bacillus lysate possesses a triple plant growth-promoting function, encompassing nitrogen fixation, phosphorus solubilization, and auxin secretion, thereby enhancing soil nutrient availability and promoting root development. Clearly, compared to Bacillus lysate alone, co-treatment with trans-isoferric acid and Bacillus lysate significantly reduced Na+. + Content, reduce Na + / K + It improves the ratio of SOD, POD, and CAT antioxidant enzyme activity, reduces MDA membrane lipid peroxidation, protects cell membrane structure, and has excellent anti-stress effects.

[0018] 4) Green, safe, and scalable: It does not use chemical regulators, is non-toxic, harmless, and leaves no residue. It is easy to operate and suitable for large-scale promotion in pear orchards in saline-alkali land. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 Changes in the abundance of lysozyme under ferulic acid treatment; Figure 2 OD of different concentrations of isoflavic acid and trans-isoflavic acid against Lysobacterium oxytocin under salt stress 600 The effect of absorbance; Figure 2 A. Trans isoferrulic acid; Figure 2 B. Isoferric acid; Figure 3 The effect of Bacillus lysinensis on the growth of Pyrus pyrifolia under salt stress; Figure 3 A. Aboveground phenotype; Figure 3 B. Root area; Figure 3 C. Root length; Figure 3 D.SPAD; Figure 3 E. Lateral root branch point; Figure 3 F. Number of lateral roots; Figure 4 To investigate the effects of Bacillus subtilis on Na+ in pear under salt stress + and K + The effect of content; Figure 4 A. Above ground K + content; Figure 4 B. Underground section K + content; Figure 4 C. Aboveground Na + content; Figure 4 D. Underground Na + content; Figure 4 E above ground Na + / K + ; Figure 4 F. Underground Na + / K + ; Figure 5 The effects of lysozyme on MDA content and antioxidant enzyme activity in pear under salt stress; Figure 5 A. MDA content; Figure 5 B. SOD activity; Figure 5C. POD activity; Figure 5 D. CAT activity Figure 6 The effect of combined treatment with isoflavic acid / trans-isoflavic acid and lysinogen on the phenotype of aerial parts of Pyrus pyrifolia under normal or saline conditions; Figure 7 The effects of combined treatment with isoflavic acid and trans-isoflavic acid on root structure and chlorophyll content of Pyrus pyrifolia; Figure 7 A. Root area; Figure 7 B. Root length; Figure 7 C. Lateral root branch point; Figure 7 D. Number of lateral roots; Figure 7 E. Chlorophyll content; Figure 8 To investigate the effects of salt stress on *Bacillus subtilis* (Na+) in *Pyrus pyrifolia* + and K + The effect of content; Figure 8 A. Above ground K + content; Figure 8 B. Underground section K + content; Figure 8 C. Aboveground Na + content; Figure 8 D. Underground Na + content; Figure 8 E above ground Na + / K + ; Figure 8 F. Underground Na + / K + ; Figure 9 The effects of isoferrulic acid and trans-isoferrulic acid combined with lysozyme on MDA content and antioxidant enzyme activity in pear; Figure 9 A. MDA content; Figure 9 B. SOD activity; Figure 9 C.POD activity; Figure 9 D.CAT activity. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1: Analysis of the proliferative effect of trans-isoferric acid on lysozyme under salt conditions 1) Take 100 g of soil and divide it into four equal parts. Add sterile water to one part as a control, add 100 mM NaCl solution as a salt treatment, add ferulic acid (0.5 mM isoflavonic acid and 0.5 mM trans-isoflavonic acid, Ferulate) to one part, and add ferulic acid containing 100 mM NaCl (0.5 mM isoflavonic acid and 0.5 mM trans-isoflavonic acid solution, Salt and Ferulate) once every 3 days, 6 mL each time. The soil is placed in an incubator at 25 ℃ for incubation.

[0023] 2) After three treatments, soil samples were collected and subjected to 16S rRNA high-throughput sequencing. The abundance of lysozyme in the soil was analyzed based on the sequencing results.

[0024] See results Figure 1 Under normal culture conditions, ferulic acid treatment (ferulate) did not significantly affect the abundance of lysins compared to the control (CK). However, under salt treatment (Salt), the abundance of lysins increased, and the abundance of lysins reached its highest level after adding ferulic acid (ferulate) under salt treatment conditions, indicating that salt stress can induce an increase in the abundance of lysins; and under salt treatment conditions, ferulic acid further increased the abundance of lysins.

[0025] Correspondence between English and Chinese abbreviations in the accompanying drawings of this invention: FA: Ferulate; IFA: Isoferulic acid; TFA: trans-Ferulic acid; CK: Control, normal; T: Salt; Lys: Lysobacter, a bacterium that lyses bacteria; SPAD: Soil-Plant Analyzer Development, relative chlorophyll level; MDA: Malondialdehyde; SOD: Superoxide Dismutase; POD: Peroxidase; CAT: Catalase.

[0026] Example 2: Screening of the optimal concentration of ferulic acid for promoting the proliferation of lysozyme under salt conditions 1) Lysobacter dokdonensis (GDMCC NO. 807941, Guangdong Provincial Microbial Culture Collection Center) was inoculated into liquid artificial seawater medium and then placed in a constant temperature shaker at 28℃ and 200 rpm for activation.

[0027] 2) Inoculate 2 mL of activated lysinogen into 200 mL of artificial seawater liquid culture medium (containing 100 mM NaCl) containing 0, 0.01, 0.1, and 1 mM isoflavic acid and trans-isoflavic acid, respectively. Incubate at 200 rpm in a 30°C constant temperature shaker, and measure OD every hour. 600 The value is used to detect the proliferation of lysozyme.

[0028] Figure 2 The results showed that under salt treatment conditions, treatment with 0.01 mM isoflavonic acid and trans-isoflavonic acid significantly increased the OD value of lysozyme, followed by 0.1 mM isoflavonic acid and trans-isoflavonic acid. Treatment with 1 mM isoflavonic acid and trans-isoflavonic acid did not significantly increase the OD value of lysozyme. These results indicate that isoflavonic acid and trans-isoflavonic acid can increase the abundance of lysozyme under salt stress, with 0.01 mM isoflavonic acid and trans-isoflavonic acid concentrations being the optimal concentrations for promoting lysozyme proliferation.

[0029] Example 3: Analysis of the effect of Bacillus lysinensis on salt stress tolerance of pear plants 1) The seeds of the wild pear were subjected to vernalization treatment in sand. After vernalization, the seeds were sown in 48-cell pots and placed in a greenhouse for cultivation until 5-7 true leaves were grown.

[0030] 2) Inoculate the activated lysinophils into artificial seawater liquid culture medium, place in a 30°C constant temperature shaker, and incubate at 200 rpm until OD reaches 100%. 600 After reaching a concentration of 0.6~0.8, centrifuge at 5500 rpm (4℃), discard the supernatant, and resuspend in sterile water until the OD value is reached. 600 =0.8.

[0031] 3) Inoculate the resuspended M27 bacterial solution into the root system of pear plants by root irrigation, once every 3 days, 25 mL each time.

[0032] 4) After irrigating with Bacillus lysozyme solution 5 times, use water as a control and treat with 200 mM NaCl solution every 3 days, 25 mL each time, until salt damage phenotype appears. Then remove the plant from the soil, gently sweep the roots to remove excess soil, and put it into a root scanner to analyze indicators such as lateral root branching points, number of lateral roots, root area and root length.

[0033] Figure 3The results showed that, under control conditions, the addition of Bacillus lysate resulted in a smaller root structure, manifested in shorter root length, fewer lateral roots, and a reduced root surface area. Aboveground growth decreased, but chlorophyll content increased. Under salt stress, numerous leaves of the *Pyrus pyrifolia* species turned yellow and fell off, significantly inhibiting underground root development. Root length, number of lateral roots, and root surface area all decreased significantly. Inoculation with Bacillus lysate alleviated leaf yellowing to some extent, but this did not restore plant survival to 100%. However, underground development was significantly improved. Compared to salt conditions, root area increased by 38.3%, root length by 34.2%, lateral root branching points by 31.2%, and the number of lateral roots by 41.3%. These results indicate that inoculation with Bacillus lysate can alleviate the inhibitory effect of salt stress on the growth of *Pyrus pyrifolia*.

[0034] Example 4: Bacillus lysinicus regulates intracellular Na+ + Analysis of salt stress tolerance in pear plants enhanced by ion content and antioxidant enzyme activity 1) Samples were taken from the above-ground and underground parts of the pear tree after the treatment in Example 3.

[0035] 2) The activities of SOD, POD, and CAT, and the content of malondialdehyde (MDA) in plants were detected using the Greens Biotechnology Superoxide Dismutase (SOD)-WST-8 Activity Assay Kit, Peroxidase (POD) Kit, Catalase (CAT) Kit, and Malondialdehyde (MDA) Content Kit.

[0036] 3) Na + and K + Content detection: The sample was washed three times in deionized water, wiped clean with a damp paper towel, and then the aboveground and underground parts were separated and dried in an oven at 110℃ for 2 hours. The samples were then ground using a grinder and placed into dry centrifuge tubes for later use. 0.5g of sample was weighed, placed in a digestion tube, and 5 mL of 100% HNO3 was added. The tube was capped and left to stand overnight. The next day, the sample was heated (170℃) in a temperature-controlled digester until 1 mL of a pale yellow or colorless transparent liquid was obtained. 10 mL of deionized water was added, and the sample was placed in the digester for 5 minutes to remove acid. The solution was then diluted to a final volume of 25 mL in a centrifuge tube for later use. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine the potassium (K) content in the aboveground leaves and underground roots of the plant. + and Na + content.

[0037] Figure 4 The results showed that under normal conditions, after inoculation with Bacillus lysinensis, the aboveground and underground parts of the plant had K + Na +The content did not change significantly. Salt stress led to a decrease in Na+ content in pear trees. + The content increased dramatically, rising 4.6 times in the aboveground parts and 2.1 times in the underground parts compared to the control. However, under salt stress conditions, the Na content in the aboveground parts of *Pyrus pyrifolia* increased significantly. + The content decreased significantly by 28.5% ( Figure 3-3 A), underground Na + The content decreased significantly by 38.9%, but K + The content did not change significantly. Under normal conditions, Na+ content increased after inoculation with lysinic bacteria. + / K + There was no significant difference, but under salt stress, inoculation with lysozyme and salt treatment showed a difference in sodium content. + / K + The levels decreased significantly, by 43.6% and 47.3%, respectively. The results indicate that inoculation with *Lysobacterium* under salt stress significantly reduced Na+ in *Pyrus pyrifolia*. + accumulation.

[0038] Figure 5 The results showed that under normal conditions, the MDA content of *Pyrus pyrifolia* did not change significantly after inoculation with *Bacillus lysinensis*. Under salt stress, the MDA content of *Pyrus pyrifolia* increased significantly, by 69.3% compared with normal conditions; after inoculation with *Bacillus lysinensis*, the MDA content decreased by 32.4% compared with salt stress, returning to the control level. Figure 5 A). Under normal conditions, the activities of SOD, POD, and CAT in *Pyrus pyrifolia* showed no significant changes after inoculation with *Bacillus lysinus*. After salt treatment, the activities of antioxidant enzymes decreased except for CAT, with POD activity showing the largest decrease compared to the control group, decreasing by 77.5%. After inoculation with *Bacillus lysinus*, SOD activity increased by 35.2% compared to salt stress treatment. Figure 5 B), POD activity was significantly increased by 125.6% ( Figure 5 C), CAT activity increased by 25.2% ( Figure 5 D). Based on this, we hypothesize that inoculation with lysozyme under salt treatment can significantly increase antioxidant enzyme activity, eliminate ROS, inhibit MDA content, and improve the salt stress tolerance of pear.

[0039] Example 5: Synergistic treatment of ferulic acid and lysozyme improves the salt tolerance of pear. 1) The seeds of the wild pear were subjected to vernalization treatment in sand. After vernalization, the seeds were sown in 48-cell pots and placed in a greenhouse for cultivation until 5-7 true leaves were grown.

[0040] 2) Inoculate the activated lysinophils into artificial seawater liquid culture medium, place in a 30°C constant temperature shaker, and incubate at 200 rpm until OD reaches 100%. 600 After reaching a concentration of 0.6~0.8, centrifuge at 5500 rpm (4℃), discard the supernatant, and resuspend in sterile water until the OD value is reached. 600 =0.8.

[0041] 3) Inoculate the pear plant roots with 25 mL of resuspended M27 bacterial solution by root irrigation, and add 20 mL of 0.01 mM isoflavonic acid or trans-isoflavonic acid every 5 days.

[0042] 4) After irrigating with lysozyme solution and ferulic acid solution 5 times, with water as a control, treat with 200 mM NaCl solution once every 3 days, 25 mL each time, until the salt damage phenotype appears. Then remove the plant from the soil, gently sweep the roots to remove excess soil, and put it into a root scanner to analyze indicators such as lateral root branching points, number of lateral roots, root area and root length.

[0043] Figures 6-7 The results showed that isoflavonic acid + lysozyme and trans-isoflavonic acid + lysozyme treatments significantly increased leaf chlorophyll content, but had no significant effect on root structure. Under salt stress, *Pyrus pyrifolia* leaves showed severe yellowing and curling. Treatment with isoflavonic acid (trans-isoflavonic acid) + lysozyme significantly improved the aboveground and underground growth of *Pyrus pyrifolia* under salt stress, mainly manifested in increased chlorophyll content, alleviated leaf damage, and increased root length, root surface area, and number of lateral roots. Compared with salt stress treatment, treatment with isoflavonic acid (trans-isoflavonic acid) + lysozyme increased chlorophyll content by approximately 40%, root length by approximately 60%-110%, root surface area by 100%-200%, number of lateral roots by 110%-207%, and lateral root branching points by 100%-160%. Based on the above analysis, compared with the treatment of bacteriolytics alone, the simultaneous application of ferulic acid and bacteriolytics can more significantly promote the development of pear under salt stress and improve the salt stress tolerance of pear.

[0044] Example 6: Physiological mechanism by which synergistic treatment of ferulic acid and lysozyme enhances salt tolerance in pear 1) Samples were taken from the above-ground and underground parts of the pear tree after the treatment in Example 5.

[0045] 2) The activities of SOD, POD, and CAT, and the content of malondialdehyde (MDA) in plants were detected using the Greens Biotechnology Superoxide Dismutase (SOD)-WST-8 Activity Assay Kit, Peroxidase (POD) Kit, Catalase (CAT) Kit, and Malondialdehyde (MDA) Content Kit.

[0046] 3) Na + and K +Content detection: The sample was washed three times in deionized water, wiped clean with a damp paper towel, and then the aboveground and underground parts were separated and dried in an oven at 110℃ for 2 hours. The samples were then ground using a grinder and placed into dry centrifuge tubes for later use. 0.5g of sample was weighed, placed in a digestion tube, and 5 mL of 100% HNO3 was added. The tube was capped and left to stand overnight. The next day, the sample was heated (170℃) in a temperature-controlled digester until 1 mL of a pale yellow or colorless transparent liquid was obtained. 10 mL of deionized water was added, and the sample was placed in the digester for 5 minutes to remove acid. The solution was then diluted to a final volume of 25 mL in a centrifuge tube for later use. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine the potassium (K) content in the aboveground leaves and underground roots of the plant. + and Na + content.

[0047] Figure 8 The results showed that under normal conditions, the Na+ content in the aboveground parts of plants increased after inoculation with isoflavone (trans-isoflavone) + lysozyme. + The content of Na in the underground part did not change significantly. + Slight increase, aboveground K + The content decreased, but the underground K content decreased. + The content increased significantly. Under salt stress, Na+ content increased in both aboveground and underground parts. + Increased content, K + The content decreased; after inoculation with isoflavonic acid (trans-isoflavonic acid) + lysinic acid, the Na content in the aboveground parts of the plant decreased. + Content decreased by 47%-60%, Na in underground parts + The content decreased by approximately 55% under other treatments, except for isoflavonic acid + lysozyme. + The content of all samples increased.

[0048] Under normal conditions, after inoculation with isoflavic acid (trans-isoflavic acid) + lysinic acid, the normal Na+ concentration is increased. + / K + No significant difference was observed in Na under salt stress conditions. + / K + Significantly increased; after inoculation with isoflavic acid (trans-isoflavic acid) + lysozyme, compared with salt treatment, Na+ in both aboveground and underground parts was significantly increased. + / K + Significant decreases were observed, with reductions of 50%-60% and 65%, respectively. The results indicate that, compared to treatment with lysozyme alone, simultaneous application of ferulic acid and lysozyme more significantly reduced Na+ in both aboveground and belowground parts. + Accumulation, thereby improving the tolerance of pear salt stress.

[0049] Figure 9The results showed that under normal conditions, isoflavonic acid (trans-isoflavonic acid) + bacteriolysis treatment had no significant effect on MDA content and POD and CAT activity, but SOD activity decreased. Under salt treatment, the MDA content of *Pyrus pyrifolia* increased, and the activities of antioxidant enzymes decreased significantly. However, after isoflavonic acid (trans-isoflavonic acid) + bacteriolysis treatment, the MDA content decreased significantly by 47.3%-54.9%, while the activities of SOD, POD, and CAT increased by approximately 45%, 60-90%, and 71%-93%, respectively. Based on the above analysis, compared with bacteriolysis treatment alone, the simultaneous application of ferulic acid and bacteriolysis can more significantly enhance antioxidant enzyme activity, reduce MDA accumulation in *Pyrus pyrifolia*, and improve its salt stress tolerance.

[0050] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for improving the salt tolerance of pear, characterized in that, Includes the following steps: Ferulic acid and lysozyme solution were applied to the roots of the pear plant at the same time.

2. The method according to claim 1, characterized in that, The ferulic acid is one or more of isofructose or trans-isofructose.

3. The method according to claim 1, characterized in that, The application concentration of ferulic acid is 0.01 mM.

4. The method according to claim 1, characterized in that, The OD of the lysozyme solution 600 The value is 0.6~0.8, and the application method is root irrigation.

5. The method according to claim 1, characterized in that, The lysozyme is *Doctonymycosis* (…). Lysobacter dokdonensis It has the functions of nitrogen fixation, phosphorus solubilization and auxin secretion.

6. The method according to claim 1, characterized in that, The combined use of ferulic acid and lysozyme can significantly reduce Na+ in pear. + Content and Na + / K + The ratio increases the activity of SOD, POD, and CAT antioxidant enzymes, reduces MDA content, and alleviates leaf yellowing, abscission, and root growth inhibition under salt stress.

7. The method according to claim 1, characterized in that, The method is applicable to the salt tolerance regulation of grafted pear trees with Pyrus pyrifolia rootstock in saline-alkali land pear orchards.

8. The application of the method according to any one of claims 1 to 7 in the cultivation of pear trees in saline-alkali land.

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