Nanomaterials that promote root elongation and stress tolerance and methods of use and applications thereof

Abstract

The application discloses a nano material related to root elongation and stress resistance and a use method and application thereof, and aims to improve the root length and stress resistance of plants. Specifically disclosed is the use of SPc or a pharmaceutically acceptable salt thereof in improving the root length and / or stress resistance of plants; the SPc or the pharmaceutically acceptable salt thereof is applied to plants, so that the root length and stress resistance of seedling plants can be improved, and the SPc or the pharmaceutically acceptable salt thereof can be used in industrial production.

Description

Technical Field

[0001] This application specifically relates to nanomaterials that promote root elongation and stress resistance, as well as their methods of use and applications. Background Technology

[0002] Promoting early root growth in plants is key to improving crop resistance, nutrient absorption capacity, and overall yield. Existing technologies for promoting early root growth mainly include environmental control, nutrient management, and biostimulation, as detailed below:

[0003] Environmental control mainly includes soil improvement, temperature management, and water control. Soil improvement includes aeration, pH adjustment, and drainage. Aeration can be improved by adding perlite, vermiculite, or organic matter (such as humus and compost) to improve soil structure and prevent compaction. pH adjustment is achieved by maintaining a suitable pH of 5.5-6.5 for most plants; lime can be added to acidic soils, and sulfur powder or organic acids can be used to adjust alkaline soils. Drainage can be improved by mixing gravel into heavy clay soils to prevent waterlogging and root rot. Temperature management mainly includes the optimal temperature for seed germination and root growth. During seed germination, the soil temperature should be maintained at 20-25℃ (25-30℃ for warm-loving crops such as tomatoes). The optimal temperature for root growth should be maintained at 15-25℃ to preserve root vitality (lower temperatures decrease root activity, while higher temperatures promote aging). Water control mainly includes moderate moisture and irrigation methods. Moderate moisture is achieved by maintaining soil humidity at 60-70% (excessive moisture leads to oxygen deficiency, while excessive dryness restricts cell elongation). Irrigation methods such as drip irrigation or subsurface irrigation are superior to flood irrigation, as they promote root growth to deeper roots.

[0004] Nutritional management mainly includes the supply of key elements and the use of organic fertilizers and biostimulants. Key elements include phosphorus, calcium, and trace elements. Phosphorus promotes the development of root tip meristems; therefore, superphosphate or potassium dihydrogen phosphate should be added to the base fertilizer. Calcium strengthens cell wall structure and prevents root tip necrosis (such as calcium deficiency leading to blossom-end rot in tomatoes). Zinc (Zn) and boron (B) participate in the synthesis of root hormones, and foliar spraying has a significant effect. Organic fertilizers and biostimulants mainly include humic acid and seaweed extract. Humic acid stimulates root hair proliferation and enhances nutrient absorption efficiency. Seaweed extract contains natural auxins and cytokinins, promoting lateral root development.

[0005] Hormones and biotechnology include plant growth regulators and microbial symbiosis. Plant growth regulators mainly include auxins, cytokinins, and ethylene inhibitors. Auxins include the use of indoleacetic acid (IAA) and naphthaleneacetic acid (NAA) for seed soaking or root irrigation (concentration 10-50 ppm). Cytokinins include the use of low concentrations of 6-BA (0.1-1 ppm) in synergy with auxins to promote lateral root differentiation. Ethylene inhibitors include the use of AVG (aminoethoxyethyleneglycine) to delay root senescence.

[0006] Microbial symbiosis includes rhizobia and nitrogen-fixing bacteria, mycorrhizal fungi, and PGPR (plant rhizosphere growth promoters). Rhizobia and nitrogen-fixing bacteria improve nitrogen use efficiency by inoculating leguminous plants with rhizobia. Mycorrhizal fungi expand the root system's absorption area and enhance stress resistance (e.g., arbuscular mycorrhizal fungi, AMF). PGPR secrete ACC deaminase to reduce ethylene levels and alleviate stress.

[0007] Cultivation techniques mainly include seed treatment, root pruning and induction, and soilless culture optimization. Seed treatment mainly includes seed soaking for root induction and seed coating. Seed soaking for root induction can break dormancy by soaking in gibberellin (GA3) or warm water (25-30℃). Seed coating can encapsulate fungicides, nutrients, and probiotics in the seeds to protect the seedling roots. Root pruning and induction mainly include root control containers and hardening-off before transplanting. Root control containers stimulate lateral root development through air-induced root pruning (e.g., non-woven fabric bag seedling cultivation). Hardening-off before transplanting promotes root development through moderate drought or low temperature. Soilless culture optimization includes hydroponic nutrient solution and aeroponics. Hydroponic nutrient solution can control the EC value to 1.2-2.0 mS / cm and increase dissolved oxygen (e.g., nanobubble aeration). Aeroponics promotes dense root hair growth by suspending the roots in a high-humidity environment.

[0008] During the seedling stage of plant growth, polymeric materials can significantly promote root elongation and enhance stress resistance (such as drought resistance, salt resistance, and disease resistance) through mechanisms such as improving the rhizosphere environment, regulating nutrient release, and inducing stress resistance signaling pathways. These materials mainly include water-retaining and slow-release types (such as polyacrylamide (SAP) and polyethylene glycol (PEG), which can absorb and retain water to alleviate drought stress and slowly release water and nutrients to maintain the stability of the rhizosphere microenvironment); biostimulant types (such as chitosan and sodium alginate, which can activate plant defense genes (such as PR proteins) and induce root antioxidant enzyme (SOD, CAT) activity to enhance stress resistance); carrier-controlled release types (such as polylactic acid (PLA) and polycaprolactone (PCL), which can load growth hormones (such as IAA, GA3) or trace elements to achieve targeted slow release and precise regulation of root development); and ion-chelating types (such as polyaspartic acid (PASP) and polyglutamic acid (γ-PGA), which can chelate Na in saline soil). + Reduce osmotic stress; adsorb heavy metals (Cd) 2+ Pb 2+ (Reducing toxicity), structurally modified (e.g., cellulose nanocrystals (CNC) and starch-based hydrogels can improve soil aggregate structure and increase permeability; simulate the physical support of root extension and promote lateral root branching)

[0009] Finding a new mechanism to promote plant elongation and enhance plant stress resistance is of great significance to researchers in this field. Summary of the Invention

[0010] The purpose of this application is to provide a method that can increase plant root length and improve plant stress resistance, especially during the seedling stage.

[0011] This application identifies a polymer material that, when applied to plants, can increase root length and enhance plant stress resistance.

[0012] In the first aspect, this application discloses the use of SPc or a pharmaceutically acceptable salt thereof, or nanomaterials containing SPc or a pharmaceutically acceptable salt thereof, in increasing plant root length and / or increasing plant stress resistance;

[0013] The SPc is as shown in formula (I);

[0014]

[0015] The nanomaterials are formed by the self-assembly of SPc and / or its pharmaceutically acceptable salts in solution.

[0016] In some embodiments, the amount of SPc used is 20 mg / L. -1 -30mg L -1 .

[0017] In some embodiments, the amount of SPc used is 20 mg / L. -1 21mg L -1 22mg L -1 23mg L -1 24mg / L -1 25mg L -1 26mg L -1 27mg L -1 28mg L -1 29mg L -1 Or 30mg L -1 .

[0018] In some embodiments, the nanomaterials are formed by the self-assembly of SPc and / or its pharmaceutically acceptable salts in solution followed by high-temperature processing.

[0019] In some embodiments, the high-temperature treatment is performed at a temperature of 121°C.

[0020] In some embodiments, the high-temperature treatment time is 20 minutes.

[0021] In some embodiments, the solvent includes water or a culture medium.

[0022] In some embodiments, the culture medium includes a plant culture medium.

[0023] In some embodiments, the plant culture medium includes MS medium, 1 / 2MS medium, White medium, B5 medium, N6 medium, SH medium, LS medium, Knop medium, or Heller medium.

[0024] In some embodiments, the plant culture medium further includes agarose.

[0025] In some embodiments, the agarose content is 0.5-5 / 100ml.

[0026] In some embodiments, the agarose content is 0.5 / 100ml, 0.6 / 100ml, 0.7 / 100ml, 0.8 / 100ml, 0.9 / 100ml, 1.0 / 100ml, 1.5 / 100ml, 2.0 / 100ml, 2.5 / 100ml, 3.0 / 100ml, 3.5 / 100ml, 4.0 / 100ml, 4.5 / 100ml, or 5.0 / 100ml. As described in this disclosure, a "pharmaceutically acceptable salt" refers to a derivative of the disclosed compound, wherein the parent compound is modified by preparing its acid addition salt or base addition salt. Examples of pharmaceutically acceptable salts include, but are not limited to, inorganic or organic acid salts of basic groups such as amines; and basic or organic salts of acidic groups such as carboxylic acids. Pharmaceutically acceptable salts include conventional non-toxic salts or quaternary ammonium salts of the parent compound, which are prepared, for example, from non-toxic inorganic or organic acids. For example, such conventional non-toxic salts include those derived from inorganic acids, such as hydrochloric acid, hydrobromic acid, sulfuric acid, aminosulfonic acid, phosphoric acid, and nitric acid; and salts prepared from organic acids, such as acetic acid, propionic acid, succinic acid, glycolic acid, stearic acid, lactic acid, malic acid, tartaric acid, citric acid, ascorbic acid, pyric acid, maleic acid, hydroxymaleic acid, phenylacetic acid, glutamic acid, benzoic acid, salicylic acid, p-aminobenzenesulfonic acid, 2-acetoxybenzoic acid, fumaric acid, toluenesulfonic acid, methanesulfonic acid, ethanedisulfonic acid, oxalic acid, and hydroxyethanesulfonic acid.

[0027] In some embodiments, the plant is selected from any of the following:

[0028] (1) Monocotyledons or dicotyledons;

[0029] (2) Poaceae or Brassicaceae;

[0030] (3) The genera *Zea* or *Arabidopsis*;

[0031] (4) Corn or Arabidopsis thaliana;

[0032] (5)(1)-(4).

[0033] In some implementations, the root length is the length of the primary root or the length of the taproot.

[0034] In some implementations, the plant is a seedling.

[0035] In some implementations, the seedling stage is 6-14 days.

[0036] In some implementations, the seedling period is 6 days, 7 days, and / or 14 days.

[0037] In some embodiments, the increase in plant root length is root elongation caused by PIN1 endocytosis.

[0038] In some implementations, the plant resistance is the plant's tolerance to environmental stresses.

[0039] In some implementations, the resistance is the tolerance to abiotic stress.

[0040] In some embodiments, the abiotic stress is selected from salt stress, drought stress, low nitrogen stress, or any combination thereof.

[0041] In some embodiments, the salt stress is NaCl stress.

[0042] In some implementations, the drought stress is PEG stress.

[0043] In some embodiments, the NaCl stress is 125mM-150mM NaCl.

[0044] In some embodiments, the NaCl stress is 125 mM NaCl and / or 150 mM NaCl.

[0045] In some embodiments, the PEG stress is 200mM-250mM PEG.

[0046] In some embodiments, the PEG stress is 200 mM PEG and / or 250 mM PEG.

[0047] In some embodiments, the PEG stress is 20 g / 100 ml PEG.

[0048] In some embodiments, the low nitrogen stress is NO3. - The concentration is 0.05 mM.

[0049] In some implementations, the use includes increasing the root length, fresh weight, germination rate, and / or cotyledon chlorophyll rate of plants.

[0050] In some implementations, the root length is the principal root length, the primary root length, and / or the root tip length.

[0051] In some implementations, the root tip length is the length from the quiescent center to the first hair cell.

[0052] In some implementation schemes, the fresh weight is the above-ground fresh weight.

[0053] On the other hand, this application discloses a plant growth regulating composition comprising the above-mentioned SPc or its pharmaceutically acceptable salt or nanomaterial as an active ingredient.

[0054] In some implementations, the growth regulation is rooting or stress resistance.

[0055] On the other hand, this application discloses a method for improving root length and / or stress resistance in plants, the method comprising the steps of applying the above-mentioned SPc or its pharmaceutically acceptable salt or nanomaterial, the above-mentioned rooting agent and / or the above-mentioned plant stress resistance agent to the plants in the cultivation of cotton plants.

[0056] In some embodiments, the SPc or its pharmaceutically acceptable salt may be used in the following ways: seed soaking, seed irrigation, root soaking, foliar spraying, spraying, composting, coating, flood irrigation, drip irrigation of plants or plant organs, application to plants or plant organs, drip application to plants or plant organs, or any combination thereof.

[0057] In some embodiments, the SPc or a pharmaceutically acceptable salt thereof is administered at a dose of 5 mg / L. -1 Up to 400mg L -1 .

[0058] In some embodiments, the dosage of the SPc or a pharmaceutically acceptable salt thereof is 5 mg / L. -1 25mg L -1 50mg L -1 100mg L -1 200mg L -1 and / or 400mg L -1 .

[0059] In some embodiments, the plant or plant organ is selected from roots, stems, leaves, flowers, fruits, and seeds.

[0060] In some embodiments, the plant or plant organ is selected from any of the following:

[0061] (1) Monocotyledons or dicotyledons;

[0062] (2) Poaceae or Brassicaceae;

[0063] (3) The genera *Zea* or *Arabidopsis*;

[0064] (4) Corn or Arabidopsis thaliana;

[0065] (5)(1)-(4).

[0066] In some implementations, the plant root length is the root length of a seedling.

[0067] In some implementations, the seedling stage is 6-14 days.

[0068] In some implementations, the seedling period is 6 days, 7 days, and / or 14 days.

[0069] In some implementations, the root length is the length of the primary root or the length of the taproot.

[0070] In some embodiments, the maize is maize line ZD958.

[0071] In some embodiments, the corn is cultured under the following conditions for 7 days: 25°C, 16 hours of light, and 8 hours of darkness.

[0072] In some implementations, Arabidopsis thaliana is Arabidopsis thaliana Columbia (Col-0).

[0073] In some implementations, the plant stress resistance is plant seedling stress resistance.

[0074] In some embodiments, the plant resistance is the tolerance to abiotic stress.

[0075] In some embodiments, the abiotic stress is selected from salt stress, drought stress, low nitrogen stress, or any combination thereof.

[0076] In some embodiments, plants treated with the SPc, the rooting agent, and the plant stress resistance reagent exhibit higher stress resistance and / or longer root length compared to plants not treated with the SPc, the rooting agent, and the plant stress resistance reagent.

[0077] On the other hand, this application discloses a method for cultivating plants, the method comprising applying the above-mentioned SPc or its pharmaceutically acceptable salt or nanomaterial, the above-mentioned rooting agent and / or the above-mentioned plant stress resistance agent to plants to obtain plants having roots, stems, leaves, flowers, fruits and seeds.

[0078] In some embodiments, the cultivation method includes soil cultivation and / or hydroponics. The hydroponics method is hydroponics.

[0079] In some embodiments, the SPc or its pharmaceutically acceptable salt may be used in the following ways: seed soaking, seed irrigation, root soaking, foliar spraying, spraying, composting, coating, flood irrigation, drip irrigation of plants or plant organs, application to plants or plant organs, drip application to plants or plant organs, or any combination thereof.

[0080] In some embodiments, the SPc or a pharmaceutically acceptable salt thereof is administered at a concentration of 5 mg / L. -1 Up to 400mg / L -1 .

[0081] In some embodiments, the dosage of the SPc or a pharmaceutically acceptable salt thereof is 5 mg / L. -1 25mg L -1 50mg L -1 100mg L -1 200mg L -1 and / or 400mg L -1 .

[0082] In some embodiments, the plant or plant organ is selected from roots, stems, leaves, flowers, fruits, and seeds.

[0083] In some embodiments, the plant or plant organ is selected from any of the following:

[0084] (1) Monocotyledons or dicotyledons;

[0085] (2) Poaceae or Brassicaceae;

[0086] (3) The genera *Zea* or *Arabidopsis*;

[0087] (4) Corn or Arabidopsis thaliana;

[0088] (5)(1)-(4).

[0089] In some implementations, the plant root length is the root length of a seedling.

[0090] In some implementations, the seedling stage is 6-14 days.

[0091] In some implementations, the seedling period is 6 days, 7 days, and / or 14 days.

[0092] In some embodiments, the maize is maize line ZD958.

[0093] In some implementations, Arabidopsis thaliana is Arabidopsis thaliana Columbia (Col-0).

[0094] In some embodiments, plants treated with the SPc, the rooting agent, and the plant stress resistance reagent exhibit higher stress resistance and / or longer root length compared to plants not treated with the SPc, the rooting agent, and the plant stress resistance reagent.

[0095] In some implementation methods, the application methods include seed soaking, seed irrigation, root soaking, foliar spraying, spraying, composting, coating, flood irrigation, drip irrigation of plants or plant organs, application to plants or plant organs, and drip application to plants or plant organs.

[0096] In some embodiments, the application concentration of SPc is 5 mg / L. -1 Up to 400mg L -1 .

[0097] In some embodiments, the application concentration is 5 mg / L. -1 25mg L -1 50mg L -1 100mg L -1 200mg / L -1 and / or 400mg L -1 .

[0098] In some embodiments, the plant or plant organ is selected from any of the following:

[0099] (1) Monocotyledons or dicotyledons;

[0100] (2) Poaceae or Brassicaceae;

[0101] (3) The genera *Zea* or *Arabidopsis*;

[0102] (4) Corn or Arabidopsis thaliana;

[0103] (5)(1)-(4).

[0104] On the other hand, this application discloses that the rooting agent comprises the SPc described above or a pharmaceutically acceptable salt thereof.

[0105] On the other hand, this application discloses plant stress-resistance agents, which contain the above-mentioned SPc or its pharmaceutically acceptable salts.

[0106] In some embodiments, the rooting agent or plant stress-resistance agent further includes a solvent, wherein the SPc has a weight ratio of 1 / 200000 to 1 / 500.

[0107] In some embodiments, the plant or plant organ is selected from any of the following:

[0108] (1) Monocotyledons or dicotyledons;

[0109] (2) Poaceae or Brassicaceae;

[0110] (3) The genera *Zea* or *Arabidopsis*;

[0111] (4) Corn or Arabidopsis thaliana;

[0112] (5)(1)-(4).

[0113] In some embodiments, the above-described plant growth regulating composition further includes a solvent, wherein the SPc is present in a weight percentage of 1 / 200,000 to 1 / 500 in the composition;

[0114] In some implementations, the SPc has a weight percentage of 1 / 200000, 1 / 40000, 1 / 20000, 1 / 10000 and / or 1 / 500.

[0115] On the other hand, this application provides compositions comprising the above-mentioned SPc and / or pharmaceutically acceptable salts thereof.

[0116] In some embodiments, the plant stress resistance agent is a seedling plant stress resistance agent.

[0117] In some implementations, the seedling stage is 6-14 days.

[0118] In some implementations, the seedling period is 6 days, 7 days, and / or 14 days.

[0119] In some embodiments, the composition, rooting agent, and / or plant stress-resistance agent are formulated as solid or liquid preparations;

[0120] In some embodiments, the composition, rooting agent and / or plant stress resistance agent further includes excipients and / or additives;

[0121] In some embodiments, the excipients include agriculturally or horticulturally acceptable diluents, fillers, solvents, spontaneous accelerators, carriers, emulsifiers, dispersants, thickeners, binders, or any combination thereof;

[0122] In some embodiments, the additive includes agriculturally or horticulturally acceptable preservatives, adjuvants, synergists, microbial additives, antifreeze agents, or any combination thereof.

[0123] In some embodiments, the composition, rooting agent, and / or plant stress resistance agent are liquid formulations;

[0124] In some embodiments, the liquid formulation includes emulsifiable concentrates, soluble concentrates, oils, dispersible liquids, electrostatic spray liquids, suspensions, microcapsule suspensions, oil suspensions, suspension emulsions, water emulsions, microemulsions, nanoemulsions, or any combination thereof;

[0125] In some embodiments, in the liquid formulation, the SPc is in an agriculturally or fertilizer-acceptable carrier;

[0126] In some embodiments, the content of SPc in the liquid formulation is 5 mg / L. -1 -400mg L -1 ;

[0127] In some embodiments, the content of SPc is 5 mg / L. -1 25mg L -1 50mg L -1 100mg L -1 200mg L -1 and / or 400mg L -1 ;

[0128] In some embodiments, the liquid formulation is used for root soaking, foliar spraying, spraying, composting, seed soaking, coating, flood irrigation, drip irrigation of plants or plant organs, application to plants or plant organs, drip application to plants or plant organs, or any combination thereof.

[0129] In some embodiments, the composition, rooting agent, and / or plant stress resistance agent are solid formulations;

[0130] In some embodiments, in the solid dosage form, the SPc is contained in an agriculturally or fertilizer-acceptable carrier;

[0131] In some embodiments, the solid preparation may be used for composting, applying to plants or plant organs, or any combination thereof;

[0132] In some embodiments, the solid dosage form is used to formulate the liquid dosage form described above.

[0133] In some embodiments, in the liquid formulation, the SPc is in an agriculturally or fertilizer-acceptable carrier;

[0134] In some embodiments, the content of SPc in the liquid formulation is 5 mg / L. -1 -400mg L -1 ;

[0135] In some embodiments, the content of SPc is 5 mg / L. -1 25mg L -1 50mg L -1 100mg L -1 200mg L -1 and / or 400mg L -1 ;

[0136] In some embodiments, the liquid formulation is used for root soaking, foliar spraying, spraying, composting, seed soaking, coating, flood irrigation, drip irrigation of plants or plant organs, application to plants or plant organs, drip application to plants or plant organs, or any combination thereof.

[0137] In some embodiments, the composition is a solid dosage form;

[0138] In some embodiments, in the solid dosage form, the SPc is contained in an agriculturally or fertilizer-acceptable carrier;

[0139] In some embodiments, the solid preparation may be used for composting, applying to plants or plant organs, or any combination thereof;

[0140] In some embodiments, the solid dosage form is used to formulate the liquid dosage form described above.

[0141] In some embodiments, the PIN1 protein is expressed in the vascular bundles. The PIN1 protein guides auxin flow to the root tip.

[0142] In some embodiments, the PIN2 protein is expressed in the root tip. The PIN2 protein directs auxin flow to the stem.

[0143] In some embodiments, the PIN3 protein is expressed in the mid-pillar and distal elongation regions. The PIN3 protein directionally modulates auxin flow in response to gravity. Beneficial effects

[0144] In recent years, polymer materials have reached the nanoscale, and star-shaped polycations (SPc) (as shown in Formula 1) have great potential in delivering synthetic plant pesticides, nucleic acids, and nutrients. SPc possesses nanoscale size, good water solubility, biocompatibility, and low cytotoxicity. Its branched four-arm structure with tertiary amine groups greatly enhances dispersion in plant tissues. This dendritic macromolecule and polymer can be rapidly internalized into cells, aiding in the delivery of target molecules. SPc can reduce its overall particle size by forming complexes with target drugs or nucleic acid molecules, thereby improving delivery efficiency. Despite the increasing interest in nanotechnology-based agriculture, little is known about the role of SPc in regulating root growth. This invention elucidates the function of nano-SPc in promoting plant root elongation, thereby enhancing plant stress resistance.

[0145] This application discloses nanomaterials related to promoting root elongation and stress resistance, as well as their usage methods and applications, addressing the technical problem of improving root length and stress resistance in plants. Specifically, it discloses the use of SPc or its pharmaceutically acceptable salts in improving plant root length and / or enhancing plant stress resistance; applying SPc or its pharmaceutically acceptable salts to plants can improve root length and stress resistance in seedlings, and can be used for industrial production. Attached Figure Description

[0146] Figure 1 This is a correlation diagram of how Spc promotes plant root growth and increases plant root length.

[0147] Figure 2 The correlation diagram for improving plant stress resistance by Spc is shown, specifically for abiotic stresses, including NaCl stress, mannitol stress, and low nitrogen stress. Detailed Implementation

[0148] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0149] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0150] The following examples used SPSS 11.5 statistical software to process the data. The experimental results are expressed as mean ± standard deviation. One-way ANOVA was used. P < 0.05 (*) indicates a significant difference, P < 0.01 (**) indicates a highly significant difference, and P < 0.001 (***) indicates a highly significant difference.

[0151] In this invention, unless otherwise stated, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. Furthermore, the terms and laboratory procedures related to protein and nucleic acid chemistry, molecular biology, cell and tissue culture, microbiology, and immunology used herein are all widely used terms and routine procedures in their respective fields. To better understand this invention, definitions and explanations of relevant terms are provided below.

[0152] The terms “comprising, comprises, and comprised of” as used herein are synonymous with “including and includes” or “containing and contains”, and are inclusive or open-ended, and do not exclude additional, unstated members, elements, or method steps. The terms “comprising, comprises, and comprised of” also include the term “composed of”.

[0153] As used herein, the terms “optional,” “optional,” or “optional” generally mean that an event or condition described subsequently may, but may not, occur, and the description includes both cases in which the event or condition occurs and cases in which the event or condition does not occur.

[0154] The terms "first" and "second" used herein are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0155] The term "stress resistance" as used in this article refers to a plant's tolerance to adverse conditions. These adverse conditions include, but are not limited to, salt stress, drought stress, and low nitrogen stress. Tolerance includes, but is not limited to, the ability to maintain normal growth, development, and reproduction. Specifically, this includes, but is not limited to, seed germination rate (seed germination rate, germination speed (germination index), radicle / plumule length, seedling survival rate after germination), seedling / mature plant growth performance (plant height, stem diameter, root length, root volume, biomass (fresh weight and dry weight of aboveground / underground parts), number of leaves, leaf area, specific leaf weight (dry weight of leaves per unit area), leaf phenotypic changes (wilt, yellowing, necrosis, salt spots)), and root characteristics (root-to-shoot ratio (root and aboveground biomass)). Ratios), root activity (dehydrogenase activity measured by TTC method), lateral root density, root hair development), photosynthesis and gas exchange (chlorophyll content (SPAD value or spectrophotometry), photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), intercellular CO2 concentration (Ci), photosystem II efficiency (Fv / Fm, chlorophyll fluorescence parameter), osmotic regulators (proline (Pro) content, soluble sugar (glucose, fructose, sucrose) content, betaine, glycine betaine content, inorganic ions (Na) + K + Ca 2+ Cl - ) concentration and Na + / K + Compared to, antioxidant systems (superoxide dismutase (SOD) activity, peroxidase (POD), catalase (CAT) activity, ascorbate peroxidase (APX) activity, malondialdehyde (MDA) content (degree of membrane lipid peroxidation), and reactive oxygen species (ROS) accumulation (such as H2O2, O2) -Content), hormone response (changes in abscisic acid (ABA), ethylene (ETH) content, cytokinin (CTK), gibberellin (GA) dynamics), cell membrane stability (electrolyte permeability (conductivity method, reflecting cell membrane damage), cytoplasmic membrane permeability (Evans Blue staining method)), gene expression level (expression levels of salt tolerance-related genes (such as SOS1, NHX1, HKT1, P5CS, BADH, etc.), transcription factor activity (such as MYB, NAC, WRKY family), signaling pathway genes (such as MAPK, CDPK, CBL-CIPK pathway)), epigenetic regulation (changes in DNA methylation level, histone modifications (such as acetylation, methylation)), proteomics (differentially expressed proteins (such as osmotic regulatory proteins, antioxidant enzymes), post-translational modifications of proteins (phosphorylation, ubiquitination)), metabolomics (primary metabolites (amino acids, ... Organic acids and sugars), secondary metabolites (flavonoids, phenols, alkaloids), cell ultrastructure (chloroplast structure (thylakoid membrane integrity), mitochondrial morphology (whether the cristae structure is damaged), vacuolar size (ion separation capacity)), cell wall properties (lignin and cellulose content, cell wall elasticity and mechanical strength), salt gland / salt sac structure (salt gland density (e.g., salt excretion structure of halophytes), salt sac secretion capacity), root salt excretion capacity (salt concentration in root exudate, rhizosphere soil salt dynamics), reproductive capacity (flowering time, fruit set rate, seed vigor), salt tolerance index, principal component analysis, cluster analysis.

[0156] Example 1: Preparation and Synthesis of SPc

[0157] The homozygous powder of SPc was obtained from the research group of Shen Jie at China Agricultural University. SPc was synthesized from pentaerythritol as a raw material using a star initiator Pt-Br. The star initiator was then polymerized with DMAEMA, and the homozygous powder of SPc was obtained by dialysis purification. Subsequently, it was dissolved in ddH2O, and the structure of SPc was confirmed by 1H nuclear magnetic resonance (1H NMR). Its molecular weight was analyzed by gel permeation chromatography (GPC), confirming its structure. The specific preparation method of the homozygous SPc powder is described in the following patent: "Patent Name: A Star Polymer and Its Preparation Method and Application, Application No.: 2018103505627, Application Date: 2018-11-13", Publication No.: CN108794710A.

[0158] The SPc structure is shown in Equation 1, which is as follows:

[0159]

[0160] This application provides a method for preparing nanomaterials: adding the above-mentioned SPc homogenate powder to water, allowing SPc to self-assemble in water to form nanomaterials.

[0161] This application also provides a method for preparing nanomaterials: adding the above-mentioned SPc pure powder to water to achieve a SPc concentration of 25 mg / L. -1 This allows SPc to self-assemble into nanomaterials in water.

[0162] This application also provides a method for preparing nanomaterials: adding the above-mentioned SPc homogenate powder to 1 / 2 MS medium to achieve a SPc concentration of 25 mg / L. -1 This allows SPc to self-assemble into nanomaterials in 1 / 2 MS medium.

[0163] This application also provides a method for preparing nanomaterials: adding the above-mentioned SPc homogenate powder to 1 / 2 MS medium to achieve a SPc concentration of 25 mg / L. -1 SPc was allowed to self-assemble in 1 / 2 MS medium, and then subjected to high-temperature treatment at 121℃ for 20 min to obtain nanomaterials.

[0164] This application also provides a method for preparing nanomaterials: adding the above-mentioned SPc homogenate powder to a 1 / 2 MS medium containing 2 g / 100 ml agarose to achieve a SPc concentration of 25 mg / L. -1 SPc was allowed to self-assemble in 1 / 2 MS medium, and then subjected to high-temperature treatment at 121℃ for 20 min to obtain nanomaterials.

[0165] Example 2: Effect of SPc on plant root length

[0166] Plant materials and growing conditions

[0167] Phenotypic observation was conducted using wild-type Arabidopsis thaliana Columbia (Col-0) provided by Professor ST. Tan of the University of Science and Technology of China. After surface sterilization, Arabidopsis thaliana seeds were vertically grown for 6 days on half-strength Murashige and Skoog (1 / 2 MS) medium under conditions of 16 h light / 8 h dark, 22 °C, and 60% humidity to obtain 6-day-old Arabidopsis thaliana.

[0168] Phenotypic observations were conducted using maize strains (ZD958 or Zhengdan 958). The maize strains were cultured on quartz sand for 7 days under conditions of 16 hours of light at 25°C followed by 8 hours of darkness at 18°C. Root length was measured using ImageJ 1.8 (National Institutes of Health, USA).

[0169] External SPc processing:

[0170] corn:

[0171] The above SPc was dissolved and diluted in ddH2O to prepare a solution of 1 g / L. -1 The original solution was diluted to 0 mg / L with ddH2O.-1 SPc aqueous solution, 50 mg / L -1 SPc aqueous solution, 100 mg / L -1 SPc aqueous solution, 200 mg / L -1 SPc aqueous solution, 400 mg / L -1 SPc aqueous solution.

[0172] Seeds from the maize line (ZD958) were used in the experiment, which was divided into 5 groups: 0 mg / L. -1 SPc group, 50mg L -1 SPc group, 100mg / L -1 SPc group, 200mg L -1 SPc group and 400mg L -1 SPc group, 22 plants per group, seeds of maize line (ZD958) were used, and each group was treated with 0 mg L. -1 SPc aqueous solution, 50 mg / L -1 SPc aqueous solution, 100 mg / L -1 SPc aqueous solution, 200 mg / L -1 SPc aqueous solution, 400 mg / L -1 SPc aqueous solution, respectively for 0 mg L -1 SPc group, 50mg L -1 SPc group, 100mg L -1 SPc group, 200mg L -1 SPc group and 400mg L -1 Maize seeds from the SPc group were sown and then seedlings were cultured on quartz sand under conditions of 25°C for 16 hours of light followed by 18°C ​​for 8 hours of darkness. The maize strain was cultured for 7 days, and phenotypes were recorded by photograph. Root length was measured using ImageJ 1.8 (National Institutes of Health, USA). Data were analyzed using SPSS Statistics 22.0 (SPSS Inc., USA) and plotted using GraphPad Prism 8.0 (GraphPad Software). Statistical significance was determined using one-way ANOVA, with Duncan's multiple range test or independent t-test used. p < 0.05 was considered significant. Data are expressed as mean ± SE. Phenotypic results are shown below. Figure 1 As shown in Figure a (0, 50, 100, 200, and 400 represent 0 mg / L), -1 SPc group, 50mg L -1 SPc group, 100mg L -1 SPc group, 200mg L -1 SPc group and 400mg L -1SPc group), primary root length histogram as shown in Figure Figure 1 As shown in b, 200mg L -1 The concentration has the best effect on the elongation of corn roots.

[0173] Primary root length: The length from the root tip to the embryo is measured. The measuring tool is a ruler.

[0174] Arabidopsis thaliana:

[0175] The above SPc was dissolved and diluted in 1 / 2 MS liquid medium to obtain a solution containing 0 mg / L. -1 SPc 1 / 2MS liquid culture medium containing 5 mg L -1 SPc 1 / 2MS liquid culture medium containing 25 mg L -1 SPc 1 / 2MS liquid culture medium containing 50 mg L - 1 SPc 1 / 2MS liquid culture medium containing 100 mg L -1 SPc 1 / 2MS liquid medium.

[0176] Seeds of wild-type Arabidopsis thaliana Columbia (Col-0) were collected, and the experiment was divided into 5 groups, i.e., 0 mg / L... -1 SPc group, 5mg L - 1 SPc group, 25mg L -1 SPc group, 50mg L -1 SPc group and 100mg L -1 SPc group, 25 plants per group, each with 0 mg L -1 SPc group, 5mg L -1 SPc group, 25mg L -1 SPc group, 50mg L -1 SPc group and 100mg L -1 Arabidopsis thaliana from the SPc group were placed at 0 mg / L -1 SPc 1 / 2MS liquid culture medium containing 5 mg L -1 SPc 1 / 2MS liquid culture medium containing 25 mg L -1 SPc 1 / 2MS liquid culture medium containing 50 mg L -1 SPc 1 / 2MS liquid culture medium containing 100 mg L -1SPc was cultured in 1 / 2 MS liquid medium and grown vertically for 6 days under 16h light / 8h dark conditions at 22℃ and 60% humidity. Root length was measured using ImageJ 1.8 (National Institutes of Health, USA). Data were analyzed using SPSS Statistics 22.0 (SPSS Inc., USA) and plotted using GraphPad Prism 8.0 (GraphPad Software). Phenotypic results are shown below. Figure 1 As shown in c (0, 5, 25, 50, and 100 represent 0 mg / L), -1 SPc group, 5mg L -1 SPc group, 25mg L -1 SPc group, 50mg L -1 SPc group and 100mg L -1 SPc group), primary root length bar chart as follows: Figure 1 As shown in d, 25mg L -1 The concentration of SPc has the best effect on the elongation of Arabidopsis roots.

[0177] Microscope imaging

[0178] Furthermore, the primary root tips of Arabidopsis thaliana were observed under a stereomicroscope (Olympus SEX16, Japan). Root tip length was measured from the quiescent center (QC) to the first root hair cell. Stereomicroscopic images of the root tips are shown below. Figure 1 As shown in Figure e, the root tip length histogram is as follows: Figure 1 As shown in f.

[0179] In summary, this invention tested the root performance of SPc in maize and Arabidopsis thaliana. Different concentrations of 0, 50, 100, 200, and 400 mg L were used. -1 After soaking seeds, SPc was grown in water-retaining quartz sand. Phenotypic observation over 7 days revealed that SPc promoted taproot length in a concentration-dependent manner. Compared to the control group, 200 mg L... -1 SPc treatment significantly increased the main root length by 15.17% ( Figure 1 (a, b) Arabidopsis thaliana was placed in solutions containing 0, 5, 25, 50, and 100 mg L. -1 SPc was cultured in half-strength Murashige and Skoog (1 / 2 MS) basal medium for 6 days. Low concentrations promoted the growth of the taproot of seedlings, while high concentrations inhibited the growth of the taproot. Figure 1 (c, d). At 25mg / L -1At the specified concentration, the growth of the taproot of Arabidopsis thaliana increased significantly by approximately 27.73% compared to the control group. Root tip activity and size are key factors determining taproot growth. At 25 mg L... -1 At the specified concentration, the root tip of Arabidopsis thaliana increased by approximately 22.06% compared to the control. Figure 1 (f) This is consistent with the trend of taproot elongation, indicating that meristematic differentiation or rapid cell elongation plays an important role in SPc-induced root elongation. In summary, SPc, as a low-level environmental stress stimulus, can promote taproot elongation by increasing root cell elongation efficiency, which means that SPc affects plant growth and development by participating in certain physiological processes.

[0180] Example 3: Effects of SPc on plant resistance to biological stress

[0181] NaCl was added to 1 / 2 MS solid medium (2% agarose) to obtain 1 / 2 MS solid medium containing 125 mM NaCl and 1 / 2 MS solid medium containing 150 mM NaCl.

[0182] Mannitol was added to 1 / 2 MS solid medium (2% agarose) to obtain 1 / 2 MS solid medium containing 200 mM mannitol and 1 / 2 MS solid medium containing 250 mM mannitol.

[0183] SPc was further dissolved in 1 / 2 MS solid medium containing 125 mM NaCl, 1 / 2 MS solid medium containing 150 mM NaCl, 1 / 2 MS solid medium containing 200 mM mannitol, and 1 / 2 MS solid medium containing 250 mM mannitol to obtain a solution containing 125 mM NaCl and 25 mg L. -1 SPc 1 / 2MS solid medium containing 150mM NaCl and 25mg L -1 SPc 1 / 2 MS solid medium, containing 200 mM mannitol and 25 mg L -1 SPc 1 / 2MS solid medium and containing 250mM mannitol and 25mg L -1 SPc 1 / 2MS solid medium.

[0184] Preparation of 20% PEG solution: Dissolve PEG in ddH2O to make the PEG concentration 20g / 100ml to obtain a 20% PEG solution.

[0185] SPc was further dissolved in a 20% PEG solution to obtain a solution containing 200 mg L. -1 An aqueous solution of SPc and 20% PEG.

[0186] Dissolve NaCl in water to obtain a 150 mM NaCl solution.

[0187] Further dissolving SPc in 150mM NaCl solution yields a solution containing 200mg L. -1 An aqueous solution of SPc and 150 mM NaCl was used. SPc was dissolved to obtain 200 mg / L. -1 An aqueous solution of SPc.

[0188] Infiltration stress:

[0189] The experiment was divided into four groups: a control group, a 125 mM NaCl group, a 150 mM NaCl group, a 200 mM mannitol group, or a 250 mM mannitol group, with 150 Arabidopsis thaliana seeds in each group. Half of the Arabidopsis thaliana seeds from each group were placed in 1 / 2 MS solid medium containing 125 mM NaCl, 150 mM NaCl, 200 mM mannitol, or 250 mM mannitol, respectively. -1 SPc 1 / 2MS solid medium containing 150mM NaCl and 25mg L -1 SPc 1 / 2 MS solid medium, containing 200 mM mannitol and 25 mg L -1 SPc 1 / 2MS solid medium and containing 250mM mannitol and 25mg L -1 SPc was inoculated into 1 / 2 MS solid medium, while the control group was inoculated into 1 / 2 MS solid medium. Both groups were vertically grown for 14 days under conditions of 16 h light / 8 h dark, 22℃, and 60% humidity. Phenotypic data were recorded by photographing, and germination rate, cotyledon greening rate, taproot length, and aboveground fresh weight were calculated. Root length was measured using ImageJ 1.8 (National Institutes of Health, USA). Data were analyzed using SPSS Statistics 22.0 (SPSS Inc., USA) and plotted using GraphPad Prism 8.0 (GraphPad Software).

[0190] And calculate the germination rate: number of germinated seeds / number of seeds sown * 100%.

[0191] Cotyledon greening rate: Number of seedlings with green cotyledons / Number of seeds sown * 100%.

[0192] Primary root length: The length from the tip of the primary root to the root initiation point. The measuring tool used is ImageJ.

[0193] Fresh weight of aboveground parts: Fresh weight of the aboveground parts of Arabidopsis thaliana seedlings. The measuring tool used was a balance with a strength of 0.0001%.

[0194] Phenotypic results Figure 2 In Figure a (125mM NaCl, 150mM NaCl, 200mM mannitol, and 250mM mannitol represent the 125mM NaCl group, 150mM NaCl group, 200mM mannitol group, or 250mM mannitol group, respectively; the control is 1 / 2 MS solid medium without SPc, and SPc is 1 / 2 MS solid medium with SPc), as shown. Under 250mM mannitol, the germination rate of SPc-treated seedlings was significantly higher than that of the untreated control (96.85% vs. 80.77%). Figure 2 (b) Plants treated with SPc also showed higher cotyledon chlorosis rates at 125 mM NaCl (98.26% vs. 97.74%), 200 mM mannitol (84.32% vs. 27.26%), and 250 mM mannitol (4.48% vs. 0%). Figure 2 (c) Under treatments with 100 mM NaCl, 125 mM NaCl, 200 mM mannitol, and 250 mM mannitol, the taproot length increased significantly by 25.89%, 20.74%, 206.99%, and 184.44% compared to the control seedlings, respectively. Figure 2 (d). Compared with the control, the fresh weight of the aboveground parts treated with 100 mM NaCl, 125 mM NaCl, and 200 mM mannitol increased by 26.04%, 19.57%, and 82.84%, respectively. Figure 2 (e).

[0195] The experiment was divided into four groups: a control group, a NaCl group, and a mannitol group. Each group contained 12 maize seeds of line ZD958. Half of the maize seeds of line ZD958 in the control group, NaCl group, and mannitol group were soaked in ddH2O, 20% PEG solution, and 150mM NaCl aqueous solution, respectively. Half of the maize seeds of line ZD958 in the control group, NaCl group, and mannitol group were soaked in 200mg / L water. -1 An aqueous solution of SPc containing 200 mg / L -1 An aqueous solution of SPc and 150mM NaCl and containing 200mg / L -1Seedlings were irrigated with an aqueous solution of SPc and 20% PEG, and then cultured on quartz sand at 25°C under 16 hours of light followed by 8 hours of darkness for 7 days. Phenotypic characteristics and taproot length were recorded by photographing. Root length was measured using ImageJ 1.8 (National Institutes of Health, USA). Data were analyzed using SPSS Statistics 22.0 (SPSS Inc., USA) and plotted using GraphPad Prism 8.0 (GraphPad Software). Phenotypic results are shown below. Figure 2 As shown in Figure j (H2O, NaCl, and PEG represent the control group, NaCl group, and mannitol group, respectively; Control is the solution without SPc, and SPc is the solution with SPc), the primary root length of the NaCl group is shown in Figure j. Figure 2 As shown in the figure (H2O and NaCl are the control group and NaCl group, respectively; Control is the solution without SPc, and SPc is the solution with SPc), the main root length of the mannitol group is as follows: Figure 2 The table below shows the results: (H2O and PEG represent the control group and mannitol group, respectively; Control is the solution without SPc, and SPc is the solution with SPc).

[0196] SPc-induced maize seedlings grown under 150 mM NaCl or 18% PEG conditions also showed increased taproot length compared to the control. Figure 2 jl).

[0197] Main root length: The length from the tip of the primary root to the embryo. It is measured using a ruler.

[0198] Low nitrogen (LN) stress:

[0199] Preparation of low-nitrogen culture medium: Add MS powder (containing only NO3-free materials) - Potassium nitrate dissolves in double-distilled water, causing NO3 to form. - The concentration was 0.05 mM, and the MS concentration was 1× to obtain a low-nitrogen medium.

[0200] Preparation of normal nitrogen medium: Add MS powder (NO3-free only) - Potassium nitrate dissolves in double-distilled water, causing NO3 to form. - The concentration was 10 mM, and the MS concentration was 1× to obtain normal nitrogen medium.

[0201] NO3 in low-nitrogen and normal-nitrogen media - It is the only nitrogen source.

[0202] SPc was further dissolved in a low-nitrogen medium to obtain a solution containing 25 mg L. -1 SPc low-nitrogen medium.

[0203] SPc was further dissolved in normal nitrogen medium to obtain a solution containing 25 mg L. -1 SPc in normal nitrogen medium.

[0204] Seeds of wild-type Arabidopsis thaliana Columbia (Col-0) were collected and divided into four groups: a normal nitrogen group and a low nitrogen group, with 12 plants in each group. Half of the seeds from the normal nitrogen group and the low nitrogen group were placed in normal nitrogen medium and low nitrogen medium, respectively. Further, half of the seeds from the normal nitrogen group and the low nitrogen group were placed in a medium containing 25 mg / L of nitrogen. -1 SPc's normal nitrogen medium and containing 25 mg L -1 SPc was vertically grown for 6 days in a low-nitrogen medium under conditions of 16 h light / 8 h dark, 22 °C, and 60% humidity. Primary root length, fresh weight, and NO in the root elongation zone were measured using ImageJ1.8 (National Institutes of Health, USA). 3- Inflow data were analyzed using SPSS Statistics 22.0 (SPSS Inc., USA) and plotted using GraphPad Prism 8.0 (GraphPad Software).

[0205] NO in the root elongation zone 3- Inflow: Measured using non-destructive ion micrometer (NMT): Root tips of nitrogen-treated Arabidopsis and maize seedlings were cut and equilibrated in a equilibration solution (0.1 mM NH4NO3, 0.1 mM KCl, 0.1 mM CaCl2, 0.3 mM MES, pH 6.0) for 10-20 min. The equilibrated root tips were then fixed in a new petri dish, and 5 mL of test buffer (4 mM Ca(NO3)2 and 0.05 mM Ca(NO3)2) was added. The sample was placed under a microscope, and NO was measured at a distance of 1200 μm from the root tip. 3- Flow rate; once the data stabilizes, begin reading. The test duration is 15 minutes, with NO recorded every 6 seconds. 3- Flow rate.

[0206] Phenotypic results are shown in Figure 2f (NN and LN represent the normal nitrogen group and the low nitrogen group, respectively, where Control or the standard nitrogen group is the medium without SPc, and SPc is the medium with SPc). To determine whether SPc has similar benefits under nutritional stress (…), Figure 2Medium nitrogen (N), medium nitrogen (NN) or normal nitrogen, and low nitrogen (LN) or low nitrogen were designated as normal nitrogen group and low nitrogen group, respectively. Control or standard nitrogen (SNP) was the medium without SPc, and SPc was the medium with SPc. Seedlings grown on low nitrogen (LN) medium showed that, compared to the control, the primary root length of Arabidopsis treated with SPc increased by 22.03%, and the fresh weight increased by 38.50%. Figure 2 Medium nitrogen (g), h, NN or normal nitrogen, and LN or low nitrogen were the normal nitrogen group and the low nitrogen group, respectively. (Control or control was the medium without SPc, and SPc was the medium with SPc). Under normal nitrogen (NN) and LN conditions, SPc-treated Arabidopsis thaliana showed significantly higher NO levels in the root elongation zone. 3 Inflow ( Figure 2 In the 1990s, NN (normal nitrogen) and LN (low nitrogen) groups, the normal nitrogen group and the low nitrogen group were respectively represented. (Control or control was the culture medium without SPc, and SPc was the culture medium with SPc).

[0207] The present invention has been described in detail above. For those skilled in the art, the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. Although specific embodiments have been given, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein. Some of the essential features can be applied within the scope of the following appended claims.

Claims

1. The use of SPc or a pharmaceutically acceptable salt thereof, or nanomaterials containing SPc or a pharmaceutically acceptable salt thereof, in enhancing plant stress resistance; The SPc is as shown in formula (I); ； The nanomaterials are formed by the self-assembly of SPc and / or its pharmaceutically acceptable salts in solution; The improvement of plant stress resistance is achieved as follows (1) or (2): (1) Improve the tolerance of Arabidopsis thaliana or maize to salt stress and / or drought stress; (2) Improve Arabidopsis thaliana’s tolerance to low nitrogen stress.

2. The use as described in claim 1, characterized in that, The uses mentioned in improving plant stress resistance include increasing root length, fresh weight, germination rate and / or cotyledon greening rate.

3. A method for improving plant stress resistance, characterized in that, The method includes, while cultivating the plant, applying the SPc of claim 1 or a pharmaceutically acceptable salt or nanomaterial thereof to the plant; The plant is Arabidopsis thaliana and / or maize; The improvement of plant stress resistance is achieved as follows (1) or (2): (1) Improve the tolerance of Arabidopsis thaliana or maize to salt stress and / or drought stress; (2) Improve Arabidopsis thaliana’s tolerance to low nitrogen stress.

4. The method as described in claim 3, characterized in that, The application methods include seed soaking, seed irrigation, root soaking, foliar spraying, spraying, composting, coating, flood irrigation in the field, adding culture medium, drip irrigation of plants or plant organs, smearing on plants or plant organs, and drip application to plants or plant organs.

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