Root system elongation promoting and stress resistance related nanometer material and using method and application thereof

Abstract

The invention discloses a related nano material for promoting root system elongation and stress resistance as well as a use method and application thereof. The technical problem to be solved is to improve the root length and stress resistance of plants. Specifically, the invention discloses application of SPc or pharmaceutically acceptable salt thereof in increasing plant root length and / or improving plant stress resistance. The SPc or the pharmaceutically acceptable salt thereof is applied to plants, so that the root length and the stress resistance of the plants at the seedling stage can be improved, and the SPc or the pharmaceutically acceptable salt thereof can be applied to industrial production.

Description

TECHNICAL FIELD

[0001] The present application specifically relates to nanomaterials that promote root elongation and stress resistance, and methods of use and applications thereof. BACKGROUND

[0002] Promoting early root growth of plants is a key to improving crop stress resistance, nutrient absorption capacity and overall yield. The existing technology for promoting early root growth of plants mainly includes environmental regulation, nutrient management, and biological stimulation, as follows:

[0003] Environmental regulation mainly includes soil improvement, temperature management and water control. Soil improvement includes air permeability, pH adjustment and drainage. Air permeability can be improved by adding perlite, vermiculite or organic matter (such as humus, compost), improving soil structure and avoiding hardening. pH adjustment can be achieved by adding lime to acidic soil and sulfur powder or organic acid to alkaline soil, as most plants prefer a pH of 5.5-6.5. Drainage can be achieved by mixing sand into heavy clay soil to prevent waterlogging and root rot. Temperature management mainly includes seed germination period and root growth temperature. The seed germination period is maintained at 20-25°C (warm crops such as tomatoes require 25-30°C). Root growth temperature is maintained at 15-25°C to maintain root activity (low temperature reduces root activity, and high temperature causes root aging). Water control mainly includes moderate humidity and irrigation methods. Moderate humidity is maintained at 60-70% (excessive humidity leads to oxygen deficiency, and excessive dryness limits cell elongation). Drip irrigation or seepage irrigation is better than flooding irrigation to promote root growth in deep soil.

[0004] Nutrient management mainly includes key element supply and organic fertilizer and biological stimulants. Key element supply includes phosphorus, calcium and trace elements. Phosphorus can promote root tip meristem development, and overlimed phosphate or dihydrogen potassium phosphate can be added to base fertilizer. Calcium can enhance cell wall structure and prevent root tip necrosis (such as tomato collar rot caused by calcium deficiency). Zinc (Zn) and boron (B) are involved in root hormone synthesis, and foliar spraying has a significant effect. Organic fertilizer and biological stimulants mainly include humic acid and seaweed extract. Humic acid can stimulate root hair proliferation and enhance nutrient absorption efficiency. Seaweed extract contains natural auxins and cytokinins, which promote lateral root development.

[0005] Hormones and biological technology include plant growth regulators and microbial symbiosis. Plant growth regulators mainly include auxins, cytokinins and ethylene inhibitors. Auxins include the use of indole acetic acid (IAA) and naphthalene acetic acid (NAA) for seed soaking or root irrigation (concentration 10-50 ppm). Cytokinins include the use of low-concentration 6-BA (0.1-1 ppm) in combination with auxins to promote lateral root differentiation. Ethylene inhibitors include the use of AVG (aminoethoxy ethylene glycine) to delay root aging.

[0006] Microbial symbiosis includes rhizobium and nitrogen-fixing bacteria, mycorrhizal fungi and PGPR (plant growth-promoting rhizobacteria). Rhizobium and nitrogen-fixing bacteria improve nitrogen utilization by inoculating rhizobium on legume plants. Mycorrhizal fungi include expanding root system absorption area and enhancing stress resistance (such as arbuscular mycorrhizal fungi AMF). PGPR (plant growth-promoting rhizobacteria) includes secreting 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 and coating technology. Seed soaking can break dormancy by soaking with gibberellin (GA3) or warm water (25-30℃). Coating technology can wrap seeds with fungicides, nutrients and probiotics to protect seedling roots. Root pruning and induction mainly include root control containers and pre-transplanting seedling training. Root control containers stimulate lateral root formation by air root cutting (such as non-woven bag seedling). Pre-transplanting seedling training promotes root development through moderate drought or low temperature training. Soilless culture optimization includes hydroponic nutrient solution and air mist cultivation. Hydroponic nutrient solution can control EC value 1.2-2.0 mS / cm and increase dissolved oxygen (such as nano-bubble oxygenation). Air mist cultivation promotes the growth of root hairs by exposing the roots to a high-humidity environment.

[0008] In seedling stage plant growth, high molecular materials can significantly promote root elongation and enhance stress resistance (such as drought resistance, salt resistance, disease resistance) through mechanisms such as improving rhizosphere environment, regulating nutrient release, and inducing stress resistance signaling pathways. Mainly include water-retaining and slow-release type (such as polyacrylate (SAP), polyethylene glycol (PEG), which can absorb water and retain water, alleviate drought stress; slowly release water and nutrients, maintain the stability of rhizosphere microenvironment), biological stimulation type (such as chitosan, sodium alginate, which can activate plant defense genes (such as PR proteins), induce root antioxidant enzyme (SOD, CAT) activity, and enhance stress resistance), carrier controlled release type (such as polylactic acid (PLA), polycaprolactone (PCL), which can load growth hormones (such as IAA, GA3) or trace elements, achieve targeted slow release, and accurately regulate root development), ion chelation type (such as polyaspartic acid (PASP), polyglutamic acid (γ-PGA), which can chelate Na + in saline soil, reduce osmotic stress; adsorb heavy metals (Cd 2+ , Pb 2+ ), reduce toxicity), structure improvement type (graphene cellulose nanocrystals (CNC), starch-based hydrogel, improve soil aggregate structure and increase air permeability; simulate the physical support of root extension, promote lateral root branching)

[0009] It is of great significance to find a new mechanism for promoting plant elongation and improving plant stress resistance for those skilled in the art. SUMMARY

[0010] The application achieves the purpose of providing a method capable of improving plant root length and improving plant stress resistance, especially at the seedling stage.

[0011] The application finds a high polymer material which, when applied to plants, can improve plant root length and improve plant stress resistance.

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

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

[0014]

[0015] The nanomaterial is self-assembled from SPc and / or a pharmaceutically acceptable salt thereof in a solution.

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

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

[0018] In certain embodiments, the nanomaterial is self-assembled from SPc and / or a pharmaceutically acceptable salt thereof in a solution, and is formed by high-temperature treatment.

[0019] In certain embodiments, the temperature of the high-temperature treatment is 121°C.

[0020] In certain embodiments, the time of the high-temperature treatment is 20 min.

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

[0022] In certain 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 certain embodiments, the plant is a seedling.

[0035] In certain embodiments, the seedling is 6d-14d.

[0036] In certain embodiments, the seedling is 6d, 7d and / or 14d.

[0037] In certain embodiments, the increased root length of the plant is PIN1 endocytosis- induced root elongation.

[0038] In certain embodiments, the plant stress tolerance is the tolerance of the plant to environmental stress.

[0039] In certain embodiments, the stress tolerance is the tolerance to abiotic stress.

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

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

[0042] In certain embodiments, the drought stress is PEG stress.

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

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

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

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

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

[0048] In certain embodiments, the low nitrogen stress is NO3 - at a concentration of 0.05mM.

[0049] In certain embodiments, the use comprises increasing the root length, fresh weight, germination rate and / or cotyledon greening rate of the plant.

[0050] In certain embodiments, the root length is the length of the primary root, the length of the primary root, the length of the root tip and / or the length of the primary root.

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

[0052] In certain embodiments, the fresh weight is the aerial fresh weight.

[0053] In another aspect, the present application discloses a plant growth regulating composition comprising the above-mentioned SPc or pharmaceutically acceptable salt thereof or nanomaterial as an active ingredient.

[0054] In certain embodiments, the growth regulation is rooting or stress resistance.

[0055] In another aspect, the present application discloses a method for improving plant root length and / or stress resistance, the method comprising the step of applying the above-mentioned SPc or pharmaceutically acceptable salt thereof or nanomaterial, the above-mentioned rooting agent and / or the above-mentioned plant stress resistance agent to a plant in cultivating a Gossypium plant.

[0056] In certain embodiments, the SPc or pharmaceutically acceptable salt thereof is used in the form of seed soaking, seed drenching, root soaking, foliar spraying, spraying, composting, coating, field flooding, drip irrigation of plant or plant organ, smearing of plant or plant organ, dripping of plant or plant organ, or any combination thereof.

[0057] In certain embodiments, the SPc or pharmaceutically acceptable salt thereof is applied at a concentration of 5 mg L -1 to 400 mg L -1 .

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

[0059] In certain embodiments, the plant or plant organ is selected from the group consisting of root, stem, leaf, flower, fruit, seed.

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

[0061] (1) monocotyledon or dicotyledon;

[0062] (2) Poaceae or Brassicaceae;

[0063] (3) Zea or Arabidopsis;

[0064] (4) corn or Arabidopsis;

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

[0066] In certain embodiments, the plant root length is seedling plant root length.

[0067] In certain embodiments, the seedling is 6d - 14d.

[0068] In certain embodiments, the seedling is 6d, 7d and / or 14d.

[0069] In certain embodiments, the root length is primary root length or main root length.

[0070] In certain embodiments, the corn is corn line ZD958.

[0071] In certain embodiments, the corn is cultured under conditions of 25°C light for 16h, dark for 8h for 7d.

[0072] In certain embodiments, the Arabidopsis is Arabidopsis thaliana Columbia (Col-0).

[0073] In certain embodiments, the plant stress tolerance is plant seedling stress tolerance.

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

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

[0076] In certain embodiments, the plant to which the SPc, the rooting agent, the plant stress tolerance agent is applied has higher stress tolerance and / or longer root length than the plant to which the SPc, the rooting agent, the plant stress tolerance agent is not applied.

[0077] In another aspect, the present application discloses a method for cultivating a plant, the method comprising the steps of applying the above-mentioned SPc or a pharmaceutically acceptable salt thereof or nanomaterial, the above-mentioned rooting agent and / or the above-mentioned plant stress tolerance agent to a plant, to obtain a plant having roots, stems, leaves, flowers, fruits, seeds.

[0078] In certain embodiments, the method for cultivating a plant comprises soil culture and / or soilless culture. The soilless culture is hydroponics.

[0079] In certain embodiments, the SPc or a pharmaceutically acceptable salt thereof is applied by seed soaking, seed drenching, root soaking, foliar spraying, spraying, composting, coating, field flooding, drip irrigation of the plant or plant organ, smearing of the plant or plant organ, dripping of the plant or plant organ, or any combination thereof.

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

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

[0082] In certain embodiments, the plant or plant organ is selected from the group consisting of roots, stems, leaves, flowers, fruits, seeds.

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

[0084] (1) the class of monocotyledons or dicotyledons;

[0085] (2) the family of Poaceae or Brassicaceae;

[0086] (3) the genus of Zea or Arabidopsis;

[0087] (4) the species of corn or Arabidopsis;

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

[0089] In certain embodiments, the plant root length is seedling plant root length.

[0090] In certain embodiments, the seedling stage is 6d-14d.

[0091] In certain embodiments, the seedling stage is 6d, 7d, and / or 14d.

[0092] In certain embodiments, the corn is corn line ZD958.

[0093] In certain embodiments, the Arabidopsis is Arabidopsis Columbia (Col-0).

[0094] In certain embodiments, the plant administered with the SPc, the rooting agent, the plant stress resistance agent is more stress resistant and / or has longer root length than a plant not administered with the SPc, the rooting agent, the plant stress resistance agent.

[0095] In certain embodiments, the mode of application is seed soaking, seed drenching, root soaking, foliar spraying, spraying, composting, coating, field flooding, drip application to a plant or plant organ, smearing to a plant or plant organ, dripping to a plant or plant organ

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

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

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

[0099] (1) monocotyledon or dicotyledon;

[0100] (2) Poaceae or Brassicaceae;

[0101] (3) Zea or Arabidopsis;

[0102] (4) corn or Arabidopsis;

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

[0104] In another aspect, the present application discloses a rooting agent comprising the above-mentioned SPc or a pharmaceutically acceptable salt thereof.

[0105] In another aspect, the present application discloses a plant stress resistance agent comprising the above-mentioned SPc or a pharmaceutically acceptable salt thereof.

[0106] In certain embodiments, the rooting agent or plant stress resistance agent further comprises a solvent, and the SPc accounts for 1 / 200,000 - 1 / 500 by weight.

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

[0108] (1) monocotyledon or dicotyledon;

[0109] (2) Poaceae or Brassicaceae;

[0110] (3) Zea or Arabidopsis;

[0111] (4) corn or Arabidopsis;

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

[0113] In certain embodiments, the above-mentioned plant growth regulating composition further comprises a solvent, wherein the SPc is present in an amount of 1 / 200000 - 1 / 500 by weight in the composition;

[0114] In certain embodiments, the SPc is present in an amount of 1 / 200000, 1 / 40000, 1 / 20000, 1 / 10000 and / or 1 / 500 by weight.

[0115] In another aspect, the present application provides a composition comprising the above-mentioned SPc and / or or a pharmaceutically acceptable salt thereof.

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

[0117] In certain embodiments, the seedling is a 6d - 14d seedling.

[0118] In certain embodiments, the seedling is a 6d, 7d and / or 14d seedling.

[0119] In certain embodiments, the composition, rooting agent and / or plant stress resistance agent is formulated as a solid formulation, a liquid formulation;

[0120] In certain embodiments, the composition, rooting agent and / or plant stress resistance agent further comprises an excipient and / or an additive;

[0121] In certain embodiments, the excipient comprises an agriculturally or horticulturally acceptable diluent, filler, solvent, spontaneity promoter, carrier, emulsifier, dispersant, thickener, binder, or any combination thereof.

[0122] In certain embodiments, the additive comprises an agriculturally or horticulturally acceptable preservative, adjuvant, synergist, microbial additive, antifreeze, or any combination thereof.

[0123] In certain embodiments, the composition, rooting agent and / or plant stress resistance agent is a liquid formulation;

[0124] In certain embodiments, the liquid formulation comprises an emulsifiable concentrate, a soluble concentrate, an oil, a dispersible concentrate, an electrostatic spray concentrate, a suspension concentrate, a microcapsule suspension concentrate, an oil suspension concentrate, a suspoemulsion, an emulsion, a microemulsion, a nanoemulsion, or any combination thereof.

[0125] In certain embodiments, the SPc is in an agriculturally or horticulturally acceptable carrier in the liquid formulation.

[0126] In certain embodiments, the liquid formulation has a content of SPc of 5 mg L -1 - 400 mg L -1 ;

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

[0128] In certain embodiments, the liquid formulation is for drenching roots, foliar spraying, spraying, composting, seed soaking, coating, flood irrigation of a field, drip irrigation of a plant or plant organ, smearing a plant or plant organ, dripping a plant or plant organ, or any combination thereof.

[0129] In certain embodiments, the composition, rooting agent and / or plant stress resistance agent is a solid formulation;

[0130] In certain embodiments, the solid formulation has the SPc in an agriculturally or fertilizierally acceptable carrier;

[0131] In certain embodiments, the solid formulation is for composting, smearing a plant or plant organ, or any combination thereof.

[0132] In certain embodiments, the solid formulation is for formulating the liquid formulation described above.

[0133] In certain embodiments, the liquid formulation has the SPc in an agriculturally or fertilizierally acceptable carrier;

[0134] In certain embodiments, the liquid formulation has a content of SPc of 5 mg L -1 - 400 mg L -1 ;

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

[0136] In certain embodiments, the liquid formulation is used for drenching roots, foliar spraying, spraying, composting, seed soaking, coating, flood irrigation in the field, drip irrigation of plants or plant organs, smearing of plants or plant organs, dripping of plants or plant organs, or any combination thereof.

[0137] In certain embodiments, the composition is a solid formulation;

[0138] In certain embodiments, in the solid formulation, the SPc is in an agriculturally or fertilizierally acceptable carrier;

[0139] In certain embodiments, the solid formulation is used for composting, smearing of plants or plant organs, or any combination thereof.

[0140] In certain embodiments, the solid formulation is used for formulating the liquid formulation described above.

[0141] In certain embodiments, the PIN1 protein is expressed in the vascular bundle. The PIN1 protein directs the flow of auxin towards the root tip.

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

[0143] In certain embodiments, the PIN3 protein is expressed in the stele and distal elongation zone. The PIN3 protein makes directional adjustments to the flow of auxin in response to gravity.

[0144] In recent years, high molecular materials have reached the nanoscale level, and star-shaped polycations (SPc) (as shown in Formula 1) have great potential in the delivery of synthetic plant pesticides, nucleic acids and nutrients, etc. SPc has nanoscale size, good water solubility, biocompatibility and low cytotoxicity. The branched four-arm structure with tertiary amine groups greatly enhances dispersion in plant tissues. This dendrimer and polymer can be rapidly internalized into cells, helping the delivery of target molecules. SPc can reduce the overall particle size by forming a complex with target drugs or nucleic acid molecules, thereby improving delivery efficiency. Although there is increasing interest in nanotechnology-based agriculture, little is known about SPc-regulated root growth. The present invention illustrates that nano-SPc can promote plant root elongation, thereby improving plant stress resistance.

[0145] The present application discloses a nano material related to promoting root elongation and stress resistance and its use method and application, which solves the technical problem of improving 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; applying SPc or a pharmaceutically acceptable salt thereof to plants can improve the root length and stress resistance of seedling plants, which can be used for industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0146] Figure 1 is a graph showing that Spc promotes plant root growth and increases the length of plant roots.

[0147] Figure 2 is a graph showing that Spc increases the stress resistance of plants, specifically non-biological stress, including NaCl stress, mannitol stress, and low nitrogen stress. DETAILED DESCRIPTION

[0148] The application will be further described in conjunction with the specific embodiments. The examples given are only to illustrate the application, and are not intended to limit the scope of the application. The examples provided below can serve as a guide for further improvement by those skilled in the art, and do not in any way constitute a limitation on the application.

[0149] In the following examples, the experimental methods are conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions, unless otherwise specified. The materials, reagents, etc. used in the following examples can be obtained commercially, unless otherwise specified.

[0150] In the following examples, the data are processed using SPSS 11.5 statistical software, and the experimental results are expressed as mean ± standard deviation. One-way ANOVA test is used, and P<0.05 (*) indicates a significant difference, P<0.01 (**) indicates a very significant difference, and P<0.001 (***) indicates a very significant difference.

[0151] In the present application, unless otherwise specified, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. Also, the terms related to protein and nucleic acid chemistry, molecular biology, cell and tissue culture, microbiology, immunology, and laboratory operation steps used herein are terms and conventional steps widely used in the corresponding fields. At the same time, in order to better understand the present application, the definitions and explanations of the related terms are provided below.

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

[0153] As used herein, the term "optionally," "optional" or "may" generally means that the subsequently described event or circumstance can or can not occur, and the description includes instances where the event or circumstance occurs and instances where it does not.

[0154] As used herein, the terms "first", "second" are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or a quantity of the specified technical features. Thus, features defined with "first", "second" can include one or more of the features implicitly or explicitly. Further, in the description of the application, the meaning of "a plurality of" is two or more unless otherwise specified.

[0155] As used herein, the term "stress tolerance" refers to the ability of a plant to tolerate stress. The stress includes, but is not limited to, salt stress, drought stress, low nitrogen stress. The tolerance includes, but is not limited to, the ability to maintain normal growth, development and reproduction, in particular embodiments, including but not limited to seed germination rate (seed germination rate, germination speed (germination index), radicle / embryo length, survival rate of seedling after germination), seedling / adult growth performance (plant height, stem diameter, root length, root volume, biomass (fresh weight / dry weight of above / underground), leaf number, leaf area, specific leaf weight (unit area leaf dry weight), leaf phenotype change (wilting, yellowing, necrosis, salt spot), root system characteristics (root / shoot ratio (root to aboveground biomass ratio), root activity (TTC method to determine dehydrogenase activity), lateral root density, root hair development), photosynthesis and gas exchange (chlorophyll content (SPAD value or spectrophotometric method), photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), intercellular CO2 concentration (Ci), photosystem II efficiency (Fv / Fm, chlorophyll fluorescence parameters), osmotic adjustment substances (proline (Pro) content, soluble sugar (glucose, fructose, sucrose) content, betaine, glycine betaine content, inorganic ions (Na + , K + , Ca 2+ , Cl - ) concentration and Na + / K + ratio), antioxidant system (superoxide dismutase (SOD) activity, peroxidase (POD), catalase (CAT) activity, ascorbate peroxidase (APX) activity, malondialdehyde (MDA) content (membrane lipid peroxidation degree), reactive oxygen species (ROS) accumulation (such as H2O2, O2 -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 (salt tolerance related gene expression (such as SOS1, NHX1, HKT1, P5CS, BADH, etc.), transcription factor activity (such as MYB, NAC, WRKY family), signal pathway gene (such as MAPK, CDPK, CBL-CIPK pathway)), epigenetic regulation (changes in DNA methylation level, histone modification (such as acetylation, methylation)), proteomics (differentially expressed proteins (such as osmoregulation proteins, antioxidant enzymes), post-translational modification of proteins (phosphorylation, ubiquitination)), metabolomics (primary metabolites (amino acids, organic acids, sugars), secondary metabolites (flavonoids, phenols, alkaloids)), cell ultrastructure (chloroplast structure (thylakoid membrane integrity), mitochondrial morphology (whether the structure of the cristae is damaged), vacuole size (ion compartmentalization ability)), cell wall characteristics (lignin, cellulose content, cell wall elasticity and mechanical strength), salt gland / salt vesicle structure (salt gland density (such as salt excretion structure of halophytes), salt vesicle secretion ability), root salt excretion ability (salt concentration in root exudates, rhizosphere soil salt dynamics), reproductive ability (flowering time, seed setting rate, seed vigor), salt tolerance index, principal component analysis, cluster analysis.

[0156] Example 1 Preparation and synthesis of SPc

[0157] The homo-pure powder of SPc was obtained from the Shenjie research group of China Agricultural University. SPc is a star initiator Pt-Br synthesized from pentaerythritol, then the star initiator is polymerized with DMAEMA, and the homo-pure powder of SPc is obtained by dialysis purification. Then it is dissolved in ddH2O, and the structure of SPc is confirmed by 1H nuclear magnetic resonance (1H NMR), and its molecular weight is analyzed by gel permeation chromatography (GPC). The specific preparation method of the homo-pure powder of SPc is as follows: “Patent name: a star polymer and its preparation method and application, application number: 2018103505627, application date: 2018-11-13”, application publication number: CN108794710A.

[0158] The structure of SPc is shown as formula 1, and formula 1 is as follows:

[0159]

[0160] The present application provides a preparation of a nanomaterial: adding the above-mentioned homo-pure powder of SPc into water, and allowing the SPc to self-assemble in water to form a nanomaterial.

[0161] The application also provides a preparation of a nanomaterial: adding the above-mentioned SPc pure powder into water to make the concentration of the SPc reach 25 mg / L -1 , and allowing the SPc to self-assemble in the water to form a nanomaterial.

[0162] The application also provides a preparation of a nanomaterial: adding the above-mentioned SPc pure powder into 1 / 2MS medium to make the concentration of the SPc reach 25 mg / L -1 , and allowing the SPc to self-assemble in the 1 / 2MS medium to form a nanomaterial.

[0163] The application also provides a preparation of a nanomaterial: adding the above-mentioned SPc pure powder into 1 / 2MS medium to make the concentration of the SPc reach 25 mg / L -1 , allowing the SPc to self-assemble in the 1 / 2MS medium, and then performing high-temperature treatment at 121°C for 20 min to obtain a nanomaterial.

[0164] The application also provides a preparation of a nanomaterial: adding the above-mentioned SPc pure powder into 1 / 2MS medium containing 2 g / 100 ml agarose to make the concentration of the SPc reach 25 mg / L -1 , allowing the SPc to self-assemble in the 1 / 2MS medium, and then performing high-temperature treatment at 121°C for 20 min to obtain a nanomaterial.

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

[0166] Plant material and growth conditions

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

[0168] Maize lines (ZD958 or Zhengdan 958) were used for phenotype observation. The maize strains were cultured on quartz sand under the conditions of 25°C light for 16h and 18°C dark for 8h for 7d. ImageJ 1.8 (National Institutes of Health, USA) was used to measure the plant root length.

[0169] Exogenous SPc treatment:

[0170] Maize:

[0171] The above-mentioned SPc was dissolved and diluted in ddH2O to prepare a stock solution of 1 g / L -1 , and ddH2O was used to dilute to 0 mg / L, respectively.-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 of maize strain (ZD958) were taken, and the experiment was divided into 5 groups, i.e. 0 mg L -1 SPc group, 50 mg L -1 SPc group, 100 mg L -1 SPc group, 200 mg L -1 SPc group and 400 mg L -1 SPc group, 22 plants in each group, seeds of maize strain (ZD958) were taken, and 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, 0 mg L -1 SPc group, 50 mg L -1 SPc group, 100 mg L -1 SPc group, 200 mg L -1 SPc group and 400 mg L -1 SPc group were irrigated, and then the seedlings were cultured on quartz sand under the conditions of 25 °C light for 16 h and 18 °C darkness for 8 h, the maize strains were cultured for 7 d, the phenotype was recorded by taking photos, and ImageJ 1.8 (National Institutes of Health, USA) was used to measure the plant root length. The data were analyzed by SPSS Statistics 22.0 (SPSS Inc., USA), and the graphs were drawn by GraphPad Prism 8.0 (GraphPad Software). The statistical significance was analyzed by one-way ANOVA, and Duncan's multiple range test or independent t test was used, p < 0.05 was significant. The data were expressed as mean ± SE. The phenotype results are shown in Table 1 Figure 1 Table 1 (0, 50, 100, 200 and 400 represent 0 mg L -1 SPc group, 50 mg L -1 SPc group, 100 mg L -1 SPc group, 200 mg L -1 SPc group and 400 mg L -1SPc group), histogram of primary root length is shown in Fig. 2 Figure 1 200 mg L -1 The concentration of 50 mg L was the best for the elongation of corn roots.

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

[0174] Arabidopsis thaliana:

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

[0176] Seeds of Arabidopsis thaliana wild type Columbia (Col-0) were taken, and the experiment was divided into 5 groups, i.e. 0 mg L -1 SPc group, 5 mg L - 1 SPc group, 25 mg L -1 SPc group, 50 mg L -1 SPc group and 100 mg L -1 SPc group, 25 plants in each group, 0 mg L -1 SPc group, 5 mg L -1 SPc group, 25 mg L -1 SPc group, 50 mg L -1 SPc group and 100 mg L -1 Arabidopsis thaliana of the SPc group was placed in 0 mg L -1 1 / 2MS liquid medium containing 5 mg L -1 1 / 2MS liquid medium containing 25 mg L -1 1 / 2MS liquid medium containing 50 mg L -1 1 / 2MS liquid 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 concentration of 25 mg L-1 SPc, the length of the main root of Arabidopsis was increased by about 27.73% compared to the control group. The activity and size of the root tip are key factors in determining the growth of the main root. At the concentration of 25 mg L-1 SPc, the root tip of Arabidopsis was increased by about 22.06% (f) compared to the control, which was consistent with the trend of the main root elongation, indicating that meristem differentiation or rapid cell elongation played an important role in the root elongation induced by SPc. In summary, as a low-level environmental stress stimulus, SPc can promote the elongation of the main root by improving the efficiency of root cell elongation, which means that SPc affects the growth and development of plants by participating in certain physiological processes of plants. -1 At the concentration of 25 mg L-1 SPc, the length of the main root of Arabidopsis was increased by about 27.73% compared to the control group. The activity and size of the root tip are key factors in determining the growth of the main root. At the concentration of 25 mg L-1 SPc, the root tip of Arabidopsis was increased by about 22.06% (f) compared to the control, which was consistent with the trend of the main root elongation, indicating that meristem differentiation or rapid cell elongation played an important role in the root elongation induced by SPc. In summary, as a low-level environmental stress stimulus, SPc can promote the elongation of the main root by improving the efficiency of root cell elongation, which means that SPc affects the growth and development of plants by participating in certain physiological processes of plants. Figure 1 At the concentration of 25 mg L-1 SPc, the length of the main root of Arabidopsis was increased by about 27.73% compared to the control group. The activity and size of the root tip are key factors in determining the growth of the main root. At the concentration of 25 mg L-1 SPc, the root tip of Arabidopsis was increased by about 22.06% (f) compared to the control, which was consistent with the trend of the main root elongation, indicating that meristem differentiation or rapid cell elongation played an important role in the root elongation induced by SPc. In summary, as a low-level environmental stress stimulus, SPc can promote the elongation of the main root by improving the efficiency of root cell elongation, which means that SPc affects the growth and development of plants by participating in certain physiological processes of plants.

[0180] Example 3 Effect of SPc on the resistance of plants to biological stress

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

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

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

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

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

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

[0187] Further SPc was dissolved in 150 mM NaCl solution to obtain 200 mg L -1 SPc and 150 mM NaCl aqueous solution. SPc was dissolved to obtain 200 mg L -1 SPc aqueous solution.

[0188] Osmotic stress:

[0189] The experiment was divided into 4 groups, namely control group, 125 mM NaCl group, 150 mM NaCl group, 200 mM mannitol group or 250 mM mannitol group, 150 Arabidopsis seeds in each group. Half of the Arabidopsis in 125 mM NaCl group, 150 mM NaCl group, 200 mM mannitol group or 250 mM mannitol group were placed in 1 / 2MS solid medium containing 125 mM NaCl, 1 / 2MS solid medium containing 150 mM NaCl, 1 / 2MS solid medium containing 200 mM mannitol and 1 / 2MS solid medium containing 250 mM mannitol for culture, respectively. Half of the Arabidopsis in 125 mM NaCl group, 150 mM NaCl group, 200 mM mannitol group or 250 mM mannitol group were placed in 1 / 2MS solid medium containing 125 mM NaCl and 25 mg L -1 SPc, 1 / 2MS solid medium containing 150 mM NaCl and 25 mg L -1 SPc, 1 / 2MS solid medium containing 200 mM mannitol and 25 mg L -1 SPc, 1 / 2MS solid medium containing 250 mM mannitol and 25 mg L -1 SPc, 1 / 2MS solid medium containing 250 mM mannitol and 25 mg L

[0190] The germination rate was calculated: the number of germinated seeds / seeded seeds * 100%.

[0191] The cotyledon greening rate was calculated: the number of cotyledon green seedlings / seeded seeds * 100%.

[0192] The primary root length was calculated: the length from the root tip to the root starting point. The measuring tool was ImageJ.

[0193] Fresh weight of above ground part: Fresh weight of above ground part of Arabidopsis thaliana seedlings. The measuring tool is using a one-hundredth scale.

[0194] Phenotype results Figure 2 Figure 1 shows the germination rate of seedlings under different treatments. The results are shown in the table. Under 250 mM mannitol, the germination rate of seedlings treated with SPc was significantly higher than that of the untreated control (96.85% vs. 80.77%) Figure 2 Figure 1b). The cotyledon greening rate of plants treated with SPc was also higher under 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 Figure 1c). The main root length was significantly increased by 25.89%, 20.74%, 206.99% and 184.44% under 100 mM NaCl, 125 mM NaCl, 200 mM mannitol and 250 mM mannitol treatments, respectively, compared to the control seedlings Figure 2 Figure 1d). The fresh weight of above ground part was also increased by 26.04%, 19.57% and 82.84% under 100 mM NaCl, 125 mM NaCl and 200 mM mannitol treatments, respectively, compared to the control Figure 2 Figure 1e).

[0195] The experiment was divided into 4 groups, namely the control group, the NaCl group, the mannitol group, 12 corn lines (ZD958) seeds in each group. Half of the corn lines (ZD958) seeds in the control group, the NaCl group and the mannitol group were soaked with ddH2O, 20% PEG solution and 150 mM NaCl aqueous solution, respectively. Half of the corn lines (ZD958) seeds in the control group, the NaCl group and the mannitol group were treated with 200 mg / L SPc, 150 mM NaCl and 200 mg / L SPc, respectively. -1 The aqueous solution of SPc, the aqueous solution containing 200 mg / L SPc and 150 mM NaCl and the aqueous solution containing 200 mg / L SPc and 150 mM NaCl were prepared by dissolving 200 mg of SPc in 100 mL of ddH2O, 100 mL of 150 mM NaCl aqueous solution and 100 mL of 150 mM NaCl aqueous solution, respectively. -1 The aqueous solution of SPc, the aqueous solution containing 200 mg / L SPc and 150 mM NaCl and the aqueous solution containing 200 mg / L SPc and 150 mM NaCl were prepared by dissolving 200 mg of SPc in 100 mL of ddH2O, 100 mL of 150 mM NaCl aqueous solution and 100 mL of 150 mM NaCl aqueous solution, respectively. -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] Further, SPc was dissolved in normal nitrogen medium to obtain normal nitrogen medium containing 25 mg L -1 Normal nitrogen medium of SPc.

[0204] The seeds of Arabidopsis thaliana wild type Columbia (Col-0) were taken, and the experiment was divided into 4 groups, i.e. normal nitrogen group and low nitrogen group, 12 plants in each group. Half of the seeds in the normal nitrogen group and the low nitrogen group were respectively placed in normal nitrogen medium and low nitrogen medium. Further, half of the seeds in the normal nitrogen group and the low nitrogen group were respectively placed in normal nitrogen medium containing 25 mg L -1 SPc and low nitrogen medium containing 25 mg L -1 SPc. The seedlings were vertically grown under the conditions of 16h light / 8h dark, 22℃, 60% humidity for 6d, and the primary root length, fresh weight, NO 3- inflow in the root elongation zone was measured by using ImageJ1.8 (National Institutes of Health, USA). The data was analyzed by using SPSS Statistics 22.0 (SPSS Inc., USA), and the graph was drawn by using GraphPad Prism 8.0 (GraphPad Software).

[0205] NO 3- inflow: non-invasive ion micro-test (NMT) was used for determination: the root tips of the main roots of Arabidopsis and corn seedlings after nitrogen treatment were cut and placed in a balanced solution (0.1mM NH4NO3, 0.1mM KCl, 0.1mM CaCl2, 0.3mM MES, pH 6.0) for 10-20min. The balanced root tips were placed in a new culture dish for fixation, 5mL test buffer (4mM Ca(NO3)2 and 0.05mM Ca(NO3)2) was added, and the sample was placed under a microscope. The NO 3- flow rate was determined at a distance of 1200μm from the root tip. After the data was stable, reading was started, and the test time was 15min. The NO 3- flow rate was recorded every 6s.

[0206] The phenotype results are shown in Table 2 (NN and LN respectively represent normal nitrogen group and low nitrogen group, wherein Control or control is the medium without adding SPc, and SPc is the medium with adding SPc). In order to determine whether SPc has similar benefits under nutrient stress Figure 2Medium g, h, NN or normal nitrogen and LN or low nitrogen are normal nitrogen group and low nitrogen group respectively, wherein, Control or control is culture medium without adding SPc, and SPc is culture medium with adding SPc). Compared with the control, the primary root length of the Arabidopsis thaliana treated by SPc increased by 22.03% and the fresh weight increased by 38.50% under the low nitrogen (LN) culture medium Figure 2 Medium g, h, NN or normal nitrogen and LN or low nitrogen are normal nitrogen group and low nitrogen group respectively, wherein, Control or control is culture medium without adding SPc, and SPc is culture medium with adding SPc). Compared with the control, the primary root length of the Arabidopsis thaliana treated by SPc increased by 22.03% and the fresh weight increased by 38.50% under the low nitrogen (LN) culture medium 3 Inflow Figure 2 Medium g, h, NN or normal nitrogen and LN or low nitrogen are normal nitrogen group and low nitrogen group respectively, wherein, Control or control is culture medium without adding SPc, and SPc is culture medium with adding SPc).

[0207] The above has been described in detail. For those skilled in the art, without departing from the purpose and scope of the present application, and without unnecessary experiments, the present application can be implemented in a wider range under the same parameters, concentrations and conditions. Although the present application gives a special example, it should be understood that the present application can be further improved. In general, according to the principle of the present application, the present application intends to include any change, use or improvement of the present application, including the change made by the conventional technology known in the art, which is out of the range disclosed in the present application. Some basic features can be applied according to the scope of the following attached claims.

Claims

1. Use of SPc or a pharmaceutically acceptable salt thereof or a nanomaterial comprising SPc or a pharmaceutically acceptable salt thereof in improving root length of a plant and / or improving stress resistance of a plant; the SPc is as formula (I); the nanomaterial is self-assembled from SPc and / or a pharmaceutically acceptable salt thereof in solution.

2. Use according to claim 1, characterized in that, the stress resistance of the plant is tolerance of the plant to environmental stress.

3. Use according to claim 1, characterized in that, the use in improving stress resistance of a plant includes improving root length, fresh weight, germination rate and / or cotyledon greening rate of a plant.

4. A plant growth regulating composition, characterized by comprising: comprising the SPc or a pharmaceutically acceptable salt thereof or the nanomaterial as claimed in claim 1 as an active ingredient.

5. The plant growth regulating composition according to claim 4, wherein the growth regulation is rooting or stress resistance.

6. A method of increasing root length and / or stress tolerance in a plant, characterized in that, the method comprises the step of applying the SPc or a pharmaceutically acceptable salt thereof or the nanomaterial as claimed in claim 1, the plant growth regulating composition as claimed in claim 4 or 5 to a plant in cultivating a Gossypium plant.

7. A method for breeding a plant, characterized by, the method comprises the step of applying the SPc or a pharmaceutically acceptable salt thereof or the nanomaterial as claimed in claim 1, the plant growth regulating composition as claimed in claim 4 or 5 to a plant, to obtain a plant having roots, stems, leaves, flowers, fruits, seeds.

8. The method of claim 6 or 7, wherein, the application mode is seed soaking, seed drenching, root soaking, foliar spraying, spraying, composting, coating, field flooding, adding culture medium, drip irrigation of plant or plant organ, smearing of plant or plant organ, dropwise addition of plant or plant organ.

9. The method of any one of claims 6-8, wherein, the plant or plant organ is selected from any one of the following: (1) monocotyledon or dicotyledon; (2) Poaceae or Brassicaceae; (3) Zea or Arabidopsis; (4) corn or Arabidopsis; (5)(1)-(4)。 10. The plant growth regulating composition according to claim 4 or 5, wherein the composition further comprises a solvent, and the weight ratio of the SPc in the composition is 1 / 200000-1 / 500; Preferably, the weight ratio of the SPc is 1 / 200000, 1 / 40000, 1 / 20000, 1 / 10000 and / or 1 / 500.

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