Application of N-acetyl-L-tryptophan, plant regulator for relieving plant water stress and method for improving tobacco water stress resistance

Abstract

The invention discloses application of N-acetyl-L-tryptophan, a plant regulator for relieving plant water stress and a method for improving tobacco water stress resistance, and belongs to the technical field of plant stress physiology and agricultural biology. The invention discloses application of N-acetyl-L-tryptophan in relieving water stress of plants. The water stress is drought stress and / or flooding stress. Based on metabonomics deep analysis of tobacco drought stress response, it is found and verified for the first time that exogenous application of N-acetyl-L-tryptophan can synergistically enhance physiological and biochemical stress resistance of tobacco by specifically regulating a tryptophan metabolic network, so that drought stress damage is effectively relieved. It is found and verified for the first time that exogenous application of N-acetyl-L-tryptophan not only can efficiently relieve drought stress, but also can remarkably relieve flooding stress, a unique two-way regulation function is shown, and a brand new thought is provided for development of broad-spectrum stress resistance agents.

Description

Technical Field

[0001] This invention relates to the application of N-acetyl-L-tryptophan, plant regulators for alleviating plant water stress, and methods for improving tobacco water stress resistance, belonging to the fields of plant stress physiology and agricultural biotechnology. Background Technology

[0002] Water is an essential element for plant growth and development, requiring a continuous amount throughout the entire growth process. Water supply significantly influences processes such as photosynthesis, respiration, nutrient absorption, and transport, which are closely related to plant productivity. Water is one of the key environmental factors affecting the growth, development, and quality formation of tobacco. As a water-sensitive economic crop, tobacco's growth, development, and quality formation are heavily influenced by water availability during its growth process.

[0003] Water stress is mainly divided into two categories: drought stress (water deficiency) and flooding stress (water excess). Although these two stresses manifest in opposite ways, both can cause serious damage to tobacco. Drought leads to stomatal closure, photosynthetic inhibition, osmotic imbalance, accumulation of reactive oxygen species, and membrane system damage, ultimately resulting in growth stagnation and reduced biomass. Flooding, on the other hand, leads to root hypoxia, disordered energy metabolism, accumulation of harmful substances, and premature leaf senescence.

[0004] Currently, the main approaches to address water stress and improve crop drought and flood resistance include breeding improvement, agronomic regulation, and the application of exogenous substances. The application of exogenous regulators has attracted attention due to its simplicity and high efficiency. Among these, the application of exogenous plant growth regulators (such as abscisic acid, salicylic acid, and melatonin) to alleviate drought stress is noteworthy for its flexibility and rapid effectiveness; however, existing regulators often suffer from high costs, limited target sites, or environmental residues. Regulators used to alleviate flood stress (such as paclobutrazol and uniconazole) typically have limited target sites, and a single substance often cannot simultaneously produce good effects on two opposing water stresses.

[0005] Chinese invention patent application CN116267950A, published on June 23, 2023, discloses the application of chitosan oligosaccharide in improving the germination and growth of rice under flood stress, a seed soaking agent, and its application method. Specifically, it provides the application of chitosan oligosaccharide in improving the germination and growth of rice under flood stress, with a concentration of 50–250 mg / L. This invention provides a new use for chitosan oligosaccharide; by preparing it into a seed soaking agent, it can enhance the ability of rice seeds to resist flood stress, improve rice germination rate and seedling height, and enable rice seedlings to quickly escape the water layer and obtain oxygen, thereby increasing rice yield.

[0006] Chinese invention patent application CN119344315A, published on January 24, 2025, discloses the application and method of naringenin in improving the resistance of tomatoes to flooding stress. Specifically, it discloses the application and method of naringenin (Nar) in improving the resistance of tomatoes to flooding stress. Spraying Nar on the leaves of tomato seedlings and watering the roots with Nar can improve the flood tolerance of tomatoes, serving as a regulator for tomato seedlings to resist flooding environments. This invention, by applying a 0.25mM to 1.00mM naringenin solution to tomato plants, alleviated lodging, leaf drying, and wilting of tomato seedlings, thereby significantly improving the resistance of tomatoes to flooding stress.

[0007] Chinese invention patent application CN120827109A, published on October 24, 2025, discloses the application of exogenous regulatory substances in alleviating drought stress in maize. Specifically, it discloses that exogenous application of serine, pantothenic acid, or raffinose can promote root morphogenesis in maize under drought stress, enhance the activity of antioxidant enzymes in maize roots, reduce MDA accumulation, and increase soluble protein content. Among them, 0.6 mM serine, 0.9 mM pantothenic acid, and 1.0 mM raffinose can effectively alleviate drought stress on maize, increase maize's water retention capacity, enhance the activity of antioxidant enzymes in maize roots, regulate the content of osmotic regulators, reduce the damage of drought stress to maize cells, and promote maize plant growth and root morphogenesis.

[0008] In summary, existing technologies have included some studies on the application of exogenous regulatory substances to resist drought or flooding stress, but these studies all focus on single water stresses. Therefore, finding a substance that can broadly enhance plants' adaptability to water adversity is an urgent problem to be solved in current agricultural production. Summary of the Invention

[0009] The first objective of this invention is to provide the application of N-acetyl-L-tryptophan in alleviating plant water stress, and to provide a new substance that can effectively alleviate plant drought stress and flooding stress.

[0010] The second objective of this invention is to provide a plant regulator for alleviating plant water stress, thereby addressing the problem that the broad-spectrum nature of existing plant regulators for alleviating plant water stress needs to be improved.

[0011] The third objective of this invention is to provide a method for improving the resistance of tobacco to water stress, providing a method for tobacco to effectively resist drought stress and flooding stress.

[0012] To achieve the above objectives, the technical solution adopted in this invention for the application of N-acetyl-L-tryptophan in alleviating plant water stress is as follows: Application of N-acetyl-L-tryptophan in alleviating water stress in plants, wherein the water stress is drought stress and / or flooding stress.

[0013] The beneficial effects of the above technical solution are as follows: The application of N-acetyl-L-tryptophan in alleviating plant water stress is a pioneering invention. Based on in-depth metabolomics analysis of tobacco's drought stress response, this invention is the first to discover and verify that exogenous application of N-acetyl-L-tryptophan can synergistically enhance the physiological and biochemical stress resistance of tobacco by specifically regulating the tryptophan metabolic network, thereby effectively alleviating drought stress damage. This invention is also the first to discover and verify that exogenous application of N-acetyl-L-tryptophan can not only efficiently alleviate drought stress but also significantly alleviate flooding stress, exhibiting a unique "bidirectional regulatory" function, providing a new approach for developing broad-spectrum stress-resistant agents.

[0014] Specifically, the drought stress is when the relative soil moisture content is below 55%; the flooding stress is when the soil moisture content reaches saturation and water accumulates continuously for more than 24 hours.

[0015] As a further improvement, the application concentration of N-acetyl-L-tryptophan is 50~200 mg / L.

[0016] As a further improvement, the application concentration of N-acetyl-L-tryptophan is 50~100 mg / L.

[0017] As a further improvement, the application involves spraying N-acetyl-L-tryptophan onto the leaves of plants; the amount of N-acetyl-L-tryptophan sprayed is (25~30) mL / plant.

[0018] As a further improvement, the plant is tobacco.

[0019] To achieve the above objectives, the technical solution adopted in this invention for a plant regulator used to alleviate plant water stress is as follows: A plant regulator for alleviating water stress in plants, comprising N-acetyl-L-tryptophan and a solvent; or comprising N-acetyl-L-tryptophan, a surfactant, and a solvent.

[0020] The beneficial effects of the above technical solution are as follows: the plant regulator of the present invention has simple ingredients, significantly reduces the cost compared with the currently commercially available plant regulators, and at the same time enhances the plant's resistance to drought stress and flooding stress.

[0021] As a further improvement, 0.1 mL of surfactant is added for every (0.5~0.8) g of N-acetyl-L-tryptophan; said surfactant includes Tween-20 and tea saponin.

[0022] To achieve the above objectives, the technical solution adopted in this invention for improving tobacco moisture stress resistance is as follows: A method for improving the resistance of tobacco to water stress includes spraying the leaves of tobacco plants with an N-acetyl-L-tryptophan solution before or at the initial stage of water stress; the concentration of the N-acetyl-L-tryptophan solution is 50~200 mg / L; the water stress is drought stress and / or flooding stress.

[0023] The beneficial effects of the above technical solution are that the method of the present invention is simple and effective, easy to apply, and suitable for large-scale promotion and use.

[0024] As a further improvement, the concentration of the N-acetyl-L-tryptophan solution is 50~100 mg / L.

[0025] As a further improvement, the tobacco is in the root elongation stage, vigorous growth stage, or maturity stage; the number of sprayings is 2 to 3 times. Attached Figure Description

[0026] Figure 1 This is a bar chart comparing the effects of different concentrations of N-acetyl-L-tryptophan (7 days after the first application of N-acetyl-L-tryptophan) on the agronomic traits (plant height, leaf area) of cigar seedlings under drought stress in Example 1 of this invention (where * represents...). P <0.05, ** represents P <0.01, *** represents P <0.001); Figure 2 The effect of spraying N-acetyl-L-tryptophan on the growth of tobacco leaves under drought treatment in Example 1 of the present invention (from top to bottom, treatments with 45% and 75% relative soil moisture content; from left to right, the concentrations of N-acetyl-L-tryptophan aqueous solution are 0 μg / L, 50 μg / L, 100 μg / L, and 200 μg / L, respectively). Figure 3 This is a bar chart illustrating the effect of spraying N-acetyl-L-tryptophan on photosynthetic parameters of cigar tobacco leaves under drought stress in Example 1 of this invention (where *** represents...). P <0.001, **** represents P <0.0001); Figure 4 This is a bar chart showing the effect of spraying N-acetyl-L-tryptophan on key indicators of the antioxidant system of cigar tobacco under drought stress in Example 1 of this invention (where * represents...). P <0.05, ** represents P <0.01); Figure 5This is a differential metabolite map based on metabolomics data in Embodiment 2 of the present invention (where the horizontal axis represents the cumulative number of substances arranged from smallest to largest fold of difference, the vertical axis represents the logarithm of the fold of difference to base 2, each point represents a substance, green points represent the top 10 substances with downregulation, and red points represent the top 10 substances with upregulation). Figure 6 This is a schematic diagram integrating the molecular mechanism and metabolic pathways by which N-acetyl-L-tryptophan alleviates tobacco drought stress in Example 2 of the present invention (wherein, the dashed lines represent the significance thresholds when the corrected FDR P values ​​are 0.05 (blue) and 0.01 (red)). Figure 7 This is a bar chart comparing the effects of different concentrations of N-acetyl-L-tryptophan (7 days after the second N-acetyl-L-tryptophan treatment) on the agronomic traits (plant height, leaf area) of cigar seedlings under flood stress (where * represents...). P <0.05, ** represents P <0.01, *** represents P <0.001); Figure 8 This is a schematic diagram illustrating the principle of N-acetyl-L-tryptophan in alleviating water stress in plants according to the present invention. Detailed Implementation

[0027] Global climate change is one of the most serious challenges facing the world today. Rising global temperatures, altered precipitation patterns, and increased extreme weather events caused by climate change pose a significant threat to agricultural production. Soil drought and flooding caused by excessive rainfall are particularly severe problems. These two water-related disasters directly affect crop growth, thereby impacting food security and sustainable agricultural development. Soil drought refers to a severe lack of soil moisture, insufficient to meet the needs of normal plant growth; while flooding refers to plants being submerged in water, where the stress of flooding creates a low-oxygen environment and makes them highly susceptible to soil-borne pathogens, leading to damaged plant growth or even death.

[0028] Currently, addressing water stress mainly relies on variety selection, water conservancy projects, and agronomic management, while the application of exogenous regulatory substances has attracted attention due to its simplicity and efficiency. However, commonly used exogenous substances that improve plant resistance to water generally only target single drought or flood stress. Finding a substance that can broadly enhance plant adaptability to water adversity is an urgent problem to be solved in current agricultural production.

[0029] Based on this, the present invention provides the application of N-acetyl-L-tryptophan in alleviating water stress in plants. This invention is not merely a simple discovery of effects, but rather based on a profound mechanistic analysis. The present invention reveals that N-acetyl-L-tryptophan has a significant alleviating effect on both drought and flooding, two opposing stresses. Its action is not a simple physiological stimulus, but rather based on a precise and systematic reprogramming of the plant's core metabolic network. After exogenous N-acetyl-L-tryptophan is absorbed by tobacco leaves, it acts as a precursor and signaling molecule, intervening in and strengthening the endogenous tryptophan metabolic network, specifically manifested as follows: 1. Direct replenishment and signal activation: Exogenous N-acetyl-L-tryptophan enters cells directly, and as a metabolite, it may feedback regulate tryptophan metabolic flux. At the same time, its degradation or transformation products may act as signaling molecules to activate the expression of downstream defense genes.

[0030] 2. Synergistic upregulation of key stress-resistance metabolites: This invention induces metabolic network remodeling far beyond changes in a single substance, not only accumulating N-acetyl-L-tryptophan itself, but also synergistically upregulating a variety of anti-stress metabolites with different mechanisms of action, such as proline (osmotic regulation) and potent antioxidant flavonoid glycosides, forming a multi-target metabolic defense system.

[0031] 3. Activation of core stress-resistance pathways: Metabolomics and transcriptomics association analysis confirmed that the treatment of this invention specifically enriched and activated KEGG pathways such as "tryptophan metabolism", "arginine biosynthesis" and "flavonoid biosynthesis", thus solidifying the above-mentioned metabolic remodeling at the gene expression level.

[0032] 4. Synergistic enhancement of physiological functions: The aforementioned changes at the molecular level ultimately integrate into significant improvements at the physiological level: a) enhanced activity of the antioxidant system (SOD, POD) and reduced oxidative damage markers (MDA); b) protected photosynthetic organ function, with net photosynthetic rate (Pn) and stomatal conductance (Gs) recovering; c) growth inhibition being reversed and biomass accumulation being restored.

[0033] 5. Mechanisms for mitigating drought stress: Metabolic hub role: Exogenous N-acetyl-L-tryptophan, as a precursor, enhances the metabolic flux of endogenous tryptophan.

[0034] Synergistic defense network construction: It does not simply enhance a single pathway, but rather synergistically induces the synthesis of multiple protective substances, including proline (osmotic regulation) and potent antioxidant flavonoids, forming a complex defense matrix.

[0035] Physiological function integration: The above metabolic changes lead to the activation of the antioxidant enzyme system (SOD, POD), the reduction of membrane lipid peroxidation (MDA), the protection of photosynthetic organs, and ultimately the recovery of growth.

[0036] 6. Mechanisms for mitigating flood stress: Energy and hormone balance: The core of flood stress is root hypoxia and ethylene accumulation. N-acetyl-L-tryptophan, as a tryptophan derivative, may regulate the formation of root aerenchyma by affecting the synthesis and signaling of its downstream products (such as auxin and melatonin), thereby balancing the "ethylene-auxin" axis and alleviating hypoxia stress.

[0037] Antioxidant protection: Similar to drought protection, it can enhance the antioxidant capacity of the aboveground parts under flood conditions, remove excess reactive oxygen species produced by hypoxic respiration, and protect leaf function.

[0038] Metabolic adaptive regulation: May promote the accumulation of metabolites that help adapt to hypoxia (such as γ-aminobutyric acid), helping to maintain basic energy and carbon skeleton supply.

[0039] 7. The unified nature of metabolic regulation: Whether it's drought or flooding, both ultimately lead to the disruption of cellular metabolic homeostasis and oxidative stress. The essence of N-acetyl-L-tryptophan lies in enhancing the robustness and plasticity of the plant's metabolic network, enabling it to flexibly mobilize different downstream defense resources through tryptophan metabolism as a core hub when facing different types of water adversity, achieving a "multi-effect" stress resistance effect.

[0040] The present invention will be further described in detail below with reference to specific embodiments. Unless otherwise specified, the equipment and reagents used in the embodiments, experimental examples and comparative examples are all commercially available.

[0041] Unless otherwise specified, the following examples were conducted under conventional experimental conditions, such as those described in Sambrook et al.'s Molecular Cloning Laboratory Manual (Sambrook J & Russell DW, Molecular cloning: alaboratory manual, 2001), or as recommended by the manufacturer's instructions.

[0042] I. Specific embodiments of the application of N-acetyl-L-tryptophan in alleviating plant water stress according to the present invention: The N-acetyl-L-tryptophan used in Examples 1-3 below was prepared as follows: Weigh 0.5 g of N-acetyl-L-tryptophan, dissolve it in a small amount of sterile water, stir until completely dissolved, and bring the volume to 10 L to obtain a stock solution of 50 mg / L. When using, add 0.1 mL of Tween-20 as a surfactant to each liter of stock solution, mix well, and it can be used for foliar spraying.

[0043] Example 1: Effect of N-acetyl-L-tryptophan on drought resistance of cigars during peak growing season This embodiment uses the CX26 cigar variety as the research object to illustrate the effect of exogenous application of N-acetyl-L-tryptophan on its drought resistance. The specific implementation operation is as follows: 1. Materials: CX26 cigar tobacco variety, potted and in its vigorous growth stage.

[0044] 2. Treatment Design: Two soil relative water content (SRWC) gradients were set up: 75±5% (normal water supply, CK) and 45±5% (drought stress, DR). Within the DR group, four treatments were set up: foliar spraying with water (DR0), 50 mg / L N-acetyl-L-tryptophan (DR50), 100 mg / L (DR100), and 200 mg / L (DR200). Each treatment was replicated three times.

[0045] 3. Application method: On the 3rd and 5th day after the start of water control (early stage of stress), spray the front and back of the tobacco leaves evenly with a small sprayer in the evening until the leaf surface is moist but no liquid drips down. The amount of spray per plant is about 25 mL. The control is sprayed with an equal amount of water.

[0046] 4. Test items: Tested 7 days after the first spraying treatment.

[0047] Agronomic traits: plant height, maximum leaf area. Results are as follows: Figure 1 and Figure 2 As shown in the figure, compared with the tobacco plants in the normal water group (CK), the plant height and maximum leaf area of ​​the drought stress group were significantly reduced, while all indicators of the DR50 treatment group were significantly better than those of the DR0 treatment, recovering to levels close to CK.

[0048] Photosynthetic parameters: Net photosynthetic rate (Pn) and transpiration rate (Tr) were measured using a Li-6400 portable photosynthesis system. Under drought stress, the net photosynthetic rate and transpiration rate of leaves decreased significantly, while those of leaves under drought stress decreased significantly. Figure 3 It can be seen that the net photosynthetic rate and transpiration rate of DR50 treatment are significantly improved compared with DR0.

[0049] Physiological indicators: Superoxide dismutase (SOD) activity, peroxidase (POD) activity, and free proline content were measured. Results are as follows: Figure 4 As shown, the SOD and POD activities and free proline content of DR50 treatment were higher than those of DR0.

[0050] Note: Superoxide dismutase (SOD) activity, peroxidase (POD) activity, and free proline content were detected using a kit that is a commonly used detection kit in this field.

[0051] Example 2: Analysis of the drought resistance mechanism of N-acetyl-L-tryptophan based on metabolomics This embodiment analyzes the drought resistance mechanism of N-acetyl-L-tryptophan, and the specific implementation is as follows: 1. Sample collection: Take tobacco leaf samples treated with CK, DR0, and DR50 in Example 1 and quick-freeze them with liquid nitrogen.

[0052] 2. Metabolomics analysis: UPLC-MS / MS was used for extensive targeted metabolomics analysis.

[0053] 3. Results Analysis: like Figure 5 As shown in the figure, the global changes in metabolites induced by N-acetyl-L-tryptophan treatment are illustrated. The figure reveals that the metabolic profile of DR50 treatment is significantly different from that of DR0 and partially converges with that of CK. In DR50 treatment, N-acetyl-L-tryptophan, L-arginine, L-histidine, and naringenin-7-O-rutin are specifically and strongly induced.

[0054] KEGG enrichment analysis ( Figure 6 Enrichment analysis of the top 20 KEGG pathways in the transcriptome-metabolome integrated analysis showed that pathways such as "tryptophan metabolism", "arginine biosynthesis" and "flavonoid biosynthesis" were significantly enriched in the DR50 vs DR0 comparison group.

[0055] 4. Conclusion: Exogenous N-acetyl-L-tryptophan specifically enhances multiple stress-resistance-related pathways, including its own metabolic pathway, by remodeling the tobacco metabolic network. This is the molecular basis for its drought-resistant function.

[0056] Example 3: N-acetyl-L-tryptophan alleviates long-term tobacco flooding stress This embodiment uses the CX26 cigar variety as the research object to illustrate the effect of exogenous application of N-acetyl-L-tryptophan on its flood resistance. The specific implementation operation is as follows: 1. Materials: CX26 cigar tobacco variety, potted and in its vigorous growth stage.

[0057] 2. Treatment Design: Normal management (CK) and flooding stress (FL, maintaining 2-3 cm of water on the soil surface) were established. Within the FL group, four treatments were set up: foliar spraying with water (FL0), 50 mg / L N-acetyl-L-tryptophan (FL50), 100 mg / L (FL 100), and 200 mg / L (FL 200). Each treatment was replicated three times.

[0058] 3. Application method: Spray once one day before flooding and once three days after flooding. Use an equal amount of clean water as a control.

[0059] 4. Measurement items: Measurements were taken 7 days after the second spraying treatment.

[0060] Agronomic traits: plant height, maximum leaf area. Results are as follows: Figure 7 As shown in the figure, compared with the tobacco plants in the normal water group (CK), the plant height and maximum leaf area of ​​the flood stress group were significantly reduced, while all indicators of the FL 50 treatment group were significantly better than those of the FL0 treatment, recovering to levels close to CK.

[0061] Therefore, 50 mg / L N-acetyl-L-tryptophan can significantly enhance the tolerance of tobacco to flooding stress.

[0062] II. Specific embodiments of a plant regulator for alleviating water stress in plants according to the present invention: Example 4: Plant regulators for alleviating plant water stress 1 The preparation of the plant regulator for alleviating plant water stress in this embodiment is as follows: Weigh 0.5 g of N-acetyl-L-tryptophan, dissolve it in a small amount of sterile water, stir until completely dissolved, and bring the volume to 10 L to obtain a stock solution of 50 mg / L. When using, add 0.1 mL of Tween-20 as a surfactant to each liter of stock solution, mix well, and it can be used for foliar spraying.

[0063] The plant growth regulator in this embodiment can be applied preventively before a prolonged drought or heavy rain is predicted, or after transplanting or during the vigorous growth period and other critical water-demanding periods, at a dosage of 30-45 L per acre.

[0064] Example 5: Plant regulator 2 for alleviating plant water stress The preparation of the plant regulator for alleviating plant water stress in this embodiment is as follows: Weigh 0.5 g of N-acetyl-L-tryptophan, dissolve it in a small amount of warm water, stir until completely dissolved, and bring the volume to 10 L to obtain a stock solution of 50 mg / L. When using, add 0.5 mL of tea saponin as a surfactant to each liter of stock solution, mix well, and then spray on the leaves.

[0065] The plant growth regulator in this embodiment can be applied preventively before a prolonged drought or heavy rain is predicted, or after transplanting or during the vigorous growth period and other critical water-demanding periods, at a dosage of 30-45 L per acre.

[0066] The specific embodiments of the method for improving tobacco water stress resistance of the present invention are similar to the specific embodiments of the application of N-acetyl-L-tryptophan in alleviating plant water stress, and will not be repeated here.

[0067] In summary, the principle of N-acetyl-L-tryptophan in this invention for alleviating plant water stress is as follows: Figure 8 As shown, exogenous N-acetyl-L-tryptophan acts as a "metabolic signal input," acting on the core engine of the "tryptophan metabolic network" within tobacco plants. When faced with two different stress signals—drought and flooding—this engine can flexibly allocate different downstream defense resources, activating physiological and biochemical response modules with different focuses but some overlap, ultimately converging into a common beneficial result: a significant increase in the overall resistance of tobacco plants to water stress.

[0068] This invention has the following advantages: 1. Highly targeted and with a clear mechanism: Based on the precise discovery of the metabolic weakness in tobacco drought response (the endogenous N-acetyl-L-tryptophan pathway is activated but insufficient), the intervention is a "metabolic engineering" approach with a clear mechanism of action, rather than a blind attempt.

[0069] 2. Significant and synergistic effects: At low concentrations of 50-100 mg / L, it can significantly improve key indicators such as plant height, stem circumference, leaf area, and net photosynthetic rate by 30%-60%, and at the same time improve multiple physiological aspects, showing excellent synergistic effects.

[0070] 3. Environmentally friendly: N-acetyl-L-tryptophan is a natural amino acid derivative that is easily degraded and poses no risk of environmental residue, which aligns with the development direction of green agriculture.

[0071] 4. Easy to apply and low cost: The application method is conventional foliar spraying, which is easy to promote in large-scale production and the raw material cost is controllable.

[0072] 5. Broad-spectrum stress resistance: For the first time, a single exogenous substance has been used to effectively alleviate two opposing water stresses in tobacco: drought and flooding. This greatly expands the application scenarios and solves the problem of single-target regulation of traditional regulators.

[0073] 6. In-depth mechanism and synergistic effect: The action is based on the systematic regulation of the tryptophan metabolic network, triggering synergistic effects of multiple pathways and substances, rather than a single effect, so the anti-stress effect is more comprehensive and more stable.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. The application of N-acetyl-L-tryptophan in alleviating plant water stress, characterized by: The water stress is drought stress and / or flooding stress.

2. The application of N-acetyl-L-tryptophan according to claim 1 in alleviating plant water stress, characterized in that: The application concentration of N-acetyl-L-tryptophan is 50~200 mg / L.

3. The application of N-acetyl-L-tryptophan according to claim 2 in alleviating plant water stress, characterized in that: The application concentration of N-acetyl-L-tryptophan is 50~100 mg / L.

4. The application of N-acetyl-L-tryptophan according to claim 2 or 3 in alleviating plant water stress, characterized in that: The application involves spraying N-acetyl-L-tryptophan onto the leaves of plants; the amount of N-acetyl-L-tryptophan sprayed is (25~30) mL / plant.

5. The application of N-acetyl-L-tryptophan according to claim 4 in alleviating plant water stress, characterized in that: The plant in question is tobacco.

6. A plant regulator for alleviating water stress in plants, characterized in that: It consists of N-acetyl-L-tryptophan and a solvent; or N-acetyl-L-tryptophan, a surfactant, and a solvent.

7. The plant regulator for alleviating plant water stress according to claim 6, characterized in that: Add 0.1 mL of surfactant for every (0.5~0.8) g of N-acetyl-L-tryptophan; the surfactant includes Tween-20 and tea saponin.

8. A method for improving the resistance of tobacco to moisture stress, characterized in that: This includes spraying tobacco plant leaves with an N-acetyl-L-tryptophan solution before or at the initial stage of water stress; the concentration of the N-acetyl-L-tryptophan solution is 50~200 mg / L; the water stress is drought stress and / or flooding stress.

9. The method for improving tobacco moisture stress resistance according to claim 8, characterized in that: The concentration of the N-acetyl-L-tryptophan solution is 50~100 mg / L.

10. The method for improving tobacco moisture stress resistance according to claim 8 or 9, characterized in that: The tobacco is in the root elongation stage, vigorous growth stage, or maturity stage; the number of spraying applications is 2 to 3.

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