A compound exogenous substance for relieving pepper salt stress and a method for relieving pepper salt stress

Abstract

The application relates to the field of agricultural plant cultivation technology, and provides a compound exogenous material for relieving salt stress of pepper and a method for relieving salt stress of pepper. The exogenous material is mainly composed of gamma-aminobutyric acid with a concentration of 200 micromoles per liter, 24-epibrassinolide with a concentration of 0.1 mg / L and spermidine with a concentration of 50 micromoles per liter. The method for relieving salt stress of pepper is to spray the compound exogenous material on the leaves of the pepper under salt stress or to perform seed soaking treatment on the pepper seeds under salt stress to promote the root growth of the pepper seeds under salt stress. The ternary compound combination is superior to all single and binary treatments in all 10 growth indexes, significantly improves the salt tolerance of the pepper through synergistic effect, promotes the normal growth and development of the pepper under salt stress, and has a significant improvement effect on the pepper root system.

Description

Technical Field

[0001] This application relates to the field of agricultural plant cultivation technology, specifically to a compound exogenous substance for alleviating salt and pepper stress and a method for alleviating salt and pepper stress. Background Technology

[0002] chili( Capsicum annuum L.) is quite sensitive to salt stress, especially in greenhouse cultivation, where the problem of secondary soil salinization is becoming increasingly prominent due to long-term excessive fertilization and lack of rainwater leaching.

[0003] Salt stress harms chili peppers mainly in three ways: first, osmotic stress, where excessive soil salinity makes it difficult for roots to absorb water, causing physiological drought in the plants; second, ion toxicity, where sodium... + and Cl - Excessive accumulation in the plant interferes with normal metabolic activities; thirdly, nutritional imbalance leads to competitive inhibition of K by salt ions. + Ca 2+ Salt stress impairs the absorption of essential nutrients. Under salt stress, chili plants exhibit reduced plant height, weak stems, yellowing leaves, decreased biomass accumulation, and inhibited root growth and development, which can lead to seedling death in severe cases.

[0004] Currently, methods for alleviating salt stress in plants mainly include: screening salt-tolerant varieties, improving agricultural practices (such as irrigation to leach salt and increasing the application of organic fertilizers), and regulating with exogenous substances. Among these, regulation with exogenous substances has become a research hotspot due to its advantages of high efficiency, convenience, and low cost. However, existing research on exogenous substances mostly focuses on the effects of applying single substances. Whether there are synergistic effects between different substances, and how to optimize compound combinations to achieve the best alleviating effect, lack systematic research. Therefore, there is an urgent need to develop a compound exogenous substance with synergistic effects and a clear efficacy to meet the actual production needs for controlling salt stress in chili peppers. Summary of the Invention

[0005] The present invention aims to solve the problems in the prior art and provide a compound exogenous substance for alleviating capsaicin stress and a method for alleviating capsaicin stress.

[0006] To achieve the above objectives, the first aspect of this application provides a compound exogenous substance for alleviating salt and pepper stress, which is mainly composed of γ-aminobutyric acid (GABA) at a concentration of 200 μmol / L, 24-epibrassinolide (EBR) at a concentration of 0.1 mg / L, and spermidine (Spd) at a concentration of 50 μmol / L.

[0007] The preferred volume ratio of the above-mentioned compound exogenous substances, which is γ-aminobutyric acid, 24-epibrassinolactone and spermidine, is (1-2):(1-2):(1-2).

[0008] Preferably, the volume ratio of the above-mentioned compound exogenous substances, γ-aminobutyric acid, 24-epibrassinolide, and spermidine is 1:1:1.

[0009] The second aspect of this application provides a method for alleviating salt stress in chili peppers by spraying the above-mentioned compound exogenous substance onto the leaves of salt-stressed chili peppers.

[0010] The preferred method described above is to spray once every 3 days, for a total of 7 sprays.

[0011] In the above-described method, preferably, the compound exogenous substance is sprayed onto the leaves of chili seedlings.

[0012] The third aspect of this application provides a method for alleviating salt stress in chili peppers, which involves soaking salt-stressed chili pepper seeds with the aforementioned compound exogenous substances to improve the germination rate and / or shoot length of the salt-stressed chili pepper seeds.

[0013] Compared with the prior art, this application has the following beneficial effects:

[0014] (1) The ternary compound combination of the present invention (γ-aminobutyric acid, 24-epibrassinolide and spermidine) is superior to all single and binary treatments in all 10 growth indicators. It significantly improves the salt tolerance of peppers through synergistic effect, promotes the normal growth and development of peppers under salt stress, and has a significant effect on improving the root system of peppers.

[0015] (2) The compound exogenous substance provided by the present invention is composed of γ-aminobutyric acid, 24-epibrassinolide and spermidine, which is safe, non-toxic and environmentally friendly.

[0016] (3) The method of applying compound exogenous substances provided by the present invention is simple and can be achieved by foliar spraying. It is low in cost and easy to promote and apply in actual production. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 The images show the effects of different ratios on the seed sprouting of chili peppers under salt stress in Example 1 (in order: left → right, then top → bottom).

[0019] Figure 2 Photographs of chili pepper growth in control group 1 (healthy control CK, without salt stress or exogenous substance treatment).

[0020] Figure 3 Photographs showing the growth status of peppers in control group 2 (salt stress control, irrigated only with 150 mM NaCl solution).

[0021] Figure 4 Photographs showing the growth status of chili peppers treated with a single exogenous substance (GABA) as the control group.

[0022] Figure 5 Photographs showing the growth status of peppers treated with foliar spraying of a single exogenous substance (EBR) as the control group.

[0023] Figure 6 Photographs showing the growth status of peppers treated with a single exogenous substance (Spd) as the control group.

[0024] Figure 7 Photographs showing the growth status of chili peppers treated with foliar spraying of the control group with a 6-component compound of exogenous substances (GABA+EBR).

[0025] Figure 8 Photographs showing the growth status of peppers treated with foliar spraying of the control group containing a binary compound of exogenous substances (GABA+Spd).

[0026] Figure 9 Photographs showing the growth status of chili peppers treated with foliar spraying of an 8-component compound exogenous substance (EBR+Spd) as the control group.

[0027] Figure 10 Photographs showing the growth status of peppers treated with foliar spraying of the ternary compound exogenous substance (GABA+EBR+Spd) in the experimental group. Detailed Implementation

[0028] To facilitate understanding of this application, the following description will be more comprehensive and detailed in conjunction with the accompanying drawings and preferred embodiments, but the scope of protection of this application is not limited to the following specific embodiments.

[0029] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of this application.

[0030] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0031] This invention conducts combination optimization experiments on three exogenous substances obtained through screening, according to different ratios, and determines that the optimal volume ratio of GABA:EBR:Spd is 1:1:1 (based on their respective optimal concentrations).

[0032] Furthermore, a pot experiment was conducted with four treatments to verify the alleviating effect of the compound exogenous substance. The results showed that compared with the salt stress control, all 10 indicators of pepper seedlings treated with the ternary compound foliar spray were significantly improved (p<0.05). Among them, six aboveground indicators (plant height, stem diameter, SPAD value, leaf length, leaf width, and aboveground fresh weight) were significantly higher than the control and exceeded the level of the salt-free CK; four indicators (underground fresh weight, total root length, root surface area, and root volume) recovered to the level with no significant difference from the salt-free CK, indicating that the compound substance has a significant promoting effect on aboveground growth while comprehensively repairing salt stress damage.

[0033] This invention is the first to discover that the combination of three exogenous substances, GABA, EBR, and Spd, has a significant synergistic effect in alleviating salt stress in chili peppers. When applied as a foliar spray, the ternary compound (GABA+EBR+Spd) not only comprehensively repaired the damage caused by salt stress to chili pepper seedlings, but also caused many aboveground growth indicators to exceed normal levels, demonstrating a significant growth-promoting effect; the repair of root structure was particularly outstanding, with total root length, root surface area, and root volume all fully recovering to normal levels.

[0034] Example 1: 1. Experimental Materials and Methods 1.1 Tested chili pepper varieties The tested chili variety was Changxing No. 8 ( Capsicum annuum L. cv. Changxing 8), identified as a salt-sensitive variety based on previous salt stress screening tests on 52 commercially available chili varieties.

[0035] 1.2 Test salt content The salt solution was prepared using NaCl (analytical grade) with a salt stress concentration of 150 mmol / L (i.e., 8.766 g / L NaCl solution).

[0036] 1.3 Exogenous substances and their preparation The exogenous substances used in the following experiments include: (1) γ-Aminobutyric acid (GABA): molecular weight 103.12 g / mol, concentration used is 200 μmol / L. First prepare a 100 mmol / L stock solution (weigh 1.0312 g GABA, dissolve in distilled water, and make up to 100 mL), and dilute 500 times before use.

[0037] (2) 24-Epibrassinolide (EBR): The concentration used is 0.1 mg / L. Prepare a 10 mg / L stock solution first, and dilute it 100 times before use.

[0038] (3) Spermine (Spd): molecular weight 145.25 g / mol, concentration used is 50 μmol / L. First prepare a 10 mmol / L stock solution (weigh 0.1453 g Spd powder, dissolve in distilled water, and make up to 100 mL), and dilute 200 times before use.

[0039] All spray solutions were mixed with 0.05% (v / v) Tween-20 as a spreading agent. GABA stock solution was stored at 4°C, while EBR and Spd stock solutions were stored at -20°C in the dark.

[0040] 1.4 Experimental Design The experiment consists of two parts: (1) Screening of the optimal ratio of three exogenous substances. Using Changxing No. 8 chili seeds as test material, the three substances obtained from screening, GABA (200 μmol / L), EBR (0.1 mg / L), and Spd (50 μmol / L), were combined and treated in different volume ratios. Plump and uniform chili seeds were selected. Capsicum annuum L. seeds were used to simulate salt stress with a 150 mM NaCl solution. Nine treatment groups were set up using 150 mM NaCl to simulate salt stress, including: (1) 0 (salt-free control group, CK0), cultured in distilled water as a blank control; (2) 150 mM (salt stress control group, CK0)... 150 (2) Cultured alone in 150 mM NaCl as a salt stress control; (3) Mixed exogenous substances in a 1:1:2 ratio, i.e., GABA, EBR, and Spd were mixed in 150 mM NaCl solution in a volume ratio of 1:1:2; (4) Mixed exogenous substances in a 1:2:1 ratio, i.e., GABA, EBR, and Spd were mixed in 150 mM NaCl solution in a volume ratio of 1:2:1; (5) Mixed exogenous substances in a 2:1:1 ratio, i.e., GABA, EBR, and Spd were mixed in 150 mM NaCl solution in a volume ratio of 2:1:1; (6) Mixed exogenous substances in a 1:2:2 ratio, i.e., GABA, EBR, and Spd were mixed in 150 mM NaCl solution in a volume ratio of 1:2:2; (7) Mixed exogenous substances in a 1:2:2 ratio, i.e., GABA, EBR, and Spd were mixed in 150 mM NaCl solution in a volume ratio of 1:2:2; (8) 2:1:2 compound exogenous substances, that is, GABA, EBR and Spd are compounded in 150 mM NaCl solution in a volume ratio of 2:1:2; (9) 2:2:1 compound exogenous substances, that is, GABA, EBR and Spd are compounded in 150 mM NaCl solution in a volume ratio of 2:2:1; (10) 1:1:1 compound exogenous substances, that is, GABA, EBR and Spd are compounded in 150 mM NaCl solution in a volume ratio of 1:1:1.

[0041] Accurately weigh NaCl, dissolve and dilute to volume with distilled water to prepare a 150 mM NaCl stock solution. Weigh each exogenous substance separately, dissolve and dilute to volume with the 150 mM NaCl stock solution according to a preset concentration gradient to prepare working solutions for each treatment group. A standard germination test was conducted using the petri dish filter paper method. Double layers of qualitative filter paper were placed in 90 mm diameter petri dishes, with 50 pepper seeds evenly placed in each dish, repeated twice. Then, 5 mL of the corresponding treatment group's working solution was added to each dish to fully saturate the filter paper. The petri dishes were placed in an artificial climate chamber and cultured in the dark at 25 ± 1℃ for 7 days. After culture, the number of germinated seeds in each treatment group was counted. Germination rate (%) was calculated based on the radicle breaking through the seed coat and a length ≥ 2 mm. The bud length (bud length, mm) was measured using vernier calipers. Each treatment was repeated 20 times. The results of each treatment scheme are shown in Table 1 and [Table data missing]. Figure 1 .

[0042] Table 1: Effects of different ratios on germination rate and shoot length of peppers under salt stress

[0043] As can be seen from Table 1, the 1:1:1 ratio of the optimal germination length (17.66 mm) is the best among all ratios, and the overall germination rate score (0.91) is the same as the highest value. Therefore, the optimal volume ratio of GABA:EBR:Spd at the selected concentration is determined to be 1:1:1.

[0044] (2) Pot experiment to verify the optimal ratio of exogenous substances. The experiment was conducted in the greenhouse of the teaching and practice base of the College of Resources and Environment, Hunan Agricultural University. 0.5-gallon plastic pots were used, and the cultivation substrate was a mixture of red and yellow soil and vermiculite in a volume ratio of 7:3. One 4-leaf and 1-heart stage pepper seedling was planted in each pot. Salt stress treatment (all treatments except healthy control group 1) was performed by watering each pot with 100 mL of 150 mM NaCl solution every other day for a total of 5 times. To systematically evaluate whether the ternary compound treatment has a synergistic effect, nine foliar spray treatments were set up in the experiment, in the following order: CK (no salt stress, no exogenous substance control - control group 1), CK+ (150mM NaCl salt stress control - control group 2), GABA (single GABA treatment - control group 3), EBR (single EBR treatment - control group 4), Spd (single Spd treatment - control group 5), G+E (GABA+EBR binary compound - control group 6), G+S (GABA+Spd binary compound - control group 7), E+S (EBR+Spd binary compound - control group 8), and G+E+S (GABA+EBR+Spd ternary compound - experimental group). Plant height, stem diameter, SPAD, leaf length, leaf width, aboveground fresh weight, underground fresh weight, total root length, root surface area, and root volume were measured, with each treatment replicated four times.

[0045] 1.5 Application Method Salt stress treatment: Except for healthy control group 1 (salt-free control), all other treatments (control groups 2-8 and experimental groups) were watered with 100 mL of 150 mM NaCl solution per pot each time, once every other day, for a total of 5 times; control group 1 was watered with the same amount of distilled water at the same time.

[0046] Foliar spraying was initiated on the day salt stress was applied, once every 3 days for a total of 7 applications. Using a small spray bottle, the spray solution was evenly applied to both sides of the leaves until droplets began to drip. The amount sprayed per pot was approximately 10 mL each time, adjusted appropriately according to plant size, ensuring the leaves were completely moistened. Control group 1 and the experimental group only required the corresponding spray solution; control groups 2-8 were sprayed with their respective alternative spray solutions. All treatments were administered simultaneously to ensure a single variable.

[0047] The specific experimental design and application methods are as follows: experimental group According to the above experimental design, a ternary compound of exogenous substances (GABA 200 μmol / L + EBR 0.1 mg / L + Spd 50 μmol / L) was applied as a foliar spray to pepper seedlings. Salt stress was initiated on the same day, and spraying was carried out once every 3 days for a total of 7 times.

[0048] Control group 1 The only difference from the experimental group was that no salt stress was applied (no NaCl solution was poured in), and the ternary compound exogenous substance spray solution was replaced with an equal amount of distilled water containing 0.05% Tween-20. All other conditions were exactly the same.

[0049] Control group 2 The difference from the experimental group was that an equal amount of distilled water containing 0.05% Tween-20 was used instead of the ternary compound exogenous substance spray solution, while all other conditions were exactly the same.

[0050] Control group 3 The difference from the experimental group was that 200 μmol / L GABA solution was used instead of the ternary compound exogenous substance spray solution, while all other conditions were exactly the same.

[0051] Control group 4 The difference from the experimental group was that the ternary compound exogenous substance spray solution was replaced with 0.1 mg / L EBR solution, while all other conditions were exactly the same.

[0052] Control group 5 The difference from the experimental group was that a 50 μmol / L Spd solution was used instead of the ternary compound exogenous substance spray solution, while all other conditions were exactly the same.

[0053] Control group 6 The difference from the experimental group was that the ternary compound exogenous substance spray solution was replaced with a binary compound solution of GABA (200 μmol / L) + EBR (0.1 mg / L), while all other conditions were exactly the same.

[0054] Control group 7 The difference from the experimental group was that the ternary compound exogenous substance spray solution was replaced with a binary compound solution of GABA (200 μmol / L) + Spd (50 μmol / L), while all other conditions were exactly the same.

[0055] control group 8 The difference from the experimental group was that the ternary compound exogenous substance spray solution was replaced with a binary compound solution of EBR (0.1 mg / L) + Spd (50 μmol / L), while all other conditions were exactly the same.

[0056] 1.6 Index Measurement Plant samples were collected on day 30 after the initial treatment. Measurements included: plant height (cm), stem diameter (mm), SPAD value, leaf length (mm), leaf width (mm), aboveground fresh weight (g), and underground fresh weight (g). In addition, root systems were collected for scanning analysis. Total root length (cm) and root surface area (cm²) were measured using a root scanner (EPSON Expression 11000XL) and WinRHIZO root analysis software. 2 ) and root volume (cm) 3 ).

[0057] 1.7 Data Analysis Microsoft Excel 2019 and SPSS were used for data processing and statistical analysis. One-way ANOVA and Duncan's new multiple range test were used for multiple comparisons (p<0.05). Different lowercase letters indicate statistical significance between treatments. Data in the table are expressed as mean ± standard error (Mean ± SE).

[0058] 1.8 Experimental Results and Analysis Experimental group: such as Figure 10 As shown, after 30 days, the chili seedlings exhibited vigorous above-ground growth, compact plant type, thick stems, dark green leaves with increased leaf area, well-developed and evenly distributed root system, and abundant root mass. Their overall growth was significantly better than that of the control treatments.

[0059] Control group 1: such as Figure 2 As shown, after 30 days, all indicators of the chili seedlings were at a normal and good level, serving as the baseline value for a healthy control.

[0060] Control group 2: such as Figure 3As shown, after 30 days, the above-ground parts of the chili seedlings withered and stunted, the plants were small, the stems were thin and weak, the leaves were small and yellow, and the overall growth was significantly inhibited. The root system was significantly shortened and the root mass was sharply reduced.

[0061] Control group 3: such as Figure 4 As shown, after 30 days, the SPAD value and leaf width of pepper seedlings recovered to a relatively high level, but the plant height, aboveground fresh weight and root system structure indicators did not reach the normal control level, and root growth was still relatively sparse.

[0062] Control group 4: such as Figure 5 As shown, after 30 days, the above-ground elongation of the chili seedlings recovered significantly, and the plant height and leaf length also recovered considerably. The total root length improved to some extent, but the SPAD value and underground fresh weight were still low, and the root system was not dense enough.

[0063] Control group 5: such as Figure 6 As shown, after 30 days, the overall recovery of chili seedlings was weak, with plant height and leaf length remaining at low levels, insufficient accumulation of aboveground biomass, and limited improvement in root structure.

[0064] Control group 6: such as Figure 7 As shown, after 30 days, the aboveground fresh weight and root structure of the chili seedlings recovered well, but the plant height was relatively short and the SPAD value was at a moderate to low level.

[0065] Control group 7: such as Figure 8 As shown, after 30 days, the overall mitigation effect of pepper seedlings was weaker in the binary combination, with lower aboveground fresh weight, poor root development, and insufficient recovery of root surface area and root volume.

[0066] Control group 8: such as Figure 9 As shown, after 30 days, the height and stem diameter of the chili seedlings recovered to a relatively good level, but the SPAD value was moderately low, the root system structure recovered poorly, and the total root length and root surface area were much lower than those of the experimental group.

[0067] Specifically, the results of the measured aboveground growth indicators, biomass, and root architecture indicators of chili peppers are shown in Tables 2 and 3, respectively.

[0068] Table 2: Effects on aboveground growth indicators of chili peppers

[0069] Note: Different lowercase letters in the same column indicate significant differences between treatments (Duncan's new multiple range method, p<0.05). The F-test indicates that the difference is highly significant (p<0.01). n=4.

[0070] Table 3: Effects on pepper biomass and root architecture indices

[0071] Note: Different lowercase letters in the same column indicate significant differences between treatments (Duncan's new multiple range method, p<0.05). The F-test indicates that the difference is highly significant (p<0.01). n=4.

[0072] As shown in Tables 2 and 3, the growth indicators of pepper seedlings treated with the ternary compound exogenous substance in the experimental group were significantly improved compared with those of the control groups. The salt stress control (control group 2) showed significantly lower values ​​than the experimental group in all 10 indicators: plant height was only 45.0% of the experimental group, stem diameter was only 69.5%, SPAD value was only 54.9%, leaf length was only 72.4%, leaf width was only 70.5%, above-ground fresh weight was only 38.9%, underground fresh weight was only 57.7%, total root length was only 52.3%, root surface area was only 47.5%, and root volume was only 35.6%. Compared with the healthy control group (control group 1) without salt stress, the plant height of each control group was lower than that of the experimental group, with decreases of 24.1%, 9.2%, 5.8%, 33.0%, 11.0%, 13.1%, and 2.1%, respectively. Only after applying the experimental group did the plant height of the pepper seedlings increase to 47.75 cm, significantly higher than that of control group 1 (40.75 cm), an increase of 17.2%. Regarding stem diameter, all control groups (comparison groups 2-8) showed a decrease compared to the experimental groups, with reductions of 20.4%, 10.8%, 5.3%, 14.9%, 7.7%, 9.4%, and 4.3%, respectively. Among them, control group 4 (3.95 mm) and control group 8 (3.98 mm) performed relatively better, but were still lower than the experimental group (4.16 mm). Regarding SPAD values, all control groups (control groups 2-8) showed a decrease compared to the experimental groups, with reductions of 45.0%, 2.2%, 2.5%, 13.6%, 13.4%, 15.1%, and 11.3%, respectively.

[0073] In terms of biomass and root architecture, the experimental group showed a more significant advantage. Compared with control group 1, the underground fresh weight of all control groups and experimental groups decreased, with reductions of 47.9%, 48.4%, 32.4%, 27.3%, 30.0%, 17.6%, 34.8%, 30.7%, and 9.6%, respectively. Only after applying the experimental group did the underground fresh weight of the peppers (3.38 g) reach the same significance level as control group 1 (3.74 g) (with the same marker a), indicating the most thorough recovery. Regarding aboveground fresh weight, the other control groups all decreased compared to control group 1 (16.85 g), with reductions of 57.0%, 16.7%, 9.2%, 15.5%, 3.8%, 18.8%, and 8.4%, respectively. Only the aboveground fresh weight of the experimental group (18.66 g) exceeded that of control group 1, with an increase of 10.7%, indicating that the ternary compound not only restored the aboveground biomass but also achieved additional growth. Regarding root architecture: the total root length of control group 2 decreased by 56.6% compared to control group 1, and the other control groups all showed significant decreases compared to control group 1, with decreases of 51.8%, 21.4%, 46.5%, 32.5%, 50.6%, and 50.2%, respectively. In contrast, the total root length of the experimental group decreased by only 17.0%, reaching the same significance level as control group 1 (label a). Regarding root surface area, the decreases in other control groups compared to control group 1 were 61.5%, 49.2%, 32.7%, 46.3%, 24.8%, 51.3%, and 54.4%, respectively, while the decrease in the experimental group was only 19.1%. Regarding root volume, the decreases in other control groups compared to control group 1 were 70.2%, 44.7%, 44.5%, 46.8%, 21.7%, 50.2%, and 54.9%, respectively, while the decrease in the experimental group was only 16.2%, also reaching the same significance level as control group 1 (label a).

[0074] The above data show that spraying the experimental group with the ternary compound exogenous substance (GABA+EBR+Spd) according to the method of the present invention can significantly promote the growth of pepper seedlings under salt stress. The key point is that the experimental group is better than all control groups in all 10 indicators. Among them, 6 aboveground indicators (plant height, stem diameter, leaf length, leaf width, SPAD, and aboveground fresh weight) even surpass the healthy control without salt stress (control group 1), which truly plays a role in comprehensively repairing salt stress damage and additionally promoting growth. In contrast, the control groups 2 to 8 are less effective than the experimental group.

[0075] Based on the above results, the following conclusions can be drawn: (1) 150 mM NaCl stress caused significant inhibitory damage to the aboveground parts and roots of pepper (Changxing No. 8), and all 10 test indicators were significantly lower than those of the healthy control group without salt stress. The damage to the root structure was particularly prominent, with a root volume reduction of 70.2% and a root surface area reduction of 61.5%.

[0076] (2) The allergic effects of the three single exogenous substances (control groups 3, 4, and 5) showed significant differences: EBR (control group 4) had the strongest effect and was the only single substance that approached or surpassed the healthy control in terms of aboveground indicators such as plant height and leaf length; GABA (control group 3) showed the best performance in improving SPAD values; and Spd (control group 5) had a relatively weak independent allergic effect. The three binary compound treatments (control groups 6, 7, and 8) were only superior to the best single treatment in some indicators, and still had significant shortcomings overall.

[0077] (3) After applying the ternary compound exogenous substance provided by this invention (experimental group: GABA 200 μmol / L + EBR 0.1 mg / L + Spd 50 μmol / L), all 10 growth indicators of peppers under salt stress were significantly improved, and all indicators exceeded the optimal values ​​of the best single treatment and the best binary treatment, confirming the synergistic effect. This compound exogenous substance not only comprehensively repaired the salt stress damage (4 root indicators recovered to no significant difference from the healthy control), but also made 6 aboveground indicators exceed the normal level, demonstrating an additional growth-promoting effect.

[0078] (4) The compound exogenous substance formulation and foliar spraying method provided by the present invention can comprehensively repair the damage to pepper caused by 150 mM NaCl stress, while improving the aboveground growth and root structure. It has the advantages of high efficiency, safety, simple operation and low cost, and has good application prospects.

[0079] The above are merely preferred embodiments of this application. It should be noted that this application is not limited to the above embodiments. For those skilled in the art, several improvements and modifications can be made without departing from the principles of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should also be considered within the scope of protection of this application.

Claims

1. A compound exogenous substance for alleviating salt and pepper stress, characterized in that, The exogenous substance is mainly composed of γ-aminobutyric acid at a concentration of 200 μmol / L, 24-epibrassinolide at a concentration of 0.1 mg / L, and spermidine at a concentration of 50 μmol / L.

2. The compound exogenous substance according to claim 1, characterized in that, The volume ratio of γ-aminobutyric acid, 24-epibrassinolactone and spermidine is (1-2):(1-2):(1-2).

3. The compound exogenous substance according to claim 1, characterized in that, The volume ratio of γ-aminobutyric acid, 24-epibrassinolactone, and spermidine is 1:1:

1.

4. A method for relieving salt and pepper stress, characterized in that, Spray the leaves of salt-stressed peppers with the compound exogenous substance as described in any one of claims 1-3.

5. The method as described in claim 4, characterized in that, Spray once every 3 days, for a total of 7 sprays.

6. The method as described in claim 4 or 5, characterized in that, The compound exogenous substance was sprayed onto the leaves of chili seedlings.

7. A method for relieving salt and pepper stress, characterized in that, Salt-stressed chili seeds were treated with a compound exogenous substance as described in any one of claims 1-3 to improve the germination rate and / or shoot length of salt-stressed chili seeds.

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