Amino acid application method for increasing wheat grain weight and drought tolerance

Abstract

The application provides an amino acid application method for improving wheat grain weight and drought resistance, and belongs to the field of agricultural technology.The method mainly sprays glutamic acid solution at the wheat heading stage and the flowering stage, and the method can significantly improve the drought resistance of plants and offspring wheat at the grain filling stage.The results of examples show that the method can improve the SPAD value, photosynthetic rate and antioxidant enzyme activity of wheat under post-flowering drought stress, prolong the grain filling duration of wheat, and finally increase the dry matter accumulation amount, total starch content and grain weight.Meanwhile, the method can also maintain the germination energy, alpha-amylase activity, soluble sugar content, plant height, root number, total root surface area, total root volume of offspring wheat under PEG-6000 stress, reduce the relative permeability of the cell membrane, reduce the harm of drought stress to offspring wheat, and finally show that the adaptability of offspring wheat to drought stress is enhanced.

Description

Technical Field

[0001] This invention belongs to the field of agricultural technology, specifically relating to a method for applying amino acids to improve wheat grain weight and drought resistance. Background Technology

[0002] Extreme weather events, such as frequent high temperatures and droughts, occur frequently in major wheat-producing areas, leading to a decline in both wheat grain yield and quality. In dryland agriculture, improving wheat's resistance to drought stress and implementing corresponding mitigation measures to reduce its adverse effects are of great significance. Amino acids are organic compounds composed of basic amino and acidic carboxyl groups, belonging to the category of organic nitrogen sources, and can exert certain fertilizer effects. Irrigation and growth regulators are key cultivation measures for controlling wheat yield and quality. Currently, there are no research reports on amino acid fertilization techniques to improve wheat grain weight and synergistically enhance drought resistance under drought stress. Improving wheat grain weight and drought resistance under drought stress is a major need in my country and worldwide for developing stress-resistant wheat varieties, and it is also a research hotspot and challenge in wheat breeding and cultivation. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide an amino acid application method for improving wheat grain weight and drought resistance. By spraying glutamic acid solution and subjecting wheat to drought stress, the grain weight and drought resistance of wheat under post-flowering drought stress can be improved. Furthermore, it can enhance the germination potential, α-amylase activity, soluble sugar content, plant height, number of roots, total root surface area, and total root volume of progeny wheat under drought stress, thereby improving the drought resistance of progeny wheat.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] This invention provides a method for applying amino acids to improve wheat grain weight and drought resistance, comprising the following steps:

[0006] Spray glutamic acid solution during the wheat heading and flowering stages respectively;

[0007] The concentration of the glutamic acid solution is 2-4 mM.

[0008] Preferably, the first application of glutamic acid solution is carried out 1-2 days after the wheat begins to head;

[0009] Apply glutamic acid solution as a second spray 1-2 days after the wheat begins to flower;

[0010] Each time the glutamic acid solution is sprayed, the dosage is 80-120 mL / m². 2 .

[0011] Preferably, the glutamic acid solution contains Tween 20; the mass concentration of Tween 20 in the glutamic acid solution is 0.1% to 0.3%.

[0012] Preferably, the method of applying the amino acids further includes subjecting the wheat to field drought stress during the flowering to maturity period.

[0013] Preferably, when subjecting the field to drought stress, the absolute soil moisture content should be maintained at ≤14.26% for 0-20 cm and ≤14.53% for 20-40 cm at flowering; ≤10.64% for 0-20 cm and ≤11.57% for 20-40 cm 10 days after flowering; ≤6.96% for 0-20 cm and ≤7.82% for 20-40 cm 20 days after flowering; and ≤4.51% for 0-20 cm and ≤5.60% for 20-40 cm 30 days after flowering.

[0014] Preferred methods for applying drought stress in the field include:

[0015] Irrigate normally from the wheat's greening stage to its flowering stage;

[0016] Stop irrigating during the wheat flowering and ripening period and protect it from rain.

[0017] Preferably, the method for normal irrigation from the greening-up period to the flowering period includes: irrigating once every 10-12 days from the greening-up period to the flowering period, with each irrigation volume being 1100-1150 m³. 3 / hm 2 .

[0018] Preferably, the wheat includes Xindong 18 wheat and / or Xindong 22 wheat.

[0019] The present invention also provides an application of the amino acid application method described above in improving the drought resistance of offspring wheat.

[0020] The present invention also provides an application of the amino acid administration method described above in any one or more of the following (1) to (14):

[0021] (1) Increase the SPAD value of the flag leaf of wheat after flowering under drought stress;

[0022] (2) Increase the photosynthetic rate of the flag leaf of wheat after flowering under drought stress;

[0023] (3) Increase the activity of antioxidant enzymes in the flag leaf of wheat after flowering under drought stress;

[0024] (4) Increase the total dry matter accumulation of wheat plants after flowering under drought stress;

[0025] (5) Under drought stress, prolong the grain-filling period after wheat flowering;

[0026] (6) Increase the grain weight of wheat after flowering under drought stress;

[0027] (7) Increase the germination potential of offspring wheat under drought stress;

[0028] (8) Increase the plant height of offspring wheat under drought stress;

[0029] (9) Under drought stress, the number of roots in offspring wheat increases;

[0030] (10) Increase the total root surface area of ​​offspring wheat under drought stress;

[0031] (11) Under drought stress, it increases the total root volume of offspring wheat;

[0032] (12) Under drought stress, the α-amylase activity of offspring wheat increases;

[0033] (13) Increase the soluble sugar content of offspring wheat under drought stress;

[0034] (14) Drought stress reduces the relative permeability of the plasma membrane of offspring wheat.

[0035] The beneficial effects of this invention are:

[0036] This invention provides a method for applying amino acids to improve wheat grain weight and drought resistance, comprising the following steps:

[0037] Spray glutamic acid solution during the wheat heading and flowering stages respectively;

[0038] The concentration of the glutamic acid solution is 2-4 mM.

[0039] The amino acid application method for improving wheat grain weight and drought resistance provided by this invention mainly involves spraying a glutamic acid solution during the wheat heading and flowering stages. This amino acid application method can increase the SPAD value, photosynthetic rate, and antioxidant enzyme activity of wheat under post-flowering drought stress, significantly improving wheat drought resistance, thereby extending the grain-filling period and ultimately increasing dry matter accumulation and grain weight. Simultaneously, the amino acid application method provided by this invention can also maintain the germination potential, α-amylase activity, soluble sugar content, plant height, root number, total root surface area, and total root volume of progeny wheat under PEG-6000 stress, reduce the relative permeability of the plasma membrane, and mitigate the harmful effects of drought stress on progeny wheat. This, in turn, promotes the absorption and utilization of more water and nutrients by progeny wheat, ultimately demonstrating enhanced adaptability to drought stress and improved drought resistance in progeny wheat.

[0040] The amino acid application method provided by this invention solves the technical bottleneck of the past difficulty in improving wheat grain weight and drought resistance under abiotic stress, as well as improving the drought resistance of offspring wheat under abiotic stress. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 A schematic diagram for improving wheat grain weight and drought resistance;

[0043] Figure 2 This figure shows the changes in differentially expressed proteins involved in glutamate metabolism under drought stress.

[0044] Figure 3 Figure showing the effect of exogenous glutamate on photosynthetic rate under drought stress;

[0045] Figure 4 Figure showing the effect of exogenous glutamate on total dry matter accumulation under drought stress;

[0046] Figure 5 This is a graph showing the effect of exogenous glutamate on glutamate content. Detailed Implementation

[0047] This invention provides a method for applying amino acids to improve wheat grain weight and drought resistance, comprising the following steps:

[0048] Spray glutamic acid solution during the wheat heading and flowering stages respectively;

[0049] The concentration of the glutamic acid solution is 2-4 mM.

[0050] This invention preferably applies drought stress to wheat during its flowering to maturity stage. In this invention, the drought stress preferably includes field drought stress. This invention does not have a specific limitation on the selection of wheat; any conventional wheat variety in the art can be used. In this invention, the wheat preferably includes Xindong 18 and / or Xindong 22. When applying drought stress in the field, the present invention preferably maintains the absolute soil moisture content at the following conditions: 0-20 cm soil moisture content ≤14.26% and 20-40 cm soil moisture content ≤14.53% at flowering time; preferably, 10 days after flowering, maintain the absolute soil moisture content at the following conditions: 0-20 cm soil moisture content ≤10.64% and 20-40 cm soil moisture content ≤11.57%; preferably, 20 days after flowering, maintain the absolute soil moisture content at the following conditions: 0-20 cm soil moisture content ≤6.96% and 20-40 cm soil moisture content ≤7.82%; preferably, 30 days after flowering, maintain the absolute soil moisture content at the following conditions: 0-20 cm soil moisture content ≤4.51% and 20-40 cm soil moisture content ≤5.60%.

[0051] The preferred method for applying drought stress to fields according to the present invention includes: normal irrigation during the wheat greening-up stage to the flowering stage; stopping irrigation and preventing rain during the wheat flowering stage to the maturity stage.

[0052] This invention preferably involves normal irrigation during the wheat's greening-up stage to flowering stage. In this invention, the method for normal irrigation during the greening-up stage to flowering stage includes: irrigating once every 10-12 days during this period; the preferred irrigation volume each time is 1100-1150 m³. 3 / hm 2 More preferably 1125 m 3 / hm 2 In this invention, it is preferable to irrigate five times during the wheat's greening-up stage to flowering stage. The total irrigation volume during this period is preferably 5500~5750 m³. 3 / hm 2 More preferably 5625 m 3 / hm 2 The preferred method for irrigation according to the present invention includes drip irrigation.

[0053] The present invention preferably suspends irrigation from the wheat flowering stage to the maturity stage and provides rain protection. The present invention does not specifically limit the method of rain protection; any method conventional in the art can be used. In the embodiments of the present invention, the preferred method of rain protection includes constructing a rain shelter.

[0054] This invention involves spraying a glutamic acid solution during the wheat heading and flowering stages, respectively; the concentration of the glutamic acid solution is preferably 2-4 mM. In this invention, the glutamic acid is preferably L-glutamic acid. Preferably, the glutamic acid solution is sprayed for the first time 1-2 days after the start of wheat heading, and for the second time 1-2 days after the start of wheat flowering. In this invention, the glutamic acid solution preferably contains Tween 20; the mass concentration of Tween 20 in the glutamic acid solution is preferably 0.1%-0.3%, more preferably 0.2%. In this invention, Tween 20 is a surfactant, a type of macromolecule with both hydrophilic and lipophilic parts, which can promote the absorption of water-insoluble macromolecules by plants. In this invention, the amount of glutamic acid solution used each time is preferably 80-120 mL / mM. 2 More preferably 100 mL / m 2 In this invention, spraying is performed after 6 PM each time to avoid high temperatures and direct sunlight. This invention, through the application of appropriate exogenous regulatory substances and abiotic stress treatment during the early stages of crop growth, induces physiological changes in the crop. When faced with the same stress again, these changes enable the crop to develop stronger tolerance, and this physiological defense mechanism is passed on to the next generation.

[0055] The amino acid application method for improving wheat grain weight and drought resistance provided by this invention first determines the core role of glutamic acid based on the effects of different levels of irrigation after wheat flowering on the accumulation of 17 free amino acids in grains and the enhancement effect on key proteins in glutamate synthesis, as well as the characteristics of different wheat varieties' responses to soil moisture at different stages after flowering. Different levels of irrigation and different concentrations of exogenous glutamate are then applied according to the number of days since heading and flowering. The amino acid application method provided by this invention can significantly increase the SPAD value of wheat 7–35 days after flowering, and significantly increase the photosynthetic rate in the early and middle stages of grain filling, as well as the antioxidant enzyme activity 7–21 days after flowering. It can significantly improve wheat drought resistance, extend the duration of grain filling, and ultimately increase the dry matter accumulation and grain weight of wheat. The amino acid application method provided by this invention solves the technical bottleneck of previously difficult-to-improve wheat grain weight and drought resistance under abiotic stress.

[0056] This invention provides an application of the amino acid application method described above in improving the drought resistance of offspring wheat.

[0057] The amino acid application method for improving wheat grain weight and drought resistance provided by this invention involves subjecting wheat to abiotic stress treatment and simultaneously spraying a glutamic acid solution during the wheat heading and flowering stages. This significantly enhances the drought resistance of progeny wheat, thereby improving its germination under drought stress. The amino acid application method provided by this invention maintains the germination potential, α-amylase activity, soluble sugar content, plant height, root number, total root surface area, and total root volume of progeny wheat under PEG-6000 stress, reduces relative plasma membrane permeability, minimizes the harmful effects of drought stress on progeny wheat, and promotes the absorption and utilization of more water and nutrients by the progeny wheat, ultimately demonstrating enhanced adaptability to drought stress in the progeny wheat.

[0058] This invention provides the application of the amino acid administration method described in the above technical solution in any one or more of the following (1) to (14):

[0059] (1) Increase the SPAD value of the flag leaf of wheat after flowering under drought stress;

[0060] (2) Increase the photosynthetic rate of the flag leaf of wheat after flowering under drought stress;

[0061] (3) Increase the activity of antioxidant enzymes in the flag leaf of wheat after flowering under drought stress;

[0062] (4) Increase the total dry matter accumulation of wheat plants after flowering under drought stress;

[0063] (5) Under drought stress, prolong the grain-filling period after wheat flowering;

[0064] (6) Increase the grain weight of wheat after flowering;

[0065] (7) Increase the germination potential of offspring wheat under drought stress;

[0066] (8) Increase the plant height of offspring wheat under drought stress;

[0067] (9) Under drought stress, the number of roots in offspring wheat increases;

[0068] (10) Increase the total root surface area of ​​offspring wheat under drought stress;

[0069] (11) Under drought stress, it increases the total root volume of offspring wheat;

[0070] (12) Under drought stress, the α-amylase activity of offspring wheat increases;

[0071] (13) Increase the soluble sugar content of offspring wheat under drought stress;

[0072] (14) Drought stress reduces the relative permeability of the plasma membrane of offspring wheat.

[0073] The amino acid application method provided by this invention can significantly increase the SPAD value of the flag leaf after wheat flowering. In this invention, compared with the drought-stressed control group, the amino acid application method can significantly increase the SPAD value 7-35 days after flowering. The increase in SPAD value can promote chlorophyll synthesis, thereby resulting in higher photosynthetic capacity.

[0074] The amino acid application method provided by this invention can significantly improve the photosynthetic rate of the flag leaf after wheat flowering. In this invention, compared with the drought stress control group, the amino acid application method can significantly improve the photosynthetic rate of wheat after flowering, which is conducive to increasing the total dry matter accumulation of wheat aboveground parts under drought stress after flowering.

[0075] The amino acid application method provided by this invention can significantly improve the activity of antioxidant enzymes in the flag leaves of wheat after flowering. In this invention, compared with the drought stress control group, the amino acid application method can significantly improve the activity of antioxidant enzymes in wheat after flowering, thereby enhancing the drought resistance of the plant.

[0076] The amino acid application method provided by this invention can significantly increase the total dry matter accumulation of wheat plants after flowering.

[0077] The amino acid application method provided by this invention can significantly prolong the grain-filling period after wheat flowering. In this invention, the amino acid application method prolongs the grain-filling period compared to the drought-stressed control group.

[0078] The amino acid application method provided by this invention can significantly increase the grain weight of wheat after flowering. In this invention, the amino acid application method increased the grain weight of wheat compared to the drought-stressed control group.

[0079] The amino acid application method provided by this invention can significantly improve the germination potential of progeny wheat under drought stress. In this invention, the amino acid application method can significantly improve the germination potential of progeny wheat under 5% and 10% PEG-6000 stress.

[0080] The amino acid application method provided by this invention can significantly improve the plant height of progeny wheat under drought stress. In this invention, the amino acid application method can significantly improve the plant height of progeny wheat under 5% and 10% PEG-6000 stress.

[0081] The amino acid application method provided by this invention can significantly increase the root number of progeny wheat under drought stress. In this invention, the amino acid application method can increase the root number of progeny wheat under 5% and 10% PEG-6000 stress.

[0082] The amino acid application method provided by this invention can significantly increase the total root surface area of ​​progeny wheat under drought stress. In this invention, the amino acid application method can increase the total root surface area of ​​progeny wheat under 5% and 10% PEG-6000 stress.

[0083] The amino acid application method provided by this invention can significantly increase the total root volume of progeny wheat under drought stress. In this invention, the amino acid application method can increase the total root volume of progeny wheat under 5% and 10% PEG-6000 stress.

[0084] The amino acid application method described in this invention increases the number of roots, total root volume, and total root surface area of ​​the offspring wheat, making it easier for the wheat to absorb and utilize more water and nutrients under drought stress.

[0085] The amino acid application method provided by this invention can significantly increase the α-amylase activity of progeny wheat under drought stress. In this invention, the amino acid application method can improve the α-amylase activity of progeny wheat under 5% and 10% PEG-6000 stress. By increasing the α-amylase activity of progeny wheat, the amino acid application method of this invention enables starch to degrade into soluble sugars more quickly and easily, thereby promoting seed germination.

[0086] The amino acid application method provided by this invention can significantly increase the soluble sugar content of progeny wheat under drought stress. In this invention, the amino acid application method can increase the soluble sugar content of progeny wheat under 5% and 10% PEG-6000 stress. This invention, by increasing the soluble sugar content of progeny wheat through the amino acid application method, provides progeny wheat with more nutrient sources during germination under drought stress.

[0087] The amino acid application method provided by this invention can reduce the relative permeability of the plasma membrane of progeny wheat under drought stress. In this invention, the amino acid application method can reduce the relative permeability of the plasma membrane of progeny wheat under 5% and 10% PEG-6000 stress. In this invention, the amino acid application method reduces the harm of drought stress to progeny wheat by decreasing the relative permeability of the plasma membrane.

[0088] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0089] Example 1

[0090] 1. Tested varieties and cultivation overview

[0091] A drought stress experiment was conducted at the teaching and experimental field of Shihezi University from September 2021 to July 2022. The previous crop in the experimental field was soybean, and the average value of the basic soil fertility index was: organic matter 15.4 g·kg⁻¹. -1 Alkaline nitrogen 63 mg·kg -1 15 mg / kg of fast-acting phosphorus -1 208 mg / kg of readily available potassium -1 The winter wheat varieties tested were Xindong 18 and Xindong 22, and the seeds were provided by the Winter Wheat Research Group of the Triticeae Crops Research Institute, College of Agriculture, Shihezi University. The field experiment was a split-plot design, with water as the principal plot factor and wheat material as the secondary plot factor, with three replicates. The plot area was 5 m × 6 m, and the row spacing was 20 cm. The seeding rate was 5.25 × 10⁻⁶ seeds. 6 grains / hm 2 The inter-cell isolation bandwidth is 50cm.

[0092] 2. Irrigation treatment

[0093] This experiment set up two irrigation treatments: (1) Suitable water control (WT), which was irrigated once every 10-12 days from the greening to maturity period, with an irrigation volume of 1125 m³ each time. 3 / hm 2 Total irrigation volume 9000 m³ 3 / hm 2 (2) Drought treatment (DT): The irrigation method before flowering was the same as the control. Irrigation was stopped from flowering to maturity. Rain shelters were erected on cloudy or rainy days. The total irrigation volume was 5625 m³. 3 / hm 2 Drip irrigation was used for both flood-prone and drought-prone conditions.

[0094] 3. Sampling and Determination

[0095] The contents of 17 amino acids and proteomics were determined in wheat at 7 and 14 days after flowering. The method for amino acid content determination followed the national standard GB 5009.124-2016; the method for proteomics determination followed the relevant descriptions in the reference (Li, C., Bao, Y., Guo, W., Li, C., & Li, C. (2024). Multi-omics analysis of response mechanism of programmed cell death in wheat endosperm to post-anthesis-drought stress. Environmental and Experimental Botany, 218, 105614.). Simultaneously, soil moisture content was measured in the WT and DT groups at the flowering stage, early grain-filling stage (10 days after flowering), mid-grain-filling stage (20 days after flowering), and late grain-filling stage (30 days after flowering). The soil moisture content results are shown in Table 2.

[0096] Soil absolute moisture content can be measured using a soil moisture meter or by the drying method. Soil moisture meter brands include Dongmei, Jiangxin Zhanfang, Fujiu, Biaokang, and Haisidi, among others; choosing one brand is sufficient. When purchasing a soil moisture meter, the manufacturer and distributor will provide an instruction manual and after-sales service. Soil moisture meters are inexpensive and easy to use. When measuring soil absolute moisture content using the drying method, a five-point soil sampling method is required. Soil samples are collected from the 0-20 cm and 20-40 cm soil layers within the plot using a soil auger. The calculation formula is: Soil moisture content (%) = (Wfresh - Wdry) / Wdry × 100%. This method is applicable to all types of soil.

[0097] 4. Technical Effects

[0098] Table 1 shows the changes in amino acid content in wheat grains under drought stress after flowering. DT-7d represents 7 days of drought treatment; DT-14d represents 14 days of drought treatment; WT-7d represents 7 days of adequate water treatment; and WT-14d represents 14 days of adequate water treatment. The rate of change of a specific amino acid content at a given time period is calculated as [(DT-WT) / WT]. 100%.

[0099] Changes in differentially expressed proteins involved in glutamate metabolism, such as Figure 2 As shown. Figure 2The data in the following categories compare the effects of different treatments on wheat varieties: XD18-DT7 / WT7: 7 days of drought treatment versus 7 days of adequate water treatment for Xindong 18 wheat; XD18-DT14 / WT14: 14 days of drought treatment versus 14 days of adequate water treatment for Xindong 18 wheat; XD22-DT7 / WT7: 7 days of drought treatment versus 7 days of adequate water treatment for Xindong 22 wheat; and XD22-DT14 / WT14: 14 days of drought treatment versus 14 days of adequate water treatment for Xindong 22 wheat. The formula for calculating the fold change in differential protein levels is: (DT-WT) / WT.

[0100] Table 1. Changes in amino acid content in wheat grains under drought stress after flowering.

[0101]

[0102] Note: "-" indicates that the content of this amino acid decreased under this treatment; WT: adequate irrigation; DT: drought stress.

[0103] As shown in Table 1, the content of most free amino acids in the grains decreased under drought stress, but the content of glutamic acid (Glu) increased. Compared with the WT treatment, the Glutamic acid content of Xindong 18 wheat increased by 41.58% and 67.44% at DT-7d and DT-14d, respectively; while the Glutamic acid content of Xindong 22 wheat increased by 36.71% and 21.10% at DT-7d and DT-14d, respectively.

[0104] Depend on Figure 2 It was found that the expression levels of more than 95% of the differentially expressed proteins involved in Glu metabolism were significantly upregulated in the early stage of drought stress, which ultimately determined that glutamate is closely related to crop stress resistance.

[0105] Example 2

[0106] 1. Tested varieties and cultivation overview

[0107] An exogenous glutamic acid spraying experiment was conducted at the teaching and experimental field of Shihezi University from October 2022 to July 2023. The previous crop in the experimental field was soybean, and the average value of the basic soil fertility index was: organic matter 16.4 g·kg⁻¹. -1 Alkaline nitrogen 67 mg·kg -1 18 mg / kg of readily available phosphorus -1 258 mg / kg of readily available potassium -1 The winter wheat varieties tested were Xindong 18 and Xindong 22, and the seeds were provided by the Winter Wheat Research Group of the Triticeae Crops Research Institute, College of Agriculture, Shihezi University. The field experiment was a split-plot design, with water as the principal plot factor and wheat material as the secondary plot factor, with three replicates. The plot area was 5 m × 6 m, and the row spacing was 20 cm. The seeding rate was 5.25 × 10⁻⁶ seeds. 6grains / hm 2 The inter-cell isolation bandwidth is 50cm.

[0108] 2. Exogenous glutamate treatment

[0109] L-Glu solutions containing 2 mM (G2) and 4 mM (G4) were sprayed on wheat during the heading and flowering stages (0.2% Tween 20 was added to the L-Glu solution to improve treatment efficiency). Specifically, the first spray was applied two days after the wheat plants in the plot began heading, and the second spray was applied two days after the wheat plants began flowering, with each application being 100 mL / m². 2 Spraying was conducted after 6 PM to avoid high temperatures and direct sunlight. The control group, designated G0, did not receive the glutamic acid solution spray.

[0110] 3. Irrigation treatment

[0111] This experiment set up two irrigation treatments: (1) Suitable water control (WT), which was irrigated once every 10-12 days from the greening to maturity period, with an irrigation volume of 1125m³ each time. 3 / hm 2 Total irrigation volume 9000m³ 3 / hm 2 (2) Drought treatment (DT): The irrigation method before flowering was the same as the control. Irrigation was stopped from flowering to maturity. Rain shelters were erected on cloudy or rainy days. The total irrigation volume was 5625 m³. 3 / hm 2 Drip irrigation was used for both flood-prone and drought-prone conditions.

[0112] The experimental groups were as follows: the water-controlled group without exogenous glutamic acid treatment was designated as control group 1, denoted as WT-G0; the drought-treated group without glutamic acid treatment was designated as control group 2, denoted as DT-G0; the drought-treated group sprayed with 2mM glutamic acid solution was designated as experimental group 1, denoted as DT-G2; and the drought-treated group sprayed with 4mM glutamic acid solution was designated as experimental group 2, denoted as DT-G4.

[0113] 4. Sampling and testing

[0114] The photosynthetic rate of flag leaves was measured at the early and middle stages of grain filling; antioxidant enzyme activity was measured at 7, 14, and 21 days after flowering; and wheat grain weight, grain filling characteristic parameters, and SPAD value were measured at 7, 14, 21, 28, and 35 days after flowering. Glutamic acid content was measured at maturity. The specific methods were the same as those described in *Principles and Techniques of Plant Physiology and Biochemistry Experiments* (Beijing: Higher Education Press, 2000), edited by Li Hesheng. Simultaneously, soil moisture content was measured in the WT and DT groups at the flowering, early grain filling (10 days after flowering), middle grain filling (20 days after flowering), and late grain filling (30 days after flowering) stages. The soil moisture content results are shown in Table 2.

[0115] Table 2. Changes in absolute soil moisture content

[0116]

[0117] Note: WT: Adequate Irrigation; DT: Drought Stress; This indicates that the difference is significant at the p < 0.05 level. This indicates that the difference is significant at the p < 0.01 level.

[0118] 5. Technical Effects

[0119] (1) The effect of exogenous glutamate on the change rate of SPAD value of flag leaf under drought stress during the grain filling period is shown in Table 3.

[0120] Table 3. Effects of exogenous glutamate on the rate of change of SPAD value in flag leaves under drought stress during the grain-filling stage.

[0121]

[0122] Explanation: WT: adequate irrigation; DT: drought stress; G0: 0 mM glutamate; G2: 2 mM glutamate; G4: 4 mM glutamate; WT-G0 / DT-G0: comparison between WT-G0 and DT-G0 treatments; SPAD change rate = [(WT-G0) - (DT-G0)) / DT-G0] 100%; DT-G2 / DT-G0: Comparison of DT-G2 and DT-G0 treatments; SPAD change rate = [(DT-G2) - (DT-G0)) / DT-G0] 100%)); DT-G4 / DT-G0: Comparison of DT-G4 and DT-G0 treatments; SPAD change rate = [(DT-G4) - (DT-G0)) / DT-G0] 100%). The same applies below.

[0123] As shown in Table 3, the changes in SPAD values ​​of the flag leaves reveal that, compared with normal drought stress (DT-G0), spraying with 2 or 4 mM glutamic acid during the heading and flowering stages significantly increased the SPAD value 7–35 days after flowering. The conclusion is that, compared with normal drought stress (DT-G0), spraying with 2 or 4 mM glutamic acid during the heading and flowering stages can promote chlorophyll synthesis, resulting in higher photosynthetic capacity.

[0124] (2) Effects of exogenous glutamate on photosynthetic rate under drought stress, such as Figure 3 As shown; Figure 3 Figure A shows the effect of exogenous glutamate on the photosynthetic rate of Xindong 18 under drought stress; Figure B shows the effect of exogenous glutamate on the photosynthetic rate of Xindong 22 under drought stress.

[0125] (3) The effects of exogenous glutamate on the activity of antioxidant enzymes under drought stress are shown in Table 4;

[0126] Table 4. Effects of exogenous glutamate on the rate of change in antioxidant enzyme activity under drought stress during the grain-filling stage.

[0127]

[0128] Explanation: WT: adequate irrigation; DT: drought stress; G0: 0 mM glutamate; G2: 2 mM glutamate; G4: 4 mM glutamate; WT-G0 / DT-G0: comparison of WT-G0 and DT-G0 treatments (change in antioxidant enzyme activity = [(WT-G0) - (DT-G0)) / (DT-G0)] 100%; DT-G2 / DT-G0: Comparison of DT-G2 and DT-G0 treatments (change in antioxidant enzyme activity = [(DT-G2) - (DT-G0)) / (DT-G0)] 100%; DT-G4 / DT-G0: Comparison of DT-G4 and DT-G0 treatments (change in antioxidant enzyme activity = [(DT-G4) - (DT-G0)) / (DT-G0)] 100%.

[0129] As shown in Table 4, compared with normal drought stress (DT-G0), spraying 2 and 4 mM glutamic acid (DT-G2, DT-G4) during the heading and flowering stages significantly increased the activity of antioxidant enzymes under post-flowering drought stress for 7-21 days, thus enhancing the drought resistance of the plants.

[0130] (4) The effect of exogenous glutamate on total dry matter accumulation under drought stress, such as Figure 4 As shown; Figure 4 The results in the left figure represent the total dry matter accumulation of Xindong 18 wheat at the corresponding stages of flowering, early grain filling, middle grain filling, and late grain filling; the results in the right figure represent the total dry matter accumulation of Xindong 22 wheat at the corresponding stages of flowering, early grain filling, middle grain filling, and late grain filling.

[0131] Explanation: WT: Adequate irrigation; DT: Drought stress; G0: 0 mM glutamate; G2: 2 mM glutamate; G4: 4 mM glutamate. WT-G0 represents the adequately irrigated control group without glutamate application; DT-G0 represents the drought stress treatment group without glutamate application; DT-G2 represents the drought stress treatment group with 2 mM glutamate application; DT-G4 represents the drought stress treatment group with 4 mM glutamate application. The same applies below.

[0132] Figure 3 Table 4 Figure 4The study demonstrated the effects of exogenous glutamate on photosynthetic rate, antioxidant enzyme activity, and dry matter accumulation under drought stress. The results showed that compared to normal drought stress (DT-G0), spraying with 2 and 4 mM glutamate during heading and flowering significantly increased photosynthetic rate in the early and mid-grain-filling stages, as well as antioxidant enzyme activity from 7 to 21 days post-flowering. Spraying with 2 and 4 mM glutamate under drought stress resulted in higher antioxidant enzyme activity and photosynthetic rate, ultimately significantly increasing the total dry matter accumulation of wheat aboveground parts under post-flowering drought stress.

[0133] (5) Changes in glutamate content under the influence of exogenous glutamate, as shown in the figure Figure 5 As shown.

[0134] Depend on Figure 5 Analysis shows that spraying 2 or 4 mM glutamic acid during the heading and flowering stages increased the glutamic acid content at maturity, but the effect varied depending on the variety.

[0135] (6) The effects of exogenous glutamic acid on grain weight changes under drought stress during the grain filling period are shown in Table 5.

[0136] Table 5. Effects of exogenous glutamate on grain weight changes under drought stress during the grain-filling stage.

[0137]

[0138] Note: WT-G0 / DT-G0: Comparison of WT-G0 and DT-G0 treatments (particle weight change rate = [(WT-G0) - (DT-G0)) / DT-G0) 100%)); DT-G2 / DT-G0: Comparison of DT-G2 and DT-G0 treatments (particle weight change rate = [(DT-G2) - (DT-G0)) / DT-G0] 100%)); DT-G4 / DT-G0: Comparison of DT-G4 and DT-G0 treatments (particle weight change rate = [(DT-G4) - (DT-G0)) / DT-G0] 100%). The same applies below.

[0139] Table 5 shows the effect of exogenous glutamic acid on grain weight change rate under drought stress. It was found that compared with normal drought stress (DT-G0), spraying 2 mM and 4 mM glutamic acid at the heading and flowering stages increased grain weight (all grain weight change rates were positive). The conclusion is that spraying 2 and 4 mM glutamic acid at the heading and flowering stages increased wheat grain weight under drought stress.

[0140] (7) The effects of exogenous glutamate on wheat grain filling parameters under drought stress are shown in Table 6.

[0141] Table 6. Effects of exogenous glutamate on wheat grain-filling parameters under drought stress.

[0142]

[0143] Note: t1: Start time of peak grouting period, t2: End time of peak grouting period, t3: Termination time of grouting. T1: Duration of gradual increase period, T2: Duration of rapid increase period, T3: Duration of slow increase period. V1: Grouting rate during gradual increase period, V2: Grouting rate during rapid increase period, V3: Grouting rate during slow increase period. Y1: Accumulated volume during gradual increase period, Y2: Accumulated volume during rapid increase period, Y3: Accumulated volume during slow increase period; Y1 = T1 V1, Y2=T2 V2, Y3 = T3 V3. WT: Adequate irrigation; DT: Drought stress; G0: 0 mM glutamate; G2: 2 mM glutamate; G4: 4 mM glutamate.

[0144] Analysis of the grain-filling characteristic values ​​in Table 6 revealed that the DT-G0 treatment for Xindong 18 wheat had the longest gradual increase period. The durations of the rapid and slow increase periods were longer in the DT-G2 and DT-G4 treatments than in the DT-G0 treatment. The grain-filling rates during the gradual, rapid, and slow increase periods were all higher in the DT-G4 treatment than in the DT-G0 treatment. The grain weight accumulation during the gradual, rapid, and slow increase periods was higher in the DT-G2 treatment than in the DT-G0 treatment. For Xindong 22 wheat, the WT-G0 treatment had the fastest grain-filling rate and the longest rapid increase period. Furthermore, the DT-G2 and DT-G4 treatments for Xindong 22 wheat had higher values ​​for all 12 grain-filling characteristic parameters than the DT-G0 treatment. Conclusion: Compared with normal drought stress (DT-G0), spraying 2 and 4 mM glutamic acid at the heading and flowering stages prolonged the grain-filling duration.

[0145] In summary, compared with normal drought stress, spraying with 2mM and 4mM glutamic acid solution during the heading and flowering stages can significantly increase the SPAD value 7-35 days after flowering, and significantly increase the photosynthetic rate in the early and middle stages of grain filling and the antioxidant enzyme activity 7-21 days after flowering. This can significantly improve the drought resistance of wheat, thereby increasing the dry matter accumulation of wheat, and ultimately increasing the duration of wheat grain filling and grain weight.

[0146] Example 3

[0147] 1. Test varieties

[0148] The test materials were seeds of Xin Dong 18 (WT-G0, DT-G0, DT-G2, DT-G4) and Xin Dong 22 (WT-G0, DT-G0, DT-G2, DT-G4) harvested in July 2023 at the teaching and experimental field of Shihezi University in Xinjiang (44°17N, 86°03E, altitude 461m), totaling 8 materials.

[0149] 2. Test treatment

[0150] Germination experiments were conducted from October to December 2023 in the light incubator of the Winter Wheat Research Group at the College of Agriculture, Shihezi University. First, wheat seeds with uniform grain plumpness were selected, then sterilized. Finally, 30 seeds were evenly placed in each petri dish, and each treatment was repeated three times. 5 mL of 0%, 5%, and 10% PEG-6000 solutions were added to 90 mm petri dishes, respectively. The filter paper in the petri dishes was kept thoroughly moistened with the stress solution daily.

[0151] 3. Sampling and Determination

[0152] Germination potential, α-amylase activity, soluble sugar content, and relative permeability of the plasma membrane were measured at 3 days after germination, and plant height, number of roots, total root surface area, and total root volume were measured at 7 days after germination.

[0153] The 3,5-dinitrosalicylic acid method was used to determine α-amylase activity. Since maltose can reduce the latter to generate the chromogenic group of 3,5-dinitrosalicylic acid, the intensity of the color is proportional to the intensity of the sugar within a certain range. Therefore, the maltose content can be calculated, and the amylase activity is expressed in milligrams of maltose.

[0154] The soluble sugar content was determined using the anthrone method, first with a glucose standard solution (100 μg / mL). -1 To prepare a standard curve, boil the sample to extract soluble sugars. Finally, take 1.0 mL of the sample extract, add 5 mL of anthrone reagent, and measure the color at 620 nm.

[0155] Five wheat seeds from each treatment that had germinated for 3 days were first rinsed three times with distilled water, then blotted dry with filter paper. The five seeds from each treatment were then placed in test tubes containing 10 mL of deionized water and soaked for 12 h. The conductivity (R1) of the extract was measured using a portable DDSJ-308F benchtop conductivity meter (Qingdao Mingbo Environmental Protection Technology Co., Ltd.). Finally, the conductivity (R2) of the extract was measured again after boiling in a water bath for 30 min and cooling to room temperature. Relative conductivity = (R1 / R2) × 100%

[0156] Three wheat plants of uniform growth from each treatment were selected after 7 days of germination. The roots were rinsed with distilled water, blotted dry with filter paper, laid flat with minimal root overlap, and root data were collected using a root scanner (Wanshen LS-A, Phantom 9850XL PLUS, China). Root parameters were analyzed using WinRHIZO-PRO2009 software.

[0157] 4. Technical Effects

[0158] (1) The effect of L-Glu spraying on the germination potential of offspring wheat under drought stress is shown in Table 7.

[0159] Table 7. Effects of L-Glu spraying on parent wheat on germination potential of offspring wheat under drought stress (unit: %)

[0160]

[0161] Table 7 shows that spraying 2 mM glutamic acid (DT-G2) on the parent wheat of Xindong 18 improved the germination potential of the progeny wheat of Xindong 18 under 5% PEG-6000 stress, and spraying 4 mM glutamic acid (DT-G4) improved the germination potential of the progeny wheat of Xindong 18 under 10% PEG-6000 stress. Similarly, spraying 2 mM glutamic acid (DT-G2) on the parent wheat of Xindong 22 improved the germination potential of the progeny wheat of Xindong 22 under both 5% and 10% PEG-6000 stress.

[0162] (2) The effect of spraying L-Glu on the plant height of offspring wheat 7 days after germination under drought stress is shown in Table 8.

[0163] Table 8. Effects of L-Glu spraying on parent wheat on plant height of offspring wheat at 7 days of germination under drought stress (unit: cm)

[0164]

[0165] As shown in Table 8, spraying the parent wheat of Xindong 18 with 2 mM and 4 mM glutamic acid solutions (DT-G2 and DT-G4) can increase the plant height of the progeny wheat of Xindong 18 under 10% PEG-6000 stress; spraying the parent wheat of Xindong 22 with 4 mM glutamic acid (DT-G4) can increase the plant height of the progeny wheat of Xindong 22 under 5% and 10% PEG-6000 stress.

[0166] (3) The effect of L-Glu spraying on the number of roots of offspring wheat 7 days after germination under drought stress is shown in Table 9.

[0167] Table 9. Effects of L-Glu spraying on parent wheat on root number at 7 days of germination in offspring wheat under drought stress treatment.

[0168]

[0169] Table 9 shows that spraying 2 mM and 4 mM glutamic acid (DT-G2 and DT-G4) on the parent wheat of Xindong 18 increased the root number of the progeny wheat of Xindong 18 under 5% and 10% PEG-6000 stress; spraying 4 mM glutamic acid (DT-G4) on the parent wheat of Xindong 22 increased the root number of the progeny wheat of Xindong 22 under 5% and 10% PEG-6000 stress. This allows the wheat to absorb and utilize more water and nutrients under drought stress.

[0170] (4) The effect of L-Glu spraying on parent wheat on the total root surface area of ​​offspring wheat germination 7 days under drought stress is shown in Table 10.

[0171] Table 10 Effect of L-Glu spraying on parent wheat on total root surface area of ​​offspring wheat at 7 days of germination under drought stress (unit: mm) 2 )

[0172]

[0173] Table 10 shows that spraying 2 mM and 4 mM glutamic acid (DT-G2, DT-G4) on the parent wheat of Xindong 18 increased the total root surface area of ​​the progeny wheat of Xindong 18 under 5% PEG-6000 stress; spraying 2 mM and 4 mM glutamic acid (DT-G2, DT-G4) on the parent wheat of Xindong 22 increased the total root surface area of ​​the progeny wheat of Xindong 22 under 10% PEG-6000 stress. This allows the wheat to absorb and utilize more water and nutrients under drought stress.

[0174] (5) The effect of L-Glu spraying on parent wheat on the total root volume of offspring wheat germination 7 days under drought stress is shown in Table 11.

[0175] Table 11 Effect of L-Glu spraying on parent wheat on total root volume of offspring wheat at 7 days of germination under drought stress (unit: mm) 3 )

[0176]

[0177] Table 11 shows that spraying 4 mM glutamic acid (DT-G4) on the parent wheat of Xindong 18 increased the total root volume of the progeny wheat of Xindong 18 under 5% and 10% PEG-6000 stress; spraying 4 mM glutamic acid (DT-G4) on the parent wheat of Xindong 22 increased the total root volume of the progeny wheat of Xindong 22 under 5% PEG-6000 stress. This allows the wheat to absorb and utilize more water and nutrients under drought stress.

[0178] (6) The effect of L-Glu spraying on parent wheat on the α-amylase activity of offspring wheat 3 days after germination under drought stress is shown in Table 12.

[0179] Table 12 Effects of L-Glu spraying on parent wheat on α-amylase activity of offspring wheat at 3 days of germination under drought stress (unit: mg / (g·min))

[0180]

[0181] Table 12 shows that spraying the parent wheat varieties Xindong 18 and Xindong 22 with 2mM and 4mM glutamic acid solution (DT-G4) can increase the α-amylase activity of the progeny wheat under 0%, 5%, and 10% PEG-6000 stress. Ultimately, this allows starch to be degraded into soluble sugars more quickly and easily, providing nutrients for seed germination.

[0182] (7) The effect of L-Glu spraying on parent wheat on the soluble sugar content of offspring wheat 3 days after germination under drought stress is shown in Table 13.

[0183] Table 13 Effect of L-Glu spraying on parent wheat on soluble sugars in offspring wheat at 3 days of germination under drought stress (unit: mg / g)

[0184]

[0185] As shown in Table 13, spraying the parent wheat of Xindong 18 with 2mM and 4mM glutamic acid solutions (DT-G2, DT-G4) can increase the soluble sugar content of the progeny wheat under 5% and 10% PEG-6000 stress; spraying the parent wheat of Xindong 22 with 2mM and 4mM glutamic acid solutions (DT-G2, DT-G4) can increase the soluble sugar content of the progeny wheat under 5% PEG-6000 stress; ultimately, this provides more nutrient sources for wheat germination under drought stress.

[0186] (8) The effect of L-Glu spraying on parent wheat on the relative permeability of the plasma membrane of offspring wheat 3 days after germination under drought stress is shown in Table 14.

[0187] Table 14 Effect of L-Glu spraying on parent wheat on relative plasma membrane permeability of offspring wheat 3 days after germination under drought stress (unit: %)

[0188]

[0189] As shown in Table 14, spraying 4 mM glutamic acid (DT-G4) on the parent wheat of Xindong 18 and Xindong 22 can reduce the relative permeability of the plasma membrane of the offspring wheat under 5% PEG-6000 stress, thereby reducing the damage of wheat to drought stress.

[0190] In summary, the method for improving the drought resistance of wheat progeny provided by this invention, by subjecting parent wheat to drought stress and spraying with glutamic acid, can increase the SPAD value, photosynthetic rate, and antioxidant enzyme activity of wheat under post-flowering drought stress, significantly improving the drought resistance of wheat, thereby extending the grain-filling period, and ultimately increasing dry matter accumulation and grain weight. Simultaneously, the method provided by this invention can also maintain the germination potential, α-amylase activity, soluble sugar content, plant height, root number, total root surface area, and total root volume of progeny wheat under PEG-6000 stress, reduce the relative permeability of the plasma membrane, and mitigate the harmful effects of drought stress on progeny wheat. This, in turn, promotes the absorption and utilization of more water and nutrients by progeny wheat, ultimately demonstrating enhanced adaptability of progeny wheat to drought stress.

[0191] Therefore, the amino acid application method provided by this invention for improving wheat grain weight and drought resistance is beneficial for increasing wheat grain weight and drought resistance under post-flowering drought stress, and also for promoting the rapid germination of offspring wheat seeds under adverse conditions, thereby improving the drought resistance of offspring.

[0192] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for applying amino acids to improve wheat grain weight and drought resistance, characterized in that, Includes the following steps: Spray glutamic acid solution during the wheat heading and flowering stages respectively; The concentration range of the glutamic acid solution is 2~4 mM; Spray glutamic acid solution for the first time 1-2 days after the wheat begins to head; Apply glutamic acid solution as a second spray 1-2 days after the wheat begins to flower; The amount of the glutamic acid solution used is 80 to 120 mL / m 2 ; The glutamic acid solution contains Tween 20; The mass concentration of Tween 20 in the glutamic acid solution is 0.1%~0.3%; The method for applying amino acids further includes: subjecting wheat to field drought stress from the flowering to maturity stage; during field drought stress, maintaining the absolute soil moisture content at 0-20cm depth ≤14.26% and at 20-40cm depth ≤14.53% at flowering; maintaining the absolute soil moisture content at 0-20cm depth ≤10.64% and at 20-40cm depth ≤11.57% 10 days after flowering; maintaining the absolute soil moisture content at 0-20cm depth ≤6.96% and at 20-40cm depth ≤7.82% 20 days after flowering; and maintaining the absolute soil moisture content at 0-20cm depth ≤4.51% and at 20-40cm depth ≤5.60% 30 days after flowering. Methods for applying drought stress in the field include: Irrigate normally from the wheat's greening stage to its flowering stage; Stop irrigation during the wheat flowering and ripening period and protect it from rain; The method for normal irrigation from the greening stage to the flowering stage includes: irrigating once every 10-12 days during the greening stage to the flowering stage, with each irrigation volume being 1100-1150 m³. 3 / hm 2 .

2. The method for administering amino acids according to claim 1, characterized in that, The wheat includes Xindong 18 wheat and / or Xindong 22 wheat.

3. The method for administering amino acids according to claim 1, characterized in that, Each spraying should be done after 6 p.m. to avoid high temperatures and direct sunlight.

4. The method for administering amino acids according to claim 1, characterized in that, The rain protection method includes building a rain shelter for rain protection.

5. The method for administering amino acids according to claim 1, characterized in that, Methods of irrigation include drip irrigation.

6. The method for administering amino acids according to claim 1, characterized in that, The total irrigation volume for the wheat from the greening stage to the flowering stage is 5500~5750m³. 3 / hm 2 .

7. The application of the amino acid application method according to any one of claims 1 to 6 in improving the drought resistance of offspring wheat.

8. The use of the amino acid administration method according to any one of claims 1 to 6 in any two or more of the following (1) to (14): (1) Increase the SPAD value of the flag leaf of wheat after flowering under drought stress; (2) Increase the photosynthetic rate of the flag leaf after flowering of wheat under drought stress; (3) Increase the activity of antioxidant enzymes in the flag leaf of wheat after flowering under drought stress; (4) Increase the total dry matter accumulation of wheat plants after flowering under drought stress; (5) Under drought stress, prolong the grain-filling period after wheat flowering; (6) Increase the grain weight of wheat after flowering under drought stress; (7) Increase the germination potential of offspring wheat under drought stress; (8) Increase the plant height of offspring wheat under drought stress; (9) Under drought stress, the number of roots in offspring wheat increases; (10) Increase the total root surface area of ​​offspring wheat under drought stress; (11) Under drought stress, it increases the total root volume of offspring wheat; (12) Under drought stress, the α-amylase activity of offspring wheat increases; (13) Increase the soluble sugar content of offspring wheat under drought stress; (14) Drought stress reduces the relative permeability of the plasma membrane of offspring wheat.

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