Method for improving high-temperature resistance of dianthus caryophyllus by utilizing exogenous silicon

Abstract

The invention relates to the technical field of biology, and discloses a method for improving high-temperature resistance of carnation by utilizing exogenous silicon, the high-temperature resistance of the carnation is improved by spraying an exogenous silicon solution on the surface of carnation leaves, and the spraying concentration of the exogenous silicon solution is 0.5-2.0 mM. According to the method for improving the high-temperature resistance of the dianthus caryophyllus by utilizing the exogenous silicon, the exogenous silicon solution is sprayed on the surface of the dianthus caryophyllus, so that the adverse effect of high temperature on the dianthus caryophyllus can be improved, the growth index of the dianthus caryophyllus under high-temperature stress is obviously improved, and the photosynthesis under the high-temperature stress is enhanced; the oxidative stress of the dianthus caryophyllus under high-temperature stress is relieved, and the oxidation resistance of plants is improved.

Description

Technical Field

[0001] This invention relates to the field of biotechnology, and in particular to a method for improving the high-temperature resistance of carnations using exogenous silicon. Background Technology

[0002] Climate change in recent years has led to a rise in global average temperatures, increasing the frequency of extreme heat events. Temperature is a crucial factor affecting plant growth, and high temperatures can hinder various physiological processes, making it a major abiotic stress limiting plant growth and production. When plants are subjected to high-temperature stress, it affects their growth, inhibiting photosynthesis, reducing chlorophyll content, accelerating the accumulation of reactive oxygen species causing oxidative damage, inhibiting root growth, affecting root architecture, and suppressing the development of lateral roots and root hairs. When temperatures rise above a critical level, high temperatures can cause irreversible damage to plant growth.

[0003] Carnations, one of the world's four major cut flowers, have extremely high ornamental value and hold a pivotal position in the market. Carnations prefer cool conditions and are intolerant of heat. However, due to the hot and dry summers in most parts of my country, the normal physiological requirements for carnation growth cannot be met under natural growing conditions, resulting in poor plant condition and a significant reduction in ornamental value.

[0004] In traditional agriculture, methods such as shading and fertilization are commonly used to improve plant resistance to high temperatures. However, in actual production, these methods are time-consuming, labor-intensive, and have low fertilizer utilization efficiency. Silicon is considered a potential element for mitigating abiotic and biotic stress in plants, but existing technologies lack patents explaining methods for foliar spraying of exogenous silicon to improve the heat resistance of carnations. Summary of the Invention

[0005] The purpose of this invention is to provide a method for improving the high-temperature resistance of carnations using exogenous silicon. Spraying exogenous silicon solution onto the leaves of carnations can mitigate the adverse effects of high temperature on carnations, significantly improve the growth indicators of carnations under high-temperature stress, enhance photosynthesis under high-temperature stress, alleviate oxidative stress of carnations under high-temperature stress, and improve the plant's antioxidant capacity.

[0006] To achieve the above objectives, the present invention provides a method for improving the high-temperature resistance of carnations by using exogenous silicon. The high-temperature resistance of carnations is improved by spraying an exogenous silicon solution onto the leaves of carnations. The concentration of the exogenous silicon solution is 0.5-2.0 mM.

[0007] Furthermore, the exogenous silicon is potassium silicate or nano silica; potassium silicate or nano silica is mixed with distilled water and sprayed evenly on the leaves of carnation to improve the high temperature resistance of carnation. Nano silica is ultrasonicated for 30 minutes before each spraying.

[0008] Furthermore, the preparation method of nano-silica is as follows: dissolve tetraethyl orthosilicate in anhydrous ethanol and prepare solution A by ultrasonic oscillation; mix anhydrous ethanol, ultrapure water and ammonia water and sonicate to prepare solution B; stir solution B at 60°C for 10 minutes, then slowly pour it into solution A; wait for the solution to react for 4 hours, centrifuge, discard the filtrate, and dry it in an oven at 60°C.

[0009] Furthermore, nano-silica can be mixed with DiI dye, and then centrifuged to obtain dyed nano-silica. Under laser confocal microscopy, it can be observed that the dyed nano-silica can enter the plant.

[0010] Furthermore, the spray concentration of the exogenous silicon solution is 0.5-1.5 mM.

[0011] Furthermore, the spray concentration of the exogenous silicon solution is 1.0 mM.

[0012] Furthermore, the spraying method is to spray once a day for 5 days. After the spraying, high temperature stress is immediately applied, while continuing to spray exogenous silicon every 3 days. When spraying the exogenous silicon solution, the standard is to moisten the carnation leaves without dripping.

[0013] Furthermore, the high-temperature stress conditions were 40 / 35℃ (day / night). When analyzing different concentrations of silicon treatment, the number of days of high-temperature stress was 9 days. When analyzing the effect of silicon on carnations under different days of high-temperature stress, the high-temperature stress was 0 days, 0.5 days, 6 days, and 12 days.

[0014] Furthermore, this invention also provides the application of exogenous silicon in improving the high-temperature resistance of carnations, wherein the exogenous silicon is potassium silicate or nano-silica, and the concentration is 0.5-2.0 mM.

[0015] Furthermore, the application specifically includes:

[0016] ① Improve the leaf tip withering and leaf yellowing of carnation under high temperature stress, and improve growth indicators;

[0017] ②Improve leaf tip damage in carnations under high temperature stress and improve photosynthetic indicators;

[0018] ③Improves the damage to carnations under high temperature stress and maintains cell turgor pressure and reactive oxygen species;

[0019] The advantages and positive effects of the method for improving the high-temperature resistance of carnations using exogenous silicon as described in this invention are:

[0020] Spraying exogenous silicon solution onto the leaves of carnations can mitigate the adverse effects of high temperatures on carnations, significantly improve their growth indicators under high temperature stress, enhance photosynthesis under high temperature stress, alleviate oxidative stress under high temperature stress, and improve the plant's antioxidant capacity.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 A is a TEM image of nano-silica (SiO2NPs), B is the particle size distribution of SiO2NPs, C is the Zeta potential of SiO2NPs, D is the fluorescence emission spectrum of DiI-SiO2NPs, E is the ultraviolet absorbance value of DiI-SiO2NPs, and F is the laser confocal image of DiI-SiO2NPs and chloroplasts.

[0023] Figure 2 The images show the phenotypic and growth index diagrams of carnations after treatment with different concentrations of exogenous silicon under high temperature stress. A represents the phenotypic value of carnations, B represents the plant height of carnations, C represents the number of leaf pairs, and D represents the SPAD value.

[0024] Figure 3 The image shows the chlorophyll fluorescence imaging of carnations after treatment with different concentrations of exogenous silicon under high temperature stress.

[0025] Figure 4 The graph shows the relevant index data of chlorophyll fluorescence parameters of carnation leaves after treatment with different concentrations of exogenous silicon under high temperature stress. A is the maximum photochemical efficiency (Fv / Fm), B is the non-photochemical quenching (NPQ), C is the actual photochemical efficiency of photosystem (II) (Y(II)), and D is the photochemical quenching coefficient (qP).

[0026] Figure 5 The values ​​represent the chlorophyll content of carnations after treatment with different concentrations of exogenous silicon under high temperature stress, where A represents carotenoids, B represents total chlorophyll, C represents chlorophyll a, and D represents chlorophyll b.

[0027] Figure 6 Phenotypic diagrams of carnation growth induced by exogenous silicon treatment after different numbers of days of high-temperature stress in embodiments of the present invention;

[0028] Figure 7 A shows the reactive oxygen species staining of carnations treated with exogenous silicon after high-temperature stress for different days; B shows the hydrogen peroxide content determination; and C shows the superoxide anion content determination.

[0029] Figure 8 The root phenotype of carnation induced by exogenous silicon treatment after 12 days of high temperature stress in this embodiment of the invention;

[0030] Figure 9 In this table, A represents total root length, B represents root surface area, C represents number of root tips, D represents total root volume, E represents average root diameter, F represents leaf area, G represents stem diameter, H represents relative water content, I represents fresh weight of above-ground parts, J represents dry weight of above-ground parts, K represents fresh weight of underground parts, L represents dry weight of underground parts, M represents nitrogen content in the plant, N represents phosphorus content in the plant, and O represents silicon content in the plant. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0033] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. Experimental instruments, equipment, and reagents in the following embodiments that do not specify their sources are all commercially available materials.

[0034] Unless otherwise defined or stated, all technical and scientific terms used in this invention have the same meaning as those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein can be applied to the methods of this invention. It should be noted that, without conflict, the embodiments and features described in this invention can be combined with each other. The carnations were purchased from Yunnan Yingmao Flower Industry Co., Ltd.

[0035] Example 1

[0036] Nano-sized silica (SiNP) is prepared according to the following method:

[0037] Solution A was prepared by dissolving 3 mL of tetraethyl orthosilicate in 50 mL of anhydrous ethanol and sonicating for 25 minutes. Solution B was prepared by mixing 150 mL of anhydrous ethanol, 4 mL of ultrapure water, and 12 mL of 25% ammonia solution and sonicating for 15 minutes. Solution B was then stirred at a constant temperature of 60 °C and slowly poured into solution A. After a period of reaction, the solution became turbid. After 4 hours, the solution was centrifuged at 18000 × g for 10 minutes, the filtrate was discarded, and the particles were collected and dried in an oven at 60 °C.

[0038] Material characterization:

[0039] The prepared SiNPs were subjected to transmission electron microscopy (TEM) imaging, particle size analysis, and potential measurement experiments.

[0040] The results are as follows Figure 1 As shown in Figure A, the nano-silica appears to be spherical and uniform in size under a transmission microscope. Figure B shows an average particle size of 26.5 ± 7.57 nm. Figure C shows a potential of -27.87 ± 1.51 mV.

[0041] Example 2

[0042] Synthesis of DiI-stained SiNP (DiI-SiNP):

[0043] Mix 4 mL of 1 mM SiNP with 200 μL of 0.3 mg·mL⁻¹ -1 The DiI dye was mixed and dissolved in DMSO, and then subjected to a reaction at 1000 r·min. -1 Vigorously mix, and then excite the resulting pink solution at 4500 rpm. -1 Centrifuge for 5 minutes, at least five times, and store the synthesized DiI-SiNP at 4°C.

[0044] Material characterization:

[0045] The fluorescence emission wavelength and ultraviolet absorbance of the prepared DiI-SiNP were measured. 1 mM DiI-SiNP and distilled water were sprayed onto the leaves of Dianthus caryophyllus. The second to third pair of true leaves were selected, and after being treated in the dark for 24 hours, they were observed under laser confocal microscopy.

[0046] The results are as follows Figure 1 As shown, D represents the fluorescence emission wavelength, with fluorescence emission observed at 580 nm. E represents the ultraviolet absorbance value, with an absorption peak observed at 553 nm for both DiI-SiNP and SiNP treatments. DiI-SiNP treated carnation leaves were observed under laser confocal microscopy. Compared to the water control group, DiI fluorescence signals were detected in the SiNP-treated carnation leaves.

[0047] Example 3

[0048] Effects of different silicon concentrations on growth parameters of carnations under high temperature stress:

[0049] The 'Carimbo' variety was selected as the material and purchased from Yunnan Yingmao Flower Industry Co., Ltd. It was planted in a substrate consisting of nutrient soil and perlite in a 6:4 volume ratio in plug trays. The plants were grown at 23℃ / 18℃ (day / night), 7200 Lux light intensity, and 70% humidity. When the carnations reached the 6-leaf stage, exogenous silicon treatment was applied. Foliar sprays of 0.5-2.0 mM potassium silicate and nano-silica were applied, with distilled water as the control group. Foliar spraying was performed once daily at 21:00 until the leaves were moist but not dripping, for a total of five days. Immediately after spraying, high-temperature stress was applied by placing the plant material in an artificial incubator at 40℃ / 35℃ (day / night). Exogenous silicon was continued to be sprayed simultaneously with high-temperature stress, every 3 days. Measurements were taken when phenotypic differences appeared. A control group was set up at room temperature (23℃ / 18℃) and a control group at high temperature (40℃ / 35℃), both of which were sprayed with distilled water and denoted as CK and HT. Under high temperature treatment, 0.5, 1.0, 1.5, and 2.0 mM potassium silicate were sprayed and denoted as Si1, Si2, Si3, and Si4, respectively. Under high temperature treatment, 0.5, 1.0, 1.5, and 2.0 mM nano-silica were sprayed and denoted as SiNP1, SiNP2, SiNP3, and SiNP4, respectively.

[0050] The results are as follows Figure 2 As shown in Figures AD, the effects of different concentrations of silicon treatment on the growth phenotype, plant height, number of leaf pairs, and SPAD value under high-temperature stress are respectively. Observations of the carnation phenotype indicate that silicon at all concentrations can effectively improve leaf tip wilting and leaf yellowing caused by high-temperature stress. Measurements of growth indicators show that a Si and SiNP concentration of 1 mM has the best effect on promoting carnation growth under high-temperature stress.

[0051] Example 4

[0052] Effects of different silicon concentrations on chlorophyll fluorescence parameters of carnation leaves under high temperature stress:

[0053] Carnation plants treated with different concentrations of silicon at high temperature were then subjected to darkness for 30 minutes. Chlorophyll fluorescence parameters were then measured using an imaging PAM system (Heinz Walz GmbH, Germany). The measured parameters were: Fv / Fm, qP, II, and Y(II).

[0054] Effects of different silicon concentrations on the photosynthetic content of carnations under high temperature stress:

[0055] Experimental Method: Chlorophyll content determination: Take 0.1g of carnation leaves from the second and third pairs of leaves from the bottom and cut them into strips less than 1mm wide along the veins. Place the weighed leaves in a centrifuge tube and add 10mL of 95% ethanol. Shake gently and place in the dark for dark treatment. After 24 hours, observe that the leaves have completely turned white. If not, extend the treatment time appropriately until the leaves turn white. After the colors are mixed, collect the supernatant and measure the absorbance at wavelengths of 470nm, 649nm, and 665nm in a cuvette. Use 95% ethanol as a blank control. Chlorophyll concentration is calculated according to the following formula:

[0056] Ca(mg·L -1 ) = 13.95A 665 -6.88A 649 ;

[0057] Cb(mg·L -1 ) = 24.96A 649 -7.32A 665 ;

[0058] Cc=(1000×A 470 -2.05×Ca-114.8×Cb) / 245;

[0059] In the formula: Ca, Cb, and Cc are the concentrations of chlorophyll a, b, and carotenoids, respectively; A 470 A 649 A 665 The absorbance values ​​of chlorophyll extraction were measured at wavelengths of 470 nm, 649 nm, and 665 nm, respectively.

[0060] Chlorophyll content (mg·g) -1 )=(C×V×n) / W;

[0061] In the formula, C is the chlorophyll concentration (mg·L). -1 V is the volume of the extract; n is the dilution factor; W is the fresh weight of the leaves.

[0062] Total chlorophyll content (mg·g) -1 ) = Chlorophyll a content (mg·g) -1 ) + Chlorophyll b content (mg·g) -1 );

[0063] The results are as follows Figures 3-5As shown, high-temperature stress severely affects the photosynthetic indicators of carnations, damaging photosystem II. Under high temperatures, chlorophyll fluorescence imaging shows heterogeneous distribution damage, mainly in the leaf tip. Low concentrations of silicon can alleviate the high-temperature damage to carnations, while the alleviating effect decreases with high concentrations of silicon. Silicon can inhibit the decrease in Fv / Fm, Y(II), and qP caused by high-temperature stress, and the increase in NPQ. While the photosynthetic pigment content in carnation leaves tends to decrease under high temperatures, it increases after treatment with both forms of silicon.

[0064] Example 5

[0065] Effects of different silicon concentrations on physiological parameters of carnations under high temperature stress:

[0066] Experimental methods: Malondialdehyde content was determined using the thiobarbituric acid method (TBA), while soluble protein content was determined using the Coomassie Brilliant Blue G250 method.

[0067] Relative conductivity content determination:

[0068] Take the second and third pairs of leaves from the bottom of the carnation, cut the leaves diagonally into long strips, weigh 0.1g, and place them in a centrifuge tube containing 10mL of deionized water. Incubate at 28℃ and 200r·min. -1 Shake in a shaker for 2.5 hours, then measure the conductivity of the extract (I1) using a conductivity meter. Boil in a water bath for approximately 30 minutes, then allow to cool naturally to room temperature and shake well. If the solution volume decreases, replenish with deionized water and measure the conductivity of the extract again (I2). The conductivity of distilled water is I0. Relative conductivity is calculated using the following formula:

[0069] Relative conductivity = (I1-I0) / (I2-I0)×100%;

[0070] The activities of POD, CAT, and SOD were determined by guaiacol oxidation, hydrogen peroxide decomposition, and NBT photoreduction, respectively.

[0071] Hydrogen peroxide content was determined using a "Hydrogen Peroxide Content Assay Kit" (Beijing Solarbio Science & Technology Co., Ltd.). The assay works based on the reaction of hydrogen peroxide with titanium sulfate to form a yellow titanium peroxide complex, with absorbance measured at 415 nm. The sample was added and measured according to the instructions. Superoxide anion content was determined using a "Superoxide Anion Content Assay Kit" (Beijing Solarbio Science & Technology Co., Ltd.). The assay works based on the reaction of superoxide anions with hydroxylamine hydrochloride to form NO. 2- NO 2- A purple-red azo compound was formed by the reaction of p-aminobenzenesulfonamide and naphthylethylenediamine hydrochloride. The absorbance was measured at 530 nm, and the superoxide anion content was calculated based on the A530 value. The results are shown in Table 1.

[0072] Table 1 Effects of different Si concentrations on physiological parameters of carnations under high temperature stress

[0073]

[0074]

[0075] High temperatures increase the content of osmotic substances such as MDA, soluble proteins, and relative conductivity. Furthermore, the content of osmotic substances increases with prolonged exposure to high temperatures. Treatment with potassium silicate and nano-silica reduced the content of osmotic substances, maintained cell turgor pressure, and mitigated the damage caused by high-temperature stress to carnations. These results demonstrate that the potassium silicate and nano-silica described in this invention can effectively alleviate high-temperature stress in carnations and reduce the harmful effects of high temperatures on the plant. Measurements of antioxidant enzymes and reactive oxygen species revealed that silicon can alleviate high-temperature damage to carnations.

[0076] Based on the above-mentioned index measurements, membership function analysis was performed on the treatments of potassium silicate and nano-silica to obtain the comprehensive index calculation membership function values ​​(1), weights (2), and comprehensive heat resistance evaluation values ​​(3), which were calculated according to the following formula:

[0077] u(Xj)=(Xj-Xmin) / (Xmax-Xmin) (j=1, 2, 3,..., n) (1)

[0078]

[0079] The results are shown in Tables 2 and 3:

[0080] Table 2. Comprehensive index CI, weight, membership function u(X), and comprehensive evaluation D value of carnations under different Si concentrations.

[0081]

[0082]

[0083] Table 3. Comprehensive index CI, weight, membership function u(X), and comprehensive evaluation D value of carnation under different SiNP concentrations.

[0084] CI1 CI2 CI3 u(X1) u(X2) u(X3) D CK SiNP 1.76 0.28 0.86 1 0.7 0.89 0.89 HT SiNP -1.31 0.98 1.17 0 0.96 1 0.44 SiNP 1 0.07 -0.22 0.07 0.45 0.51 0.61 0.49 SiNP 2 0.06 1.08 -1.67 0.45 1 0 0.53 SiNP 3 -0.16 -0.57 -0.22 0.37 0.37 0.51 0.4 SiNP 4 -0.41 -1.56 -0.2 0.29 0 0.52 0.24 Weight 0.55 0.29 0.16

[0085] It was found that both potassium silicate and nano-silica had the highest comprehensive heat resistance evaluation value at a Si concentration of 1 mM under high temperature treatment, which means they were the best at alleviating the high temperature stress effect.

[0086] Example 6

[0087] The effect of silicon on the growth of carnations under high temperature stress for different durations:

[0088] The experimental materials were treated in the same way as in Example 3, with the addition of two treatment groups: ion-exchange silicon and nano-silica sprayed at room temperature. The optimal spray concentration, determined from previous experiments, was 1 mM. Observations and sampling were conducted on days 0, 0.5, 6, and 12 of high-temperature stress. Phenotypic changes in different treatment groups at different time points were observed by taking photographs.

[0089] The results are as follows Figure 6 As shown in the figure, the phenotypic changes of carnations after different treatments for different number of days were observed. It can be seen from the figure that the leaves of carnations wilted after 6 days of high temperature. As the high temperature time was prolonged, chlorophyll synthesis was destroyed, which led to the leaves turning pale and yellow. After spraying with potassium silicate and nano silica prepared in Example 1, the phenotypic changes of carnations were significantly and effectively alleviated.

[0090] Example 7

[0091] The effect of silicon on reactive oxygen species (ROS) in carnations under high-temperature stress for different durations:

[0092] DAB (3,3'-diaminobenzidine) and NBT (nitrocyanate tetrazolium) were used to detect ROS accumulation in carnation leaves. Fully expanded carnation leaves from the second-to-last and third-to-last leaf pairs were collected from different treatment groups. 17.9 g of Na₂HPO₄·12H₂O was dissolved in distilled water and diluted to 1000 mL to prepare solution A. 7.8 g of NaH₂PO₄·2H₂O was dissolved in distilled water and diluted to 1000 mL to prepare solution B. 22.875 mL of solution A and 21.45 mL of solution B were thoroughly mixed to prepare a phosphate buffer solution with a pH of 0.05 mol / L. 0.1 g of DAB and NBT were respectively diluted to 100 mL with the prepared phosphate buffer solution. The pH of the prepared DAB staining solution was adjusted to 3.8 with acetic acid. The fully expanded leaves were completely immersed in the DAB and NBT staining solutions and treated in the dark for 24 hours. After the dark treatment, place the leaves in the light at room temperature for 40-60 minutes until the leaves show color changes. Then, place them in a water bath at 80°C and add a decolorizing solution prepared by mixing 75% ethanol and 5% glycerol. After the chlorophyll in the leaves has completely disappeared, take photos for observation.

[0093] Hydrogen peroxide content was determined using a "Hydrogen Peroxide Content Determination Kit" (Beijing Solarbio Science & Technology Co., Ltd.), and superoxide anion content was determined using a "Superoxide Anion Content Determination Kit" (Beijing Solarbio Science & Technology Co., Ltd.).

[0094] The results are as follows Figure 7As shown, after high-temperature stress treatment with silicon for different durations, DAB caused brownish-red halos to appear on the leaves, especially at the leaf tips, indicating hydrogen peroxide accumulation, while NBT caused dark blue patches, indicating superoxide anion accumulation. High temperature significantly reduced the hydrogen peroxide and superoxide anion content in carnation leaves. Silicon treatment reduced the area of ​​brown and blue patches caused by DAB and NBT, and lowered the levels of hydrogen peroxide and superoxide anions, thus alleviating oxidative damage. Therefore, silicon can maintain the homeostasis of reactive oxygen species in carnation leaves, alleviate the accumulation of reactive oxygen species under high-temperature stress, and reduce oxidative damage.

[0095] Example 8

[0096] The roots of carnations, after being exposed to high temperatures for 12 days, were rinsed to remove any attached soil. The rinsing process was done gently to avoid damaging the roots. The roots were then blotted dry with filter paper and laid flat in distilled water for scanning using a root scanner (LA 2400, REGENTINS TRUMENTS INC., USA). Root length, total surface area, number of root tips, volume, and average root diameter were analyzed using a DJ-3010 root image analysis system. The third-to-last pair of leaves were fully expanded, and the leaves were completely removed before photographing. Leaf area was obtained through analysis using Fiji ImageJ. The cleaned carnations were separated into above-ground and underground parts. After blotting dry with filter paper, the fresh weight was measured using an electronic balance. The fresh sample was then placed at 105°C for 30 minutes and subsequently dried in an 80°C oven to constant weight. The dry weight was then measured again using an electronic balance for analysis. Completely immerse the carnation plant in distilled water and shield it from light. After absorbing the surface moisture with filter paper, weigh it immediately and record the saturated fresh weight. The relative moisture content is calculated using the following formula:

[0097] RWC(%)=(FW-DW) / (TW-DW)×100%;

[0098] FW represents fresh weight, DW represents dry weight, and TW represents saturated fresh weight.

[0099] After drying and grinding the carnation plants, 1.0g was weighed out and digested in concentrated sulfuric acid using copper sulfate and potassium sulfate as catalysts. The nitrogen content was determined using a Kjeldahl nitrogen analyzer. Similarly, the phosphorus content was determined using the same dried and ground plants via the molybdenum-antimony-D-isoascorbic acid method, with absorbance measured at 700nm using a spectrophotometer. A standard curve was plotted using phosphate standard solutions of different concentrations, and the phosphorus content was calculated based on the absorbance values. Silicon content was determined using a "Plant Silicon Content Test Kit" (Shanghai Kanglang Biotechnology Co., Ltd.). The plant was mixed with NaOH solution, and the amorphous SiO2 was dissolved after a 1-hour boiling water bath. The leachate was neutralized with acid, and the absorbance was measured at 650nm using the silica blue colorimetric method. 650The value is used to calculate the silicon content in plants.

[0100] The results are as follows Figure 8 and Figure 9 As shown, high temperatures inhibit plant root growth, damage root morphology, reduce the number of root hairs, and decrease water and nutrient absorption capacity, thus lowering root-related indicators. Silicon can alleviate high-temperature stress. Potassium silicate restored 39.06% of total root length, 15.26% of total root surface area, 23.49% of total root tip number, 6.31% of total root volume, and 18.32% of average root diameter. Nano-silica restored 52.16% of total root length, 35.22% of total root surface area, 30.35% of total root tip number, 31.63% of total root volume, and 24.07% of average root diameter. Plant leaf area and stem diameter decreased. Leaf area increased by 66.91% and 71.23% respectively under potassium silicate and nano-silica treatments, while stem diameter increased by 39.47% and 32.04% respectively under the two forms of silicon treatments. Under high temperatures, both above-ground and below-ground parts, as well as their relative water content, decreased. Potassium silicate treatment increased the plant's relative water content by 4.43%, above-ground fresh weight by 49.52%, above-ground dry weight by 19.51%, below-ground fresh weight by 40.98%, and below-ground dry weight by 17.91%. Nano-silica treatment increased the plant's relative water content by 1.61%, above-ground fresh weight by 49.79%, above-ground dry weight by 40.58%, below-ground fresh weight by 47.52%, and below-ground dry weight by 5.97%. The nitrogen, phosphorus, and silicon content within the plant decreased. Silicon treatment promoted the absorption of nitrogen and phosphorus by carnations. Potassium silicate increased the nitrogen content in carnations by 29.55% and phosphorus by 55.98%, while nano-silica increased it by 46.20% and 70.09%, and also increased the silicon content by 20.16% and 49.50%, respectively.

[0101] Therefore, the present invention adopts the above-mentioned method of using exogenous silicon to improve the high temperature resistance of carnation. Spraying exogenous silicon solution on the leaves of carnation can improve the adverse effects of high temperature on carnation, significantly improve the growth indicators of carnation under high temperature stress, enhance photosynthesis under high temperature stress, alleviate oxidative stress of carnation under high temperature stress, and improve the antioxidant capacity of plants.

[0102] 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 preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for improving the high-temperature resistance of carnations using exogenous silicon, characterized in that, High temperature resistance of carnations can be improved by spraying exogenous silicon solution onto the leaves. The concentration of exogenous silicon solution sprayed is 0.5-2.0 mM.

2. The method for improving the high-temperature resistance of carnations using exogenous silicon according to claim 1, characterized in that: The exogenous silicon is potassium silicate or nano-silica; potassium silicate or nano-silica is mixed with distilled water and sprayed evenly on the leaves of carnation to improve the high temperature resistance of carnation.

3. The method for improving the high-temperature resistance of carnations using exogenous silicon according to claim 2, characterized in that, The preparation method of nano-silica is as follows: dissolve tetraethyl orthosilicate in anhydrous ethanol and prepare solution A by ultrasonic oscillation. Mix anhydrous ethanol, ultrapure water and ammonia water and sonicate to prepare solution B. After stirring solution B at 60°C for 10 minutes, slowly pour it into solution A. After waiting for the solution to react for 4 hours, centrifuge, discard the filtrate, and dry it in an oven at 60°C.

4. The method for improving the high-temperature resistance of carnations using exogenous silicon according to claim 1, characterized in that: The concentration of the exogenous silicon solution applied is 0.5-2.0 mM.

5. A method for improving the high-temperature resistance of carnations using exogenous silicon according to claim 4, characterized in that: The concentration of the exogenous silicon solution applied was 1.0 mM.

6. The method for improving the high-temperature resistance of carnations using exogenous silicon according to claim 1, characterized in that: The spraying method is to spray once a day for a total of 5 days. After the end of the day, high temperature stress is immediately applied, while exogenous silicon is continued to be sprayed once every 3 days.

7. A method for improving the high-temperature resistance of carnations using exogenous silicon according to claim 6, characterized in that: The conditions for high-temperature stress were daytime temperature of 40℃ and nighttime temperature of 35℃; the number of days of high-temperature stress was 9 days when different concentrations of silicon were treated; the effects of silicon on carnations under high-temperature stress for different durations were analyzed for 0 days, 0.5 days, 6 days, and 12 days.

8. The application of exogenous silicon in improving the high-temperature resistance of carnations, characterized in that: The exogenous silicon is potassium silicate or nano-silica, with a concentration of 0.5-2.0 mM.

9. The application according to claim 8, characterized in that, Specifically: ① Improve the leaf tip withering and leaf yellowing of carnation under high temperature stress, and improve growth indicators; ②Improve leaf tip damage in carnations under high temperature stress and improve photosynthetic indicators; ③Improves the damage to carnations under high temperature stress and maintains cell turgor pressure and reactive oxygen species; ④ It improves root damage to carnations under high temperature stress and enhances their ability to absorb water and nutrients.

Images