Method for improving low temperature stress tolerance of cherry tomato seedlings by exogenous tyrosol

Abstract

The present application relates to the field of agricultural cultivation technology, and more particularly to a method for improving the low-temperature stress tolerance of cherry tomato seedlings by exogenous tyramine. The method selects cherry tomato seedlings at the 4-leaf 1-heart stage, and sprays the cherry tomato seedlings in the experimental group with a tyramine water solution at a concentration of 1-2.5 mg / L at 5 pm every day. The spraying is performed according to the standard of covering the leaves with mist droplets and no dripping. The cherry tomato seedlings in the normal temperature and low temperature control groups are sprayed with distilled water. The influence of tyramine on cherry tomatoes under low-temperature stress is observed. The test results prove that exogenous tyramine significantly alleviates the growth of cherry tomatoes under low-temperature stress, reduces the MDA and H2O2 contents in the leaves of cherry tomatoes, increases the proline and soluble sugar contents, and enhances the activity of antioxidant enzymes, thereby effectively reducing the damage of low-temperature stress to cherry tomato plants.

Description

Technical Field

[0001] This invention relates to the field of agricultural cultivation technology, and in particular to a method for improving the low-temperature stress resistance of cherry tomato seedlings with exogenous tyrosol. Background Technology

[0002] Cherry tomatoes (Solanum lycopersicum var. cerasiforme) are herbaceous plants belonging to the genus Solanum in the family Solanaceae. They originated in Peru, Ecuador, and Bolivia in South America and later spread globally, now being widely cultivated in China. This variety prefers warm climates and has strong heat tolerance, with an optimal growth temperature of 20-30℃. Cherry tomatoes are popular with consumers due to their small size, rich flavor, and high nutritional value. With rapidly increasing market demand, they have gradually become a popular variety for greenhouse cultivation. Due to their biological characteristics, cherry tomatoes have stricter requirements for environmental conditions, especially in low winter temperatures, which can severely impact their growth, development, and yield.

[0003] Low temperature is a common abiotic stress in crop cultivation. Cherry tomatoes are a typical cold-sensitive crop, and low temperature can damage them at all stages of growth and development. Low temperatures lead to a decrease in the relative growth rate of cherry tomatoes, a significant reduction in root length and root surface area, smaller leaf area, and in severe cases, browning and wilting of leaves, softening of tissues, necrosis of the growing point, and ultimately plant death. In addition, under low temperature conditions, excessive accumulation of reactive oxygen species (ROS) in plants leads to cell membrane lipid peroxidation, causing oxidative damage and affecting plant growth. To mitigate oxidative damage caused by low temperatures, plants increase the activity of antioxidant enzymes such as peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT), and increase the content of osmotic regulators (such as proline and soluble sugars) to remove excess ROS, reduce intracellular osmotic potential, maintain the integrity of plant cell structure and function, and increase plant cold resistance.

[0004] Tyrosol is a natural phenylpropanoid compound widely distributed in plants such as Rhodiola rosea, olive, and privet. As a phenolic antioxidant, tyrosol possesses various biological activities, including antioxidant and anti-inflammatory effects. In the chemical industry, tyrosol is an important synthetic intermediate used to prepare high-value natural products such as hydroxytyrosol, rhodioloside, and oleuropein. In the pharmaceutical industry, tyrosol serves as a key precursor in the synthesis of cardiovascular drugs (such as betalol and metoprolol). Furthermore, in the food industry, tyrosol is used as a flavor enhancer; for example, adding it to wine can improve its taste and quality.

[0005] Tyrosol belongs to the phenol family and was originally derived from olive oil. Its molecular formula is C8H2O. 10O2, molecular weight is 138.164. CAS number: 501-94-0. Alias: p-hydroxyphenylethanol; English name: Tyrosol. Molecular structure formula:

[0006] .

[0007] Currently, there is limited research both domestically and internationally on the role of tyrosol in enhancing plant stress resistance, and its value in growth regulation and stress resistance potential still needs to be further explored. Summary of the Invention

[0008] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a method for improving the low-temperature stress tolerance of cherry tomato seedlings with exogenous tyrosol. Four-leaf, one-heart stage cherry tomato 'Hong Sheng' seedlings were selected, and the seedlings were sprayed with a tyrosol aqueous solution at a concentration of 1–2.5 mg / L at 5 PM daily. The spraying was carried out until the leaves were covered with a mist of droplets without dripping. This spraying was repeated for three consecutive days. Simultaneously, control groups at room temperature and low temperature were set up. The control group's cherry tomato seedlings were sprayed with distilled water. The exogenous tyrosol significantly alleviated the growth of cherry tomatoes under low-temperature stress, reduced the MDA and H2O2 content in cherry tomato leaves, increased the content of proline and soluble sugars, and enhanced the activity of antioxidant enzymes, thereby effectively reducing the damage of low-temperature stress to cherry tomato plants.

[0009] This invention provides a method for improving the low-temperature stress tolerance of cherry tomato seedlings with exogenous tyrosol, comprising the following steps:

[0010] S1. Seedling selection: Select cherry tomato seedlings at the 4-leaf-1-heart stage;

[0011] S2. Spraying: Cherry tomato seedlings in the test group were sprayed with tyrosol spray solution. The standard for spraying was that the leaves were covered with mist droplets without dripping. At the same time, a control group was set up, and distilled water was sprayed on the leaves of cherry tomato seedlings in the control group.

[0012] S3. Detection Results: After 7 days of cultivation, cherry tomato seedlings were photographed and their phenotypes were recorded. Plant height and stem diameter were measured. The 3rd to 4th true leaves were collected and preserved in liquid nitrogen. The malondialdehyde content, hydrogen peroxide content, proline content, soluble sugar content, and superoxide dismutase, peroxidase, and catalase activities were measured.

[0013] According to the method for improving the low-temperature stress resistance of cherry tomato seedlings with exogenous tyrosol provided by the present invention, the preparation method of the tyrosol spray solution in S2 is as follows: tyrosol is dissolved in distilled water to obtain a tyrosol spray mother liquor, the tyrosol spray mother liquor is diluted again with distilled water to obtain a tyrosol spray solution, the concentration of the tyrosol spray mother liquor is 500 mg / L, the concentration of the tyrosol spray solution is 1-2.5 mg / L, the amount of the tyrosol spray solution used for each spray is 5 mL, the spraying time of the tyrosol spray solution is 3 consecutive days, and the spraying time of the tyrosol spray solution is 5 pm every day.

[0014] According to the method for improving the resistance of cherry tomato seedlings to low temperature stress by exogenous tyrosol provided by the present invention, the optimal concentration of the tyrosol spray solution is 2 mg / L.

[0015] According to the method for improving the low-temperature stress resistance of cherry tomato seedlings with exogenous tyrosol provided by the present invention, the environmental conditions for the 7-day culture in S3 are as follows: the seedlings are cultured under low temperature conditions of 15℃ day / 5℃ night in a light incubator with 12h light / 12h darkness and 15000lx light intensity for 7 days.

[0016] According to the method for improving the low-temperature stress resistance of cherry tomato seedlings with exogenous tyrosol provided by the present invention, the plant height mentioned in S3 refers to the vertical distance from the base of the cherry tomato stem to the growing point measured with a ruler, and the stem diameter is the diameter of the stem measured with vernier calipers 1 cm below the cotyledons.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] This invention provides a method for improving the low-temperature stress tolerance of cherry tomato seedlings using exogenous tyrosol. Using 4-leaf, 1-heart stage cherry tomato seedlings of the 'Hong Sheng' variety as experimental material, exogenous tyrosol solution was applied, followed by 7 days of low-temperature stress treatment in a light-controlled incubator. Phenotypic results were observed, and physiological and biochemical indicators were measured. Phenotypic analysis showed that exogenous tyrosol significantly alleviated the inhibitory effect of low-temperature stress on the growth of cherry tomato seedlings. Physiological and biochemical analysis showed that exogenous tyrosol significantly reduced the MDA and hydrogen peroxide content in cherry tomato leaves, increased the content of osmotic regulators such as proline and soluble sugars, and enhanced the activity of antioxidant enzymes. The 2 mg / L tyrosol treatment showed the most significant effect in alleviating low-temperature stress in cherry tomato seedlings.

[0019] In summary, exogenous application of tyrosol improved the stability of cherry tomato cell membranes, the content of osmotic regulators, and the activity of antioxidant enzyme systems under low-temperature stress, thereby effectively alleviating low-temperature damage to cherry tomato plants. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 Figure showing the effect of different concentrations of exogenous tyrosol on the phenotype of cherry tomato seedlings under low temperature stress;

[0022] Figure 2 Figure showing the effect of different concentrations of exogenous tyrosol on the plant height of cherry tomato seedlings under low temperature stress;

[0023] Figure 3 Figure showing the effect of different concentrations of exogenous tyrosol on stem diameter of cherry tomato seedlings under low temperature stress;

[0024] Figure 4 Figure showing the effect of different concentrations of exogenous tyrosol on malondialdehyde content in cherry tomato seedlings under low temperature stress;

[0025] Figure 5 Figure showing the effect of different concentrations of exogenous tyrosol on hydrogen peroxide content in cherry tomato seedlings under low temperature stress;

[0026] Figure 6 Figure showing the effect of different concentrations of exogenous tyrosol on the proline content of cherry tomato seedlings under low temperature stress;

[0027] Figure 7 Figure showing the effect of different concentrations of exogenous tyrosol on the soluble sugar content of cherry tomato seedlings under low temperature stress;

[0028] Figure 8 Figure showing the effect of different concentrations of exogenous tyrosol on the peroxidase content of cherry tomato seedlings under low temperature stress;

[0029] Figure 9 Figure showing the effect of different concentrations of exogenous tyrosol on the catalase content of cherry tomato seedlings under low temperature stress;

[0030] Figure 10 The effect of different concentrations of exogenous tyrosol on the superoxide dismutase content of cherry tomato seedlings under low temperature stress. Detailed Implementation

[0031] Example 1

[0032] This embodiment provides a method for improving the low-temperature stress resistance of cherry tomato seedlings with exogenous tyrosol. The cherry tomato 'Hong Sheng' required for the experiment was purchased from Qingxian Liangdasheng Agricultural Technology Extension Center, and the tyrosol was purchased from Beijing Jinkelong Biotechnology Co., Ltd. The experiment was conducted in the greenhouse of the Horticulture Experiment Station of Shanxi Agricultural University, using 32-cell trays for seedling cultivation. When the cherry tomatoes grew to the four-leaf-one-heart stage, cherry tomato seedlings with uniform growth were selected for experimental treatment.

[0033] This experiment included 6 treatments, as shown in Table 1 below:

[0034] Table 1 Specific processing methods

[0035] Group Name Handling method CK Spray with distilled water + room temperature treatment LT Spraying with distilled water + low temperature treatment T1 Spray with 1 mg / L tyrosol + low temperature treatment T1.5 Spray with 1.5 mg / L tyrosol + low temperature treatment T2 Spray with 2 mg / L tyrosol + low temperature treatment T2.5 Spray with 2.5 mg / L tyrosol + low temperature treatment

[0036] Cherry tomato seedlings were sprayed with tyrosol solution or distilled water at 5 PM daily for 3 consecutive days. Each spray consisted of 5 mL of tyrosol solution, spraying until the leaves were covered with a mist of liquid without dripping. Afterwards, cherry tomato seedlings requiring low-temperature treatment were placed in a 15°C day / 5°C night, 12h light / 12h dark, 15000lx light incubator for low-temperature stress treatment.

[0037] After 7 days of treatment under low temperature conditions, cherry tomato seedlings were photographed to record their phenotype, plant height and stem diameter were measured, and the 3rd to 4th true leaves were collected and preserved in liquid nitrogen for the purpose of measuring malondialdehyde content, hydrogen peroxide content, proline content, soluble sugar content, and the activities of superoxide dismutase, peroxidase and catalase.

[0038] Plant height and stem diameter were measured using a ruler and vernier calipers, respectively. Plant height was measured as the vertical distance from the base of the cherry tomato stem to the growing point using a ruler, while stem diameter was measured as the stem diameter 1 cm below the cotyledons using vernier calipers. Malondialdehyde (MDA) content was determined using the thiobarbituric acid method, hydrogen peroxide content using the potassium iodide colorimetric method, proline content using the sulfosalicylic acid method, soluble sugar content using the anthrone colorimetric method, superoxide dismutase (SOD) activity using the nitroblue tetrazolium reduction method, peroxidase activity using the guaiacol colorimetric method, and catalase activity using ultraviolet spectroscopy.

[0039] All data obtained during the experiment were processed using Microsoft Excel 2016, SPSS 20.0 was used for significance analysis, and GraphPad Prism 8.0 was used for graphing. The data results are analyzed below:

[0040] ① Effects of exogenous tyrosol on the phenotype, plant height, and stem diameter of cherry tomatoes under low temperature stress:

[0041] The effects of exogenous application of different concentrations of tyrosol on the phenotype of cherry tomato seedlings under low temperature stress, as follows: Figure 1 As shown, compared with the CK group, the cherry tomato seedlings in the LT group were shorter and wilted overall. However, spraying different concentrations of tyrosol alleviated the stress on the plants to varying degrees.

[0042] The effects of exogenous application of different concentrations of tyrosol on the plant height and stem diameter of cherry tomato seedlings under low temperature stress are as follows: Figure 2 and 3 As shown, compared with the CK group, the plant height and stem diameter of the LT group were significantly reduced, by 27% and 17.6%, respectively. The application of tyrosol alleviated the inhibition of plant growth by low temperature stress to varying degrees, with the T2 group showing the most significant effect. Compared with the LT group, the plant height and stem diameter were significantly increased, by 19.1% and 22.4%, respectively.

[0043] The results showed that exogenous application of tyrosol alleviated the effects of low temperature stress on the phenotype of cherry tomato seedlings.

[0044] ② Effects of exogenous tyrosol on malondialdehyde content in cherry tomato seedlings under low temperature stress:

[0045] Malondialdehyde (MDA) is the final decomposition product of membrane lipid peroxidation, and its content can reflect the degree of stress damage suffered by plants. The effects of exogenous application of different concentrations of tyrosol on the MDA content of cherry tomato seedlings under low-temperature stress are as follows: Figure 4 As shown, compared with the CK group, low temperature treatment significantly increased the MDA content in the leaves of cherry tomato seedlings. With the increase of exogenous tyrosol concentration, the MDA content showed a trend of first decreasing and then increasing, with the MDA content of the T2 group being significantly lower than that of the LT group.

[0046] The results showed that exogenous application of tyrosol effectively reduced membrane lipid peroxidation damage caused by low temperature stress and enhanced the cold resistance of cherry tomato seedlings.

[0047] ③ Effect of exogenous tyrosol on hydrogen peroxide content in cherry tomato seedlings under low temperature stress:

[0048] Hydrogen peroxide (H2O2) is a significant representative of reactive oxygen species. When plants face biotic and abiotic stresses, it can induce the production and accumulation of intracellular hydrogen peroxide. The effects of exogenous application of different concentrations of tyrosol on the H2O2 content of cherry tomato seedlings under low-temperature stress are investigated. Figure 5 As shown, compared with the CK group, low temperature treatment significantly increased the hydrogen peroxide content in the leaves of cherry tomato seedlings. With the increase of exogenous tyrosol concentration, the H2O2 content showed a trend of first decreasing and then increasing. Compared with the LT group, the H2O2 content of the T2 group was significantly reduced by 31.6%.

[0049] The results showed that exogenous application of tyrosol effectively removed H2O2 accumulated under low-temperature stress and reduced oxidative damage.

[0050] ④ Effect of exogenous tyrosol on proline content in cherry tomato seedlings under low temperature stress:

[0051] Proline (PRO), as an important osmotic regulator, plays a crucial role in protecting cellular osmotic balance and subcellular structural stability. When plants are subjected to abiotic stress, they accumulate large amounts of PRO, thereby enhancing their ability to adapt to the stress. The effects of exogenous application of different concentrations of tyrosol on the PRO content of cherry tomato seedlings under low-temperature stress are investigated. Figure 6 As shown, compared with the CK group, the low temperature treatment significantly increased the PRO content in the leaves of cherry tomato seedlings by 59.3%. With the increase of exogenous tyrosol concentration, the PRO content showed a further upward trend, with the PRO content in the T2 group increasing by 84.8% compared with the LT group and by 194.3% compared with the CK group.

[0052] The results showed that exogenous application of tyrosol could significantly induce the accumulation of PRO and enhance the osmotic regulation ability of cherry tomato seedlings under low temperature stress.

[0053] ⑤ Effect of exogenous tyrosol on the soluble sugar content of cherry tomato seedlings under low temperature stress:

[0054] Changes in soluble sugar (SS) content are an important indicator of plant response to abiotic stress, as plants increase SS content under stress conditions to maintain water balance, raise cell osmotic pressure, and protect cell membranes, thereby protecting plant cells from damage. The effects of exogenous application of different concentrations of tyrosol on SS content in cherry tomato seedlings under low-temperature stress are investigated. Figure 7 As shown, compared with the CK group, low temperature treatment significantly increased the SS content in the leaves of cherry tomato seedlings by 6.5%. With the increase of exogenous tyrosol concentration, the SS content showed a trend of first increasing and then decreasing, reaching a peak in the T2 group. Compared with the LT group, the soluble sugar content was significantly increased by 21%, and compared with the CK group by 28.9%. The results indicate that exogenous application of tyrosol can further induce the accumulation of SS and enhance the osmotic regulation capacity and cell protection of cherry tomato seedlings under low temperature stress.

[0055] ⑥ Effects of exogenous tyrosol on the antioxidant enzyme activity of cherry tomato seedlings under low temperature stress:

[0056] Peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) are important antioxidant enzymes in plant cells. They maintain intracellular redox balance by scavenging reactive oxygen species, thereby mitigating oxidative damage. The effects of exogenous application of different concentrations of tyrosol on POD, CAT, and SOD in cherry tomato seedlings under low-temperature stress are as follows: Figure 8, 9 As shown in Figure 10, the activities of antioxidant enzymes in cherry tomato seedlings were significantly increased after low-temperature stress. Compared with the control group, the LT group showed a 46.2% increase in POD activity, a 49.4% increase in CAT activity, and a 29.7% increase in SOD activity. With increasing exogenous tyrosol concentration, the antioxidant enzyme activities of cherry tomato seedlings showed a further upward trend. When sprayed with a 2 mg / L tyrosol solution, the activities of all three enzymes reached their maximum values. Compared with the LT group, the T2 group showed a 92.1% increase in POD activity, a 137.4% increase in CAT activity, and a 28.9% increase in SOD activity.

[0057] The results showed that exogenous tyrosol could further activate the antioxidant enzyme system, enhance the antioxidant capacity of cherry tomato seedlings under low temperature stress, and thus reduce membrane lipid peroxidation damage.

[0058] In conclusion, low temperature stress significantly inhibited the growth and development of cherry tomato seedlings, exacerbated cell membrane lipid peroxidation, and induced an increase in the activity of antioxidant enzymes and the content of osmotic regulators in the plant.

[0059] Based on this, the study found that exogenous tyrosol alleviated the inhibitory effect of low-temperature stress on the growth of cherry tomato seedlings, significantly reduced malondialdehyde and hydrogen peroxide content, increased the accumulation of proline and osmotic regulators of soluble sugars, and enhanced the activity of antioxidant enzymes, thereby effectively reducing the damage of low temperature to the plants. The effect of tyrosol at a concentration of 2 mg / L was the most significant in alleviating low-temperature stress in cherry tomato seedlings.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for improving the tolerance of cherry tomato seedlings to low-temperature stress using exogenous tyrosol, characterized in that, Includes the following steps: S1. Seedling selection: Select cherry tomato seedlings at the 4-leaf-1-heart stage; S2. Spraying: Cherry tomato seedlings in the test group were sprayed with tyrosol spray solution. The standard for spraying was that the leaves were covered with mist droplets without dripping. At the same time, a control group was set up, and distilled water was sprayed on the leaves of cherry tomato seedlings in the control group. S3. Detection Results: After 7 days of cultivation, cherry tomato seedlings were photographed and their phenotypes were recorded. Plant height and stem diameter were measured. The 3rd to 4th true leaves were collected and preserved in liquid nitrogen. The malondialdehyde content, hydrogen peroxide content, proline content, soluble sugar content, and superoxide dismutase, peroxidase, and catalase activities were measured.

2. The method for improving the low-temperature stress tolerance of cherry tomato seedlings using exogenous tyrosol according to claim 1, characterized in that, The preparation method of the tyrosol spray solution described in S2 is as follows: tyrosol is dissolved in distilled water to obtain a tyrosol spray mother liquor, and the tyrosol spray mother liquor is diluted again with distilled water to obtain the tyrosol spray solution. The concentration of the tyrosol spray mother liquor is 500 mg / L, and the concentration of the tyrosol spray solution is 1-2.5 mg / L. The amount of tyrosol spray solution used for each spray is 5 mL, and the spraying time is 3 consecutive days, with the spraying time being 5 pm every day.

3. The method for improving the low-temperature stress tolerance of cherry tomato seedlings with exogenous tyrosol according to claim 2, characterized in that, The concentration of the tyrosol spray solution is 2 mg / L.

4. The method for improving the low-temperature stress tolerance of cherry tomato seedlings using exogenous tyrosol according to claim 1, characterized in that, The environmental conditions for culturing for 7 days as described in S3 are as follows: culturing for 7 days under low temperature conditions of 15℃ daytime / 5℃ nighttime, in a light incubator with 12h light / 12h darkness and 15000lx light intensity.

5. The method for improving the low-temperature stress tolerance of cherry tomato seedlings with exogenous tyrosol according to claim 1, characterized in that, In S3, the plant height and stem diameter measurements refer to the vertical distance from the base of the cherry tomato stem to the growing point, measured with a ruler. The stem diameter is the diameter of the stem measured with calipers 1 cm below the cotyledons.

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