Application of melatonin to improvement of drought resistance of elytrigia elongata

Abstract

The invention relates to the technical field of pasture cultivation, in particular to application of melatonin to improvement of drought resistance of elytrigia elongata. According to the method, the plant height and biomass of the thinopyrum elongatum subjected to spraying treatment by using the 150 [mu] mol L <-1 > melatonin solution are respectively 19.43% and 111.84% higher than those of the thinopyrum elongatum subjected to spraying treatment by using distilled water; the chlorophyll content and superoxide enhanced enzyme activity of leaves treated by 150 [mu] mol L <-1 > melatonin are respectively 52.54% and 18.39% higher than those of leaves treated by spraying distilled water; in addition, 150 [mu] mol L <-1 > melatonin is used for treatment, so that the content of glutathione and proline in leaves of elytrigia elongata can be increased, and the field yield is increased. The method for improving the drought resistance of the seedlings of the elytrigia elongata is low in cost and easy to operate, the popularization and application of the elytrigia elongata in arid and semi-arid soil are fully played, and the method has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of forage cultivation, and in particular to the application of melatonin in improving the drought resistance of Elytrigia elongata Background Art

[0002] Elytrigia elongata Elytrigia elongata is an excellent perennial tussock rhizomatous herb of the genus Elytrigia in the Triticeae tribe of the Poaceae family. Belonging to the Triticeae tribe, it has very important utilization value. Elytrigia elongata adapts to a wide range of soil types and climates. Its rhizomes grow fast, it has strong tillering ability and ground covering ability, and its aboveground biomass is as high as 5270 kg·hm -2 . In addition, Elytrigia elongata has many traits that can be used for wheat variety improvement, such as high protein content, resistance to various fungal and viral diseases, drought resistance, cold resistance, salt tolerance, wide adaptability, etc. Therefore, Elytrigia elongata is an ideal perennial herb in ecological construction and can be used as livestock feed and a wild genetic resource for wheat variety improvement. Therefore, taking certain measures to enhance the drought resistance of Elytrigia elongata is of great significance for forage utilization and variety breeding.

[0003] In the prior art, the drought resistance of Elytrigia elongata can be enhanced through multiple aspects such as genetic improvement, cultivation management, soil improvement, irrigation technology, etc., but each of the above technical methods has its advantages and disadvantages. For example, the genetic improvement method is cumbersome to operate and has a long R & D cycle, the soil improvement method has environmental safety risks, and the cultivation management and irrigation technology have high labor intensity and high human and material costs.

[0004] Therefore, how to provide a simple and effective method for enhancing the drought resistance of Elytrigia elongata has become a technical problem urgently to be solved in this field. Summary of the Invention

[0005] In order to solve the above technical problems, through a large number of screenings of plant hormones, the present invention discovers that melatonin can effectively improve the drought resistance of Elytrigia elongata. The improvement of the drought resistance of Elytrigia elongata seedlings is manifested in: increasing the fresh weight and dry weight of the aboveground and underground parts, increasing the total chlorophyll content to enhance its photosynthetic efficiency, increasing the antioxidant enzyme activity and the content of antioxidant substances (such as glutathione), increasing the proline content to enhance the osmotic pressure regulation ability of cells, etc., so as to improve its drought resistance.

[0006] Melatonin is a pleiotropic molecule with a wide range of cellular and physiological functions in living organisms including animals and plants. It plays a crucial role in plant growth and development as well as their resistance to adversity, helping plants survive and thrive. Some studies have shown that the application of exogenous melatonin or the overexpression of synthetic enzyme genes enhances the stress tolerance of many plant species, including Arabidopsis thaliana, cassava, cotton, and rice. However, melatonin is not effective in enhancing the tolerance of all plants to abiotic stresses (such as salt stress, heavy metal stress, drought stress, etc.). Through extensive screening of plant hormones, the present invention has found that melatonin can effectively improve the drought resistance of Thinopyrum elongatum.

[0007] Furthermore, the present invention provides the use of melatonin in the preparation of a product for improving the drought resistance of Thinopyrum elongatum.

[0008] Preferably, the product is a plant growth regulator.

[0009] Furthermore, the present invention provides a method for improving the drought resistance of Thinopyrum elongatum, comprising: applying a melatonin solution during the seedling stage of Thinopyrum elongatum.

[0010] Preferably, the seedling stage is the three-leaf stage.

[0011] Preferably, the application method is spraying.

[0012] Preferably, the melatonin solution is sprayed after placing the Thinopyrum elongatum at the seedling stage in a dark environment for more than 1 h.

[0013] Preferably, the melatonin solution is sprayed once every other day for more than 3 days.

[0014] Preferably, the volume of the melatonin solution sprayed each time is 20 - 30 mL.

[0015] Preferably, the concentration of the melatonin solution is 50 - 200 μmol·L -1 .

[0016] Most preferably, the concentration of the melatonin solution is 140 - 160 μmol·L -1 .

[0017] The present invention has also found that the exogenous application of the melatonin solution at the above concentration has the best effect on improving the drought resistance of Thinopyrum elongatum. When the concentration of the added exogenous melatonin is 150 μmol·L -1When applied, it can significantly increase the aboveground and underground biomass of Elytrigia elongata, increase the total chlorophyll content to enhance its photosynthetic efficiency, increase the antioxidant enzyme activity and the content of antioxidant substances. At the same time, it can increase the proline content to improve the osmotic adjustment ability of Elytrigia elongata under drought stress, maintain the balance of osmotic pressure, and thus improve the drought resistance of Elytrigia elongata.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a simple and effective method for enhancing the drought resistance of Elytrigia elongata. Spraying the seedlings of Elytrigia elongata with exogenous melatonin solution can improve its drought resistance, and can give full play to the popularization and application of Elytrigia elongata in arid and semi-arid soils. It has high practical significance for forage production, the development of forage and livestock industries, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Effects of exogenous melatonin on plant height and biomass of Elytrigia elongata under drought stress.

[0020] Figure 2 Effects of exogenous melatonin on chlorophyll content and superoxide dismutase (SOD) activity of Elytrigia elongata under drought stress.

[0021] Figure 3 Effects of exogenous melatonin on glutathione (GSH) content and proline (Pro) content of Elytrigia elongata under drought stress.

[0022] Figure 4 Effects of exogenous melatonin at different concentrations on plant height and biomass of Elytrigia elongata. DETAILED DESCRIPTION OF THE INVENTION

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention. In the embodiments provided in this specification, those not specifying specific techniques or conditions are carried out according to the techniques or conditions described in the literature in the field or according to the product specifications. The reagents or instruments not indicating the manufacturer are all conventional products that can be obtained through regular channels.

[0024] The culture solution for Elytrigia elongata seedlings is Hoagland nutrient solution, and its composition is: 2 mmol·L -1 KNO 3 , 0.5 mmol·L -1 NH 4 H2 PO 4 ,0.25 mmol·L -1 MgSO 4 ·7H 2 O,1.5 mmol·L -1 Ca(NO 3 ) 2 ·4H 2 O,0.5 mmol·L - 1 Fe-citrate,92 μmol·L -1 H 3 BO 3 ,18 μmol·L -1 MnCl 2 ·4H 2 O,1.6 μmol·L -1 ZnSO 4 ·7H 2 O,0.6 μmol·L -1 CuSO 4 ·5H 2 O,0.7 μmol·L -1 (NH 4 ) 6 Mo 7 O 24 ·4H 2 O。

[0025] Example 1 This example provides a method for improving the drought resistance of Elytrigia elongata, and the steps are as follows: Select mature, plump and uniform Elytrigia elongata seeds. After wrapping them with gauze, disinfect them with 10% NaClO solution for 15 min, rinse them with distilled water multiple times, and place them in a petri dish lined with two layers of filter paper for germination. After the seeds germinate for 10 d, select healthy and uniformly growing seedlings and transfer them to a black hydroponic box (20 cm × 10 cm × 7 cm) filled with Hoagland nutrient solution. Place the hydroponic box in an artificial climate chamber for cultivation, and the cultivation conditions are: photoperiod 16 h light / 8 h dark, temperature 25℃ / 18 ℃, relative humidity 60% - 80%, light intensity 800 μmol·m -2 ·s -1 −2, and adjust the pH value of the nutrient solution to 5.8 with 0.1 mol HCl or 0.1 mol NaOH every day. Supplement Hoagland nutrient solution daily and change the nutrient solution every 4 d.

[0026] Cultured until the three-leaf stage (the 16th day of colonization and growth), when the plant height reached 10 - 15 cm, melatonin solution (MT) was sprayed, and its concentration was: 50 μmol·L -1 . The spraying time was set 1 h after the seedlings were placed in the dark. The adaxial and abaxial surfaces of the seedling leaves were evenly sprayed using the spraying method until visible water droplets condensed and dripped from the leaves. The spraying amount was about 20 mL / replicate. After the solution on the leaf surface naturally evaporated, it was sprayed again after 1 day, and the treatment was carried out continuously for 3 times. The control group (CK) was sprayed with an equal amount of deionized water. After the MT spraying treatment was completed, a certain amount of PEG-6000 was added to the Hoagland nutrient solution to make the concentration of PEG-6000 in the nutrient solution 15% to simulate drought stress. The control group was set as normal Hoagland nutrient solution culture + distilled water spraying (CK), and the spraying amount was the same as that of the MT treatment. There were a total of 2 treatments in the experiment (MT 0 , MT 50 ). Continuous aeration was maintained during the experimental treatment, and the nutrient solution was changed once every 7 days. After culturing for 21 days, the plants were harvested and samples were collected.

[0027] Example 2 This example provides a method for improving the drought resistance of Elytrigia elongata. The only difference in the steps from Example 1 is that the concentration of the melatonin solution is 100 μmol·L -1 , and the spraying amount is about 22 mL / replicate.

[0028] Example 3 This example provides a method for improving the drought resistance of Elytrigia elongata. The only difference in the steps from Example 1 is that the concentration of the melatonin solution is 150 μmol·L -1 , and the spraying amount is about 25 mL / replicate.

[0029] Example 4 This example provides a method for improving the drought resistance of Elytrigia elongata. The only difference in the steps from Example 1 is that the concentration of the melatonin solution is 200 μmol·L -1 , and the spraying amount is about 30 mL / replicate.

[0030] Comparative Example 1 This comparative example provides a method for improving the drought resistance of Elytrigia elongata. The only difference in the steps from Example 3 is that the melatonin solution is replaced with the same volume of distilled water.

[0031] Comparative Example 2 This comparative example provides a method for improving the drought resistance of Elytrigia elongata. The only difference in the steps from Example 3 is that the melatonin solution is replaced with a salicylic acid solution of the same concentration.

[0032] Test Example 1 In this test example, the plant heights, above-ground and below-ground biomasses of the plant samples in the above-mentioned examples and comparative examples were measured. The test results are as Figure 1 shown. The plant heights of Examples 1-4 were 4.12%, 8.60%, 19.43%, and 10.84% higher than that of Comparative Example 1 respectively; the biomasses of Examples 1-4 were 33.55%, 35.66%, 111.84%, and 36.58% higher than that of Comparative Example 1 respectively.

[0033] The plant heights of Examples 1-4 were 0.98%, 5.32%, 15.82%, and 7.5% higher than that of Comparative Example 2 respectively; the biomasses of Examples 1-4 were 4.64%, 6.29%, 65.98%, and 7.01% higher than that of Comparative Example 2 respectively.

[0034] Among them, Example 3 had the best effect.

[0035] Test Example 2 In this test example, the chlorophyll content, superoxide dismutase activity, glutathione content, and proline content of the plant samples in the above-mentioned examples and comparative examples were measured. Among them, the chlorophyll content (Chl) was determined by the direct extraction method, referring to the method of Gao Junfeng (Gao Junfeng. Experimental Guide for Plant Physiology [M]. Beijing: Higher Education Press, 2006). The superoxide dismutase activity, glutathione content, and proline content of the seedling leaves were determined using a kit purchased from Beijing Boxbio Science & Technology Co., Ltd.

[0036] The test results of the chlorophyll content and superoxide dismutase activity are as Figure 2 shown, and the test results of the glutathione content and proline content are as Figure 3 shown. The results showed that the leaf chlorophyll contents of Examples 1-4 were 12.96%, 26.96%, 52.54%, and 31.68% higher than that of Comparative Example 1 respectively; the leaf superoxide dismutase activities of Examples 1-4 were 6.07%, 9.74%, 18.39%, and 10.53% higher than that of Comparative Example 1 respectively; the glutathione contents of Examples 1-4 were 13.17%, 21.81%, 42.39%, and 24.96% higher than that of Comparative Example 1 respectively; the proline contents of Examples 1-4 were 6.41%, 10.40%, 23.35%, and 11.07% higher than that of Comparative Example 1 respectively.

[0037] The chlorophyll contents of the leaves in Examples 1-4 were 2.20%, 14.87%, 38.01%, and 19.14% higher than that in Comparative Example 2, respectively; the superoxide dismutase activities of the leaves in Examples 1-4 were 2.89%, 6.45%, 14.85%, and 7.22% higher than that in Comparative Example 2, respectively; the glutathione contents in Examples 1-4 were 2.68%, 10.52%, 29.19%, and 13.17% higher than that in Comparative Example 2, respectively; the proline contents in Examples 1-4 were 5.41%, 9.37%, 22.20%, and 10.03% higher than that in Comparative Example 2, respectively.

[0038] Among them, the chlorophyll content, superoxide dismutase activity, glutathione content, and proline content in Example 3 were the highest.

[0039] Test Example 3 This test example investigated the effects of melatonin at different concentrations on the plant height and biomass of Elytrigia elongata. Elytrigia elongata was treated according to the method of Example 3, and the spraying amount was about 25 mL / replicate. The effects of melatonin at different concentrations (25, 75, 125, 150, 175, 225 μmolˑL -1 ) on the plant height and biomass of Elytrigia elongata were studied. The results are shown in Figure 4 .

[0040] It can be seen from Figure 4 that melatonin solutions at different concentrations had certain effects on the plant height and biomass of Elytrigia elongata seedlings, and the plant height and biomass of Elytrigia elongata were the highest under the treatment of 150 μmolˑL -1 .

[0041] In addition, the above tests of only changing the melatonin concentration while keeping the spraying volume unchanged were also conducted on other examples, and the results were basically the same, that is, the plant height and biomass of Elytrigia elongata were the highest under the treatment of 150 μmolˑL -1 .

[0042] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing examples, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. Application of melatonin in improving drought resistance of Elytrimus elongatus.

2. Application of melatonin in the preparation of products for improving the drought resistance of Elytrimus elongatus.

3. The use according to claim 2, characterized in that: The product is a plant growth regulator.

4. A method for improving the drought resistance of Elytrimus elongatus, characterized in that: include: Melatonin solution was applied to the seedlings of Elytium longispinum.

5. The method according to claim 4, characterized in that The seedling stage is the three-leaf stage.

6. The method according to claim 4, characterized in that The application method is spraying.

7. The method according to claim 4, characterized in that The seedlings of Elymus elongatus were placed in a dark environment for more than 1 hour and then sprayed with melatonin solution.

8. The method according to claim 4, characterized in that Spray the melatonin solution every other day for more than 3 days.

9. The method according to any one of claims 4 to 8, characterized in that The concentration of the melatonin solution is 50-200 μmolˑL -1 .

10. The method according to claim 9, characterized in that The concentration of the melatonin solution is 140-160 μmolˑL -1 .

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