A treatment method for improving cold tolerance of elephant grass

Abstract

The present application relates to the technical field of forage grass planting, and discloses a treatment method for improving cold tolerance of elephant grass, wherein 1000 mg / L chitosan solution is used as an exogenous substance to be applied to elephant grass, and more preferably, 1000 mg / L chitosan solution and biochar are used as exogenous substances to be applied to elephant grass. The present application uses chitosan as a biological stimulant to stimulate the production of cold-resistant substances in plants, which helps to protect plant cells from damage under low-temperature conditions. The use of chitosan solution to treat elephant grass and the determination of the optimal use concentration for improving the cold tolerance of elephant grass through experiments significantly enhance the cold tolerance of elephant grass. The present application further improves the cold tolerance of elephant grass by applying biochar in combination with the application of chitosan solution.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of forage grass planting, and particularly relates to a treatment method for improving cold tolerance of elephant grass. BACKGROUND

[0002] Elephant grass (Pennisetum purpureum) is an annual or perennial forage grass of the genus Pennisetum in the family Poaceae, and has a plant height of 3-5 m and a stem diameter. The elephant grass has high nutritional value, high protein content and high digestibility, is soft and juicy, has good palatability, and has high utilization rate. Cattle, horses, sheep, rabbits, ducks, geese and the like like to eat the elephant grass, and the tender period of the elephant grass is also good feed for raising pigs and fish. In addition to providing green forage for livestock and poultry in all seasons, the elephant grass can also be made into hay or silage. In addition, the elephant grass can also replace coal and oil for power generation, and the energy generated by planting 1 hectare of the elephant grass can replace 36 barrels of oil. The root system of the elephant grass is very developed, and the elephant grass planted on the bank of a pond or a dike can play a role in protecting the dike and soil. The elephant grass can also be cut as a cover material for perennial crops. Therefore, the elephant grass has high economic value. However, the elephant grass is sensitive to low-temperature stress, and lacks the ability to adapt to and resist low-temperature environment, which seriously limits the popularization and planting of the elephant grass in temperate zones and cold and cool areas at high altitudes. Therefore, it is an urgent problem to be solved to improve the cold tolerance of the elephant grass and broaden the planting range of the elephant grass.

[0003] The ability of a plant to adapt to and resist low temperature is referred to as the cold tolerance of the plant. At present, the methods for improving the cold tolerance of a plant include improving agricultural measures to reduce the harm of low temperature to the plant, using hybrid breeding or genetic engineering to cultivate a variety with superior cold resistance to reduce the adverse effects of low temperature, but the improvement of agricultural measures is time-consuming and labor-intensive, the selection cycle of hybrid breeding is long, and the genetic engineering technology is difficult. Recently, some studies have shown that the spraying of some exogenous substances on plants can effectively improve the cold resistance of the plants. For example, chitosan plays a role in resisting low-temperature stress of cucumber, pepper and banana and the like, can promote the growth of the plants, promote the synthesis of anti-permeation substances, improve the antioxidant enzyme activity of the plants, and protect the membrane system, thereby enhancing the self-resistance of the plants. Spraying of 20 mmol / L of betaine on plants can effectively improve the ability of the plants to adapt to low temperature. However, the effects of different exogenous substances on crops may not be the same, and at present, no suitable exogenous substance for improving the cold tolerance of elephant grass has been disclosed. SUMMARY

[0004] In view of the problems in the background art, the purpose of the present application is to provide a treatment method for improving the cold tolerance of elephant grass, so as to find a suitable exogenous substance for improving the cold tolerance of elephant grass and reasonably apply the exogenous substance, so as to improve the cold tolerance of the elephant grass, thereby broadening the planting range of the elephant grass and meeting the needs of different regions for the elephant grass.

[0005] In order to achieve the above technical effects, the technical scheme of the present application is as follows:

[0006] The application provides a treatment method for improving cold tolerance of elephant grass, which is applying 1000 mg / L chitosan solution as an exogenous substance to elephant grass.

[0007] Further, the application method of the chitosan solution is foliar spraying, and the spraying amount is 6-7 L / m 2 Elephant grass.

[0008] More preferably, the foliar spraying amount of the chitosan solution is 6.4 L / m 2 Elephant grass.

[0009] Further, the chitosan solution contains 0.3% mass concentration of a Tween surfactant.

[0010] Further, the Tween surfactant is Tween 20.

[0011] In some embodiments of the application, the treatment method further comprises applying biochar as an exogenous substance to elephant grass.

[0012] Further, the application method of the biochar is root application, and the biochar is mixed with elephant grass cultivation soil at a mass ratio of 1:10 and then used in the area where the root system of the elephant grass is distributed.

[0013] Further, the application amount of the biochar root application is 15-16 Kg biochar / m 2 Elephant grass.

[0014] More preferably, the application amount of the biochar root application is 15.3 Kg biochar / m 2 Elephant grass.

[0015] Chitosan (CTS) is a polyamino glucosamine, which is an anti-stress signal molecule induced by plants to respond to abiotic stress. Chitosan and its derivatives can remove excessive free radicals generated by cells under low temperature stress, promote photosynthesis and synthesis of osmotic regulation substances in cells, and thus enhance the ability of plants to resist low temperature. Chitosan is the only alkaline polysaccharide existing in a large amount in the biological world, and is a non-toxic and non-polluting animal-derived hormone substance. Chitosan has the characteristics of solubility, biodegradability, disease resistance induction and edibility, and is widely used in industry, agriculture and medicine. Chitosan can improve nutrient absorption by increasing plant cell permeability, promote root development, improve plant photosynthesis, regulate crop growth and induce plant stress resistance. Studies have shown that exogenous chitosan can induce plant defense response, improve plant cold tolerance and promote plant growth.

[0016] The application utilizes the characteristics of chitosan as a biological stimulant to stimulate the production of cold-resistant substances in plants, to help protect plant cells from damage under low temperature conditions, uses chitosan solution to treat elephant grass, and determines the optimal use concentration for improving the cold resistance of elephant grass through tests, and significantly enhances the cold resistance of elephant grass.

[0017] Biochar is a product formed by pyrolysis of agricultural and forestry waste biomass under anaerobic conditions. Due to its abundant pores, large specific surface area and stable properties, it is often used to improve soil. Studies have shown that the application of biochar can affect plant root development. Adding biochar to rice field soil seedling raising substrate can promote the elongation and thickening of seedling roots, which is beneficial to the formation of developed roots. Studies have found that biochar can improve the cold resistance of rice seedlings under low temperature stress. The application combines the application of chitosan solution with the application of biochar, further improving the cold resistance of elephant grass.

[0018] Compared with the prior art, the application has the beneficial effects that:

[0019] The application provides a treatment method for improving the cold resistance of elephant grass, which significantly enhances the cold resistance of elephant grass by externally applying chitosan and biochar. The method is simple to operate, low in use cost, and chitosan and biochar are renewable resources without environmental pollution problems, and is suitable for large-scale popularization and application in production practice. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 Figure 1 is a phenotype photo of elephant grass treated with different concentrations of chitosan solution before and after low temperature stress according to the embodiment 1 of the application;

[0021] Figure 2 Figure 2 is a columnar data graph of the relative conductivity of elephant grass treated with different concentrations of chitosan solution after low temperature stress according to the embodiment 1 of the application;

[0022] Figure 3 Figure 3 is a columnar data graph of the chlorophyll content of elephant grass treated with different concentrations of chitosan solution after low temperature stress according to the embodiment 1 of the application;

[0023] Figure 4 Figure 4 is a columnar data graph of the chlorophyll fluorescence of elephant grass treated with different concentrations of chitosan solution after low temperature stress according to the embodiment 1 of the application;

[0024] Figure 5 Figure 5 is a columnar data graph of the malondialdehyde content in elephant grass treated with different concentrations of chitosan solution after low temperature stress according to the embodiment 1 of the application;

[0025] Figure 6 Figure 6 is a phenotype photo of elephant grass treated with different concentrations of biochar by root application before and after low temperature stress according to the embodiment 2 of the application;

[0026] Figure 7A columnar data chart of relative conductivity of Hyparrhenia rufa after low temperature stress and root application of different concentrations of biochar in Example 2 of the present application;

[0027] Figure 8 A columnar data chart of chlorophyll content of Hyparrhenia rufa after low temperature stress and root application of different concentrations of biochar in Example 2 of the present application;

[0028] Figure 9 A columnar data chart of chlorophyll fluorescence of Hyparrhenia rufa after low temperature stress and root application of different concentrations of biochar in Example 2 of the present application;

[0029] Figure 10 A columnar data chart of malondialdehyde content in Hyparrhenia rufa after low temperature stress and root application of different concentrations of biochar in Example 2 of the present application;

[0030] Figure 11 A phenotype photo of Hyparrhenia rufa in different treatment groups before and after low temperature stress in Example 3 of the present application;

[0031] Figure 12 A columnar data chart of relative conductivity of Hyparrhenia rufa in different treatment groups after low temperature stress in Example 3 of the present application;

[0032] Figure 13 A columnar data chart of relative water content of Hyparrhenia rufa in different treatment groups after low temperature stress in Example 3 of the present application;

[0033] Figure 14 A columnar data chart of chlorophyll fluorescence of Hyparrhenia rufa in different treatment groups after low temperature stress in Example 3 of the present application;

[0034] Figure 15 A columnar data chart of chlorophyll content of Hyparrhenia rufa in different treatment groups after low temperature stress in Example 3 of the present application;

[0035] Figure 16 A columnar data chart of malondialdehyde content in Hyparrhenia rufa in different treatment groups after low temperature stress in Example 3 of the present application.

[0036] The lowercase English letters connected with the columns in the above columnar data charts represent the results of significant difference analysis. DETAILED DESCRIPTION

[0037] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below in combination with specific embodiments.

[0038] Example 1, Effect Test of Exogenous Spraying of Chitosan Solution on Hyparrhenia rufa Cold Resistance

[0039] (1) Test materials:

[0040] Hyparrhenia rufa variety: Yunmu No. 1;

[0041] Cultivated soil: field soil;

[0042] Test pots: 10 cm in diameter.

[0043] (2) Test method:

[0044] The lower stems of elephant grass were selected and soaked in water, then covered with soil in pots, and placed in a constant temperature and humidity environment (25°C during the day; 23°C at night; humidity 60%) for management and growth. After the elephant grass grew for six weeks and produced seedlings, 50 mL of different concentrations of chitosan solution (containing 0.3wt% Tween 20) were sprayed on the leaves, and after drying, they were placed in a light incubator for low temperature stress (4°C, 12h). The phenotypic changes were observed, as shown in Figure 1 .

[0045] The concentration of chitosan solution (CTS) was set at 0 mg / L (control), 250 mg / L, 500 mg / L, 1000 mg / L, 1500 mg / L, and 2000 mg / L.

[0046] (3) Physiological index determination

[0047] The elephant grass after low temperature stress was measured for the following physiological indexes:

[0048] 1. Relative conductivity: Fresh weight of leaf blades of about 0.1 g (FW) was cut from the same part and wrapped with ordinary absorbent paper. The leaf blades were immersed in a 50 ml centrifuge tube containing 30 ml water, and the initial conductivity S1 was measured after 24h at room temperature. After boiling in a water bath to completely kill the plant tissue, it was cooled to room temperature, and the final conductivity S2 was measured. The relative conductivity was L = S1 / S2. The measured data are shown in Figure 2 .

[0049] 2. Chlorophyll content: 0.15 g of fresh leaves were washed and immediately immersed in 15 ml of dimethyl sulfoxide (DMSO) solution at room temperature in the dark for 8 hours, and the absorbance of the extract was detected at 663 and 645 nm using a spectrophotometer (Spectronic Instruments, Rochester, NY, USA). The measured data are shown in Figure 3 .

[0050] 3. Chlorophyll fluorescence: The Fv / Fm reading was determined and recorded by using a chlorophyll fluorescence meter. The measured data are shown in Figure 4 .

[0051] 4. Malondialdehyde (MDA) content: Grind 0.15 g of fresh plant tissue in 2 ml of pre-cooled phosphate-buffered saline (50 mM, pH 7.8) and centrifuge at 10000 g for 15 minutes. The supernatant is used to determine the MDA content. Add 0.5 ml of the supernatant to 1 ml of reaction solution (20% w / v trichloroacetic acid and 0.5% w / v thiobarbituric acid), then heat at 100 °C for 10 minutes. After cooling to room temperature, centrifuge the mixture at 8000 g for 10 minutes and measure the absorbance of the supernatant at 532 and 600 nm. See the results below. Figure 5 As shown.

[0052] (4) Test Results

[0053] See Figure 1 As shown, elephant grass leaves exhibited varying degrees of wilting and curling after low-temperature stress. However, with increasing chitosan solution concentration, the degree of wilting initially lessened and then worsened. When the concentration of exogenous chitosan solution exceeded 1000 mg / L, the wilting of elephant grass leaves became more pronounced. This experiment further measured the relative conductivity, chlorophyll content, chlorophyll fluorescence, and malondialdehyde content of elephant grass treated with different concentrations of chitosan solution after low-temperature stress. (See [reference needed]). Figures 2 to 5 As shown, with increasing chitosan solution concentration, the relative conductivity and malondialdehyde content of elephant grass initially decreased and then increased, while chlorophyll fluorescence and chlorophyll content initially increased and then decreased. Significant differences were observed between the chitosan-treated group and the control group without chitosan, and significant differences were also found between the 1000 mg / L chitosan solution-treated group and the groups treated with other concentrations of chitosan solution. These results indicate that exogenous application of chitosan solution can improve the resistance of elephant grass to low-temperature stress, with 1000 mg / L chitosan solution achieving the optimal effect.

[0054] Example 2: Experiment on the effect of exogenous biochar application on the cold resistance of target grasses

[0055] (1) Experimental materials:

[0056] Elephant grass variety: Yunmu No. 1;

[0057] Cultivated soil: field soil;

[0058] Experimental basin: 10cm in diameter.

[0059] (2) Experimental methods:

[0060] The lower stems of elephant grass growing vigorously were immersed in water and then placed in pots with soil. The pots were placed in a constant temperature and humidity environment (25°C during the day and 23°C at night, with a humidity of 60%) to manage the growth of the elephant grass. After the elephant grass grew for six weeks and produced seedlings, root treatment was performed using different concentrations of biochar. The root treatment method was to mix biochar with 1.2 kg of field soil at different mass ratios and then use the mixture in the area where the roots of the elephant grass were distributed. After growing for one week, the elephant grass was placed in a light incubator for low-temperature stress (4°C for 12 hours). The phenotypic changes were observed, as shown in Figure 6 .

[0061] The mass ratio of biochar (BC) to field soil in the mixture was set to 0 (i.e., the biochar usage concentration was 0%, control), 3:100 (i.e., the biochar usage concentration was 3%), 5:100 (i.e., the biochar usage concentration was 5%), 10:100 (i.e., the biochar usage concentration was 10%), and 20:100 (i.e., the biochar usage concentration was 20%) in five gradients.

[0062] (3) Physiological index determination

[0063] The physiological indexes of the elephant grass after low-temperature stress were determined. The determination items and methods were the same as in Example 1. The determination data are shown in Figures 7 to 10 .

[0064] (4) Test results

[0065] As shown in Figure 6 , the leaves of the elephant grass after low-temperature stress were wilted and curled to varying degrees. However, with the increase in the biochar usage concentration, the wilted degree first decreased and then increased. When the exogenous root biochar usage concentration was ≤10%, the wilted degree of the leaves of the elephant grass gradually decreased with the increase in the concentration. However, when the exogenous root biochar usage concentration exceeded 10%, the leaves of the elephant grass began to wilt again. Then, the relative electrical conductivity, chlorophyll content, chlorophyll fluorescence, and malondialdehyde content of the elephant grass treated with biochar after low-temperature stress were further determined, as shown in Figures 7 to 10 . It was found that with the increase in the biochar usage concentration, the relative electrical conductivity and malondialdehyde content of the elephant grass presented a trend of first decreasing and then increasing, while the chlorophyll fluorescence and chlorophyll content presented a trend of first increasing and then decreasing. There were obvious differences between the treatment group with root biochar and the control group without root biochar, and between the treatment group with 10% biochar and the treatment group with other concentrations of biochar. The results showed that exogenous root biochar could improve the resistance of elephant grass under low-temperature stress, and the optimal effect was achieved when the biochar usage concentration was 10%.

[0066] Example 3, Influence of applying different exogenous objects on the cold resistance of elephant grass

[0067] (1) Test materials:

[0068] Elephant grass variety: Yunmu No. 1;

[0069] Cultivated soil: field soil;

[0070] Experimental basin: 10cm in diameter.

[0071] (2) Experimental methods:

[0072] The following six treatment groups and one control group were set up:

[0073] Control group (CK): No exogenous substances were applied;

[0074] Treatment Group 1 (CTS): Foliar spraying with 1000 mg / L chitosan solution (application method and dosage are the same as in Example 1);

[0075] Treatment Group 2 (BC): Root application of 10% biochar (application method and dosage are the same as in Example 2);

[0076] Treatment group 3 (CTS+BC): Foliar spraying of 1000 mg / L chitosan solution + root application of 10% biochar (the application method and amount of chitosan solution are the same as in Example 1, and the application method and amount of biochar are the same as in Example 2);

[0077] Treatment group 4 (CTS+GB): Foliar spraying of 1000 mg / L chitosan solution + 20 mmol / L betaine (the application method and amount of chitosan solution are the same as in Example 1, and the application method and amount of betaine are the same as in Example 1, except that the chitosan solution in Example 1 is replaced with betaine).

[0078] Treatment group 5 (BC+GB): Foliar spraying of 20 mmol / L betaine + root application of 10% biochar (the application method and amount of biochar are the same as in Example 2, and the application method and amount of betaine are the same as in treatment group 5).

[0079] Treatment Group 6 (CTS+BC+GB): Foliar spraying of 1000 mg / L chitosan solution + 20 mmol / L betaine + root application of 10% biochar (the application method and amount of chitosan solution are the same as in Example 1, the application method and amount of biochar are the same as in Example 2, and the application method and amount of betaine are the same as in Treatment Group 5).

[0080] Phenotypic changes of elephant grass before and after low-temperature stress in each treatment group are shown in the figure. Figure 11 .

[0081] (3) Measurement of physiological indicators

[0082] Physiological indicators of elephant grass subjected to low-temperature stress were measured. The measurement items and methods were the same as in Example 1, and the measurement data are shown below. Figures 12 to 16 As shown.

[0083] Relative moisture content: Approximately 0.1g of leaf material was cut and submerged in a 10ml centrifuge tube filled with water. After 24 hours of saturation, the leaves were removed, surface moisture was wiped off, and the saturated fresh weight was measured. The leaves were then placed in an oven at 105℃ for 45 minutes to de-enzyme, followed by drying at 75℃ until constant weight, and the dry weight was measured. Calculation formula: Relative moisture content (%) = (fresh weight - dry weight) / (saturated fresh weight - dry weight) × 100%. Measurement data are available in [link to data]. Figure 13 As shown.

[0084] (4) Test Results

[0085] See Figure 11 As shown, elephant grass leaves in both the control group and each treatment group exhibited varying degrees of wilting and curling after low-temperature stress. Treatment group 3 (CTS+BC) showed the least degree of wilting. Further analysis of the relative conductivity, chlorophyll fluorescence, chlorophyll content, relative water content, and malondialdehyde (MDA) content in both the control and treatment groups after low-temperature stress revealed a decreasing trend in relative conductivity and MDA content. Significant differences were observed between each treatment group and the control group, with treatment group 3 (CTS+BC) showing a significant difference from other treatment groups. Conversely, chlorophyll fluorescence, chlorophyll content, and relative water content showed an increasing trend, with significant differences between each treatment group and the control group, and with treatment group 3 (CTS+BC) showing a significant difference from other treatment groups. These results indicate that exogenous application of a combination of chitosan and biochar can more effectively improve the resistance of elephant grass to low-temperature stress.

[0086] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A treatment method for improving cold tolerance of Pennisetum purpureum, characterized by: The treatment method is applying biochar and a 1000 mg / L chitosan solution as exogenous substances to elephant grass, the biochar is applied by root application, and the biochar is mixed with the elephant grass cultivation soil at a mass ratio of 1:10 and then used in the area where the roots of the elephant grass are distributed.

2. The treatment method of claim 1, wherein: The method of applying the chitosan solution is foliar spraying, and the spraying amount is 6-7 L / m 2 Eleusine indica.

3. The treatment method of claim 2, wherein: The foliar spraying amount of the chitosan solution is 6.4 L / m 2 Eleusine indica.

4. The treatment method of claim 1, wherein: The chitosan solution contains 0.3% by mass of a Tween surfactant.

5. The treatment method of claim 4, wherein: The Tween surfactant is Tween 20.

6. The treatment method of claim 1, wherein: The application amount of the biochar root application is 15-16 Kg biochar / m 2 Elephant grass.

7. The treatment method of claim 6, wherein: The application amount of the biochar root application is 15.3 Kg biochar / m 2 Elephant grass.

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