Method for controlling low-temperature stress of tomatoes based on nano copper sulphide

Abstract

The invention discloses a method for controlling low-temperature stress of tomatoes based on nano copper sulfide, and belongs to the technical field of novel cold resistance. According to the invention, the copper sulfide nanoparticles are prepared and are used for promoting the tomato to resist low-temperature stress. According to the method, the low-temperature stress of the tomatoes is controlled by applying the CuS NPs on the leaf surfaces, so that the plant height of the tomatoes under the low-temperature stress is increased by 14.96%, and the fresh weight of the overground part and the fresh weight of the underground part are increased by 32.21% and 64.37% respectively. The effect of the prepared copper sulfide nanoparticles is better than that of a conventional copper-based material, a sulfur-based material, a traditional anti-cold agent and other sulfur-based nanoparticles.

Description

Technical Field

[0001] The present invention relates to a method for controlling low - temperature stress of tomatoes based on copper sulfide nanoparticles, belonging to the field of novel cold - resistance technologies. Background Art

[0002] With the sharp increase in the global population, it is expected that the global demand for crop yields will increase by 50 - 80% in 2050. How to ensure the realization of this goal is a major challenge facing humanity. In recent years, the frequent occurrence of extreme climates globally has posed a serious threat to crop growth and yields. Among them, the reduction in crop yields caused by low - temperature freezing disasters accounts for more than 30% of the reduction in crop yields caused by extreme climates, and generally shows an increasing trend in occurrence frequency and an expanding trend in the affected area.

[0003] With the rapid development of nanotechnology, nanomaterials with high chemical activity and biological effectiveness have shown great application potential in controlling crop cold damage. However, current research on using nanomaterials to control crop diseases mainly focuses on silver - based nanomaterials. Compared with traditional cold - resistance agents, although silver - based nanomaterials show better performance in controlling crop cold damage, silver is expensive, and the harm of silver enrichment to the environment is relatively large, so it is still not suitable for long - term use.

[0004] Therefore, developing an efficient and safe crop cold - resistance agent is of great significance for coping with the increasingly severe low - temperature stress. Summary of the Invention

[0005] To solve the above problems, the present invention prepares copper sulfide nanoparticles and uses them to promote the cold - resistance of tomatoes under low - temperature stress; this application detects the optimal application method and optimal application concentration of copper sulfide nanoparticles for controlling the low - temperature stress of tomatoes, and compares the effects of different sulfur - based nanomaterials in controlling crop cold damage.

[0006] One object of the present invention is to provide a method for promoting the cold - resistance of tomatoes under low - temperature stress, by treating tomato seeds with copper sulfide nanoparticles for seed dressing or treating tomato leaves with copper sulfide nanoparticles for foliar application.

[0007] Preferably, a method for promoting the cold - resistance of tomatoes under low - temperature stress is to treat tomato leaves with copper sulfide nanoparticles for foliar application.

[0008] In one embodiment, in the treatment of tomato seeds with copper sulfide nanoparticles for seed dressing, the concentration of copper sulfide nanoparticles is 20 - 200 mg / kg of tomato seeds;

[0009] Preferably, the concentration of copper sulfide nanoparticles is 50 - 100 mg / kg of tomato seeds.

[0010] In one embodiment, for the treatment of tomato seeds by coating with copper sulfide nanoparticles, the copper sulfide nanoparticles are moistened with water to obtain moistened copper sulfide nanoparticles; the moistened copper sulfide nanoparticles are mixed with tomato seeds, and after shaking until the copper sulfide nanoparticles (NPs) are evenly attached to each seed, sowing is carried out.

[0011] In one embodiment, for the foliar application of copper sulfide nanoparticles to tomato leaves, the concentration of copper sulfide nanoparticles is 20 - 200 mg / L, the spraying amount is 4 - 6 mL / plant / day, for 4 - 6 consecutive days;

[0012] Preferably, the concentration of copper sulfide nanoparticles is 200 mg / L, the spraying amount is 5 mL / plant / day, for 5 consecutive days.

[0013] In one embodiment, the preparation method of copper sulfide nanoparticles is as follows:

[0014] (1) Add the copper chloride ethanol solution to the thioacetamide ethanol solution, and carry out ultrasonic treatment and standing;

[0015] (2) After standing, take the upper supernatant and mix it with water, and stir for reaction; after the reaction, cool down, centrifuge, wash, and dry to obtain copper sulfide nanoparticles.

[0016] In one embodiment, in step (1), the mass ratio of copper chloride to thioacetamide is 1 - 1.5:1 - 2; the volume ratio of the copper chloride ethanol solution to the thioacetamide ethanol solution is 120 - 160:180 - 210;

[0017] Preferably, the mass ratio of copper chloride to thioacetamide is 1.22:1.60; the volume ratio of the copper chloride ethanol solution to the thioacetamide ethanol solution is 150:200.

[0018] In one embodiment, in step (1), the copper chloride ethanol solution is added to the thioacetamide ethanol solution at a rate of 1 - 3 mL / s;

[0019] Preferably, the copper chloride ethanol solution is added to the thioacetamide ethanol solution at a rate of 2 mL / s.

[0020] In one embodiment, in step (2), the volume ratio of the upper supernatant to water is 200 - 300:200 - 300;

[0021] Preferably, the volume ratio of the upper supernatant to water is 300:300.

[0022] In one embodiment, in step (2), the stirring reaction is carried out at 35 - 45 °C for 0.5 - 1 h;

[0023] Preferably, the stirring reaction is carried out at 40 °C for 0.5 h.

[0024] Another object of the present invention is to provide the application of any of the above methods in the agricultural field.

[0025] The present invention also provides a method for promoting tomato resistance to low temperature stress using zinc sulfide nanoparticles (ZnS NPs) and molybdenum disulfide nanoparticles (MoS2 NPs), which includes the step of foliar application of zinc sulfide nanoparticles (ZnS NPs) or molybdenum disulfide nanoparticles (MoS2 NPs) to tomato leaves.

[0026] Advantages of the present invention

[0027] The present invention prepares copper sulfide nanoparticles and uses them to promote tomato resistance to low temperature stress; detects the optimal application method and optimal application concentration of copper sulfide nanoparticles for controlling tomato low temperature stress, and compares the effects of different sulfur-based nanomaterials on controlling crop chilling injury.

[0028] Specifically,

[0029] (1) The effect of controlling tomato low temperature stress by foliar application of CuS NPs in the present invention is better than seed dressing treatment; 200 mg / L is the optimal application concentration of foliar application of CuS NPs for controlling tomato low temperature stress;

[0030] (2) The copper sulfide nanoparticles prepared in the present invention have better effects than conventional copper-based materials (CuSO4, CuCl2), sulfur-based materials (Na2SO4), traditional cold-resistant agents, and other sulfur-based nanoparticles (ZnS NPs, MoS2 NPs);

[0031] (3) Foliar application treatment (200 mg / L) of the copper sulfide nanoparticles prepared in the present invention increases the plant height of tomato under low temperature stress by 14.96%, and the fresh weight of the above-ground part and the fresh weight of the underground part increase by 32.21% and 64.37% respectively. Description of the drawings

[0032] Figure 1 TEM and XRD diagrams of different nanoparticles; among them, A is the TEM image of CuS NPs; B is the TEM photograph of large CuS particles (BPs); C is the TEM photograph of MoS2 NPs; D is the TEM photograph of ZnS NPs; E is the XRD spectra of CuS NPs, CuS BPs, MoS2 NPs and ZnS NPs.

[0033] Figure 2 Effects of seed dressing treatment and foliar application of different concentrations of CuS NPs on the plant height (A) and biomass of the above-ground and underground parts (B) of tomatoes under low temperature stress; among them, D20, D50, D100, D200 are seed dressing treatments, and S20, S50, S100, S200 are foliar application treatments.

[0034] Figure 3 Effects of foliar application of 200 mg / L CuS NPs, CuS BPs, CuCl2, Na2SO4, CuSO4, and cryoprotectant on plant height (A) and shoot and root biomass (B) of tomato under low temperature stress.

[0035] Figure 4 Effects of foliar application of 200 mg / L CuS NPs, ZnS NPs, and MoS2 NPs on plant height (A) and shoot and root biomass (B) of tomato under low temperature stress.

[0036] Figure 5 Photos of the effects of foliar application of 200 mg / L CuS NPs on shoot and root of tomato under low temperature stress. Detailed implementation mode

[0037] The following describes the preferred embodiments of the present invention. It should be understood that the embodiments are for better explaining the present invention and are not used to limit the present invention.

[0038] Raw materials used in the embodiments:

[0039] CuS BPs, CuCl2, thioacetamide, ZnCl2, Na2MoO4, and glutathione were purchased from sigma reagent company.

[0040] Example 1: Preparation of copper sulfide nanoparticles

[0041] The preparation of copper sulfide nanoparticles is as follows:

[0042] (1) Weigh 1.22 g of CuCl2 into a beaker, add 150 mL of absolute ethanol and disperse it by ultrasonic to obtain a blue and clear copper chloride ethanol solution; weigh 1.60 g of thioacetamide (TAA) into a beaker, add 200 mL of absolute ethanol and disperse it by ultrasonic to obtain a colorless and transparent TAA ethanol solution;

[0043] (2) Add the copper chloride solution to the TAA solution at a rate of 2 mL / s and ultrasonicate for 10 min. The solution changes from yellowish-brown to light yellow emulsion, and then stands for 8 h; after standing, the solution is layered, with a light yellow supernatant on the upper layer and a large amount of light yellow flocs on the lower layer;

[0044] (3) Take 300 mL of the light yellow supernatant and add it to 300 mL of ultrapure water at a rate of 2 mL / s under stirring conditions. The beaker wall becomes hot and a large number of bubbles are generated in the solution. The solution turns into a brown suspension. Stir and react at 40 °C for 0.5 h, and the solution turns dark green. After the solution temperature drops to room temperature, centrifuge this dark green solution at 15000 rpm, wash it several times with anhydrous ethanol and ultrapure water respectively, and then dry it in a vacuum drying oven at 40 °C to obtain black solid, which is copper sulfide nanoparticles (CuS NPs).

[0045] Comparative Example 1: Preparation of zinc sulfide nanoparticles

[0046] The steps for preparing zinc sulfide nanoparticles are as follows:

[0047] (1) Weigh 1.28 g of ZnCl2 into a beaker, add 200 mL of anhydrous ethanol and disperse it by ultrasonic wave to obtain a colorless, clear and transparent zinc chloride ethanol solution; weigh 1.60 g of TAA into a beaker, add 200 mL of anhydrous ethanol and disperse it by ultrasonic wave to obtain a colorless and transparent TAA ethanol solution.

[0048] (2) Slowly add the zinc chloride solution to the TAA solution and ultrasonicate for 10 min. The solution is a colorless and transparent solution. Let it stand for 8 h to obtain a zinc sulfide precursor solution. There is a little white precipitate formed at the bottom of the beaker after standing. This precursor can stably exist in the ethanol solution under sealed conditions.

[0049] (3) Take 300 mL of the precursor supernatant and slowly add it to 300 mL of secondary water under stirring conditions. The beaker wall becomes hot and there are bubbles in the solution. Stir and react at 40 °C for 9 h. The clear and transparent solution turns into a white hydrocolloid. Centrifuge at 15000 rpm, wash with anhydrous ethanol and distilled water, and dry to obtain a white solid, which is zinc sulfide nanoparticles (ZnS NPs).

[0050] Comparative Example 2: Preparation of molybdenum disulfide nanoparticles

[0051] The steps for preparing molybdenum disulfide nanoparticles are as follows:

[0052] Dissolve 0.1 g of Na2Mo04 in 10 mL of ultrapure water, adjust the pH value to 6.5 with HCl (0.1 mol / L, 40 μL), and then add glutathione (0.172 g) and ultrapure water (20 mL) under stirring.

[0053] Mix the mixture for 5 minutes, transfer it to a reaction kettle, heat it at 200 °C for 12 hours, naturally cool it to room temperature and centrifuge for 10 minutes, and then collect the supernatant. Finally, filter the above supernatant through a 0.22 μM microporous filter membrane, and the filtered liquid is dried to obtain a black solid, which is molybdenum disulfide nanoparticles (MoS2 NPs).

[0054] The prepared CuS NPs, ZnS NPs, MoS2 NPs in Example 1, Comparative Example 1 and Comparative Example 2, and the purchased CuS BPs were characterized by transmission electron microscopy and XRD, and the results are as follows: Figure 1 as shown.

[0055] The results showed that the particle sizes of CuS NPs, ZnS and MoS2 NPs were about 10 nm, and the particle size of CuS BPs was about 1 μm; the XRD results showed that both CuS NPs and CuS BPs had CuS characteristic peaks, ZnS NPs had ZnS characteristic peaks, and MoS2 NPs had MoS2 characteristic peaks.

[0056] Example 2: Copper sulfide nanoparticles control low temperature stress in tomatoes

[0057] 1. Detect the effects of different copper sulfide concentrations and application methods on the low temperature stress resistance of tomatoes.

[0058] The experimental groups were as follows: healthy control group (Healthy control), low temperature control group (Cold control), seed dressing treatment group, including: 20, 50, 100 and 200 mg / kg seeds of CuS NPs, and leaf spraying treatment group, including: 20, 50, 100 and 200 mg / L aqueous solution of CuS NPs.

[0059] The healthy control group was not subjected to low temperature treatment, but the same amount of ultrapure water was sprayed on the leaves and treated with CuS NPs; the low temperature control group was subjected to low temperature treatment, and at the same time, the same amount of ultrapure water was sprayed on the leaves and treated with CuS NPs.

[0060] Seed dressing treatment group: Soak tomato seeds (cooper 903) in warm water for 4 h, and then air-dry them in the dark; weigh NPs according to a certain mass ratio (NPs / seeds), and moisten the NPs with 20 μL of water; then mix the moistened NPs powder with tomato seeds, place them in a shaker at 170 rpm and shake for 30 min. After the NPs are evenly attached to each seed, sow them.

[0061] Leaf spraying treatment group: Six weeks after sowing the tomatoes, the first leaf spraying was carried out, that is, the NPs solution of the corresponding concentration was ultrasonically dispersed for 30 min and then evenly sprayed on the tomato leaves. 5 mL of the solution was sprayed on each plant every day for 5 consecutive days. Then the plants were moved into a low temperature environment (10 °C) for one week, and then moved into a normal environmental temperature to continue growing for one week and then harvested.

[0062] The results are as follows: Figure 2As shown, the results indicate that compared with the healthy control group, the plant height, above-ground fresh weight, and underground fresh weight of tomatoes in the low-temperature exposure control group all decreased significantly. Both the seed dressing treatment and the foliar application treatment could, to a certain extent, increase the plant height, above-ground fresh weight, and underground fresh weight of tomatoes under low-temperature stress. Among them, the seed dressing treatment D100 (100 mg / L CuS NPs) had a better effect, while D200 (200 mg / L CuS NPs) had a worse effect; the foliar application treatment S200 (200 mg / L CuS NPs) showed the best effect, significantly better than the low-temperature exposure control group.

[0063] Therefore, the selection of foliar application treatment is the optimal application method for CuS NPs to enhance the cold tolerance of tomatoes, and 200 mg / L is the optimal application concentration of CuS NPs to control tomato low-temperature stress.

[0064] 2. Detect the cold tolerance enhancement effect of different copper-based materials on tomatoes

[0065] 200 mg / L CuS NPs, an equal amount of CuS BPs, an equal amount of copper CuCl2, an equal amount of sulfur Na2SO4, an equal amount of copper and sulfur CuSO4, and a traditional cold-resistant agent at the agricultural guidance concentration in the foliar application treatment were applied to tomatoes by foliar spraying. The experimental process was the same as in 1.

[0066] The results are as Figure 3 shown. The results indicate that in terms of plant height, foliar application of 200 mg / L CuS NPs significantly increased the plant height of tomatoes under low-temperature stress by 11.05%. In terms of above-ground fresh weight, foliar application of CuS NPs, CuS BPs, Na2SO4, and the cold-resistant agent all significantly increased the biomass of tomatoes under low temperature. CuS NPs showed the best performance, significantly increasing the above-ground fresh weight of tomatoes under low temperature by 32.33%. In terms of underground fresh weight, foliar application of CuS NPs also showed the best performance, significantly increasing the underground fresh weight of tomatoes under low temperature by 63.01%.

[0067] In summary, the above results indicate that foliar application of 200 mg / L CuS NPs has the best effect in alleviating tomato low-temperature stress, and is significantly better than the control effects of other copper-based materials and traditional cold-resistant agents.

[0068] 3. Detect the cold tolerance enhancement effect of different sulfur-based nanomaterials on tomatoes

[0069] Take the CuS NPs, ZnS NPs, and MoS2 NPs prepared in Example 1, Comparative Example 1, and Comparative Example 2 to detect the cold tolerance enhancement effect of the nanoparticles on tomatoes.

[0070] 200 mg / L CuS NPs, ZnS NPs, and MoS2 NPs in the foliar application treatment were applied to tomatoes by foliar spraying. The experimental process was the same as in Experiment 1.

[0071] The results of plant height and fresh weight are as Figure 4 shown, and the photos of tomato plants are as Figure 5 shown. The results show that among the plant heights, foliar application of 200 mg / L CuS NPs, ZnS NPs, and MoS2 NPs increased the plant heights of low-temperature tomatoes by 14.96%, 3.67%, and 6.58%, respectively, with CuS NPs showing the best performance; in the above-ground fresh weight, foliar application of CuS NPs, ZnS NPs, and MoS2 NPs significantly increased the above-ground fresh weight of low-temperature tomatoes by 32.21%, 25.17%, and 27.23%; in the below-ground fresh weight, foliar application of CuS NPs and MoS2 NPs significantly increased the below-ground fresh weight of low-temperature tomatoes by 64.37% and 43.68%.

[0072] In summary, the results show that compared with other sulfur-based nanomaterials, foliar application of 200 mg / L CuS NPs has the best effect in alleviating low-temperature stress in tomatoes.

[0073] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person familiar with this technology can make various modifications and decorations without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the claims.

Claims

1. A method for promoting tomato resistance to low temperature stress, characterized in that, Treat tomato seeds by coating them with copper sulfide nanoparticles or treat tomato leaves by foliar application of copper sulfide nanoparticles.

2. The method according to claim 1, wherein When treating tomato seeds by coating them with copper sulfide nanoparticles, the concentration of copper sulfide nanoparticles is 20 - 200 mg / kg of tomato seeds; Preferably, the concentration of copper sulfide nanoparticles is 50 - 100 mg / kg of tomato seeds.

3. The method according to claim 2, wherein To treat tomato seeds by coating them with copper sulfide nanoparticles, moisten the copper sulfide nanoparticles with water to obtain moistened copper sulfide nanoparticles; mix the moistened copper sulfide nanoparticles with tomato seeds, and shake until the copper sulfide nanoparticles are evenly attached to each seed, then sow the seeds.

4. The method according to claim 1, wherein When treating tomato leaves by foliar application of copper sulfide nanoparticles, the concentration of copper sulfide nanoparticles is 20 - 200 mg / L, the spraying amount is 4 - 6 mL / plant / day, for 4 - 6 consecutive days; Preferably, the concentration of copper sulfide nanoparticles is 200 mg / L, the spraying amount is 5 mL / plant / day, for 5 consecutive days.

5. The method according to any one of claims 1 to 4, characterized in that The preparation method of copper sulfide nanoparticles is as follows: (1) Add a copper chloride ethanol solution to a thioacetamide ethanol solution, and perform ultrasonic treatment and then let it stand; (2) After standing, take the upper supernatant and mix it with water, and stir for reaction; after the reaction, cool down, centrifuge, wash, and dry to obtain copper sulfide nanoparticles.

6. The method according to claim 5, wherein In step (1), the mass ratio of copper chloride to thioacetamide is 1 - 1.5:1 - 2; the volume ratio of the copper chloride ethanol solution to the thioacetamide ethanol solution is 120 - 160:180 - 210; Preferably, the mass ratio of copper chloride to thioacetamide is 1.22:1.60; the volume ratio of the copper chloride ethanol solution to the thioacetamide ethanol solution is 150:

200.

7. The method according to claim 5, wherein In step (1), the copper chloride ethanol solution is added to the thioacetamide ethanol solution at a rate of 1 - 3 mL / s; Preferably, the copper chloride ethanol solution is added to the thioacetamide ethanol solution at a rate of 2 mL / s.

8. The method according to claim 5, characterized in that, In step (2), the volume ratio of the upper supernatant to water is 200 - 300:200 - 300; Preferably, the volume ratio of the upper supernatant to water is 300:

300.

9. The method according to claim 5, wherein In step (2), the stirring reaction is carried out at 35 - 45 °C for 0.5 - 1 h; Preferably, the stirring reaction is carried out at 40 °C for 0.5 h.

10. The application of the method according to any one of claims 1 - 9 in the agricultural field.

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