Application of nano titanium dioxide solution in melon cultivation

Abstract

The invention relates to the technical field of agricultural planting, and particularly discloses application of a nano titanium dioxide solution in melon cultivation. According to the application, the nanometer titanium dioxide solution with the concentration of 10 micrograms / mL-80 micrograms / mL is used for promoting germination of melon seeds, and the nanometer titanium dioxide solution with the concentration of 50 mg / L-300 mg / L is used for promoting growth and development of melon plants or inhibiting powdery mildew of melons. The application provided by the invention can remarkably promote seed germination, improve plant biomass, enhance chlorophyll synthesis and photosynthesis efficiency, improve antioxidant enzyme activity and effectively inhibit diseases such as powdery mildew, has the characteristics of efficient action, low use concentration, environment friendliness, simplicity and convenience in operation and low cost, and has a good popularization and application prospect.

Description

Technical Field

[0001] This invention relates to the field of agricultural planting technology, specifically to the application of nano-titanium dioxide solution in melon cultivation. Background Technology

[0002] As a globally important economic crop, melons are highly susceptible to the negative effects of biotic (such as powdery mildew) and abiotic stresses (such as strong ultraviolet light) during cultivation, leading to inhibited growth and development. Therefore, there is a current need to develop a new method to promote the growth and development of melons. Summary of the Invention

[0003] To develop a method for promoting the growth and development of melons, this invention provides the application of nano-titanium dioxide solution in melon cultivation. The application provided by this invention can significantly promote seed germination, increase plant biomass, enhance chlorophyll synthesis and photosynthetic efficiency, increase antioxidant enzyme activity, and effectively inhibit the occurrence of diseases such as powdery mildew. It features high efficiency, low concentration, environmental friendliness, ease of operation, and low cost.

[0004] This invention provides the application of nano-titanium dioxide solution in melon cultivation, wherein the application is as follows: Nano-titanium dioxide solutions with concentrations of 10 μg / mL to 80 μg / mL were used to promote melon seed germination. Nano-titanium dioxide solutions with concentrations of 50 mg / L to 300 mg / L are used to promote the growth and development of melon plants and / or inhibit powdery mildew in melons.

[0005] The application provided by this invention can significantly promote seed germination, increase plant biomass, enhance chlorophyll synthesis and photosynthetic efficiency, improve antioxidant enzyme activity, and effectively inhibit the occurrence of diseases such as powdery mildew. It has the characteristics of high efficiency, low concentration, environmental friendliness, simple operation, and low cost.

[0006] Furthermore, the inhibition of powdery mildew in melons involves reducing the number of infected leaves and the density of pathogenic spores and mycelia on the leaf surface.

[0007] Furthermore, the promotion of melon plant growth and development includes: increasing melon plant biomass, enhancing chlorophyll synthesis and photosynthetic efficiency, increasing antioxidant enzyme activity, and reducing the number of temporary starch granules in leaves.

[0008] Furthermore, the antioxidant enzymes include superoxide dismutase, peroxidase, and catalase.

[0009] Furthermore, the solvent for the nano-titanium dioxide solution is water.

[0010] Furthermore, to promote melon seed germination, the filter paper is soaked in the aforementioned nano-titanium dioxide solution before seed germination culture is carried out.

[0011] Furthermore, promoting the growth and development of melon plants and / or inhibiting powdery mildew in melons involves spraying the nano-titanium dioxide solution onto the melon plants during the two-leaf-one-heart stage to the six-leaf stage.

[0012] Furthermore, the spraying is a foliar spray, with a spraying amount of 8 mL / plant to 12 mL / plant, sprayed once a week for 3 to 4 weeks.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention utilizes low-concentration nano-titanium dioxide solution for germination through infiltration and foliar spraying. The results show that TiO2NPs solution significantly improves melon seed germination rate, fresh weight, dry weight, number of leaves, stem diameter, and plant height. Different concentrations of TiO2NPs solution (50 mg / L, 150 mg / L, 300 mg / L) significantly increase chlorophyll content in melon leaves, while also significantly improving photosynthetic rate. After spraying with nano-titanium dioxide, the number of spores and hyphae causing major damage by cucurbitaceous powdery mildew on leaves and petioles significantly decreased, the number of infected leaves decreased, and the activities of SOD, POD, and CAT enzymes significantly increased. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 The graph shows the seed germination rate after treatment with TiO2NPs solution of different concentrations. In the graph, a represents the seed germination rate after treatment with TiO2NPs solution of different concentrations; b represents the seed germination rate on the second day after treatment with TiO2NPs solution of different concentrations; c represents the seed germination rate on the fourth day after treatment with TiO2NPs solution of different concentrations; and d represents the seed germination rate on the sixth day after treatment with TiO2NPs solution of different concentrations.

[0016] Figure 2The effects of different concentrations of TiO2NPs solution on the growth and development of potted melon (Bissekich) were investigated. In the figure, a represents the plant phenotype on day 25 after TiO2NPs solution treatment; b represents the plant phenotype on day 40 after TiO2NPs solution treatment; c represents the root phenotype on day 40 after TiO2NPs solution treatment; d represents the plant height on day 40 after TiO2NPs solution treatment; e represents the stem diameter on day 40 after TiO2NPs solution treatment; f represents the number of leaves on day 40 after TiO2NPs solution treatment; g represents the root length on day 40 after TiO2NPs solution treatment; h represents the fresh weight of the plant on day 40 after TiO2NPs solution treatment; and i represents the dry weight of the plant on day 40.

[0017] Figure 3 The effects of different concentrations of TiO2NPs solution on the growth and development of potted melon (Xizhoumi) were investigated. In the figure, a represents the plant phenotype on day 25 after TiO2NPs solution treatment; b represents the plant phenotype on day 40 after TiO2NPs solution treatment; c represents the root phenotype on day 40 after TiO2NPs solution treatment; d represents the plant height on day 40 after TiO2NPs solution treatment; e represents the stem diameter on day 40 after TiO2NPs solution treatment; f represents the number of leaves on day 40 after TiO2NPs solution treatment; g represents the root length on day 40 after TiO2NPs solution treatment; h represents the fresh weight of the plant on day 40 after TiO2NPs solution treatment; and i represents the dry weight of the plant on day 40 after TiO2NPs solution treatment.

[0018] Figure 4 The figure shows the PCA analysis of metabolites; in the figure, a represents the PCA analysis of differential metabolites in the NEG mode; b represents the PCA analysis of differential metabolites in the POS mode; in the figure, the horizontal axis PC1 and the vertical axis PC2 represent the scores of the first and second principal components, respectively, and the scatter points of different colors represent samples of different experimental groups, where class A represents the control group of 0 mg / L TiO2NPs solution; class B represents the treatment group of 150 mg / L TiO2NPs solution; the ellipse represents the 95% confidence interval.

[0019] Figure 5This is a partial least squares discriminant analysis (PLS-DA) plot for differential metabolites. In the plot, a represents the PLS-DA analysis of differential metabolites under NEG mode; b represents the PLS-DA analysis of differential metabolites under POS mode. The horizontal axis PC1 and the vertical axis PC2 represent the scores of the first and second principal components, respectively. Different colored scatter points represent samples from different experimental groups, where class A represents the 0 mg / L TiO2NPs solution control group; class B represents the 150 mg / L TiO2NPs solution treatment group. The ellipse represents the 95% confidence interval. R2Y represents the explanatory power of the model, and Q2Y is used to evaluate the predictive ability of the PLS-DA model. A value greater than R2Y indicates that the model is well established.

[0020] Figure 6 KEGG enrichment analysis of differential metabolites; in the figure, a is the KEGG enrichment analysis of differential metabolites under NEG mode; b is the KEGG enrichment analysis of differential metabolites under NEG mode; the horizontal axis in the figure is x / y, which represents the number of differential metabolites in the corresponding metabolic pathway / the total number of metabolites identified in the pathway; the color of the point represents the p-value of the hypergeometric test; the size of the point represents the number of differential metabolites in the corresponding pathway.

[0021] Figure 7 The images show the results of microscopic observation of mesophyll cells in melon leaves. In the figures, a to d represent the transmission results of leaves from the control group, the 50 mg / L TiO2NPs solution treatment group, the 150 mg / L TiO2NPs solution treatment group, and the 300 mg / L TiO2NPs solution treatment group, respectively. The scale bar of the upper image is 1 μm, and the scale bar of the lower image is 400 nm.

[0022] Figure 8 The effects of TiO2NPs solutions (0 mg / L, 50 mg / L, 150 mg / L, 300 mg / L) on powdery mildew in the leaves of *Cypripedia macrantha* (field-grown melon) were investigated. In the figure, a represents the statistical distribution of susceptible nodes in melon leaves treated with nano-TiO2NPs solution; b represents the susceptibility phenotype of melon leaves treated with TiO2NPs solution; c represents the SOD enzyme activity in the leaves of each treatment group; d represents the POD enzyme activity in the leaves of each treatment group; and e represents the CAT enzyme activity in the leaves of each treatment group.

[0023] Figure 9The effect of TiO2NPs solution on powdery mildew in the leaves of *Cypripedia macrantha* (potted) is shown in the figure. Figures a to d show Coomassie brilliant blue staining of melon leaves treated with 0 mg / L, 50 mg / L, 150 mg / L, and 300 mg / L TiO2NPs solutions (under a 10x microscope); e to h show Coomassie brilliant blue staining of melon leaves treated with 0 mg / L, 50 mg / L, 150 mg / L, and 300 mg / L TiO2NPs solutions (under a 20x microscope); i represents the spore count; j represents the number of leaves susceptible to powdery mildew; and k to m represent the SOD, POD, and CAT enzyme activities in the leaves of each treatment group. Detailed Implementation

[0024] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, the experimental methods described in the embodiments of the present invention are conventional methods, and the materials and reagents used in the following embodiments are commercially available unless otherwise specified.

[0025] Example 1: Application of nano-titanium dioxide (TiO2NPs) solution in melon cultivation.

[0026] I. Experimental Methods 1. Seed germination and cultivation of melon Filter paper was placed at the bottom of the seed germination box. Fifty melon seeds of similar size and plumpness (purchased from Xinjiang Seed Industry Co., Ltd.) were evenly placed on the filter paper. The control group used distilled water to moisten the filter paper, while the treatment groups used 0 μg / mL, 10 μg / mL, 40 μg / mL, and 80 μg / mL TiO2NPs solutions (prepared by dissolving TiO2NPs purchased from Aladdin in distilled water) to moisten the filter paper. The seeds were then placed in a 28℃ constant temperature seed germination chamber for seed germination culture.

[0027] 2. Cultivation and exposure experiment of melon plants Potted cultivation of melon plants: Sow 3 melon seeds (Bisekkechi and Xizhoumi) in 8 cm × 12 cm ceramic flower pots. The daytime temperature is 27℃ and the nighttime temperature is 19℃. Water thoroughly every 3 days (200 mL).

[0028] Field cultivation of melon plants: Melon seeds (Bishekchi and Xizhoumi) were planted in greenhouses of Yongjian Fourth Team, Dianba Town, Changji City, Xinjiang (daytime temperature 22℃ to 28℃, nighttime temperature 16℃ to 18℃, relative humidity 60%).

[0029] Exposure experiment: TiO2NPs were weighed and dissolved in distilled water to prepare TiO2NPs solutions of 0 mg / L, 50 mg / L, 150 mg / L, and 300 mg / L, respectively. The TiO2NPs solutions were placed in light-proof containers and ultrasonically cleaned (40 Hz) for 30 min. The TiO2NPs solutions were then sprayed onto the melon plants using a nano-spray gun at a rate of 10 mL per plant. The 50 mg / L, 150 mg / L, and 300 mg / L TiO2NPs solutions served as the three treatment groups, while the 0 mg / L TiO2NPs solution (distilled water) served as the control group. For potted melon plants, spray the first time when they have two leaves and one bud, and spray once every 7 days. After spraying 3 times, record and observe the plant growth status and measure and count the number of melon leaves, above-ground plant height, stem diameter, fresh weight, dry weight, and root length. For field-grown melon plants, start spraying when they have 6 leaves, and spray once every 5 days. After spraying 4 times, record and observe the plant growth status and measure and count the number of melon leaves, above-ground plant height, stem diameter, fresh weight, dry weight, and root length.

[0030] 3. Non-targeted metabolomics (LC-MS / MS) analysis of melon leaves After foliar spraying with TiO2NPs solution, fresh leaves from the 150 mg / L TiO2NPs treatment group and the control group were selected, frozen in liquid nitrogen, and stored at -80℃. All samples were submitted to Beijing Novogene Technology Co., Ltd. for non-targeted metabolite extraction. 100 mg of tissue sample ground in liquid nitrogen was placed in an EP tube, and 500 μL of 80% methanol aqueous solution was added; after vortexing for 1 min, the sample was incubated on ice for 5 min, and centrifuged at 15000 g, 4℃ for 20 min. A certain amount of the supernatant was diluted with mass spectrometry-grade water to a methanol content of 53%, centrifuged at 15000 g, 4℃ for 20 min, and the supernatant was collected and analyzed by LC-MS. For multivariate statistical analysis, the data were transformed using metabolomics data processing software MetaX, followed by principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) to obtain the VIP value for each metabolite. In the univariate analysis, the statistical significance (P-value) of each metabolite between the two groups was calculated based on the t-test, and the fold change (FC) of the metabolite between the two groups was also calculated. The default criteria for screening differentially expressed metabolites were VIP>1, P-value<0.05, FC>2, and FC<0.5, and metabolites were annotated using the KEGG database.

[0031] 4. Transmission electron microscopy (TEM) imaging of melon leaves Fresh melon leaves from each group were fixed at 4℃ in 2.5% glutaraldehyde for 24 h, and then 1 mm... 3Samples were washed three times with 0.1 M phosphate buffer (pH 7.0) and then fixed with 1% osmium tetroxide for 2 h. After dehydration with a gradient of acetone, samples were embedded in resin and stained with uranyl acetate (50% ethanol) and lead citrate (0.2% ethanol) for 10 min each. Finally, sections were prepared using a Leica UC7 microtome (70 nm to 90 nm) and observed and photographed under a Hitachi H-7650 transmission electron microscope.

[0032] 5. Statistics on the effect of TiO2NPs on powdery mildew susceptibility in melons Disease susceptibility statistics: The number of diseased leaves was counted for potted melon plants; the height of diseased nodes was counted for field-grown melon plants.

[0033] Coomassie Brilliant Blue Staining: Leaves from the same node height of each group of melons were harvested and cut into small pieces (0.5 cm to 1 cm), with three biological replicates per treatment group. The leaves were immersed in 0.15% trichloroethanol:chloroform (75:25, V / V) in a constant temperature water bath at 70℃ for 30 min until the leaves were decolorized and transparent. After rinsing with water, the leaves were stained in a mixture of 0.15% trichloroacetic acid and 0.6% Coomassie Brilliant Blue R-250 (dissolved in 99% methanol) (1:1, V / V) for 15 s before observation under an optical microscope using water as a floater. Subsequently, the growth status of the leaves and powdery mildew was observed and photographed under an optical microscope, and the number of powdery mildew spores under the same magnification field was counted. The structure and state of spores and hyphae were observed.

[0034] 6. Determination of SOD, POD, and CAT enzyme activities in melon leaves Preparation of crude enzyme solution: Take 0.1 g of melon leaves from each group, place them in a pre-cooled mortar, add 1.6 mL of 50 mmol / L PBS (pH 7.8) phosphate buffer and grind them. Then centrifuge at 4℃ and 12000 g for 20 min, and take the supernatant as crude enzyme solution.

[0035] SOD activity assay: 100 mL of 14.5 mM methionine, 0.37 mL of 30 μM EDTA-2Na, 3.33 mL of 0.05 mol / L PBS (pH 7.8), 3.7 mL of 2.25 mM NBT, and 3.7 mL of 60 μM riboflavin were mixed to obtain the reaction solution. 3 mL of the reaction solution was mixed with 30 μL of crude enzyme solution and reacted under 4000 lux light for 20 min. 3 mL of the reaction solution was then mixed with 30 μL of PBS, and the mixture was subjected to both light and no-light treatments. The spectrophotometer was zeroed using the no-light group, and the light-light group was used as the Ack. The absorbance of each sample was measured at 560 nm. SOD activity was calculated using the following formula:

[0036] SOD(U / g)=(Ack-Ae)V / (0.5Ack×W×Vt); In the formula, Ae is the absorbance of each sample at a wavelength of 560 nm, W is the fresh weight of the leaf (g), and Vt is the total volume of the crude enzyme solution (1.6 mL).

[0037] POD activity assay: 200 mL of 0.2 M PBS (pH 6) and 0.076 mL of guaiacol were heated (60℃) until completely dissolved. After stirring and cooling to 25℃, 0.112 mL of 30% hydrogen peroxide was added to obtain the reaction solution. 3 mL of the reaction solution was mixed with 30 μL of crude enzyme solution. Using PBS as a control, the absorbance of each sample was measured at 470 nm per minute. POD activity was calculated using the following formula:

[0038] POD (U / g) = (△470×Vt) / (W×VS×t×0.01); In the formula, △470 is the change in absorbance of each sample at a wavelength of 470 nm within 1 min, W is the fresh weight of the leaf (g), Vt is the total volume of crude enzyme solution (1.6 mL), Vs is the volume of enzyme solution at the time of measurement (0.03 mL), and t is the reaction time (1 min).

[0039] CAT activity assay: 200 mL of 0.15 M PBS (pH 7) and 0.309 mL of 30% hydrogen peroxide were mixed to obtain the reaction solution. 3 mL of the reaction solution was mixed with 100 μL of crude enzyme solution. Using PBS as a control, the absorbance of each sample was measured at 240 nm per minute. CAT activity was calculated using the following formula:

[0040] CAT(U / g)=(△240×Vt) / (W×VS×t×0.01); In the formula, △240 is the change in absorbance of each sample at a wavelength of 240 nm within 1 min, W is the fresh weight of the leaf (g), Vt is the total volume of crude enzyme solution (1.6 mL), Vs is the volume of enzyme solution at the time of measurement (0.1 mL), and t is the reaction time (1 min).

[0041] II. Test Results During the seed germination stage, the seeds were immersed in low concentrations of TiO2NPs solution (0 μg / mL, 10 μg / mL, 40 μg / mL, 80 μg / mL) for germination. Figure 1Figures a-d show that from day 2 of germination, the germination rate of melon seeds in all three TiO2NPs solution treatment groups was about 20% higher than that in the control group, with no significant difference between the treatment groups; by day 4 and day 6, the germination rate of the TiO2NPs solution treatment groups continued to increase significantly, while the increase in the control group was smaller. The results indicate that TiO2NPs promotes earlier germination of melon seeds and significantly increases the germination rate. Further pot experiments revealed that after 25 days of foliar spraying with different concentrations (50 mg / L, 150 mg / L, 300 mg / L) of TiO2NPs solution (…),… Figure 2 a, Figure 3 (a) The growth of both Bixiekeqi and Xizhoumi melon plants in the TiO2NPs solution treatment group was better than that in the control group; 40 days after spraying ( Figure 2 b~c, Figure 3 (b~c) In the control group, the plants completely withered and died, while in the TiO2NPs solution treatment group, only leaf yellowing was observed; the plants remained alive, and the number of lateral roots significantly increased. Biostatistical analysis showed ( Figure 2 d~i、 Figure 3 Treatment with TiO2NPs solution significantly improved physiological indicators of melons, including plant height, stem diameter, number of leaves, fresh weight, dry weight, and root length.

[0042] The effects of TiO2NPs solution treatment on melon leaf metabolites were analyzed using non-targeted metabolomics. 742 and 280 metabolites were identified in positive ion (POS) and negative ion (NEG) modes, respectively, with lipid molecules accounting for the highest proportion in both modes (POS: 30.02%; NEG: 35.32%). Principal component analysis (PCA) Figure 4 Results (a) and (b) showed that the first principal component (PMC) of the treated group deviated by 30.11% from the control group under NEG mode and by 25.01% under POS mode, indicating that TiO2 NPs significantly altered the metabolite composition of melon. Partial least squares discriminant analysis (PLS) Figure 5 (a) and (b) further validated this result, with the first principal component deviating by 22.84% and 15.51% in the NEG and POS modes, respectively. Differential metabolite analysis identified 33 significantly altered metabolites (POS: 27; NEG: 6), and KEGG enrichment analysis (…). Figure 6 (a) and (b) indicate that these differentially metabolized substances are mainly involved in important metabolic pathways such as phenylpropane metabolism, riboflavin metabolism, and anthocyanin synthesis. Therefore, TiO2NPs treatment improves the sugar metabolism efficiency of melon plants by affecting the metabolite composition of melon leaves, thereby enhancing the plant's antibacterial ability and promoting growth and development.

[0043] Results of cell microstructure observation ( Figure 7As shown in (a~d), compared with the control, the mesophyll cell structure was intact after spraying with TiO2NPs solution, and the number of temporary starch granules in chloroplasts was significantly reduced.

[0044] In addition, from Figure 8 Statistical analysis of powdery mildew infection in the field of Datian showed that, compared with the control group, the number of infected leaves decreased significantly with increasing TiO2NPs solution concentration, and the powdery mildew spots on the tenth and eleventh true leaves were significantly reduced or absent. Figure 8 (b) The activity of antioxidant enzymes (SOD, POD, and CAT) was significantly enhanced. Figure 8 c~e); Microscopic observation results of Bixiekechi (bonsai) ( Figure 9 The results (a~h) indicate that TiO2NPs treatment caused irregular shrinkage, shriveling, and morphological damage to powdery mildew spores and hyphae, and the percentage of infected leaves ( Figure 9 i), powdery spores ( Figure 9 All of these (j) were significantly reduced, and the activities of SOD, POD and CAT (j) were also significantly reduced. Figure 9 The concentrations of TiO2NPs (k~m) were significantly increased. These results indicate that TiO2NPs can significantly reduce the number of leaves susceptible to powdery mildew in melons, inhibit the spread of pathogens from lower leaves to upper leaves, and reduce the density of spores and mycelia on the leaf surface, thus effectively controlling disease development. Physiological and biochemical index measurements showed that the activities of SOD, POD, and CAT enzymes in the leaves of the treatment group were positively correlated with the concentration of TiO2NPs solution; the higher the concentration, the more significant the increase in enzyme activity. This indicates that TiO2NPs can systematically enhance the plant's immune defense capabilities through pathways such as activating antioxidant enzyme systems, reducing reactive oxygen species damage, maintaining cell membrane stability, and promoting the synthesis of antibacterial metabolites.

[0045] Although preferred embodiments of the invention have been described, those skilled in the art, once they have learned the basic inventive concept, can make other changes and modifications to these embodiments.

[0046] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. The application of nano-titanium dioxide solution in melon cultivation, characterized in that, The application is as follows: Nano-titanium dioxide solutions with concentrations of 10 μg / mL to 80 μg / mL were used to promote melon seed germination. Nano-titanium dioxide solutions with concentrations of 50 mg / L to 300 mg / L are used to promote the growth and development of melon plants and / or inhibit powdery mildew in melons.

2. The application of the nano-titanium dioxide solution according to claim 1 in melon cultivation, characterized in that, The method of inhibiting powdery mildew in melons is to reduce the number of infected leaves and the density of pathogenic spores and mycelia on the leaf surface.

3. The application of the nano-titanium dioxide solution according to claim 1 in melon cultivation, characterized in that, The measures to promote the growth and development of melon plants include: increasing the biomass of melon plants, enhancing chlorophyll synthesis and photosynthetic efficiency, increasing the activity of antioxidant enzymes, and reducing the number of temporary starch granules in leaves.

4. The application of the nano-titanium dioxide solution according to claim 3 in melon cultivation, characterized in that, The antioxidant enzymes include superoxide dismutase, peroxidase, and catalase.

5. The application of the nano-titanium dioxide solution according to claim 1 in melon cultivation, characterized in that, The solvent for the nano-titanium dioxide solution is water.

6. The application of the nano-titanium dioxide solution according to claim 1 in melon cultivation, characterized in that, To promote the germination of melon seeds, the filter paper was soaked in the aforementioned nano-titanium dioxide solution before seed germination culture was carried out.

7. The application of the nano-titanium dioxide solution according to claim 1 in melon cultivation, characterized in that, Promoting the growth and development of melon plants and / or inhibiting powdery mildew in melons involves spraying the nano-titanium dioxide solution onto the melon plants during the two-leaf-one-heart stage to the six-leaf stage.

8. The application of the nano-titanium dioxide solution according to claim 7 in melon cultivation, characterized in that, The spraying is a foliar spray, with a spraying amount of 8 mL / plant to 12 mL / plant, sprayed once a week for 3 to 4 weeks.

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