Foliar fertilizer for improving drought resistance of peach trees

Abstract

The invention discloses a foliar fertilizer for improving the drought resistance of peach trees. The foliar fertilizer for improving the drought resistance of peach trees provided by the invention consists of lecithin, lauric acid and sodium silicate. By using the foliar fertilizer, the damage of drought to leaf tissue can be significantly reduced, the relative electrical conductivity of the leaves can be significantly reduced, the relative water content and photosynthetic rate of peach leaves under drought conditions can be increased, the ability of peaches to resist drought stress can be increased, the growth of plants can be promoted, the yield and quality of peaches can be improved, and the fertilizer has the advantages of quick effect, simple use and easy acceptance by the public.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural fertilizers, and in particular relates to a foliar fertilizer for improving the drought resistance of peach trees. Background Art

[0002] Peach is an important fruit tree species, and its cultivated area ranks third among deciduous fruit trees in my country, second only to apple and pear trees. Water participates in various metabolic processes and the formation of life substances in the tree, and plays an important role in the growth and development of peach trees. However, droughts occur frequently in the north every year, especially spring droughts and summer droughts, which are extremely serious. At the same time, most peach orchards are mainly built on barren mountainous land without irrigation conditions. Drought and water shortage are key factors restricting the development of peach production. In addition, reduced precipitation also causes frequent drought disasters, which seriously affects the normal growth and development of peach trees and the quality of fruits. Therefore, it is extremely necessary to research and develop fertilizers that improve the drought resistance of peach trees.

[0003] However, the existing fertilizer formulas for improving the drought resistance of fruit trees are complex and contain many active ingredients, which leads to high costs and is not conducive to market promotion and use. In addition, the existing drought-resistant fertilizers have a single function and need to be combined with other fertilizers in actual planting to promote the growth of peach trees.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The object of the present invention is to provide a foliar fertilizer for improving the drought resistance of peach trees, which has the advantages of simple formula and low cost. By using the foliar fertilizer provided by the present invention, the relative conductivity of peach leaves is significantly reduced, the relative water content and photosynthetic rate of the leaves are significantly improved, and the peach yield and quality are improved while increasing the ability of peach trees to resist drought stress.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The invention discloses a foliar fertilizer for improving the drought resistance of peach trees, which is composed of lecithin, lauric acid and sodium silicate.

[0008] The weight parts of the components in the foliar fertilizer are as follows: 100 weight parts of lecithin, 10-11 weight parts of lauric acid, and 1-2 weight parts of sodium silicate.

[0009] Preferably, the weight parts of the components in the foliar fertilizer are as follows: 100 weight parts of lecithin, 10 weight parts of lauric acid, and 1.4-1.5 weight parts of sodium silicate.

[0010] The invention also provides application of the foliar fertilizer in improving drought resistance of peach trees.

[0011] The varieties of the peach trees are 'Jinxiayoupan' and 'Jinchun'.

[0012] The invention also provides a method for improving the drought resistance of peach trees, comprising the following steps: diluting the foliar fertilizer with water and spraying the foliar fertilizer on the leaves of the peach trees.

[0013] In the mixed solution obtained by dilution, the mass concentration of lecithin is 500-550 mg / L, the mass concentration of lauric acid is 45-55 mg / L, and the mass concentration of sodium silicate is 7-10 mg / L. Preferably, the mass concentration of lecithin is 500 mg / L, the mass concentration of lauric acid is 50 mg / L, and the mass concentration of sodium silicate is 7.32 mg / L.

[0014] The foliar fertilizer is sprayed on the entire crown of the peach tree so as to be evenly sprayed on all parts of the crown.

[0015] The foliar fertilizer is sprayed 3 times per month.

[0016] The foliar fertilizer is sprayed throughout the drought period.

[0017] In the foliar fertilizer for improving drought resistance of peach trees provided by the present invention, the functions of the components are as follows:

[0018] 1. As a crop protection agent, lecithin can enhance the efficacy of active ingredients, reduce the dosage of active ingredients, and ensure the stability of aqueous emulsions containing active ingredients.

[0019] Lecithin has the function of preventing and controlling pests and diseases of crops such as vegetables and rice. Because it is non-toxic and non-polluting, it is superior to current pesticides. Lecithin can be used in combination with commonly used pesticides. For example, it can be mixed with insecticides such as dimethoate, carbendazim, thiophanate-methyl and thiophanate-methyl that inhibit various fungal viruses, so that the amount of fungicide used can be reduced by 30%, greatly reducing costs, public hazards and environmental pollution. Lecithin can also be used alone or mixed with edible oil and alcohol solvents. For example, lecithin can be directly diluted with water to a solution of more than 2 mg / L, which can be used to prevent and control wasps and powdery mildew. It can also simultaneously prevent and control three common pests and diseases of rice, such as rice blast, sheath blight and bacterial leaf blight. Under drought and salt stress conditions, lecithin can significantly reduce cell membrane damage.

[0020] 2. Lauric acid, as a natural fatty acid, can activate plant resistance. Studies have shown that lauric acid can act through the jasmonic acid signaling pathway to improve plant drought resistance.

[0021] 3. The mechanism of sodium silicate in drought resistance has been partially elucidated at the physiological and biochemical level, including increasing root water intake, maintaining nutritional balance, reducing leaf water loss, promoting photosynthetic rate, and increasing antioxidant enzyme activity and non-enzyme antioxidant activity to improve antioxidant capacity, and regulating the balance of hormones in plants under stress conditions. The present invention further found that sodium silicate has a synergistic effect when used together with the active substance lauric acid and the protective substance lecithin, which has a more significant effect on improving plant drought resistance, thereby increasing the yield and quality.

[0022] The present invention is beneficial in that:

[0023] The foliar fertilizer provided by the invention has the advantages of simple formula and low cost. By applying the foliar fertilizer, the relative conductivity of peach leaves is significantly reduced, the relative water content and photosynthetic rate of the leaves are significantly improved, and the peach yield and quality are improved while increasing the ability of peach trees to resist drought stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The growth status and antioxidant capacity of peach seedlings under drought stress; Figure 1 (a) shows the growth status of peach seedlings under drought stress; (b) shows the Evans blue staining photo of the peach seedling roots; (c) shows the Evans blue staining photo of the peach seedling leaves; (d) shows the status of the stomata of the peach seedling leaves.

[0025] Figure 2 The alleviating effect of lauric acid on drought stress in peach seedlings; Figure 2 (a) is the stomatal status of peach leaves in each treatment; (b) is the average stomatal aperture of peach leaves in each treatment; (c) is the initial fluorescence value (F0), maximum fluorescence value (Fm), maximum quantum yield of PSII (Fv / Fm), actual photochemical efficiency of FPSII (FPSII) and photochemical quenching coefficient (qP) of peach leaves in each treatment; (d) is the ETR-PAR light response curve of each treatment.

[0026] Figure 3 The net photosynthetic rate of peach seedling leaves treated with different concentrations of lecithin under drought stress.

[0027] Figure 4 The stomatal density and size of leaves of peach seedlings treated with different concentrations of lecithin under drought stress.

[0028] Figure 5 The proline content and electrolyte exudation rate of peach seedling leaves treated with different concentrations of lecithin under drought stress; Figure 5 (a) represents the proline content, and (b) represents the electrolyte permeation rate.

[0029] Figure 6 The effect of lecithin on root cell activity under drought stress.

[0030] Figure 7 To investigate the effect of lecithin on root cell integrity under drought stress.

[0031] Figure 8 To investigate the effect of lecithin on root cell membrane integrity under drought stress.

[0032] Fig. 9 The invention discloses the influence of the foliar fertilizer provided by the invention on the electrolyte exudation rate and relative water content of peach leaves under drought conditions.

[0033] Fig.10 The invention discloses the influence of the foliar fertilizer provided by the invention on the net photosynthetic rate of peach leaves and the soluble solids of fruits under drought conditions.

[0034] Fig.11 The invention discloses the influence of the foliar fertilizer provided by the invention on the single fruit weight and single plant yield of peach fruits under drought conditions. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with specific embodiments. The given examples are only for illustrating the present invention, but not for limiting the scope of the present invention.

[0036] Description of the materials and reagents used in the following examples:

[0037] Lecithin: purchased from Beijing Solebow Technology Co., Ltd.

[0038] Lauric acid: purchased from Sigma-Aldrich.

[0039] Sodium silicate: purchased from Beijing Bailingwei Technology Co., Ltd.

[0040] The drought stress test in the following examples refers to: using 10% polyethylene glycol (PEG) solution to control the water content of quartz sand in a flowerpot to simulate drought conditions.

[0041] Example 1

[0042] The experiment used peach (Amygdalus persica) seedlings as test materials, and conducted a drought stress test at the Experimental Station of the South Campus of Shandong Agricultural University in 2021.

[0043] First, a preliminary test was conducted to screen the appropriate concentration of sodium silicate to alleviate drought stress in peach. Five-leaf peach seedlings with uniform growth and no diseases were selected as the test materials. The seedlings were planted in a cylindrical pot with an inner diameter of 24 cm and a height of 12.8 cm. The pot was filled with quartz sand. They were cultured in a greenhouse with light (20,000 lux), a day and night temperature of 28℃ / 18℃, and an air humidity of 50%. The water content of the quartz sand in the flowerpot was regulated with a 10% polyethylene glycol (PEG) solution to simulate drought conditions. Different concentrations of sodium silicate solutions were applied, and the sodium silicate concentrations were 0mmol / L, 0.03mmol / L, 0.06mmol / L, 0.09mmol / L and 0.12mmol / L, respectively. Fifteen pots were treated each time. After 6 days of treatment, the net photosynthetic rate of peach leaves in each treatment was measured. The results showed that under drought conditions, the net photosynthetic rates of peach leaves treated with 0 mmol / L, 0.03 mmol / L, 0.06 mmol / L and 0.12 mmol / L sodium silicate were 6.73 μmol·m -2 ·s -1 , 7.02 μmol·m -2 ·s -1 , 7.96 μmol·m -2 ·s -1 , 7.87 μmol·m -2 ·s -1 , 7.52 μmol·m -2 ·s -1 Among them, the net photosynthetic rate of peach leaves treated with 0.06mmol / L sodium silicate was the highest, indicating that this concentration had a better effect on alleviating drought stress in peach seedlings.

[0044] Next, the alleviating effect of 7.32 mg / L sodium silicate (i.e. 0.06 mmol / L Na2SiO3) on drought stress in peach seedlings was further systematically studied.

[0045] Three treatments were set up: control (CK; clean water); drought stress (10% polyethylene glycol PEG; 10% PEG solution); drought stress + silicon (10% PEG + Si; 10% PEG + 0.06 mmol / L Na2SiO3).

[0046] Thirty five-leaf peach seedlings with uniform growth and no pests and diseases were selected for each treatment. The seedlings were planted in cylindrical pots with an inner diameter of 24 cm and a height of 12.8 cm. The pots were filled with quartz sand and cultured in a greenhouse with a light intensity of 20,000 lux, a day and night temperature of 28°C / 18°C, and an air humidity of 50%. The water content of the quartz sand in the pots was regulated by 10% PEG solution to simulate drought. The water content of the CK treatment was 60%, and the water content of the quartz sand in the 10% PEG and 10% PEG+Si treatment groups was 40%. For silicon treatment, 0.06 mmol / L Na2SiO3 solution was applied to the roots, a total of 100 mL, and clean water was used as a control.

[0047] After 10 days of treatment, the morphology of peach seedlings was observed, the leaves were stained with Evans blue, the state of stomata was observed, and the effect of sodium silicate on the alleviation of drought stress in peach seedlings was analyzed.

[0048] The specific determination method is: using Evans blue to dye the leaves, observing the effects of different treatments on the leaves and roots, and using an electron microscope to observe the stomatal state of peach leaves with different treatments.

[0049] The results showed that under drought stress conditions, the water content of plant leaves decreased as the stress intensity increased, and the water content reflected the drought resistance of plants to a certain extent. Figure 1 As shown in Figure 2, drought stress caused the leaves of peach seedlings to wilt and lose water severely, but compared with the control, exogenous silicon treatment alleviated the wilting of leaves and reduced the water loss of leaves ( Figure 1 a). Evans blue staining was used to detect oxidative damage in seedlings under drought stress. It was found that the staining degree of leaves and roots of seedlings treated with silicon was significantly reduced compared with the control ( Figure 1 b and 1c), indicating that the oxidative stress damage to peach seedlings treated with silicon was significantly lower than that of the control. Observation of stomatal pores in leaves showed that drought stress significantly affected the state of stomatal pores in leaves. Compared with the control, drought stress caused stomatal closure in peach seedling leaves ( Figure 1 d).

[0050] The above research results show that 7.32 mg / L sodium silicate can alleviate the damage of drought stress to peach seedlings, thereby improving the drought resistance of peach trees.

[0051] Example 2

[0052] The experiment used peach (Amygdalus persica) seedlings as test materials, and conducted a drought stress test at the Experimental Station of the South Campus of Shandong Agricultural University in July 2021.

[0053] First, the effect of different concentrations of lauric acid on drought stress in peach seedlings was studied to screen the appropriate concentration of lauric acid. Five-leaf peach seedlings with consistent growth and no diseases were selected as experimental materials. The seedlings were planted in pots. The pots were cylindrical with an inner diameter of 24 cm and a height of 12.8 cm. The pots were filled with quartz sand. The following five treatments were set up respectively: treatment 1 was the control, and 100 ml of 0 mg / L lauric acid, i.e., clean water, was applied on the first day, and no water was supplied afterwards; treatment 2: 100 ml of 1 mg / L lauric acid was applied on the first day, and no water was supplied afterwards; treatment 3: 100 ml of 10 mg / L lauric acid was applied on the first day, and no water was supplied afterwards; treatment 4: 100 ml of 50 mg / L lauric acid was applied on the first day, and no water was supplied afterwards; treatment 5: 100 ml of 100 mg / L lauric acid was applied on the first day, and no water was supplied afterwards. After 15 days of treatment, the net photosynthetic rate of peach leaves in each treatment was measured. It was found that the net photosynthetic rate of peach leaves in treatment 1, treatment 2, treatment 3, treatment 4, and treatment 5 was 12.56 μmol·m -2 ·s -1 , 12.89 μmol·m -2 ·s -1 , 13.59 μmol·m -2 ·s -1 , 14.71 μmol·m -2 ·s -1 , 11.52 μmol·m -2 ·s -1 Among them, the net photosynthetic rate of peach leaves treated with 50 mg / L lauric acid was the highest, indicating that this concentration had a better effect on alleviating drought stress in peach seedlings.

[0054] Next, the effect of 50 mg / L lauric acid on the alleviation of drought stress in peach seedlings was further systematically studied. Four treatments were set up in the experiment: CK: normal watering, 100 ml of water on the first day of treatment, and watering once every 5 days thereafter. LA treatment: 100 ml of lauric acid with a concentration of 50 mg / L was watered on the first day of treatment, and lauric acid was watered once every 5 days thereafter. CK-D: No watering was done from the first day of treatment, and the drought state was maintained. LA-D: 100 ml of lauric acid with a concentration of 50 mg / L was watered on the first day of treatment, and no water or lauric acid was applied thereafter, and the drought state was maintained.

[0055] Thirty five-leaf peach seedlings with uniform growth and no pests and diseases were selected for each treatment. The seedlings were planted in cylindrical pots with an inner diameter of 24 cm and a height of 12.8 cm. The pots were filled with quartz sand and cultured in a greenhouse with light (20,000 lux), a day and night temperature of 28°C / 18°C, and an air humidity of 50%.

[0056] On the 14th day of treatment, three leaves were collected from the same part of each plant to observe the stomatal morphology and degree of stomatal opening, and the chlorophyll fluorescence parameters of each treatment were determined.

[0057] The specific measurement method is as follows: 3 leaves were collected from the same part of each plant to observe the stomatal morphology and the degree of stomatal opening. Colorless acrylic nail polish was evenly applied to the back of each peach leaf collected. After 5 minutes, the hardened nail polish was removed with tweezers. The fragments painted with nail polish were then placed on a microscope slide and examined with a fluorescence microscope at 400 times magnification (AXI0, Carl Zeiss, Germany). We randomly selected three locations on each fragment for imaging. In order to calculate and identify the degree of opening, the stomatal aperture was measured using ImageJ software (National Institutes of Health, Bethesda, Maryland, USA).

[0058] The following parameters were measured using the IMAGING-PAM chlorophyll fluorescence system (Heinz Walz, Effeltrich, Germany): minimum fluorescence (F0), maximum fluorescence (Fm), maximum quantum efficiency (Fv / Fm), actual quantum efficiency (FPSII), photochemical quenching (qP), non-photochemical quenching (NPQ) and electron transfer rate (ETR). To determine Fv / Fm, peach leaves were dark-adapted in dark clamps for 30 min.

[0059] The results showed that under normal conditions, the stomatal opening of drought-treated leaves was significantly smaller than that of control leaves. Exogenous LA application can increase the stomatal aperture of leaves ( Figure 2 (a)); Compared with the CK treatment, the LA treatment significantly increased the average stomatal pore size by 2.41 times ( Figure 2 (b)).

[0060] The initial fluorescence value (F0), maximum fluorescence value (Fm), maximum quantum yield of PSII (Fv / Fm), actual photochemical efficiency of FPSII (FPSII) and photochemical quenching coefficient (qP) of peach seedlings were significantly reduced under drought treatment ( Figure 2 (c)). LA treatment increased F0, Fm, Fv / Fm, FPSII and qP by 18.54%, 33.71%, 7.75%, 19.41% and 11.39%, respectively. The corresponding color photos of the leaves show the status of the four parameters under different treatments ( Figure 2 c). LA-D treatment can effectively alleviate the damage caused by drought stress. ETR-PAR light response curve ( Figure 2 Middle (d) shows that LA-D treatment increased the ETRmax of peach seedlings by 51.45%.

[0061] The above research results show that 50 mg / L lauric acid can alleviate the damage of drought stress to peach seedlings.

[0062] Example 3

[0063] The experiment used the current year's hairy peach (Amygdalus persica L) seedlings as test materials. A drought stress experiment was carried out at the Experimental Station of South Campus of Shandong Agricultural University in 2017. The alleviating effect of different concentrations of phosphatidylcholine (PC) on drought stress of peach seedlings was studied.

[0064] The experiment set up 6 treatments: C1, clean water control; C2, clean water control + 500mg / L PC; D1: no PC added under drought stress; D2: 200mg / L PC added under drought stress; D3: 500mg / L PC added under drought stress; D4: 1000mg / L PC added under drought stress; each treatment started with the first treatment on the first day, and then treated once every 1 day, 100mL each time, for a total of three times. After the third treatment, the seedlings were placed in a rain shelter for drought stress treatment, and their net photosynthetic rate was measured on the first, third, sixth, ninth, and twelfth days after treatment, and then samples were taken to measure electrolyte exudation rate, proline, observe stomatal status, leaf cell integrity and other related indicators.

[0065] Thirty peach seedlings were selected for each treatment and planted in pots, with one plant planted in each pot. The pots were cylindrical with an inner diameter of 24 cm and a height of 12.8 cm. The cultivation medium in the pots was quartz sand. The plants were cultured in a greenhouse with a light intensity of 20,000 lux, a day and night temperature of 28°C / 18°C, and an air humidity of 50%.

[0066] Determination and calculation method of indicators:

[0067] Net photosynthetic rate: The net photosynthetic rate of fully expanded functional leaves was measured using the CIRAS-3 portable photosynthetic meter system (PP Systems, UK), repeated three times, and the average value was taken. The stomatal state of the leaves was observed using an electron microscope, and the stomatal size and area were measured using ImageJ.

[0068] Electrolyte permeability: Use tweezers to gently take out the soaked leaves to be tested, and place them in a 20ml test tube with 10ml deionized water. Put 3 leaf discs in each tube, cover the tube mouth with a clean plastic film, and wrap it with a rubber band. Set up 3 replicates (i.e. 3 test tubes) for each treatment. Put the test tubes in a 50℃ incubator for 0.5 hour, and use room temperature (20℃) as a control. After the treatment, rinse the test tubes with tap water for 5 minutes to balance them to room temperature.

[0069] Conductivity determination: A) Shake well and measure the first conductivity value G1. B) Boil the test tube in boiling water for 20 minutes to kill the tissue, balance at room temperature for 10 minutes and cool to room temperature to measure the second conductivity value G2.

[0070] Relative conductivity value (%) = first conductivity value / conductivity value after killing × 100%

[0071] Electrolyte extravasation rate (%) = (relative conductivity of sample - relative conductivity of control) / (100% - relative conductivity of control) × 100%

[0072] Proline: Use ninhydrin colorimetry. Weigh 0.5g of fresh sample, add 5mL of sulfosalicylic acid, seal and boil in water for 10min, cool, filter with filter paper funnel, suck 2mL of filtrate (control suck 2mL of distilled water), add 2mL of glacial acetic acid, then add 3mL of acidic hydrated ninhydrin colorimetric solution, boil in water for 40min, cool, add 5mL of toluene, shake thoroughly, let stand to separate, take the upper toluene solution and compare color at 520nm.

[0073] Proline (μg / gFW or DW) = Y×V / a×W

[0074] Relative activity of root cells: determined by Evans blue staining. To fix the root samples, we first soaked them in 2.5% glutaraldehyde at 4°C, then rinsed them in PBS buffer for 10 minutes and three times; next, we fixed the samples with 1% citric acid at 4°C for 2 hours, followed by a second set of three 10-minute PBS buffer rinses; finally, the samples were dehydrated using an ethanol series gradient dehydration (using 30%, 50%, 70%, 90%, and 100% ethanol solutions). The samples were soaked for 10 minutes at each step of the series and soaked twice in 100% ethanol solution; then the samples were embedded in Epon812 epoxy resin before incubation and cured in 3 stages at 37°C, 45°C, and 65°C, each for 24 hours. Next, the samples were sliced ​​using an UltracutE ultramicrotome. Finally, the samples were stained with uranyl lead acetate. Tested on the machine.

[0075] The results of the study found that there was no significant difference in the net photosynthetic rate and chlorophyll content (i.e., SPAD value) between peach seedlings that were watered normally, regardless of whether or not exogenous lecithin was used for treatment. In contrast, the net photosynthetic rate and SPAD value of drought-stressed plants decreased over time. The net photosynthetic rate and SPAD value of plants added with 200 mg / L, 500 mg / L, and 1000 mg / L lecithin were higher than those of the control. Within 12 days, the net photosynthetic rate and SPAD value of the 500 mg / L lecithin treatment decreased the least ( Figure 3 ).

[0076] Table 1 Effects of different concentrations of lecithin on drought stress in peach seedlings

[0077]

[0078]

[0079] Depend on Figure 4 As can be seen from Table 1, observations at 400 times magnification showed that the stomata in the lower part of the leaves of peach seedlings with sufficient water were short in length and long in width. Therefore, the overall shape of their guard cells is round and plump, and their stomata are open. It was found that there was no significant difference in the shape and density of the stomata of non-stressed plants, regardless of whether lecithin was applied. In contrast, the stomata of plants under drought stress became longer and narrower, and the stomatal density was lower than that of plants under non-drought stress. The stomata of untreated drought-stressed plants remained closed, while the stomata of lecithin-treated plants were partially open. It was found that the stomatal openness of 500 mg / L lecithin treatment was the highest.

[0080] Depend on Figure 5 It can be seen that the proline content of plants not subjected to drought stress was not much different, regardless of whether lecithin was supplemented or not. The average proline content in the roots of unstressed and untreated plants was 18.13 μg / ml, while the proline content in the roots of plants treated with 500 mg / L lecithin was 17.6 μg / ml, both lower than the drought stress control group.

[0081] Electrical conductivity is a physiological indicator that measures the diffusion of cellular contents from the body of peach trees to the outside of the cells, and can reflect the degree of damage to the cell membrane. Figure 5 It can be seen that under drought stress, the electrolyte exudation rate of the root system of the plant treated with 500 mg / L lecithin was significantly lower than that of the D1 group. This indicates that the 500 mg / L lecithin treatment significantly reduced the degree of damage to the membrane protein of the peach seedling leaves, reduced the cytoplasmic cytosolic exudation, effectively protected the cell membrane system, and enhanced the drought resistance of the leaves.

[0082] Depend on Figure 6 It can be seen that Evans blue is a cell viability dye used to detect the integrity of the cell membrane and whether the cell is alive. Living cells will not be stained light blue, while dead cells will be stained blue. Figure 6 It reflects the effect of Evans blue staining solution on the activity of root cells. Figure 6 It can be seen that the cell activities of D3 and D4 are significantly higher than those of D1, and the activity of root cells treated with D3 is the highest. It may be that lecithin protects the integrity of root cell membranes under drought stress, thereby enhancing the activity of plant root cells.

[0083] from Figure 7It can be seen that when the plants were well hydrated, the cell integrity of the plants treated with lecithin was little different from that of the untreated plants. However, when the plants were subjected to drought stress, the cell structural integrity and cell membrane structure of the plants not treated with lecithin were destroyed, e.g. Figure 8 As shown, the root cell integrity and protection of cell membranes of plants treated with 500 mg / L lecithin were significantly higher.

[0084] Example 4

[0085] In 2022, experiments were conducted in the peach orchard of the Horticultural Experimental Station of Shandong Agricultural University to study the effects of foliar fertilizer in this invention on peach drought stress and peach yield and quality.

[0086] From April to May 2022, there was no effective rainfall for two consecutive months.

[0087] Four-year-old 'Jinxiayoupan' and 'Jinchun' were used as test materials. Twenty plants of each variety with basically the same growth were selected for treatment. The planting spacing of the two varieties was 2 meters × 5 meters (67 plants per mu).

[0088] Treatment: Use a diluted mixture containing 500 mg / L lecithin, 50 mg / L lauric acid and 7.32 mg / L sodium silicate as foliar fertilizer, and spray it on the entire crown of the peach tree with an electric sprayer, so that all parts of the tree are sprayed evenly. The spraying frequency is 3 times / month, and each time the foliar fertilizer is sprayed, spray an equal amount of clean water as a control. The first treatment starts on May 10 and lasts until the fruit matures.

[0089] Determination and calculation method of indicators:

[0090] 1. The calculation method of electrolyte extravasation rate is the same as described in Example 3.

[0091] 2. Relative water content: Select 6 peach leaves of each variety, weigh them, put them in a sealed bag filled with distilled water, put them in a 4°C refrigerator and soak them for 24 hours, then weigh them (saturated mass), dry them, and calculate the relative water content of the leaves. Relative water content of peach leaves (RWC) = [(fresh mass - dry mass) / (saturated mass - dry mass)] × 100%.

[0092] 3. Photosynthetic rate: The net photosynthetic rate of fully expanded functional leaves was measured using the CIRAS-3 portable photosynthetic meter system (PP Systems, UK). This was repeated three times and the average value was taken.

[0093] 4. Average single fruit weight and single plant yield: Three trees of each variety were randomly selected for each treatment, and the total number of fruits on each tree was measured. Ten fruits in the middle of the outer crown of each tree were selected, and the single fruit weight was measured to calculate the yield of each tree.

[0094] 5. Soluble solids content: Soluble solids were measured using a TD-4 sugar meter, repeated 3 times, and the average value was taken.

[0095] like Fig. 9 , Fig.10 , Fig.11 As shown, after spraying the foliar fertilizer of the present invention, the electrolyte exudation rate of the leaves of 'Jinxiayoupan' and 'Jinchun' decreased by 27.6% and 35.9% respectively, the relative water content increased by 18.7% and 32.6% respectively, the photosynthetic rate increased by 23.6% and 29.4% respectively, and the soluble solid content increased by 9.6% and 10.1% respectively; the average single fruit weight increased by 10.2% and 11.3% respectively, and the single plant yield increased by 22.3% and 24.8% respectively. It can be seen that by using the foliar fertilizer, the relative conductivity of the leaves decreased significantly, the relative water content and photosynthetic rate of the leaves increased significantly, and the peach yield and quality were improved while increasing the ability of peach trees to resist drought stress.

[0096] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A method for improving the drought resistance of peach trees, comprising the following steps: diluting foliar fertilizer with water and spraying the foliar fertilizer on the leaves of the peach trees; The foliar fertilizer consists of lecithin, lauric acid and sodium silicate; In the mixed solution obtained by dilution, the mass concentration of lecithin is 500-550 mg / L, the mass concentration of lauric acid is 45-55 mg / L, and the mass concentration of sodium silicate is 7-10 mg / L.

2. The method according to claim 1, characterized in that: The foliar fertilizer is sprayed on the entire crown of the peach tree so as to be evenly sprayed on all parts of the crown.

3. The method according to claim 1 or 2, characterized in that: The foliar fertilizer is sprayed 3 times per month.

4. The method according to claim 1 or 2, characterized in that: The foliar fertilizer is sprayed throughout the drought period.

5. The method according to claim 1, characterized in that: The varieties of the peach trees are 'Jinxiayoupan' and 'Jinchun'.

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