LU503348B1

LU503348B1 - Foliar fertilizer for improving drought resistance of peach trees

Info

Publication number: LU503348B1
Application number: LU503348A
Authority: LU
Inventors: Futian Peng; Yuansong Xiao
Original assignee: Univ Shandong Agricultural
Priority date: 2023-01-13
Filing date: 2023-01-13
Publication date: 2023-07-13

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 is composed of lecithin, lauric acid and sodium silicate. By using the foliar fertilizer, the damage of drought to leaf tissues can be significantly reduced, the relative electrical conductivity of leaves can be significantly reduced, the relative water content and photosynthetic rate of peach leaves under drought conditions can be increased, the ability of peach to resist drought stress can be increased, the plant growth can be promoted, and the yield and quality of peach can be improved. It has the advantages of quick response, simple use and easy acceptance by the public.

Description

DESCRIPTION

LU503348

FOLIAR FERTILIZER FOR IMPROVING DROUGHT RESISTANCE OF PEACH

TREES

TECHNICAL FIELD

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

BACKGROUND

Peach tree is an important fruit tree species, and its cultivated area is the third largest among deciduous fruit trees in China, next only to apple trees and pear trees.

Water plays an important role in the growth and development of peach trees by participating in various metabolic processes and the formation of life substances in the trees. However, drought occurs frequently every year in the north, especially in spring and summer. At the same time, most peach orchards are mainly built in thin soils at mountain ridge, without irrigation conditions. Drought and water shortage are the key factors that restrict the production and development of peach trees. In addition, the decrease of precipitation also causes frequent drought disasters, which seriously affects the normal growth and development of peach trees and fruit quality. Therefore, it is extremely necessary to research and develop fertilizers improve the drought resistance of peach trees.

However, the existing fertilizer for improving the drought resistance of fruit trees has complex formula and many active ingredients, which leads to high cost and is not conducive to market popularization and use. In addition, the existing drought-resistant fertilizer has a single function, so it needs to be combined with other fertilizers in actual planting to promote the growth of peach trees.

In view of this, the present invention is proposed.

SUMMARY LU503348

The purpose of the 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 invention, the relative conductivity of peach leaves is obviously reduced, the relative water content and photosynthetic rate of leaves are obviously improved, and the yield and quality of peach are improved while the drought stress resistance of peach trees is increased.

To achieve the above purpose, the present invention provides the following technical scheme:

A foliar fertilizer for improving drought resistance of peach trees is composed of lecithin, lauric acid and sodium silicate.

The foliar fertilizer comprises the following components in parts by weight: 100 parts by weight of lecithin, 10-11 parts by weight of lauric acid and 1-2 parts by weight of sodium silicate.

Preferably, the foliar fertilizer comprises the following components in parts by weight: 100 parts by weight of lecithin, 10 parts by weight of lauric acid and 1.4-1.5 parts by weight of sodium silicate.

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

The varieties of peach trees are 'Jinxiayoupan' and 'Jinchun'.

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

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

The foliar fertilizer is sprayed on the whole crown of the peach tree to ensure that each part of the whole crown is uniformly sprayed.

The spraying frequency of the foliar fertilizer is 3 times per month.

The foliar fertilizer is sprayed during the whole drought period.

According to the foliar fertilizer for improving the drought resistance of peach trees provided by the invention, the effects of each component are as follows: 1. As a crop protective agent, lecithin can enhance the efficacy of active ingredients,

reduce the dosage of active ingredients, and ensure the stability of aqueous emulsion containing active ingredients. 7505348

Lecithin has the function of controlling diseases and insect pests of crops such as vegetables and rice. As it is nontoxic and pollution-free, it has more advantages than the existing pesticides. Lecithin can be used in combination with common pesticides, for example, it can be used in combination with dimethoate insecticide, carbendazim, chlorothalonil and thiophanate, etc. which can inhibit various fungal viruses, so that the dosage of bactericide can be reduced by 30%, the cost can be greatly reduced, and public hazards and environmental pollution can be reduced. Lecithin can also be used alone or mixed with edible oil and alcohol solvents. For example, lecithin can be directly diluted with water into a solution of more than 2mg/L, which can be used to control wasps and powdery mildew. It can also control three common diseases and pests of rice, such as rice blast, rice sheath blight and rice bacterial blight. Under the condition of drought and salt stress, lecithin can significantly reduce cell membrane damage. 2. As a natural fatty acid, lauric acid can activate the resistance of plants. Studies have shown that lauric acid can act through jasmonic acid signaling pathway to improve the drought resistance of plants. 3. The mechanism of sodium silicate in drought resistance has been partially clarified at physiological and biochemical level, including increasing root water intake, maintaining nutritional balance, reducing leaf water loss, promoting photosynthetic rate, improving antioxidant capacity by increasing antioxidant enzyme activities and non-enzymatic antioxidant activities, and regulating hormone balance in plants under stress conditions. The invention further finds that sodium silicate, lauric acid as an active substance and lecithin as a protective substance have synergistic effect, and the effect of improving drought resistance of plants is more obvious, so that the effect of improving yield and quality is more obvious.

The invention has the advantages that:

The foliar fertilizer provided by the invention has the advantages of simple formula and low cost. By using the foliar fertilizer provided by the invention, the relative conductivity of peach leaves is obviously reduced, the relative water content and photosynthetic rate of leaves are obviously improved, and the yield and quality of peach are improved while the drought stress resistance of peach trees is increased.

BRIEF DESCRIPTION OF THE FIGURES LU503348

FIG. 1 shows the growth status and antioxidant capacity of peach seedlings under drought stress; where, (a) in FIG. 1 shows the growth status of peach seedlings under drought stress; (b) in FIG. 1 is Evans blue dye photo of peach seedlings roots; (c) in FIG. 1 is Evans blue dye photo of peach seedling leaves; (d) shows the status of stomata in peach seedling leaves.

FIG. 2 shows the alleviating effect of lauric acid on drought stress of peach seedlings; where, (a) in FIG. 2 shows the stomatal conditions of peach leaves in each treatment; (b) in FIG. 2 shows the average pore diameters of peach leaves in each treatment; (c) in FIG. 2 shows the initial fluorescence value (FO), maximum fluorescence value (Fm), maximum quantum yield (Fv/Fm) of PSII, actual photochemical efficiency (FPSII) and photochemical quenching coefficient (qP) of FPSII of peach leaves of each treatment; (d) in FIG. 2 shows ETR-PAR light response curves of each treatment.

FIG. 3 shows the net photosynthetic rate of peach seedling leaves treated with different concentrations of lecithin under drought stress.

FIG. 4 shows the stomatal density and size of peach seedling leaves treated with different concentrations of lecithin under drought stress.

FIG. 5 shows proline content and electrolyte leakage rate of peach seedling leaves treated with different concentrations of lecithin under drought stress; where, (a) in FIG. 5 shows proline content and (b) shows electrolyte leakage rate.

FIG. 6 shows the effect of lecithin on root cell activity under drought stress.

FIG. 7 shows the effect of lecithin on the integrity of root cells under drought stress.

FIG. 8 shows the effect of lecithin on the integrity of root cell membrane under drought stress.

FIG. 9 shows the effect of foliar fertilizer provided by the invention on the electrolyte leakage rate and the relative water content of peach leaves under drought conditions.

FIG. 10 shows the effect of foliar fertilizer provided by the invention on the net photosynthetic rate of peach leaves and soluble solids of fruit under drought conditions.

FIG. 11 shows the effect of foliar fertilizer provided by the invention on the single fruit weight and single plant yield of peach fruit under drought conditions.

DESCRIPTION OF THE INVENTION LU503348

The invention will be further described in detail with reference to the following specific embodiments. The examples given are only to illustrate the invention, but not to limit the scope of the invention.

Description of materials and reagents used in the following examples:

Lecithin: purchased from Beijing Solarbio Science & Technology Co., Ltd..

Lauric acid: purchased from sigmaaldrich Company of Merck.

Sodium silicate: purchased from Beijing J&K Scientific Co, Ltd..

The drought stress test in the following examples refers to the simulation of drought conditions by regulating the water content of quartz sand in flowerpots with 10% polyethylene glycol (PEG) solution.

Example 1

The seedlings of Amygdalus persica are used as test materials, and the drought stress test is carried out at the test station of South Campus of Shandong Agricultural

University in 2021.

Firstly, a preliminary test is carried out to screen the appropriate concentration of sodium silicate to relieve peach drought stress. Five seedlings of Amygdalus persica with uniform growth and no disease are selected as experimental materials. The seedlings are planted in a cylindrical pot with an inner diameter of 24cm and a height of 12.8cm, and the pot contains quartz sand. The seedlings are cultured in a greenhouse with light (20,000lux), 28°C/18°C day and night temperature and 50% air humidity. 10% polyethylene glycol (PEG) solution is used to regulate the water content of quartz sand in flowerpots to simulate drought conditions. Different concentrations of sodium silicate solutions are applied, and the sodium silicate concentrations are 0 mmol/L, 0.03 mmol/L, 0.06 mmol/L, 0.09 mmol/L and 0.12mmol/L respectively. There are 15 pots per treatment.

After 6 days of treatment, the net photosynthetic rate of peach leaves in each treatment is measured. The results show that 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 are 6.73 umolsm-2=s' 7.02 yumolsm?-s", 7.96 pmolm=2=s’' 7.87 yumolsm#-s" and 7.52 umolem”?-s"" respectively. Where, the net photosynthetic rate of peach leaves treated with 0.06 mmol/L sodium silicate is the highest, which indicates that this concentration has a good effect on relieving drought stress of peach seedlings.

Next, the alleviating effect of 7.32mg/L sodium silicate (i.e. 0.06 mmol/L NazSiO3) on drought stress of peach seedlings is studied systematically.

Three treatments are set: control (CK Clear water); drought stress (10% polyethylene glycol PEG; 10% PEG solution); drought + silicon (10% PEG+Si; 10 AB

PEG + 0.06 mmol/L Na2SiOs).

For each treatment, 30 seedlings of Amygdalus persica with 5 leaves and no diseases and insect pests are selected. The seedlings are planted in a cylindrical pot with an inner diameter of 24cm and a height of 12.8cm, and the pot contains quartz sand.

The seedlings are cultured in a greenhouse with light (20,000lux), 28°C/18°C day and night temperature and 50% air humidity. 10% polyethylene glycol (PEG) solution is used to regulate the water content of quartz sand in flowerpots to simulate drought conditions.

The water content of CK treatment is 60%, and that of quartz sand in 10%PEG and 10%PEG+Si treatment groups is 40%. The treatment method of silicon is to apply 0.06 mmol/L NazSiO3 solution to the root, a total of 100mL, and clean water is used as the control.

After 10 days of treatment, the morphology of peach seedlings is observed, the leaves are dyed with Evans blue to observe the stomatal state, and the alleviating effect of sodium silicate on peach seedlings under drought stress is analyzed.

The specific measurement method is: dyeing leaves with Evans blue, and observing the effects of different treatments on leaves and roots. Electron microscope is used to observe the stomatal state of peach leaves with different treatments.

The results show that under drought stress, the water content of plant leaves decreased with the increase of stress intensity, which reflects the drought resistance of plants to some extent. As shown in FIG. 1, drought stress caused leaf wilting and severe water loss of peach seedlings, but compared with the control, exogenous silicon treatment alleviates leaf wilting and reduces leaf water loss (FIG. 1a). The oxidative damage of seedlings under drought stress is detected by Evans blue dye. Compared with the control, the dying degrees of leaves and roots of seedlings treated with silicon are significantly reduced (FIG. 1b and FIG. 1c), which indicates that the oxidative damage of peach seedlings treated with silicon is significantly lower than that of the control. Observation on stomata of leaves shows that drought stress significantly affects the stomatal state of leaves. Compared with the control, drought stress causes the stomata of peach seedling leaves to close (FIG. 1d).

The above results show that 7.32mg/L sodium silicate can alleviate the damage of peach seedlings caused by drought stress, thus improving the drought resistance of peach trees.

Example 2 !

The seedlings of Amygdalus persica are used as test materials, and the drought 509946 stress test is carried out at the test station of South Campus of Shandong Agricultural

University in July 2021.

Firstly, the alleviating effect of different concentrations of lauric acid on peach seedlings under drought stress is studied, and the appropriate application concentration of lauric acid is selected. Five seedlings of Amygdalus persica with uniform growth and no disease are selected as experimental materials. The seedlings are planted in a cylindrical pot with an inner diameter of 24cm and a height of 12.8cm, and the pot contains quartz sand. The following five treatments are set respectively. Treatment 1: applying 100ml of 0 mg/L lauric acid of control, that is, clean water, on the first day, and then stopping supplying water. Treatment 2: applying 100ml of 1mg/ L lauric acid on the first day, and then stopping supplying water; Treatment 3: applying 100ml of 10mg/L lauric acid on the first day, and then stopping supplying water; Treatment 4: applying 100ml of 50mg/L lauric acid on the first day, and then stopping supplying water;

Treatment 5: applying 100ml of 100mg/L lauric acid on the first day and then stopping supplying water. After 15 days of treatment, the net photosynthetic rate of peach leaves is measured. It is found that the net photosynthetic rates of peach leaves in Treatment 1,

Treatment 2, Treatment 3, Treatment 4 and Treatment 5 are 12.56umol=m-2=s™ 12.89umol=m-2=s' 13.59umol=m-2=s' 14.71umol=m-=2=s' 11.52umol=m=2=s-!, respectively.

Where, the net photosynthetic rate of peach leaves treated with 50mg/L lauric acid is the highest, which indicates that this concentration has a good effect on relieving drought stress of peach seedlings.

Next, the mitigation effect of 50mg/L lauric acid on drought stress of peach seedlings is systematically studied. Four treatments are set in the experiment. CK: normal watering, watering 100ml of water on the first day of treatment, and watering every five days thereafter. Treatment LA: 100ml of lauric acid with a concentration of 50mg/L is poured on the first day of treatment, and then every five days. CK-D: No watering is started on the first day of treatment, and the drought state is maintained all the time. LA-D: On the first day of treatment, 100ml of lauric acid with a concentration of 50mg/L is poured. After that, neither water nor lauric acid is poured, and it remained in a dry state.

For each treatment, 30 seedlings of Prunus persica with 5 leaves and no diseases and insect pests are selected. The seedlings are planted in a cylindrical pot with an inner diameter of 24cm and a height of 12.8cm. The pot is made of quartz sand, and they are cultured in a greenhouse with light (20.000lux) day and night temperature of 28°C/18°C and air humidity of 50%. 1000868

On the 14th day of treatment, three leaves are collected from the same part of each plant, the stomatal morphology and stomatal opening degree are observed, and the chlorophyll fluorescence parameters of each treatment are measured.

The specific measurement method is as follows: Collecting 3 leaves from the same part of each plant, observing the stomatal morphology and stomatal opening degree.

Painting colorless acrylic nail polish evenly on the back of each collected peach leaf, and after 5 minutes, remove the hardened nail polish with tweezers. then placing the nail polish-coated fragments on a microscope slide and examining under a fluorescence microscope at 400 magnifications (AXIO, Carl Zeiss, Germany). Randomly selecting three positions on each piece of debris for imaging. To calculate and identify openness, measuring pore sizes by using ImageJ software (National Institutes of Health, Bethesda,

Maryland, USA).

The following parameters are measured using an IMAGING-PAM chlorophyll fluorescence system (Heinz Walz, Effeltrich, Germany): minimal fluorescence (FO), maximal fluorescence (Fm), optimal/maximal photochemical efficiency of PSI in the dark (Fv/Fm), actual quantum efficiency (FPSII), photochemical quenching (qP), non-photochemical quenching (NPQ) and electron transport rate (ETR). To determine

Fv/Fm, peach leaves are dark adapted in a dark clip joint for 30 minutes.

The results show that under normal conditions, the stomatal opening of drought-treated leaves is significantly lower than that of control leaves. The application of exogenous LA could increase the pore size of leaves ((a) in FIG. 2); compared with CK treatment, LA treatment significantly increases the mean pore size by 2.41 times ((b) in

FIG. 2).

The minimal fluorescence (FO), maximal fluorescence (Fm), optimal/maximal photochemical efficiency of PSI in the dark (Fv/Fm), actual quantum efficiency (FPSII). photochemical quenching (qP) under drought treatment is significantly decreased ((c) in

FIG. 2). The LA treatment increases FO, Fm, Fv/Fm, FPSII, and gP by 18.54%, 33.71%, 7.75%, 19.41%, and 11.39%, respectively. The corresponding color photos of the leaves show the states of the four parameters under different treatments ((c) in FIG. 2). LA-D treatment can effectively alleviate the damage caused by drought stress. ETR-PAR liopt 503348 response curve ((d) in FIG. 2) show that the treatment of LA-D increases the ETRmax of peach seedlings by 51.45%, respectively.

The above results show that 50mg/L lauric acid can alleviate the damage of peach seedlings caused by drought stress.

Example 3

In this experiment, the seedlings of Amygdalus persica L are used as materials, and the drought stress experiment is conducted in the south campus of Shandong

Agricultural University in 2017, to study the alleviating effect of different concentrations of lecithin (PC) on peach seedlings under drought stress.

Six treatments are set in the experiment: C1, clean water control; C2, clean water control+500mg/L PC; D1: no PC added under drought stress; D2: 200 mg/L PC added under drought stress; D3: 500 mg/L PC added under drought stress; D4: 1000 mg/L PC added under drought stress; each treatment is performed for the first time starting from the first day, and then every other day for a total of three times with 100mL each time.

After the third treatment, putting the seedlings in a rain shelter for drought stress treatment, measuring the net photosynthetic rate on the first day, the third day, the sixth day, the ninth day and the twelfth day after the treatment, and then sampling and measuring electrolyte extravasation rate, proline, stomatal state observation, leaf cell integrity and other related indexes. seedlings of Pr Amygdalus persica L are selected for each treatment. The seedlings are planted in pots, one in each pot. The pot is cylindrical, with an inner diameter of 24cm and a height of 12.8cm. The cultivation medium in the pot is quartz sand, and the seedlings are cultured in a greenhouse with light (20,000lux), day and night temperature of 28°C/18°C and air humidity of 50%.

The measurement and calculation method of index:

Net photosynthetic rate: Using CIRAS-3 portable photosynthetic apparatus measuring system (PPSystems, UK) to measure the net photosynthetic rate of fully developed functional leaves, repeating 3 times, and taking the average value. observing the stomatal state of leaves by electron microscope, and measuring the size and area of stomata by ImageJ.

Electrolyte extravasation rate: gently taking out the soaked leaves to be measured 5033 48 with tweezers, putting them into 20ml test tubes with 10ml deionized water, putting three leaf discs in each tube, covering the nozzle with a clean plastic film, and wrapping them up with rubber bands. Each treatment has three repetitions (i.e., three test tubes), and putting the test tubes in an incubator at 50°C for 0.5h, with room temperature (20°C) as a control. After the treatment, the test tubes are rinsed with tap water for 5 minutes to balance to room temperature.

Measurement of conductivity: A) Shaking well and measuring the first conductivity value G1. B) Boiling the test tube in boiling water for 20 minutes to kill tissues, balancing at room temperature for 10 minutes and cooling to room temperature, then measuring the second conductance G2.

Relative conductance value (%) = the first conductance value/the conductance value after killing tissuex 100%

Electrolyte leakage rate (%) = (relative conductivity of sample-relative conductivity of control) /(100%- relative conductivity of control) x100%

Proline: Ninhydrin colorimetry is used. Weighing 0.5g of fresh sample, adding 5mL of sulfosalicylic acid, sealing and putting in boiling water bath for 10min, cooling, filtering with filter paper funnel, absorbing 2mL of filtrate (2mL of distilled water in control), adding 2mL of glacial acetic acid, then adding 3mL of acid ninhydrin chromogenic solution, soaking it in boiling water for 40min, cooling, adding 5ML of toluene, fully shaking it, letting it stand for layering, and taking the upper toluene solution for color comparison at 520nm.

Proline (ug/gFW or DW) =YxV/a xW.

Relative activity of root cells: Evans blue staining is used. In order to fix the root samples, first soaking them in 2.5% glutaraldehyde at 4°C, then rinsing them in PBS buffer for 10 minutes and three times; next, fixing the sample with 1% citric acid at 4°C for 2 hours, and then performing the second group of three times of 10-minute PBS buffer washing; finally, dehydrating the samples by ethanol series gradient dehydration (using 30%, 50%, 70%, 90% and 100% ethanol solutions). The samples are soaked for 10 minutes in each step of the series, and soaked in 100% ethanol solution twice; then, the samples are embedded in Epon812 epoxy resin before hatching, and curing at 37°C, 45°C and 65°C for three consecutive stages, each stage lasting 24 hours. Next, the UltracutE 5033 48 ultramicrotome is used to slice the sample. Finally, the sample is dyed with uranyl lead acetate and then tested on the machine.

The results show that there is no significant difference in the net photosynthetic rate and the chlorophyll content (SPAD value) between peach seedlings with or without exogenous lecithin treatment. On the contrary, the net photosynthetic rate and SPAD value of plants under drought stress decrease with time. The net photosynthetic rate and

SPAD value of plants supplemented with 200mg /L, 500mg /L and 1000mg /L lecithin are higher than those of the control. Within 12 days, the net photosynthetic rate and SPAD value of 500 mg/L lecithin treatment decrease the least (FIG. 3).

Table 1 Alleviating effect of different concentrations of lecithin (PC) on peach seedlings under drought stress length (mm) width (mm) area

TT clean water drought stress + 200mg/L drought stress + 500mg/L drought stress + 1000mg/L

As can be seen from FIG. 4 and Table 1, 400 times magnification observation shows that the length and width of stomata at the lower part of leaves of peach seedlings with sufficient water are short. Therefore, the overall shape of their guard cells is round and full, and their stomata are open. It is found that there is no significant difference in stomatal shape and density of non-stressed plants whether lecithin is applied or not. [N 503348 contrast, the stomata of plants under drought stress become longer and narrower, and the stomatal density is lower than that of plants under non-drought stress. The stomata of untreated plants remained closed under drought stress, while the stomata of lecithin-treated plants partially opened. It is found that the stomatal opening degree of 500 mg/L lecithin is the highest.

As can be seen from FIG. 5, there is little difference in proline content of plants without drought stress, whether or not lecithin is supplemented. The proline content in roots of untreated and stressed plants is 18.13 ug/ml on average, while that in roots of plants treated with 500 mg/L lecithin is 17.6 ug/ml, which is lower than that in drought stress control group.

Electrical conductivity is a physiological index to measure the diffusion of cell contents in peach trees to the outside of cells, which can reflect the damage degree of plasma membrane. FIG. 5 shows that under drought stress, the electrolyte leakage rate of the roots of plants treated with 500 mg/L lecithin is significantly lower than that of D1 group. The results show that 500 mg/L lecithin treatment significantly reduces the damage degree of membrane protein of peach seedling leaves, reduces the exosmosis of cytoplasm, effectively protects the cell membrane system and enhances the drought resistance of leaves.

As can be seen from FIG. 6, Evans Blue is a cell active dye, which is used to detect the integrity of cell membrane and whether cells are alive. Living cells will not be dyed light blue, but dead cells will be dyed blue. FIG. 6 shows the effect of Evans blue staining solution on the activity of root cells. It can be seen from FIG. 6 that the activity of D3 and

D4 cells is significantly higher than that 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 membrane under drought stress, thus enhancing the activity of plant root cells.

It can be seen from FIG. 7 that when the plant has sufficient water, the cell integrity of the plant treated with lecithin is less different from that of the untreated plant. However, when plants are subjected to drought stress, the cell structure integrity and cell membrane structure of untreated plants are destroyed, as shown in FIG. 8, while the root cell integrity and cell membrane protection of plants treated with 500 mg/L lecithin are significantly higher. LU503348

Example 4

The experiment is carried out in the peach garden of the horticultural experimental station of Shandong Agricultural University in 2022 to study the effects of the foliar fertilizer of the invention on drought stress and yield and quality of peach.

From April to May in 2022, there is no effective rainfall for two consecutive months.

Taking four-year-old' Jinxiayoupan' and' Jinchun' as test materials, 20 plants with basically identical growth vigor are selected from each variety for treatment, and the row spacing of the plants of the two varieties is determined to be 2 m x5 m (67 plants per mu).

Treatment: The diluted mixed solution containing 500mg/L lecithin, 50mg/L lauric acid and 7.32mg/L sodium silicate is used as foliar fertilizer, and spraying by using the electric sprayer on the whole crown of peach tree, and it is advisable to spray all parts of the whole tree evenly. The spraying frequency is 3 times/month, and spraying the same amount of clear water for each foliar fertilizer is used as a control. The first treatment begins on May 10th, until the end of fruit ripening.

Determination and calculation method of index: 1. The calculation method of the electrolyte extravasation rate was the same as that described in Embodiment 3. 2. Relative water content. selecting six peach leaves of each variety, weighing, putting into a sealing bag filled with distilled water, soaking in a refrigerator at 4°C for 24h, weighing (saturated mass), drying and calculating the relative water content of the leaves. Relative water content (RWC) of peach leaves = [(fresh mass - dry mass)/(saturated mass - dry mass) ]x100%. 3. Photosynthetic rate: using the CIRAS-3 portable photosynthetic apparatus measurement system (PPSystems, the UK) to measure the net photosynthetic rate of fully developed functional leaves, and repeating the measurement three times to obtain the average value. 4. Average single fruit weight and single plant yield: randomly selecting three trees for each variety in each treatement, and measuring the total number of fruits of each tree; selecting ten fruits at the periphery and middle part of each tree crown, measuring the single fruit weight, and then calculating the yield per plant. LU503348 5. Soluble solid content: measuring soluble solid with TD-4 glucose meter and repeating three times to obtain the average value.

As shown in FIG. 9, FIG. 10 and FIG.11, after spraying the foliar fertilizer of the present invention, the electrolyte leakage rate of leaves of 'Jinxia Youpan' and 'Jinchun' decreases by 27.6% and 35.9% respectively, the relative water content increases by 18.7% and 32.6% respectively, the photosynthetic rate increases by 23.6% and 29.4% respectively, and the soluble solid content increases by 9.6% and 10% respectively. The average fruit weight increases by 10.2% and 11.3% respectively, and the yield per plant increases by 22.3% and 24.8% respectively. It can be seen that by using this foliar fertilizer, the relative electrical conductivity of leaves decreases significantly, the relative water content and photosynthetic rate of leaves increases significantly, and the yield and quality of peach trees are improved at the same time as the drought resistance of peach trees is increased.

Although the present invention has been described in detail by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention are within the scope of the present invention.

Claims

CLAIMS LU503348

1. A foliar fertilizer for improving drought resistance of peach trees is composed of lecithin, lauric acid and sodium silicate.

2. The foliar fertilizer according to claim 1, characterized in that the foliar fertilizer comprises the following components in parts by weight: 100 parts by weight of lecithin, 10-11 parts by weight of lauric acid and 1-2 parts by weight of sodium silicate.

3. An application of the foliar fertilizer according to claim 1 or 2 in improving the drought resistance of peach trees.

4. The application according to claim 3, characterized in that the varieties of peach trees are 'Jinxia Youpan' and 'Jinchun'.

5. A method for improving the drought resistance of peach trees, comprising the following steps: diluting the foliar fertilizer according to claim 1 or 2 with water, and spraying the foliar fertilizer on the peach leaves of the peach trees.

6. The method according to claim 5, characterized in that in the diluted mixed solution, the mass concentration of lecithin is 500-550mg/L, the mass concentration of lauric acid is 45-55mg/L, and the mass concentration of sodium silicate is 7-10mg/L.

7. The method according to claim 5 or 6, characterized in that the foliar fertilizer is sprayed on the whole crown of the peach tree to ensure that each part of the whole crown is uniformly sprayed.

8. The method according to claim 5, characterized in that the spraying frequency of the foliar fertilizer is 3 times/month.

9. The method according to claim 5, characterized in that the foliar fertilizer is sprayed during the whole drought period.