A composition and method for improving the receptivity of mango stigmas and the fruit set of mangoes under low temperature stress conditions

Abstract

The application relates to the technical field of tropical fruit tree cultivation, and discloses application of L-serine in improving the pollination of mango pistil heads and / or the fruit setting rate of mangoes under low-temperature stress conditions, a composition and a method for promoting the fruit setting rate of mangoes. The application provides a new use of L-serine and a complexing agent thereof in improving the pollen vitality, the pollination of mango pistil heads and the fruit setting of mangoes under low-temperature stress conditions. Gamma-aminobutyric acid (GABA) and L-serine are complexed in a composition containing 100-300 umol of gamma-aminobutyric acid and 1-5 g of L-serine per liter, the composition is sprayed on plants in the initial flowering period, the composition has the functions of promoting the pollen germination, pollen tube elongation and pollination of mangoes, and the fruit setting rate is improved, thereby providing technical support for solving the unstable yield problem in the industry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tropical fruit tree cultivation, more particularly, to a composition and method for improving the receptivity of mango flower stigma and the fruit setting rate of mango under low temperature stress conditions. BACKGROUND

[0002] Mangifera indica L. is an important tropical fruit tree in the world. In China, mango is mainly planted in Guangxi, Yunnan, Sichuan, Hainan, Guangdong and other southern tropical and subtropical regions. In 2019, the mango planting area in China was 323,000 hectares, with a yield of 2,782,000 tons, ranking third in the world, becoming the fourth largest tropical fruit in China after lychee, longan and banana.

[0003] In China's atypical tropical main producing areas such as Guangxi, Guangdong and the Jinshajiang dry-hot valley, mangoes often encounter low temperature and other adverse weather during flowering, resulting in poor pollination and fertilization, often "flowers full of trees, fruit setting is rare", which seriously affects the yield stability.

[0004] The so-called "temperature stress" factor refers to an environmental factor that causes a decline in the physiological function of plant cells as a result of exposure of the plant to a temperature environment that deviates from the optimum temperature, in which the temperature exceeds the upper or lower limit of the optimum temperature for the growth or germination of the plant. The temperature stress factor is referred to as a high temperature stress factor in the case where the temperature exceeds the upper limit of the optimum temperature, and as a low temperature stress factor in the case where the temperature exceeds the lower limit of the optimum temperature. The optimum temperature for the growth or germination of the plant varies depending on the plant, and generally, the optimum temperature for germination is often higher than the optimum temperature for growth.

[0005] Temperature stress of a plant can be monitored by comparing changes in the following plant phenotypes between a plant not exposed to a temperature stress factor and a plant exposed to a temperature stress factor.

[0006] A large number of studies have shown that low temperature during flowering reduces pollen germination rate and stigma receptivity, affects pollination efficiency, and has an adverse effect on yield (Wang Baipo et al. 1989, Ouyang Shijin et al. 2007, Yang Qin et al. 2013). Low temperature slows down pollen germination and pollen tube growth, and the mechanism may be that low temperature reduces the physiological metabolic activity of pollen, thereby reducing the production of metabolic products necessary for pollen germination and pollen tube growth (Zhang Shaoling et al. 2004). Mango is a tropical fruit tree, and is particularly sensitive to low temperature. When the temperature during flowering drops below 22°C, the pollen germination rate of most varieties decreases significantly, while it germinates well between 25-30°C (Sukhvibul et al. 1999).

[0007] At present, in the conventional production, the method of picking flowers to delay flowering period is often used to avoid adverse weather to improve the fruit setting rate, but picking flowers to delay flowering period needs a large amount of labor, and due to global climate change and unstable early spring weather, the technology of picking flowers to delay flowering period also often inevitably encounters adverse weather, therefore, a new type of pollen germination and stigma receptivity promoter which is ecological safety, simple, labor-saving and efficient is needed to improve the fruit setting rate and provide technical support for solving the problem of unstable yield in the industry. SUMMARY

[0008] The present application provides an application of L-serine in improving stigma receptivity of mango flowers and / or fruit setting rate of mango under low temperature stress conditions.

[0009] The present application provides an application of L-serine in preparing a composition for improving stigma receptivity of mango flowers and / or fruit setting rate of mango under low temperature stress conditions.

[0010] The present application provides a composition for improving stigma receptivity of mango flowers and / or fruit setting rate of mango under low temperature stress conditions.

[0011] The present application provides a method for improving stigma receptivity of mango flowers and / or fruit setting rate of mango under low temperature stress conditions.

[0012] To solve the above technical problems, the technical scheme of the present application is as follows:

[0013] An application of L-serine in improving stigma receptivity of mango flowers and / or fruit setting rate of mango under low temperature stress conditions.

[0014] The low temperature stress in the present application refers to the result of exposing mango to a temperature environment deviating from the optimal temperature (i.e., the temperature exceeds the lower limit of the optimal temperature for the growth or flowering of mango) when the air temperature is 15-22℃, which causes the physiological function of plant cells to decline.

[0015] The present application finds that the fruit setting rate of mango is affected by pollen germination, pollen tube elongation and stigma receptivity, especially the low temperature during flowering slows down the pollen germination and pollen tube growth rate, and the mechanism may be that low temperature reduces the physiological metabolic activity of pollen, thereby reducing the production of metabolic products necessary for pollen germination rate, pollen tube growth and stigma receptivity, affecting pollination efficiency, and further affecting the fruit setting rate.

[0016] L-serine is one of the amino acids necessary for protein synthesis in plants, and is also a precursor for the synthesis of various important substances in plant cells. The present application unexpectedly finds that L-serine has a significant promoting effect on pollen germination, pollen tube elongation and stigma receptivity of mango, especially under low temperature stress.

[0017] Use of L-serine in the preparation of a composition for improving the receptivity of mango flower stigma and / or the fruit setting rate of mango under low temperature stress conditions.

[0018] A composition for improving the receptivity of mango flower stigma and / or the fruit setting rate of mango under low temperature stress conditions, comprising L-serine and water.

[0019] Preferably, the concentration of L-serine is 1-5 g / L.

[0020] Preferably, the concentration of L-serine is 2-3 g / L.

[0021] Preferably, the composition for improving the receptivity of mango flower stigma and / or the fruit setting rate of mango under low temperature stress conditions further comprises gamma-aminobutyric acid. Gamma-aminobutyric acid (GABA) is an important non-protein amino acid naturally occurring in animals and plants, widely exists in plants, is a zwitterion containing amino and carboxyl groups, and plays an important role in plant growth and development and non-biological stress resistance response. Studies in the field show that appropriate concentration of GABA treatment can inhibit fruit chilling injury and maintain its quality. Exogenous GABA treatment can increase the antioxidant enzyme activity of plant seedlings, effectively scavenge active oxygen, and thus enhance the aluminum stress resistance of plants.

[0022] Preferably, each liter of the composition consists of: gamma-aminobutyric acid 100-300 umol, L-serine 1-5 g, and the rest is water.

[0023] Preferably, each liter of the composition consists of: gamma-aminobutyric acid 200-300 umol, L-serine 2-3 g, and the rest is water.

[0024] Preferably, the concentration ratio of gamma-aminobutyric acid (GABA) and L-serine is 200 umol / L: 2-3 g / L.

[0025] A method for improving the receptivity of mango flower stigma and / or the fruit setting rate of mango under low temperature stress conditions, taking the composition for improving the fruit setting rate of mango, and spraying the whole plant with the composition at the initial flowering stage.

[0026] Preferably, a method for improving the receptivity of mango flower stigma and / or the fruit setting rate of mango under low temperature stress conditions, taking the composition for improving the fruit setting rate of mango, and spraying the whole plant with the composition at the initial flowering stage.

[0027] Preferably, the environmental temperature for spraying is 15-22℃.

[0028] Compared with the prior art, the beneficial effects of the technical scheme of the present application are:

[0029] The application provides a new use of gamma-aminobutyric acid (GABA), L-serine and a compound thereof for improving pollen viability, stigma receptivity and fruit setting under low temperature stress conditions. The gamma-aminobutyric acid (GABA) and / or L-serine are compounded in a certain proportion, and are sprayed on plants at the initial flowering stage, so as to promote pollen germination, pollen tube elongation and stigma receptivity, thereby improving the fruit setting rate and providing technical support for solving the unstable yield problem in the industry.

[0030] The formula agent adopted in the application is ecologically safe, widely exists in plants, has obvious effects on promoting pollen germination, stigma receptivity and fruit setting under low temperature stress, has good water solubility and is simple to prepare.

[0031] The conventional flower picking technology needs to consume a large amount of labor cost, wastes a large amount of tree nutrients and has unstable effects, the application is more light, simple, labor-saving and efficient, and the amino acid component also has the function of a leaf fertilizer. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a micrograph of pollen after culture under the condition that the whole plant of 'Renong No. 1' mango is sprayed with water (control) and gamma-aminobutyric acid (GABA) for 24 hours under low temperature stress.

[0033] Figure 2 is a micrograph of pollen after culture under the condition that the whole plant of 'Tainong No. 1' mango is sprayed with water (control) and gamma-aminobutyric acid (GABA) for 24 hours under low temperature stress.

[0034] Figure 3 is a micrograph of stigma after benzidine-hydrogen peroxide determination under the condition that the whole plant of 'Renong No. 1' mango is sprayed with water (control) and L-serine for 24 hours under low temperature stress.

[0035] Figure 4 is a micrograph of stigma after benzidine-hydrogen peroxide determination under the condition that the whole plant of 'Tainong No. 1' mango is sprayed with water (control) and L-serine for 24 hours under low temperature stress.

[0036] Figure 5 is a flower setting situation under the condition that the whole plant of 'Renong No. 1' mango is sprayed with water (control) and 200 umol / L gamma-aminobutyric acid (GABA) + 3 g / L serine under low temperature stress.

[0037] Figure 6 is a flower setting situation under the condition that the whole plant of 'Tainong No. 1' mango is sprayed with water (control) and 200 umol / L gamma-aminobutyric acid (GABA) + 2 g / L serine under low temperature stress.

[0038] Figure 7The plant of 'Taikang No. 1' mango is sprayed with water (control) and 200 umol / L GABA + 2 g / L serine under low temperature stress conditions. DETAILED DESCRIPTION

[0039] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0040] The raw materials used in the following examples and comparative examples are commercially available, and the materials and methods used are as follows:

[0041] 1.1 Material: The tested varieties are 'Renong No. 1' and 'Taikang No. 1' mangoes.

[0042] 1.2 Pesticide spraying and treatment

[0043] Pesticide spraying method: Under low temperature stress (15-22℃), whole plant leaf surface spraying is adopted, both front and back surfaces are sprayed, and the leaf surface is completely wetted. The control (CK) is water.

[0044] The main mango varieties are used as materials, different concentrations of exogenous GABA and L-serine treatment are set, and the effects on pollen germination and stigma receptivity are studied.

[0045] The effects of γ-aminobutyric acid and L-serine single agent and complex agent treatment on mango fruit setting are set.

[0046] 1.3 Pollen viability detection:

[0047] The pollen germination method is adopted, the anthers of the newly flowered stamens after 24h treatment are selected, the upper part of which is changed from bright red to grayish white, and is taken off with a camera, and after 3-6h culture, microscopic examination is carried out under a microscope, 3 fields of view (more than 100 pollen grains per field of view) are randomly examined for each glass slide, and the germination rate and pollen tube length are counted. Each treatment is repeated 3 times. The pollen germination standard is that the pollen tube is longer than the pollen grain diameter. Pollen germination rate = (germinated pollen number / total pollen number) x 100%.

[0048] 1.4 Detection of stigma receptivity

[0049] The stigma of newly bloomed flowers after 24h treatment was collected and put into a reaction solution with a volume ratio of 1% benzidine: 3% hydrogen peroxide: water = 4: 11: 22. The stigma was immersed in the solution. Within 10 min, the staining part of the stigma was observed under a microscope. If the stigma had a large number of bubbles in at least 2 / 3 of the part, it was considered to have the ability to be pollinated. Otherwise, it was considered to have no ability to be pollinated. Then, the percentage of the number of stigmas with the ability to be pollinated in the total number of small flower stigmas was calculated. 20 stigmas were used for each treatment, and 3 replicates were set for each treatment.

[0050] 1.5 Investigation of the number of fruits

[0051] The number of fruits was investigated after the second physiological fruit drop period (30-40 days after flowering). 20 panicles were investigated, and 3 replicates were set. The number of fruits per panicle was counted.

[0052] Example 1 Effect of L-serine on the ability of mango flower stigma to be pollinated

[0053] A composition for improving the ability of mango flower stigma to be pollinated under low temperature stress conditions, comprising L-serine and water. L-serine solutions with concentrations of 1, 2, 3, 4, 5, 6, and 10 g / L were prepared respectively. The control group was water.

[0054] For plants that encountered low temperature stress (15-22°C) at the initial flowering stage, the above different concentrations of L-serine solution and water were sprayed on the leaves according to the method of 1.2. After 24h, the ability of the stigma to be pollinated was detected according to the method of 1.4, and the detection results are shown in Table 1. The microscopic photograph of the stigma after benzidine-hydrogen peroxide determination is shown in Figures 3-4 .

[0055] As shown in Table 1, compared with the control group, the mangoes that were sprayed with L-serine solution with a concentration of 1-10 g / L had an improved ability of mango flower stigma to be pollinated. The ability of stigma to be pollinated under the treatment of 2-3 g / L L-serine solution was significantly higher than that of the water control group, and the rest of the treatments had no significant difference with the water control group.

[0056] Table 1 Effect of different concentrations of L-serine solution on the ability of mango flower stigma to be pollinated

[0057]

[0058]

[0059] Note: The data in the table are the average values of three replicates. Different lowercase letters in each column of the table indicate that the difference is significant at the 0.05 level (the same below)

[0060] Example 2 Effect of L-serine on the fruit setting rate of mango

[0061] A composition for improving the fruit setting rate of mango under low temperature stress conditions, comprising L-serine and water. Solutions with L-serine concentrations of 2 and 3 g / L were prepared, respectively. The control group was water.

[0062] For plants that encountered low temperature stress (15-22°C) at the initial flowering stage, 1.2 agents were sprayed and treated, and the above different concentrations of L-serine solution and water were sprayed on the leaves. The number of fruits was investigated 30-40 days after flowering, and the test results are shown in Table 2.

[0063] Compared with the water control group, the number of fruits of mango varieties treated with 2-3 g / L L-serine single agent increased.

[0064] Table 2 Effect of exogenous L-serine single agent on fruit setting of mango inflorescences under low temperature stress

[0065]

[0066] Example 3 Effect of compound agent on pollen viability of mango

[0067] A composition for improving the fruit setting rate of mango, comprising γ-aminobutyric acid, L-serine and water. A water-soluble compound agent of γ-aminobutyric acid and L-serine was prepared, and the control group was water.

[0068] For plants that encountered low temperature stress (15-22°C) at the initial flowering stage, 1.2 agents were sprayed and treated, and the above different concentrations of compound agent were sprayed on the leaves. After 24 h, pollen was cultured in vitro, and the pollen germination rate was observed under a microscope. The test results are shown in Table 3. The microphotograph of pollen after culture is shown in Figures 1-2 .

[0069] Compared with the water control group, the pollen germination rate of mango varieties treated with 200-300 umol / L γ-aminobutyric acid single agent or its and L-serine compound agent significantly increased and was significantly higher than that of other treatments.

[0070] Table 3 Effect on pollen viability of mango under low temperature stress

[0071]

[0072] Example 4 Effect of compound agent on the receptivity of mango stigma

[0073] A composition for improving the receptivity of mango stigma under low temperature stress conditions, comprising γ-aminobutyric acid, L-serine and water. A water-soluble compound agent of γ-aminobutyric acid and L-serine was prepared, and the control group was water.

[0074] The plants which encounter low temperature stress (15-22℃) at the initial flowering stage are sprayed with the above-mentioned different concentrations of the compound agent according to 1.2 agent spraying and treatment, pollen is observed under a microscope after pollen in vitro germination 24 hours later, and the pollen germination rate is detected, and the detection results are shown in Table 4.

[0075] Compared with the water control group, the mango stigma receptivity under the treatment of γ-aminobutyric acid and 2-3 g / L L-serine compound agent is significantly increased, and is higher than that of other treatments.

[0076] Table 4 Influence of low temperature stress on mango flower stigma receptivity

[0077]

[0078] Example 5 Influence of compound agent on mango fruit setting rate

[0079] A composition for improving the fruit setting rate of mango under low temperature stress conditions, comprising γ-aminobutyric acid, L-serine and water. γ-aminobutyric acid and L-serine aqueous solution compound agent is prepared, and the control group is water.

[0080] The plants which encounter low temperature stress (15-22℃) at the initial flowering stage are sprayed with the above-mentioned different concentrations of the compound agent and water according to 1.2 agent spraying and treatment, the fruit setting number is investigated 30-40 days after flowering, the detection results are shown in Table 5, and the fruit setting situation is shown in Figures 5-7 .

[0081] Compared with the control group, the fruit setting number of mango varieties under the treatment of 200 umol / L γ-aminobutyric acid and 2-3 g / L L-serine compound agent is significantly increased, and is higher than that of other treatments.

[0082] Table 5 Influence of low temperature stress on mango inflorescence fruit setting

[0083]

[0084]

[0085] Comparative Example 1 Influence of γ-aminobutyric acid single agent on mango fruit setting rate

[0086] Comparative Example 1 γ-aminobutyric acid and water are used to prepare γ-aminobutyric acid aqueous solution, and the control group is water.

[0087] The plants which encounter low temperature stress (15-22℃) at the initial flowering stage are sprayed with the above-mentioned different concentrations of the compound agent and water according to 1.2 agent spraying and treatment, the fruit setting number is investigated 30-40 days after flowering, the detection results are shown in Table 5, and the fruit setting situation is shown in

[0088] The number of fruits of the mango variety treated with the aqueous solution of γ-aminobutyric acid was increased compared with the control, but the effect was still significantly lower than that of the complexing agent of Example 5.

[0089] Table 6: Effect of low temperature stress on fruit setting of mango inflorescences

[0090]

[0091] The embodiments of the present application are not limited to the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement manners and shall be included in the protection scope of the present application.

Claims

1. A composition for improving the receptivity of mango stigmas and / or the fruit set rate of mangoes under low-temperature stress, characterized in that, Each liter of the composition consists of the following components: 100-300 μmol of γ-aminobutyric acid, 1-5 g of L-serine, and the remainder is water.

2. The composition according to claim 1 for improving the receptivity of mango stigmas and / or mango fruit set rate under low-temperature stress, characterized in that, Each liter of the composition consists of the following components: 200-300 μmol of γ-aminobutyric acid, 2-3 g of L-serine, and the remainder is water.

3. A method for improving the receptivity of mango stigmas and / or the fruit set rate of mangoes under low-temperature stress, characterized in that, The composition for improving mango fruit setting rate as described in claim 1 or 2 is sprayed onto the entire mango plant during the initial flowering stage.

4. The method for improving the receptivity of mango stigmas and / or mango fruit set rate under low-temperature stress according to claim 3, characterized in that, The ambient temperature for spraying is 15–22℃.

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