Foliar fertilizer for promoting sugar increasing and coloring of citrus fruits and inhibiting floating skin and application of foliar fertilizer

Abstract

The invention discloses a foliar fertilizer for promoting sugar increase and coloring of citrus fruits and inhibiting floating skin and application of the foliar fertilizer. The foliar fertilizer is prepared from the following components: 5.2 to 6.4 g / L of medium trace element fertilizer, 1 to 3 mg / L of 5-aminolevulinic acid and 0.05 to 0.07 mg / L of coronatine. The medium trace element fertilizer comprises sugar alcohol calcium, magnesium sulfate, boric acid, selenomethionine and sodium molybdate. The medium trace elements in the fertilizer can be used for supplementing deficient nutrition for the tree body and inhibiting the occurrence of floating bark at the later stage of fruit ripening; 5-aminolevulinic acid can promote chlorophyll synthesis and improve photosynthesis, so that fruit sugar accumulation is promoted; coronatine promotes fruits to be colored in advance by activating a jasmonic acid signal pathway. The components of the foliar fertilizer disclosed by the invention have a synergistic interaction function, and the foliar fertilizer can obviously promote sugar increase and coloring of fruits and inhibit occurrence of floating peels in a full ripening period, so that early and delayed harvesting of citrus is realized, and the market economic benefits are greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of fruit fertilizers, and particularly relates to a foliar fertilizer for promoting sugar increase and coloring of citrus fruits and inhibiting peel puffiness, and its application. Background Art

[0002] Citrus (Citrus reticulata Blanco) belongs to the Rutaceae family and the Citrus subfamily. China has a citrus cultivation history of more than 4,000 years, and its main production areas are distributed in more than 20 provinces such as Zhejiang, Jiangxi, Hubei, and Hunan. China is rich in citrus cultivation resources, mainly including loose-skinned citrus, sweet oranges, pomelos, kumquats, etc. As one of the most important cultivated varieties of loose-skinned citrus, Satsuma mandarin is native to Zhejiang Province, China. Because of its excellent traits such as seedlessness, delicate flesh, and good flavor, it is deeply loved by consumers and has high social and economic value.

[0003] However, there are differences in cultivation techniques in different citrus production areas in China. The quality of citrus in some areas has been significantly reduced, showing a decrease in fruit sugar content and a deterioration in color. In order to pursue higher yields, a large number of citrus orchards have over-applied nitrogen fertilizers while neglecting the application of medium and trace element fertilizers, resulting in a continuous decline in the quality of citrus trees and fruits. Due to unbalanced citrus fertilization, a lack of medium and trace elements has occurred overall, leading to a decrease in fruit sugar and an increase in acidity and a deterioration in color, affecting the flavor and nutritional quality of the fruits. Therefore, it is necessary to supplement foliar fertilizers to promote sugar increase and coloring of citrus and improve the comprehensive quality of fruits.

[0004] Peel puffiness is a physiological disease with a relatively high incidence in the late maturity stage of citrus, and often occurs in loose-skinned citrus such as Satsuma mandarin, Ponkan, and Satsuma. Citrus peel puffiness refers to the phenomenon that the spongy layer collapses loosely and the peel and pulp are separated to produce voids, and it is characterized by thick-skinned large fruits, low sugar and acid content, and weak flavor. In the areas where the postharvest ripening cultivation technology has been promoted in Zhejiang Province, the incidence of peel-puffed fruits of Satsuma mandarin is as high as 30%-40%, seriously hindering the development of the citrus industry. At the same time, a lack of calcium and boron during the fruit expansion period of citrus is likely to induce fruit peel puffiness. Therefore, it is necessary to supplement foliar fertilizers to provide the mineral nutrients lacking in the tree body and inhibit the occurrence of peel puffiness in citrus fruits during the postharvest ripening period.

[0005] Regarding the decline in fruit sugar content and color and the peel puffiness phenomenon during the postharvest ripening period in the process of citrus cultivation, the foliar fertilizers reported currently can only have a certain influence on promoting sugar increase and coloring of fruits or inhibiting peel puffiness, and there is no foliar fertilizer that can simultaneously solve the problems of fruit sugar reduction, color fading, and peel puffiness. Therefore, it is necessary to develop a foliar fertilizer that can improve the quality of citrus and contribute to postharvest ripening cultivation, so as to improve the comprehensive quality of fruits, avoid the peak listing period at the same time, and thus improve the market economic benefits. Summary of the Invention

[0006] The present invention is to solve the above problems and provides a foliar fertilizer for promoting sugar increase and coloring of citrus fruits and inhibiting peel puffiness.

[0007] In order to achieve the above purpose, the technical solution adopted is:

[0008] A foliar fertilizer for promoting sugar increase and coloration of citrus fruits and inhibiting peel floating, comprising the following components in the following concentrations: 5.2-6.4 g / L of medium and trace element fertilizers, 1-3 mg / L of 5-aminolevulinic acid, and 0.05-0.07 mg / L of coronatine.

[0009] The medium and trace element fertilizer comprises sugar alcohol calcium, magnesium sulfate, boric acid, selenomethionine and sodium molybdate. The medium and trace element fertilizer is configured with the following concentrations: 0.8-1.2 g / L sugar alcohol calcium, 2.8-3.2 g / L magnesium sulfate, 1.2-1.8 g / L boric acid, 0.12-0.18 g / L selenomethionine, and 0.12-0.18 g / L sodium molybdate.

[0010] Preferably, the foliar fertilizer is composed of components with the following concentrations: 1 g / L calcium sulfoxide, 3 g / L magnesium sulfate, 1.5 g / L boric acid, 0.15 g / L selenomethionine, 0.15 g / L sodium molybdate, 2 mg / L 5-aminolevulinic acid, and 0.06 mg / L coronatine.

[0011] When preparing the foliar fertilizer, the medium and trace element fertilizer is first dissolved in water, and then 5-aminolevulinic acid and coronatine are added in sequence, and after being fully mixed, the foliar fertilizer is obtained.

[0012] Another object of the present invention is to provide the use of any of the above-mentioned foliar fertilizers in promoting sugar and coloring of citrus fruits and inhibiting peeling, so as to achieve the purpose of high-quality fruit production and staggered harvesting of citrus.

[0013] The method for spraying the foliar fertilizer is as follows: after the citrus enters the fruit expansion period, the foliar fertilizer is sprayed on the whole tree, once every 15 to 20 days, and a total of 3 to 4 times; the citrus species is Wenzhou mandarin orange, ponkan orange or satsuma orange.

[0014] Preferably, when spraying the foliar fertilizer on citrus trees, it is evenly sprayed on the leaves and fruit surfaces until the leaves drip water.

[0015] The present invention has the following beneficial effects: The foliar fertilizer provided by the present invention, by compounding medium and trace element fertilizers and plant growth regulators, is sprayed on the whole plant during the fruit expansion period of citrus, and has a synergistic effect in promoting fruit sugar increase and coloring and inhibiting puffy peel. 5-aminolevulinic acid and coronatine promote sugar accumulation and early coloring of citrus fruits by improving leaf photosynthesis and activating the jasmonic acid signaling pathway respectively; while medium and trace element fertilizers can provide the mineral nutrients lacking in the tree body and inhibit the occurrence of puffy peel in citrus fruits during the ripening period. Each component of the foliar fertilizer of the present invention has a synergistic function, can significantly increase the soluble solids and soluble sugar contents of citrus fruits, promote early fruit color conversion and increase the peel color index, reduce the occurrence of puffy peel fruits during the full-ripening cultivation period, so as to achieve early or delayed harvesting of citrus, stagger the peak period of citrus market, and greatly improve economic benefits. Brief Description of the Drawings

[0016] Figure 1 Shows the effects of the foliar fertilizer on the peel coloring and puffy peel of Satsuma mandarin.

[0017] Figure 2 Shows the effects of the foliar fertilizer on the sugar accumulation of Satsuma mandarin fruits. The standard deviation was calculated from 3 biological replicates, and different lowercase letters indicate significant differences between different treatments at the same stage (P<0.05); Figure A shows the effect of the foliar fertilizer on the soluble solids content of Satsuma mandarin fruits; Figure B shows the effect of the foliar fertilizer on the soluble sugar content of Satsuma mandarin fruits.

[0018] Figure 3 Shows the effects of the foliar fertilizer on the color change of the peel of Satsuma mandarin. The standard deviation was calculated from 3 biological replicates, and different lowercase letters indicate significant differences between different treatments at the same stage (P<0.05); Figure A shows the effect of the foliar fertilizer on the citrus color index CCI of the peel of Satsuma mandarin; Figure B shows the effect of the foliar fertilizer on the brightness L* of the peel of Satsuma mandarin; Figure C shows the effect of the foliar fertilizer on the red-green color a* of the peel of Satsuma mandarin; Figure D shows the effect of the foliar fertilizer on the yellow-blue color b* of the peel of Satsuma mandarin.

[0019] Figure 4 Shows the effects of the foliar fertilizer on the changes in the physical indexes of puffy peel of Satsuma mandarin fruits. The standard deviation was calculated from 3 biological replicates, and different lowercase letters indicate significant differences between different treatments at the same stage (P<0.05); Figure A shows the effect of the foliar fertilizer on the peel thickness of Satsuma mandarin; Figure B shows the effect of the foliar fertilizer on the single fruit weight of Satsuma mandarin; Figure C shows the effect of the foliar fertilizer on the transverse diameter of Satsuma mandarin; Figure D shows the effect of the foliar fertilizer on the longitudinal diameter of Satsuma mandarin. Detailed Embodiments

[0020] In order to make the technical solutions and advantages of the present invention clearer, the present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments that can be obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0021] The main reagents of the embodiments of the present invention are as follows:

[0022] Sugar alcohol calcium: Ca content ≥180g / L, complex sugar alcohol ≥100g / L, using chelation technology to promote effective absorption of foliar calcium fertilizer, produced by Qingdao Danluofeng Biotechnology Co., Ltd.

[0023] Magnesium sulfate heptahydrate (MgSO 4 7H 2 O): white solid, purity ≥99%, CAS No. 10034-99-8.

[0024] Boric acid (H 3 BO 3 ): White solid, purity ≥99.5%, CAS No. 10043-35-3.

[0025] Selenomethionine: white powder, purity 98%, CAS number 3211-76-5.

[0026] Sodium molybdate (Na 2 MoO 4 ): White powder, purity ≥99%, CAS No. 7631-95-0.

[0027] 5-Aminolevulinic acid (ALA): Contains 5% active ingredient, produced by Caozhou Agricultural Chemical Co., Ltd.

[0028] Coronatine (COR): Contains 0.006% active ingredient and is produced by Chengdu Xinchaoyang Crop Science Co., Ltd.

[0029] Example 1

[0030] 1. Prepare citrus foliar compound fertilizer

[0031] According to the foliar fertilizer formula in Table 1, water is used as a solvent, and medium and trace element fertilizers (sugar alcohol calcium, magnesium sulfate, boric acid, selenomethionine, sodium molybdate) are added in proportion, stirred evenly until the powder is completely dissolved, and then plant growth regulators (5-aminolevulinic acid and coronatine) are added in sequence, and the foliar fertilizer solution is obtained after sufficient mixing. The content of each component in Table 1 represents the final concentration when the citrus foliar fertilizer is sprayed.

[0032] Table 1 Citrus foliar fertilizer formula

[0033] II. Application of Foliar Fertilizer on Satsuma Mandarin Trees

[0034] 1. Test Materials and Location: In this experiment, 10-year-old 'Miyagawa' satsuma mandarin trees were selected as test materials. The test location was the citrus mountain test base in Sanmen County, Taizhou City, Zhejiang Province. Compared with the characteristic brand Yongquan tangerines in neighboring Linhai City, the sugar content and other flavor qualities of citrus in this production area were relatively low. Therefore, Sanmen County was chosen as the test base to improve the comprehensive quality of satsuma mandarin fruits in this production area.

[0035] 2. Treatments and Fertilization Techniques: Four treatment groups were set up in this experiment, including T1, T2, T3, and CK. Six trees were selected for each treatment, and the growth vigor and fruit-bearing numbers of different satsuma mandarin trees were roughly the same, without any adverse symptoms such as pests and diseases. During the fruit expansion period of citrus (from July 30th to September 30th), foliar fertilizer was used to spray the whole plant, spraying once every 15 - 20 days, for a total of 3 - 4 times. The spraying time was from 7 to 10 am. When using, spray both the front and back sides of the leaves and the fruit surface evenly, and spray until water drips from the leaf surface and the fruit surface.

[0036] 3. Detection of Fruit Quality Indicators: Fruits were collected at the late color change stage (October 20th), maturity stage (November 10th), and full maturity stage (November 30th) of citrus fruits. Eight fruits were collected from each tree, and a total of 48 fruits were collected for each treatment. The collected fruit samples were immediately transported back to the laboratory, and the fruit quality indicators were measured and photographed on the same day. The pulp samples were stored in a -20°C refrigerator for subsequent determination of related physiological indicators.

[0037] The soluble solids content of citrus fruits was measured using a portable digital refractometer PR101α, and the soluble sugar content in the pulp was determined by the anthrone colorimetric method.

[0038] The color of citrus peel (L*, a*, b*) was measured using a Mini Scan XE Plus colorimeter. Twelve fruits were used for each treatment, divided into 3 biological replicates. The L* value represents the brightness of the peel, and the larger the value, the brighter the peel; the a* value represents the red-green color of the peel, with positive values for red and negative values for green; the b* value represents the yellow-blue degree of the peel, with positive values for yellow and negative values for blue.

[0039] The calculation formula for the citrus color index is CCI = 1000 × a* / (L* × b*). The CCI value represents the coloring degree of citrus fruits. Positive values indicate red-orange, negative values indicate blue-green, and the larger the value, the more the color tends to red-yellow, which can be used to judge the coloring situation of citrus peel and the fruit maturity.

[0040] The single fruit weight was measured using a one-percent balance, and the peel thickness, fruit transverse diameter, and longitudinal diameter were measured using a vernier caliper.

[0041] III. Test Results and Analysis

[0042] The test results are shown in Table 2-11. The values in the table represent the mean ± standard error of 3 biological replicates. Different lowercase letters in the chart indicate significant differences between different treatments at the same stage (P<0.05).

[0043] 1. As can be seen from Figure 1 , the foliar compound fertilizers of the present invention can all effectively promote the early color change of the peel of Satsuma mandarin, and the fruits after foliar fertilizer treatment have brighter and fuller colors during the entire mature picking period (November). Among them, the foliar fertilizer T3 has the most obvious effect on promoting peel color change, harvesting the fruits 15 - 20 days earlier than the control group, and presenting a plump orange - red color after maturity, greatly improving the commercial value.

[0044] 2. As can be seen from Table 2-3 Figure 2 , the foliar fertilizers of the present invention have all effectively increased the soluble solids content and soluble sugar content of Satsuma mandarin fruits. Among them, the foliar fertilizer T3 has the most obvious effect on promoting sugar increase in citrus fruits. At the mature picking stage (October 10th), compared with the control group, the soluble solids of citrus fruits treated with T3 increased by 14.25%, and the soluble sugar increased by 22.43%. Moreover, compared with the single use of foliar fertilizers T1 and T2, the sugar - increasing effect of T3 treatment is better, indicating that the mixed use of medium and trace elements and plant growth regulators has a synergistic effect in promoting fruit sugar increase.

[0045] Table 2 Soluble Solids Content of Citrus Fruits (unit: °Brix) Date CK T1 T2 T3 October 20th 10.07±0.20c 10.93±0.23b 10.62±0.14bc 11.53±0.12a November 10th 10.53±0.15b 11.67±0.09a 11.60±0.21a 12.03±0.09a November 30th 11.07±0.20b 11.77±0.35ab 11.90±0.10ab 12.67±0.35a

[0046] Table 3 Soluble Sugar Content of Citrus Fruits (unit: %) Date CK T1 T2 T3 October 20th 12.08±0.74b 14.80±0.75a 14.01±0.52ab 14.16±0.63ab November 10th 13.60±0.36b 15.95±0.48a 15.60±0.33a 16.65±0.50a November 30th 13.98±0.26b 15.31±0.23ab 14.38±0.43b 16.26±0.58a

[0047] 3. As can be seen from Table 4-7 Figure 3 , the foliar fertilizers of the present invention all have the effect of improving the color of the peel of Satsuma mandarin. At the fruit color - changing stage (October 20th), each treatment significantly increased the brightness of the citrus peel and promoted the fruit to fade green and turn yellow; during the entire maturity period of the fruit, each treatment improved the orange - red color of the peel, making the fruit more commercially valuable. Among them, the foliar fertilizer T3 has the most obvious effect on promoting citrus coloring. Compared with the control group, the CCI value of the peel increased by 37.77%, and the red - green color index a* increased by 23.52%. Moreover, the foliar fertilizer T3 is better than the treatments of T1 and T2, indicating that the mixed use of medium and trace elements and plant growth regulators has a synergistic effect in promoting peel coloring.

[0048] Table 4 Color Index CCI of Citrus Peel

[0049] Table 5 Brightness L* of Citrus Peel Date CK T1 T2 T3 October 20th 53.54±0.41d 58.05±0.40b 56.24±0.58c 60.03±0.31a November 10th 60.61±0.13a 59.90±0.41a 60.67±0.25a 58.02±0.19b November 30th 58.96±0.53a 58.91±0.35a 58.34±0.46ab 56.90±0.72b

[0040] Table 6 Red-Green Color Index a* of Citrus Peel Date CK T1 T2 T3 October 20th -3.34±0.56c 6.23±1.71b 2.32±1.07b 15.52±1.55a November 10th 16.40±0.86c 23.62±0.88b 21.40±1.05b 28.54±0.60a November 30th 24.79±1.04c 27.37±0.72b 28.22±0.22b 30.62±0.65a

[0041] Table 7 Yellow-Blue Color Index b* of Citrus Peel Date CK T1 T2 T3 October 20th 52.04±0.28c 62.54±1.26a 57.74±1.24b 65.46±1.30a November 10th 67.30±0.30bc 69.39±0.58a 68.95±1.00ab 65.94±0.22c November 30th 65.61±1.02a 63.48±0.26ab 63.07±0.63ab 61.13±1.11b

[0042] 4. From Figure 1 、 Figure 4 、Tables 8 - 11, it can be seen that the foliar fertilizer of the present invention can effectively inhibit the formation of puffy fruits during the full-ripening period (November 30th) of Satsuma mandarin, and among them, the foliar fertilizer T3 has the best inhibitory effect. When Satsuma mandarin enters the late mature stage, the fruits in the CK group show puffy symptoms, manifested as loose white sponge layer, larger and separated central column, and gaps between the peel and the pulp. While the foliar fertilizer T3 can significantly inhibit the puffy occurrence of citrus during the full-ripening cultivation period. Compared with the control group, the peel thickness is reduced by 21.64%, the single fruit weight is inhibited by 32.37%, the transverse diameter is reduced by 16.01%, and the longitudinal diameter is reduced by 21.61%. Since the medium and small fruits of Satsuma mandarin are regarded as high-quality fruits, the selling price of fruits with a diameter of 50 - 65 mm is significantly higher than that of fruits with a diameter of 65 - 75 mm. Therefore, the foliar fertilizer of the present invention improves the economic value of fruits by inhibiting the continuous growth and puffy occurrence of citrus during the full-ripening period.

[0043] Table 8 Citrus Peel Thickness (Unit: mm) Date CK T1 T2 T3 October 20th 2.30±0.14b 2.74±0.13a 2.34±0.09b 2.75±0.04a November 10th 2.99±0.29a 2.40±0.07b 2.31±0.05b 2.34±0.02b November 30th 3.42±0.21a 3.09±0.05ab 3.05±0.15ab 2.68±0.20b

[0044] Table 9 Single Fruit Weight of Citrus (Unit: g) Date CK T1 T2 T3 October 20th 105.94±8.20a 114.71±9.98a 101.27±1.34a 101.23±9.63a November 10th 130.84±1.32a 116.00±5.14b 125.50±0.39ab 105.41±3.69c November 30th 149.86±2.65a 130.21±10.97a 128.56±2.89a 101.34±5.61b

[0045] Table 10 Transverse Diameter of Citrus Fruit (Unit: mm) Date CK T1 T2 T3 October 20th 62.96±1.98a 66.44±2.48a 60.71±0.25a 63.73±2.36a November 10th 66.53±0.24a 66.03±0.92a 66.40±0.30a 63.58±1.05b November 30th 75.25±3.78a 69.22±4.46ab 68.01±0.53ab 63.20±1.94b

[0046] Table 11 Longitudinal Diameter of Citrus Fruit (Unit: mm) Date CK T1 T2 T3 October 20th 52.23±2.29a 52.34±1.40a 50.01±0.28a 50.87±1.50a November 10th 54.19±0.14a 54.28±0.43a 54.43±0.94a 51.83±0.27b November 30th 61.65±4.78a 56.79±3.82ab 56.06±0.25ab 48.33±1.48b

[0047] 5. Conclusion: The above test results show that the foliar fertilizer T3 of the present invention can significantly increase the soluble solids and soluble sugar contents of Satsuma mandarin fruits, increase the color index of fruits during the maturity period, and at the same time inhibit the occurrence of puffy fruits in the late mature stage of citrus. Therefore, the use of foliar fertilizer T3 can not only promote sugar accumulation and coloring of citrus fruits, but also inhibit the puffy symptoms of citrus during the post-harvest cultivation period, ultimately improving the comprehensive quality of fruits. At the same time, the effect of foliar fertilizer T3 is better than that of treatments T1 and T2, indicating that the medium and trace nutrient elements and plant growth regulators of the present invention have a synergistic effect, and their application in production has the effects of promoting sugar accumulation and coloring of citrus and inhibiting the occurrence of puffiness, and can advance or delay the harvest by 15 - 20 days, avoiding the peak period of concentrated listing of citrus, thus greatly improving the economic benefits.

Claims

1. A foliar fertilizer for promoting sugar and coloring of citrus fruits and inhibiting peeling, characterized in that: The invention is composed of the following components in the following concentrations: 5.2-6.4 g / L medium and trace element fertilizer, 1-3 mg / L 5-aminolevulinic acid, and 0.05-0.07 mg / L coronatine.

2. Foliar fertilizer according to claim 1, characterized in that, The medium and trace element fertilizer comprises calcium saccharide, magnesium sulfate, boric acid, selenomethionine and sodium molybdate.

3. Foliar fertilizer according to claim 2, is characterized in that, The medium and trace element fertilizer is prepared from components with the following concentrations: 0.8-1.2 g / L sugar alcohol calcium, 2.8-3.2 g / L magnesium sulfate, 1.2-1.8 g / L boric acid, 0.12-0.18 g / L selenomethionine, and 0.12-0.18 g / L sodium molybdate.

4. Foliar fertilizer according to claim 1, characterized in that, During the preparation, the medium and trace element fertilizer is first dissolved in water, and then 5-aminolevulinic acid and coronatine are added in sequence, and after being fully mixed, the foliar fertilizer is obtained.

5. Use of the foliar fertilizer according to claim 1 in promoting sugar increase and coloration of citrus fruits and inhibiting peeling.

6. The use according to claim 5, characterized in that: The method for spraying the foliar fertilizer is as follows: when the citrus enters the fruit expansion period, the whole tree is sprayed, sprayed once every 15 to 20 days, and sprayed 3 to 4 times in total.

7. The use according to claim 5, characterized in that: When spraying the foliar fertilizer on citrus trees, the foliar fertilizer is evenly sprayed on the front and back sides of the leaves and the fruit surfaces until water drips from the leaf surfaces and the fruit surfaces.

Images