A method for increasing the β-cryptoxanthin content in mandarin oranges using artificial lighting.

Abstract

This invention belongs to the field of citrus cultivation technology, specifically relating to a method for increasing the β-cryptoxanthin content in mandarin oranges through artificial lighting. This invention involves applying specific wavelengths of artificial lighting to fully mature mandarin orange trees, including Satsuma mandarins, during the period from late September (Autumn Equinox) to the harvest season when natural daylight hours are shorter. This effectively increases the β-cryptoxanthin content in mandarin oranges. Furthermore, the method described in this invention is simple, easy to implement, low-cost, and suitable for widespread application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of citrus cultivation, and particularly relates to a method for increasing the content of β-cryptoxanthin in wide-skinned citrus by artificial light supplement. BACKGROUND

[0002] β-cryptoxanthin belongs to a kind of carotenoids, and is also the most abundant carotenoid in citrus fruits. Carotenoids are a class of natural pigments that play an important role in human health. They are not only precursors of vitamin A, but also can scavenge free radicals in the body, improve immunity, prevent cardiovascular disease, and have anticancer effects. Vitamin A is an essential micronutrient for the human body, which can promote growth, maintain bone, epithelial tissue, vision and normal secretion of mucosal epithelium, and many other physiological functions. At present, α-carotene, β-carotene and β-cryptoxanthin are considered to be the most important vitamin A in animals. At the same time, existing research shows that the main carotenoids with anticancer activity are α-carotene, β-carotene, β-cryptoxanthin, etc. However, medical research shows that the anticancer ability of β-cryptoxanthin is about 5 times that of β-carotene, and has obvious anticancer effect. In addition, some existing research shows that increasing the intake of β-cryptoxanthin during pregnancy can reduce the risk of anxiety in pregnant women, and can enhance the cognitive and receptive language abilities of infants in the future. Therefore, increasing the intake of β-cryptoxanthin is of great benefit to human health.

[0003] Citrus is one of the fruits with the highest content of carotenoids, and is an important source of carotenoids. The main carotenoid accumulated in the flesh of wide-skinned citrus is β-cryptoxanthin, and its content is significantly higher than that of sweet orange, sour orange, grapefruit, lemon and other citrus varieties. Wenzhou mandarin is the most widely cultivated wide-skinned citrus variety in the world, and is also one of the largest wide-skinned citrus varieties cultivated in China at present. Its flesh contains rich carotenoids, mainly including β-cryptoxanthin, zeaxanthin, violaxanthin, antheraxanthin, lutein and β-carotene, especially β-cryptoxanthin, which accounts for more than 43% of the total carotenoid content. Therefore, Wenzhou mandarin is a very good source of β-cryptoxanthin. Since Wenzhou mandarin has a large consumption, if the natural β-cryptoxanthin content in the flesh can be further increased through cultivation techniques, it will not only benefit people's health, but also bring higher economic benefits to agricultural production.

[0004] In order to further improve the quality of Wenzhou mandarin, improve the nutritional value of the fruit, and increase economic benefits, facilities are used to delay the harvest period of the fruit and produce high-quality Wenzhou mandarin through complete maturation cultivation technology. However, there is no method for increasing the content of β-cryptoxanthin in citrus through cultivation techniques at present. SUMMARY

[0005] The present application aims to provide a method for increasing the content of beta-cryptoxanthin in broad-skinned citrus by artificial light supplement, which can significantly increase the content of beta-cryptoxanthin in the flesh of broad-skinned citrus including Wenzhou Citrus.

[0006] The present application provides a method for increasing the content of beta-cryptoxanthin in broad-skinned citrus by artificial light supplement, which comprises the following steps: from the end of September to the harvest period every year, using light supplement lamps to perform artificial light supplement treatment on the broad-skinned citrus trees, wherein the light supplement lamps comprise combination light supplement lamps or white light supplement lamps.

[0007] The combination light supplement lamps comprise red light and / or blue light, wherein the wavelength of the red light is 605-700 nm, the wavelength of the blue light is 435-480 nm, and the ratio of the light quantum flux density of the red light to the blue light is (0-4):(0-4).

[0008] The light quantum flux density of the light supplement lamps at a position 50 cm below the lamps is 130-510 μmol·m -2 ·s -1 .

[0009] Preferably, the time of the artificial light supplement treatment is 4-6 h / day.

[0010] Preferably, from the end of September to the beginning of November every year, the time of the artificial light supplement treatment is 4 h / day, and from the beginning of November to the harvest period every year, the time of the artificial light supplement treatment is 6 h / day.

[0011] Preferably, from September 22 to September 24 and from November 7 to November 8 every year, the broad-skinned citrus trees are supplemented with light for 2 h before sunrise and after sunset, respectively, and from November 7 to November 8 and from the harvest period every year, the broad-skinned citrus trees are supplemented with light for 3 h before sunrise and after sunset, respectively.

[0012] Preferably, the light source of the light supplement lamps is a light-emitting diode.

[0013] Preferably, when performing artificial light supplement treatment on the broad-skinned citrus trees, the light supplement lamps are hung to a position 50 cm above the top of the crown of the broad-skinned citrus trees, and a white light-reflecting film is laid on the ground of the broad-skinned citrus.

[0014] Preferably, the broad-skinned citrus trees comprise broad-skinned citrus trees with natural open heart-shaped trees.

[0015] Preferably, the broad-skinned citrus comprises Wenzhou Citrus.

[0016] Preferably, the method for increasing the content of beta-cryptoxanthin in broad-skinned citrus comprises a method for increasing the content of beta-cryptoxanthin in the fruit of broad-skinned citrus.

[0017] Beneficial effects:

[0018] The application provides a method for increasing the content of beta-cryptoxanthin in wide-skinned citrus by artificial light supplementing, comprising the following steps: performing artificial light supplementing treatment on wide-skinned citrus trees in facility complete maturation cultivation by using a light supplementing lamp from late September to the harvesting period every year, wherein the light supplementing lamp comprises a combination light supplementing lamp or a white light supplementing lamp; the combination light supplementing lamp comprises red light and / or blue light, the wavelength of the red light is 605-700 nm, the wavelength of the blue light is 435-480 nm, and the ratio of the light quantum flux density of the red light to that of the blue light is (0-4):(0-4); and the light quantum flux density of the light supplementing lamp at a position 50 cm below the lamp is 130-510 μmol·m -2 ·s -1 The application can effectively increase the content of beta-cryptoxanthin in wide-skinned citrus by performing light supplementing treatment on wide-skinned citrus trees in facility complete maturation cultivation including Wenzhou citrus under the condition that the natural sunshine time is shortened from late September (Autumn Equinox) to the harvesting period every year, and the method is simple, low in cost and suitable for promotion. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed in the embodiments.

[0020] Figure 1 The different letters in the content of carotenoids and the content of beta-cryptoxanthin in Wenzhou citrus fruits in Examples 1-7 represent significant differences (P<0.05) compared with the control. DETAILED DESCRIPTION

[0021] The application provides a method for increasing the content of beta-cryptoxanthin in wide-skinned citrus by artificial light supplementing, comprising the following steps: performing artificial light supplementing treatment on wide-skinned citrus trees in facility complete maturation cultivation by using a light supplementing lamp from late September to the harvesting period every year, wherein the light supplementing lamp comprises a combination light supplementing lamp or a white light supplementing lamp:

[0022] The combination light supplementing lamp comprises red light and / or blue light, the wavelength of the red light is 605-700 nm, the wavelength of the blue light is 435-480 nm, and the ratio of the light quantum flux density of the red light to that of the blue light is (0-4):(0-4);

[0023] The light quantum flux density of the light supplementing lamp at a position 50 cm below the lamp is 130-510 μmol·m -2 ·s -1 .

[0024] As an embodiment, the wide-skinned citrus fruit of the present application includes, but is not limited to, Citrus unshiu Marc. As an embodiment, the method for increasing the content of β-cryptoxanthin in the wide-skinned citrus fruit includes increasing the content of β-cryptoxanthin in the fruit of the wide-skinned citrus fruit; as another embodiment, the method for increasing the content of β-cryptoxanthin in the wide-skinned citrus fruit includes increasing the content of β-cryptoxanthin in the pulp of the wide-skinned citrus fruit.

[0025] As an embodiment, the light supplementing treatment of the present application is performed for 4-6 hours per day; as another embodiment, the light supplementing treatment of the present application is performed for 4 hours per day from the end of September to the beginning of November, and for 6 hours per day from the beginning of November to the harvest period; as another embodiment, the light supplementing treatment of the present application is performed for 2 hours before sunrise and after sunset from September 22 to September 24 and from November 7 to November 8, and for 3 hours before sunrise and after sunset from November 7 to November 8 to the harvest period; as another embodiment, the light supplementing treatment of the present application is performed for 2 hours before sunrise and after sunset from the autumnal equinox to the first day of winter, and for 3 hours before sunrise and after sunset from the first day of winter to the harvest period. The reason why the light supplementing treatment of the present application is performed for different time lengths before and after the autumnal equinox and the first day of winter is that the sunlight time is less than 12 hours from the beginning of the autumnal equinox, and gradually less than 10 hours before and after the first day of winter. By adjusting the time length of the light supplementing treatment, the wide-skinned citrus fruit can be ensured to receive sufficient light for a sufficient time and intensity, thereby increasing the content of β-cryptoxanthin in the wide-skinned citrus fruit.

[0026] As an embodiment, the light source of the light supplementing lamp is a light-emitting diode. The combination light supplementing lamp of the present application can be in the form of red light, blue light, or a combination of red light and blue light; as an embodiment, the wavelength peak of the red light can be 660 nm; the wavelength peak of the blue light can be 450 nm; as an embodiment, the ratio of the light quantum flux density of the red light to the blue light can be (1-4):(1-4); as another embodiment, the ratio of the light quantum flux density of the red light to the blue light can be 1:4 or 4:1. As an embodiment, when the light supplementing lamp is a combination light supplementing lamp, the light quantum flux density of the light supplementing lamp at a position 50 cm below the lamp can be 130-170 μmol·m -2 ·s -1 .

[0027] As an embodiment, when the light supplementing lamp is white light, the light quantum flux density of the light supplementing lamp at a position 50 cm below the lamp can be 350-510 μmol·m -2 ·s -1As an implementation form, the light supplementing lamp has a light quantum flux density of 350 pmol m -2 ·s -1 .

[0028] As an implementation form, when the wide-skinned citrus trees are subjected to artificial light supplementing treatment, the light supplementing lamp is hung 50 cm above the top of the crown of the wide-skinned citrus tree, and a white light-reflecting film is laid on the ground of the wide-skinned citrus tree. As another implementation form, the white light-reflecting film is made of high-density polyethylene fiber. As an implementation form, the wide-skinned citrus tree can be, but is not limited to, a wide-skinned citrus tree with a natural open heart-shaped tree shape. The natural open heart-shaped tree shape provided in the present application can ensure that 10%-20% of the light above the light supplementing lamp can directly reach the bottom of the tree disc, i.e., the light spot area directly reaching the bottom of the tree disc through the leaf gaps accounts for 10%-20% of the entire tree shadow area.

[0029] In order to further illustrate the present application, the technical solutions provided by the present application are described in detail below in combination with the drawings and examples, but they should not be understood as limiting the scope of protection of the present application.

[0030] Example 1

[0031] A method for increasing the content of β-cryptoxanthin in citrus fruits of Citrus unshiu Marc. by light supplementing, comprising the following steps:

[0032] The light supplementing test was carried out in a citrus orchard of Citrus unshiu Marc. subjected to facility complete maturation cultivation in Xingan County, Ji'an City, Jiangxi Province. The light supplementing lamp was hung at a position 50 cm away from the top of the crown, one for each tree. The ground was covered with a white light-reflecting film made of high-density polyethylene fiber for reflecting the light irradiated to the ground. At the same time, the tree shape was pruned to a natural open heart shape, and 15% of the light above could directly reach the bottom of the tree disc.

[0033] The light supplementing lamp was an LED light supplementing lamp with full red light and a wavelength peak value of 660 nm. The light quantum flux density at a position 50 cm away from the lamp was 130 pmol m -2 ·s -1 .

[0034] The light supplementing started on September 23, 2023, the autumnal equinox. The light supplementing time was 2 hours before sunrise and 2 hours after sunset, a total of 4 hours per day. On November 8, 2023, after the beginning of winter, the light supplementing time was adjusted to 3 hours before sunrise and 3 hours after sunset, a total of 6 hours per day, until the completion of fruit harvesting.

[0035] Example 2

[0036] A method for increasing the content of β-cryptoxanthin in citrus fruits of Citrus unshiu Marc. by light supplementing, comprising the following steps:

[0037] The light supplementing method in Example 1 was used for light supplementing of Citrus unshiu, the only difference being that the light supplementing lamp was set differently: the light supplementing lamp was a LED light supplementing lamp, full blue light, with a wavelength peak of 450 nm, and the red light quantum flux density at a position 50 cm below the lamp was 65 μmol·m -2 ·s -1 .

[0038] Example 3

[0039] A method for increasing the content of β-cryptoxanthin in Citrus unshiu fruit by light supplementing, the steps being as follows:

[0040] The light supplementing method in Example 1 was used for light supplementing of Citrus unshiu, the only difference being that the light supplementing lamp was set differently: the light supplementing lamp was a LED light supplementing lamp, full blue light, with a wavelength peak of 450 nm, and the red light quantum flux density at a position 50 cm below the lamp was 65 μmol·m -2 ·s -1 , and the blue light quantum flux density was also 65 μmol·m -2 ·s -1 .

[0041] Example 4

[0042] A method for increasing the content of β-cryptoxanthin in Citrus unshiu fruit by light supplementing, the steps being as follows:

[0043] The light supplementing method in Example 1 was used for light supplementing of Citrus unshiu, the only difference being that the light supplementing lamp was set differently: the light supplementing lamp was a LED light supplementing lamp, full blue light, with a wavelength peak of 450 nm, and the red light quantum flux density at a position 50 cm below the lamp was 65 μmol·m -2 ·s -1 , and the blue light quantum flux density was also 65 μmol·m -2 ·s -1 .

[0044] Example 5

[0045] A method for increasing the content of β-cryptoxanthin in Citrus unshiu fruit by light supplementing, the steps being as follows:

[0046] The light supplementing method in Example 1 was used for light supplementing of Citrus unshiu, the only difference being that the light supplementing lamp was set differently: the light supplementing lamp was a LED light supplementing lamp, full blue light, with a wavelength peak of 450 nm, and the red light quantum flux density at a position 50 cm below the lamp was 65 μmol·m -2 ·s -1 , and the blue light quantum flux density was also 65 μmol·m -2·s -1 .

[0047] Example 6

[0048] A method for increasing the content of β-cryptoxanthin in citrus fruit by light supplementing, comprising the following steps:

[0049] The citrus fruits are light supplemented by the light supplementing method in Example 1, with the only difference being that the light supplementing lamp is set differently: the light supplementing lamp is a LED light supplementing lamp, full white light, and the red light quantum flux density at a position 50 cm away from the lamp is 350 μmol·m -2 ·s -1 .

[0050] Example 7

[0051] A method for increasing the content of β-cryptoxanthin in citrus fruit by light supplementing, comprising the following steps:

[0052] The citrus fruits are light supplemented by the light supplementing method in Example 1, with the only difference being that the light supplementing lamp is set differently: the light supplementing lamp is a LED light supplementing lamp, full white light, and the red light quantum flux density at a position 50 cm away from the lamp is 510 μmol·m -2 ·s -1 .

[0053] Test Example 1

[0054] The light supplementing in Examples 1-7 is ended when the citrus fruits are harvested and put on the market, and the total carotenoid content and the content of β-cryptoxanthin in the fruit pulp are analyzed after the fruits are harvested, with the citrus fruits not treated by light supplementing and not covered by white light-reflecting films made of high-density polyethylene fibers serving as a control. When sampling, 3 branches are selected, and at least 5 fruits on each branch are selected as one biological repeat, with a total of 3 repeats.

[0055] The total carotenoid content in the fruit pulp is determined by the following method:

[0056] 1) About 0.5 g of fresh citrus fruit pulp is taken and cut and mixed.

[0057] 2) The cut and mixed sample is placed in a 10 mL centrifuge tube, 8 mL of acetone solution with a volume concentration of 80% is added, and the sample is extracted at room temperature for 48 h in the dark to obtain an extraction solution.

[0058] 3) The extraction solution is centrifuged at 1000 rpm for 10 min, and then the supernatant is poured out and diluted to 10 mL with acetone solution with a volume concentration of 80%, and shaken to obtain a carotenoid extraction solution.

[0059] 4) Carotenoid extract solution was added into 1 cm light path cuvette, and the absorbance was measured at wavelength 663 nm, 646 nm and 470 nm with 80% volume concentration of acetone solution as blank control.

[0060] The calculation method of carotenoid content in pulp is as follows:

[0061] C a = 12.21A 663 - 2.81A 646

[0062] C b = 20.13A 646 - 5.03A 663

[0063]

[0064] In the above formula, Ca and Cb are the concentrations of chlorophyll a and chlorophyll b in the extract solution (μg / mL), respectively; A 663 , A 646 and A 470 are the absorbances of the extract solution at wavelength 663 nm, 646 nm and 470 nm, respectively, and W is the sample weight (g).

[0065] The determination method of β-cryptoxanthin content in pulp is as follows:

[0066] 1) 5 g of Citrus unshiu pulp was weighed into a 50 mL centrifuge tube, 15 mL of carotenoid extraction solution was added, and vortexed to mix.

[0067] 2) After 6 min of vigorous shaking by a sample grinder, centrifugation was performed at 4000 g for 10 min, and the supernatant was transferred to another 50 mL centrifuge tube. The precipitate was extracted twice with 15 mL of carotenoid extraction solution until colorless (total of three times, and the supernatant was transferred to the same centrifuge tube).

[0068] 3) The supernatant was combined, and the supernatant was repeatedly washed with saturated NaCl (10%) aqueous solution in a 50 mL separatory funnel until neutral, and the lower layer (water layer) was discarded.

[0069] 4) The supernatant was transferred to 10 mL centrifuge tubes in batches, and vacuum concentrated to dryness. After vacuum concentration, 2 mL of MTBE (containing 0.1‰ BHT) was used for dissolution, and 2 mL of 10% KOH-methanol solution (containing 0.1‰ BHT) was added, and saponification was performed for 10 h under light shielding conditions.

[0070] 5) 4 mL of saturated NaCl aqueous solution and 2 mL of MTBE (containing 0.1‰ BHT) were added to better separate the layers, and the water layer was removed with a rubber suction tube, and 3 times of 5 mL of saturated NaCl aqueous solution was added to wash to neutral.

[0071] 6) The rest of the pigment supernatant was transferred to 2 mL centrifuge tubes in batches, vacuum concentrated to dryness (can be temporarily stored in a -80°C refrigerator, and then dissolved before detection), and then dissolved with 0.15-1 mL (concentration low, only 0.15 mL can be added, can be filtered with a membrane) MTBE to constant volume.

[0072] 7) 15871 g was centrifuged for 30 min, filtered with a membrane, and transferred to a sample injection bottle, and then high performance liquid chromatography detection was performed.

[0073] 8) Preparation of mobile phase for liquid chromatography detection: mobile phase A: acetonitrile:methanol = 3:1 (750 mL:250 mL, containing 0.01% BHT); mobile phase B: 100% MTBE (containing 0.01% BHT).

[0074] 9) After preparation, a vacuum filtration instrument with a 0.22 μm organic filter membrane was used to filter the mobile phase to remove impurities.

[0075] 10) The mobile phase was placed in an ultrasonic instrument and ultrasonicated for 30 min to remove bubbles.

[0076] 11) HPLC analysis program:

[0077] Mobile phase: flow rate 1 mL / min, injection volume 20 μL.

[0078] Gradient elution was used: 0 min: A-B (95:5); 0-10 min: A-B (95:5); 10-19 min: A-B (86:14); 19-29 min: A-B (75:25); 29-54 min: A-B (50:50); 54-66 min: A-B (26:74); 67-76 min: A-B (95:5).

[0079] Data analysis: according to the peak time of the sample, the β-cryptoxanthin peak map was determined, and the content of β-cryptoxanthin was calculated automatically according to the peak area. The qualitative information of the standard carotenoid is shown in Table 1.

[0080] Table 1 Qualitative information of standard carotenoid components

[0081]

[0082]

[0083] The total carotenoid content and β-cryptoxanthin content of the flesh of Citrus unshiu Marc. after light supplementation in Examples 1-7 are shown in Table 1 and Table 2. Figure 1

[0084] Table 2 Total carotenoid content and β-cryptoxanthin content of flesh of different examples ​

[0085]

[0086] By Figure 1 and Table 2 can be drawn: by artificial supplement of red light, blue light, red and blue mixed light and white light with higher light intensity, the content of β-cryptoxanthin in the fruit of Citrus unshiu Marc can be significantly improved, and under the condition of the same light intensity, the effect of blue light is better than that of red light. As the test analysis result shows, under the condition of the red light quantum flux density of 26 μmol·m -2 ·s -1 , the blue light quantum flux density is also 104 μmol·m -2 ·s -1 (Example 4) and the white light quantum flux density is 350 μmol·m -2 ·s -1 (Example 6), it is more suitable for the light supplement of Citrus unshiu Marc in winter to improve the content of β-cryptoxanthin in the carotenoids of the fruit.

[0087] From the above examples, it can be concluded that the method described in the present application can significantly improve the content of β-cryptoxanthin in the flesh of wide-skinned citrus including Citrus unshiu Marc.

[0088] Although the above examples have made a detailed description of the present application, it is only a part of the examples of the present application, but not all the examples, and people can also obtain other examples under the non-creative premise according to the present examples, and these examples all belong to the protection scope of the present application.

Claims

1. A method for increasing the content of β-cryptoxanthin in broad rind citrus by artificial light supplementation, characterized in that, The method comprises the following steps: performing artificial light supplementing treatment on the facility full-mature cultivation wide-skin citrus trees by using light supplementing lamps from late September to harvesting period each year, wherein the light supplementing lamps comprise combined light supplementing lamps or white light supplementing lamps. The combined light supplementing lamps comprise red light and / or blue light, the wavelength of the red light is 605-700 nm, the wavelength of the blue light is 435-480 nm, and the ratio of the light quantum flux density of the red light and the blue light is (0-4):(0-4). The light supplement lamp has a light quantum flux density of 130-510 μmol·m -2 ·s -1 .

2. The method of claim 1, wherein, The time of the artificial light supplementing treatment is 4-6 hours per day.

3. The method of claim 2, wherein, The time of the artificial light supplementing treatment is 4 hours per day from late September to early November each year, and the time of the artificial light supplementing treatment is 6 hours per day from early November to harvesting period each year.

4. The method of claim 3, wherein, From September 22 to September 24 and from November 7 to November 8 each year, the wide-skin citrus trees are respectively supplemented with light for 2 hours before sunrise and after sunset, and from November 7 to November 8 to harvesting period each year, the wide-skin citrus trees are respectively supplemented with light for 3 hours before sunrise and after sunset.

5. The method of claim 1, wherein, The light source of the light supplementing lamps is a light emitting diode.

6. The method of claim 1, wherein, When performing the artificial light supplementing treatment on the wide-skin citrus trees, the light supplementing lamps are hung to be 50 cm above the top of the canopies of the wide-skin citrus trees, and a white light reflecting film is laid on the ground of the wide-skin citrus trees.

7. The method of claim 1, wherein, The wide-skin citrus trees comprise wide-skin citrus trees with natural open heart-shaped tree shapes.

8. The method according to any one of claims 1 to 7, characterized in that, The wide-skin citrus trees comprise Wenzhou Citrus.

9. The method of claim 8, wherein, The method for increasing the content of β-cryptoxanthin in the wide-skin citrus comprises increasing the content of β-cryptoxanthin in the fruits of the wide-skin citrus. The method comprises the following steps: performing artificial light supplementing treatment on the facility full-mature cultivation wide-skin citrus trees by using light supplementing lamps from late September to harvesting period each year, wherein the light supplementing lamps comprise combined light supplementing lamps or white light supplementing lamps. The combined light supplementing lamps comprise red light and / or blue light, the wavelength of the red light is 605-700 nm, the wavelength of the blue light is 435-480 nm, and the ratio of the light quantum flux density of the red light and the blue light is (0-4):(0-4). The time of the artificial light supplementing treatment is 4-6 hours per day. The time of the artificial light supplementing treatment is 4 hours per day from late September to early November each year, and the time of the artificial light supplementing treatment is 6 hours per day from early November to harvesting period each year. From September 22 to September 24 and from November 7 to November 8 each year, the wide-skin citrus trees are respectively supplemented with light for 2 hours before sunrise and after sunset, and from November 7 to November 8 to harvesting period each year, the wide-skin citrus trees are respectively supplemented with light for 3 hours before sunrise and after sunset. The light source of the light supplementing lamps is a light emitting diode. When performing the artificial light supplementing treatment on the wide-skin citrus trees, the light supplementing lamps are hung to be 50 cm above the top of the canopies of the wide-skin citrus trees, and a white light reflecting film is laid on the ground of the wide-skin citrus trees. The wide-skin citrus trees comprise wide-skin citrus trees with natural open heart-shaped tree shapes. The wide-skin citrus trees comprise Wenzhou Citrus. The method for increasing the content of β-cryptoxanthin in the wide-skin citrus comprises increasing the content of β-cryptoxanthin in the fruits of the wide-skin citrus.

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