Method for regulating and controlling flowering stage of azalea

Abstract

The invention discloses a method for regulating and controlling the flowering phase of azalea, and belongs to the technical field of plant flowering phase regulation. According to the method, Rhododendron delavayi 'Yufeng' is taken as a test object, on the 26th-30th day after the flower bud formation rate reaches 88-92%, gibberellic acid with the concentration of 1600-1800 mg / L is sprayed to leaf surfaces for dripping, spraying is performed once every 6-8 days, and spraying is continuously performed for 2-4 times. According to the method, the rhododendron flowering stage can be remarkably advanced, the full-bloom stage of the rhododendron can be effectively prolonged, the method is convenient to operate and low in cost, the problems that the accurate rhododendron flowering stage regulation and control technology is immature and unstable in effect are solved, an efficient technical scheme is provided for regulation and control of the rhododendron flowering stage of the garden green land, and the method has important application value.

Description

Technical Field

[0001] This invention relates to the field of plant flowering period regulation technology, and in particular to a method for regulating the flowering period of azaleas. Background Technology

[0002] Rhododendrons are prized for their ornamental value and are widely used woody flowering plants in landscaping, earning the high praise in British gardens where "no garden is complete without rhododendrons." my country boasts abundant rhododendron resources, and as a core group with a concentrated flowering period in spring (March-May), rhododendrons are extensively used in parks, residential areas, and other green spaces in southern cities such as Fuzhou, Guangzhou, and Hangzhou. However, the natural flowering period of rhododendrons does not coincide with important holidays such as the Spring Festival, making it difficult to meet the concentrated viewing demands of urban greening and landscape design during these periods. Therefore, research on precise and efficient flowering period control techniques for rhododendrons is of significant practical value.

[0003] The differentiation and development of azalea flower buds is a complex process. The rhythm of flower bud differentiation and development can be intervened through exogenous hormone treatment and protected cultivation to advance or delay the flowering period, thus matching the demands of holiday viewing. Existing research shows that exogenous application of paclobutrazol can significantly increase the flower bud formation rate of azaleas. By controlling environmental factors such as temperature, light duration, and light quality in protected cultivation, combined with low temperature, shading, and gibberellic acid (GA3) treatment, the flowering time of azaleas can be effectively advanced. However, protected cultivation is costly and complex, making it difficult to promote and apply on a large scale in gardens and green spaces. In contrast, plant growth regulators have advantages such as low cost, convenient application, and compatibility with open-field environments, making them the preferred technical approach for controlling the flowering period of azaleas in gardens and green spaces.

[0004] Gibberellin (GA3) is one of the most commonly used growth regulators for controlling the flowering period of ornamental plants. It can promote flower bud development and advance the flowering period. This regulatory effect has been verified in various horticultural crops such as chrysanthemum, peony, sunflower, rose, and hydrangea. In the field of rhododendron flowering period regulation, existing studies have confirmed that gibberellins have a significant flowering-inducing effect on rhododendrons and azaleas. However, the effect of gibberellins is closely related to the timing of application. Applying GA3 during the pre-differentiation stage of flower buds can inhibit the formation of flower buds in short-day rhododendrons.

[0005] Current research on rhododendron flowering period regulation mainly focuses on interventions during the flower bud differentiation stage, with insufficient attention paid to key technical aspects such as the division of morphological development stages after flower bud formation, the optimal application time of exogenous hormones, and the effects of application concentrations. The developmental process of rhododendron flower buds after formation is synergistically regulated by multiple factors, including endogenous hormones and carbon and nitrogen metabolism. Existing research still lacks a systematic understanding of the physiological and biochemical basis of GA3-regulated anatomical changes in flower bud development, the response of endogenous hormone levels, and the metabolic mechanisms of carbon and nitrogen compounds. This results in immature and unstable techniques for precise regulation of rhododendron flowering period in urban green spaces, making it difficult to meet the needs of large-scale engineering applications. Summary of the Invention

[0006] In view of this, the present invention provides a method for regulating the flowering period of azaleas. Using Rhododendron 'Miyo-no-Sakae' as material, the present invention explores the effects of exogenous GA3 treatment on flower bud growth, flowering traits, flower bud anatomy, endogenous hormones and carbon and nitrogen metabolism, and elucidates the physiological mechanism by which it regulates the development of azalea flower buds. The aim is to provide a theoretical basis and technical support for the precise regulation of the flowering period of azaleas in gardens and green spaces.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] This invention provides a method for regulating the flowering period of azaleas. On the 26th to 30th day after the flower bud formation rate reaches 88-92%, gibberellic acid at a concentration of 1600-1800 mg / L is sprayed onto the whole plant until the leaves are dripping wet. The spraying is repeated once every 6-8 days for 2-4 consecutive times. This method can advance the flowering period of azaleas and prolong the peak flowering period.

[0009] Preferably, the volume ratio of the rhododendron cultivation substrate formula is peat moss:vermiculite = 3:1.

[0010] Preferably, the method regulates the endogenous hormone balance of GA3 / ABA, IAA / ABA, and ZT / ABA by increasing the content of GA3 and IAA in flower buds and decreasing the content of ABA. At the same time, it promotes the accumulation of soluble proteins and soluble sugars in flower buds, accelerates the development of stamens, pistils and ovaries in flower buds, and achieves the regulation of azalea flowering period.

[0011] Preferably, the rhododendron variety is 'Oyo no Ei'.

[0012] This invention also provides the application of gibberellic acid in regulating the flowering period of azaleas. Spraying at a concentration of 1600-1800 mg / L on the 26th to 30th day after the azalea flower bud formation rate reaches 88-92%, once every 6-8 days, for 2-4 consecutive times, can advance the flowering period and prolong the peak flowering period.

[0013] Preferably, the gibberellic acid is applied by spraying the entire plant until water drips from the leaves.

[0014] Preferably, the rhododendron variety is 'Oyo no Ei'.

[0015] By adopting the above technical solution, this invention has the following beneficial effects: Using the 'Yudai no Eri' azalea as the experimental subject, on the 26th to 30th day after its flower bud formation rate reaches 88-92%, the entire plant is sprayed with gibberellic acid at a concentration of 1600-1800 mg / L until the leaves drip. This is repeated every 6-8 days for 2-4 consecutive applications. This method can significantly advance the azalea flowering period and effectively prolong the peak flowering period. It is convenient to operate, low in cost, suitable for open-field cultivation in gardens and green spaces, and has strong potential for large-scale promotion. It solves the problems of immature and unstable effects in precise control of azalea flowering period, providing an efficient technical solution for controlling azalea flowering period in gardens and green spaces, and has significant value for garden applications. Attached Figure Description

[0016] Figure 1 This is a temperature and humidity map of the test site during the test period.

[0017] Figure 2 The figure shows the effect of different concentrations of GA3 at different times on the growth trend of rhododendron flower buds.

[0018] Figure 3 Figure 1 shows the effect of different concentrations of GA3 at different times on the longitudinal growth trend of rhododendron flower buds.

[0019] Figure 4 Principal component analysis of azalea flowering indicators and scores for each treatment.

[0020] Figure 5 Effects of GA3 treatment on rhododendron flowering period

[0021] Figure 6 The figures show the morphological development changes of flower buds treated with 1700 mg / L GA3 and the control group 28 days after flower bud formation. Figure A shows the comparison of the appearance changes of the flower buds in the treatment and control groups during the growth process; Figure B shows the comparison of the changes in the petals of the flower buds in the treatment and control groups during the growth process; Figure C shows the comparison of the changes in the internal structure of the flower buds in the treatment and control groups during the growth process; s1 is the flower bud formation period, s2 is the pistil and stamen development period, s3 is the swelling period, and s4 is the coloring period; the scale bar in the figure represents the actual length of 1 mm.

[0022] Figure 7 The graph shows the changes in the development of the ovary and pistil of the flower buds after 28 days of treatment with 1700 mg / L GA3 and the control group. AD represents the ovary development of the treatment group, and EF represents the ovary development of the A3B2 treatment group. S1 represents the flower bud formation period, S2 represents the pistil and stamen development period, S3 represents the swelling period, and S4 represents the coloring period. OV represents the ovule, OW represents the ovary wall, and OC represents the ovary locules.

[0023] Figure 8The effect of GA3 treatment on the endogenous hormone content in rhododendron flower buds. Different lowercase letters at the same time point indicate significant differences between treatments (P < 0.05), and the same applies below.

[0024] Figure 9 The effect of GA3 treatment on the dynamic balance of endogenous hormones in rhododendron flower buds.

[0025] Figure 10 The effect of GA3 treatment on the nutrient content of rhododendron flower buds. Detailed Implementation

[0026] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0027] In this experiment, all 195 potted 'Oyo no Eri' azaleas were purchased from Yonggen Azalea Cultivation Co., Ltd. in Jinhua City, Zhejiang Province. All were healthy, disease-free, 5-year-old potted seedlings. They were cultivated in square plastic containers with a top diameter of 20 cm × 20 cm, a bottom diameter of 18 cm × 18 cm, and a height of 25 cm. One azalea was planted in each container. The substrate formula was V. 泥炭土 V 蛭石 The experiment was conducted at a ratio of 3:1 and placed in the horticulture greenhouse of Fujian Agriculture and Forestry University. Temperature and humidity meters (TH2OR-EX-H, Miaoguan Technology Co., Ltd., Pingyang County, Wenzhou, Zhejiang) were installed in all directions, and data were recorded hourly. The experiment was centrally managed. The temperature and humidity conditions of the experimental environment are detailed below. Figure 1 .

[0028] Data from this invention embodiment are presented as averages of at least three replicates. All data were processed using Microsoft Excel, analyzed using SPSS 22.0, and images were integrated and formatted using Adobe Photoshop CC 2018 and charts were created using Origin 2021. Statistical analysis employed one-way ANOVA based on Duncan's multiple range test to assess the significance of different treatment effects.

[0029] Example 1

[0030] 195 plants were divided into 13 groups, with each group representing one treatment, and each treatment consisting of 15 pots. Based on previous research by the research group, the day after flower bud formation was defined as 90% flower bud formation. Four levels were set for the number of days after flower bud formation (A) (each level's start date was the same as the GA3 spraying start time): day 0, day 14, day 28, and day 42 after flower bud formation. Three levels were set for the GA3 spraying concentration (B): 1400 mg / L, 1700 mg / L, and 2000 mg / L. A crossover experiment was conducted, with 12 level combinations (3*4), each consisting of 5 pots and three replicates. GA3 was sprayed onto the entire plant until the leaves dripped, once every 7 days, for a total of 3 applications. A control group was sprayed with water, and all treatments were managed uniformly. The treatment numbers are detailed in Table 1.

[0031] Table 1 Factorial Experimental Design

[0032]

[0033] 1. Determination of rhododendron flower bud growth under GA3 treatment

[0034] From the time of flower bud formation, 30 healthy flower buds were randomly selected from each treatment and the control group and tagged. Every week, the transverse and longitudinal diameters of the flower buds under different treatments were measured using electronic calipers. The transverse diameter was the widest distance, and the longitudinal diameter was the distance from the base of the bud to the tip (retaining two decimal places). Measurements continued until the flower buds of each treatment reached the color-revealing stage (one-third of the bud scales showed color). The results are as follows: Figure 2 As shown.

[0035] Figure 2 The results showed that after GA3 treatment, the cumulative growth of flower bud diameter gradually increased in each treatment. In time periods A1, A2, and A4, the cumulative growth of flower bud diameter after spraying with 2000 mg / L GA3 was greater than 1400 mg / L and 1700 mg / L, respectively. However, in time period A3, the cumulative growth of flower bud diameter after spraying with 1700 mg / L GA3 was greater than 1400 mg / L and 2000 mg / L. Figure 3 It can be seen that the cumulative growth of the longitudinal diameter of flower buds in all treatments consistently showed an increasing trend, and the growth was always greater than that in the control (CK). The growth rate in other time periods was consistent with that in the transverse diameter. In summary, all GA3 treatments at all time periods promoted the growth of both the longitudinal and transverse diameters of flower buds. Among them, the 2000 mg / L GA3 treatment showed the fastest flower bud growth in time periods A1, A2, and A4, while the 1700 mg / L GA3 (A3B2) treatment in time period A3 had the best promoting effect on the growth of both the longitudinal and transverse diameters of flower buds.

[0036] 2. Observation of rhododendron flowering under GA3 treatment

[0037] After the swelling stage, the flowering status of each treatment was observed every 3 days. The swelling stage, color-revealing stage, initial flowering stage, full bloom stage, and end flowering stage of each treatment were recorded, and the number of days of early flowering for each treatment was calculated. The results are shown in Table 2.

[0038] Days earlier (d): The difference between the initial flowering period of the treatment group and the initial flowering period of the control group is the number of days earlier;

[0039] During the swelling stage: 50% of the bud scales begin to separate, revealing light-colored linear or angular shapes on the sides;

[0040] Coloring period: 50% of bud scales show color on one-third of the area;

[0041] Initial flowering period / day: the number of days from when 5% of the flower buds have opened to when 50% of the flower buds have opened;

[0042] Peak bloom / day: Number of days from 50% of flower buds to 95% of flower buds in bloom; End of bloom / day: Number of days from 95% of flower buds to 50% of flower buds withering.

[0043] Flowering period: The number of days from the beginning of the initial flowering period to the end of the final flowering period;

[0044] Flowering uniformity: the ratio of peak bloom period to the total bloom period multiplied by 100%.

[0045] Table 2. Effects of different concentrations and durations of GA3 on rhododendron flowering.

[0046] deal with date days in advance early flowering period Peak bloom Late flowering period Flowering period Flowering uniformity CK 3.7 0d 6.00±2.00bc 29.67±2.52cde 3.33±1.53c 39.00±1.00cd 76.21±8.38abc A1B1 3.17 -8.33±1.53f 3.33±1.53c 24.33±3.06ef 3.33±0.58c 31.00±1.00e 78.34±7.46abc A1B2 3.14 -5.33±2.08e 3.33±1.15c 29.67±1.53cde 3.67±1.53c 36.67±1.53de 81.06±6.70ab A1B3 2.29 10.67±2.08b 4.00±2.00c 40.67±2.52a 3.33±1.53c 48.00±5.30ab 85.04±4.89a A2B1 2.28 12.33±1.53b 4.33±1.53c 32.33±3.51bcd 4.33±1.53bc 41.00±1.73bcd 78.75±6.10abc A2B2 2.28 12.67±2.52b 6.67±1.53bc 32.33±5.03bcd 8.00±1.00a 47.00±7.55abc 68.83±0.36c A2B3 2.28 13.00±2.00b 4.00±1.00c 27.00±3.00def 8.00±1.73a 39.00±3.61cd 69.16±2.54c A3B1 2.25 12.33±1.53b 5.33±2.08c 38.33±4.04ab 6.33±1.15abc 50.00±5.57a 76.72±2.51abc A3B2 2.22 16.3333±1.53a 3.33±0.58c 39.67±5.03ab 7.33±2.08ab 50.33±3.52a 78.60±4.46abc A3B3 2.28 12.67±1.53b 3.67±2.08c 35.33±5.51abc 9.00±2.00a 48.00±5.29ab 73.40±4.52bc A4B1 3.25 -19.33±1.53g 9.00±2.00b 21.67±5.51f 5.67±1.53abc 36.33±4.73de 59.00±8.00d A4B2 3.28 -19.33±1.53g 17.67±3.51a 23.00±6.25ef 4.33±4.16bc 45.00±6.08abc 50.44±7.65d A4B3 2.28 7.67±1.53c 5.33±2.08c 33.00±1.00bcd 7.33±1.53ab 45.67±1.15abc 72.26±1.11bc

[0047] Note: Different lowercase letters indicate significant differences between different treatments (P < 0.05).

[0048] Table 2 shows that the flowering period of all treatments in time periods A2 and A3 was significantly advanced, with treatment A3B2 being the most advanced by 16.33 days, while treatments A1B1, A1B2, A4B1, and A4B2 delayed the flowering period. Treatment A4B2 had the longest initial flowering period at 17.67 days. Treatments A1B3, A3B1, and A3B2 performed well in the full bloom stage, with flowering periods of 40.67 days, 38.33 days, and 39.67 days, respectively. Overall, the flowering period of all three treatments in time period A3 was significantly longer than that of the control group. Treatments A1B2 and A2B1 showed better flowering uniformity.

[0049] Principal component analysis was performed on each treatment and indicator, such as Figure 4As shown, principal component analysis extracted two principal components with contribution rates of 66.6% and 22.7%, respectively, for a cumulative contribution rate of 89.2%. The first principal component mainly included five indicators: advance flowering days, flowering period, peak flowering period, end of flowering period, and flowering uniformity. The second principal component mainly included the initial flowering period. According to the comprehensive score of principal component analysis, the A3B2 combination had the highest comprehensive score, and the top five combinations were A3B2, A3B3, A3B1, A2B2, and A2B3. In summary, advance flowering days, flowering period, and peak flowering period are key indicators, and treatment during the A3 time period is more conducive to promoting earlier flowering. The A3B2 treatment (spraying 1700 mg / L GA3 28 days after flower bud formation) significantly advanced the flowering period by 16.33 days, extended the peak flowering period by 10 days, and extended the flowering period by 11.33 days compared to the control, and also showed good flowering uniformity (78.60%). The A3B2 treatment performed best in flowering-related indicators and is the optimal treatment combination.

[0050] Depend on Figure 5 The changes between A3B2 and CK can be compared more intuitively. The A3B2 combination significantly shortened the development process of the pistils and stamens of rhododendron flower buds, advanced the flower bud swelling period and color-revealing period, advanced the initial flowering period to around February 15, and significantly extended the peak flowering period.

[0051] 3. Anatomical observation of rhododendron flower bud development under GA3 treatment

[0052] From the time of flower bud formation, three healthy flower buds were randomly selected from each treatment and the control group and photographed every two weeks to track and record their growth process. To observe the macroscopic and microscopic morphological changes of the stamens and pistils inside the bud, six flower buds representing the overall growth level were randomly selected every week. When dissecting the flower buds, the outer scales were removed with pointed forceps, and the buds were cut about 1 cm below the base with a scalpel before observation under a stereomicroscope. For paraffin sections, the outer scales were removed to expose the inner bud, which was then placed in FAA fixative. The buds and their internal structure were observed using an M205FA stereomicroscope (LEICA, Germany), and the paraffin sections were observed using a DMI8 fluorescence microscope (LEICA, Germany).

[0053] Based on the morphological structure of rhododendron flower buds, the developmental process from flower bud formation to color emergence is divided into four stages: flower bud morphogenesis stage, pistil and stamen development stage, swelling stage, and color emergence stage. Figure 6 As shown in A, during flower bud development, the transverse and longitudinal diameters increase over time. Figure 6 As shown in B, during the flower bud formation stage, the petals are all yellowish-green. After entering the pistil and stamen development stage, the petal color changes from yellowish-green to light green. During the swelling stage, the petal tips begin to turn red, until the petals turn entirely red during the color-revealing stage. Figure 6 As shown in C, during the flower bud morphology formation stage, the style of the pistil is light green, while the stamens are yellow, and the style of the pistil is significantly taller than the stamens. After entering the pistil and stamen development stage, the anthers of the stamens gradually turn pink, and the calyx and its hairs elongate. Subsequently, the pistil, stamens, and sepals further elongate during the swelling stage until the calyx gradually covers part of the stamens during the color-revealing stage. Comparing the flower bud growth and development processes of the optimal treatment A3B2 and CK, it was found that the flower buds of A3B2 developed faster than those of CK after GA3 spraying. In conclusion, spraying GA3 during the pistil and stamen development stage can significantly accelerate the development process of pistil and stamens, thereby promoting earlier flowering.

[0054] Further observation of the ovary development process of A3B2 and CK pistils was conducted using paraffin sections. Figure 7 It can be seen that during the flower bud morphogenesis stage, the ovary is in the initial developmental stage. At this time, the carpel has evolved into a ventricle, placenta, and ovule, and it can be clearly observed that rhododendrons have fused carpel pistils with four ventricles. As development progresses, the carpels undergo further folding and evolution, the ovule and ventricle become clearly distinguishable, and the dorsal and ventral sutures gradually appear. After A3B2 was sprayed with GA3, its ovary development progressed significantly faster than CK. Subsequently, the base of the placenta in A3B2 began to elongate, the ovary ventricle significantly enlarged, and further developed into axile placentation, while CK was still in the pistil and stamen development stage. When A3B2 entered the swelling stage ( Figure 7 In the H stage, gaps appear between the placentas, the ovules continue to develop, the vascular bundles of the dorsal and ventral sutures are clearly visible, the ovary locules are significantly enlarged, the septa and ovary walls become thinner, and the pedicels, integuments, and pistils of the anatropous ovules are clearly formed; CK is in the flower bud swelling stage. This indicates that after spraying GA3 during the pistil and stamen development stage, the ovary development process of A3B2 is generally faster than that of CK.

[0055] 4. Determination of endogenous hormone content in rhododendron flower buds under GA3 treatment

[0056] The extraction of endogenous hormones was performed according to the method of Zhi Xu et al. (Determination of plant endogenous hormones in Scutellaria baicalensis by high performance liquid chromatography-tandem mass spectrometry. 2023). After extraction, the hormones were detected by instrument (Zevo TQS micro, waters).

[0057] from Figure 8 As shown in A, from the time GA3 was sprayed until the color-revealing stage, the GA3 content of A3B2 gradually increased, reaching its maximum value 91 days after flower bud formation and then decreasing. The overall change in GA3 content of CK was not significant. Figure 8As shown in D, the ABA content in both the A3B2 and CK groups increased slowly, then decreased sharply 105 days after flower bud formation. The ABA content in the treatment groups was significantly lower than that in the control group, and the rate of decrease in ABA in the treatment groups was greater than that in the control group during the swelling period. The results indicate that during flower bud development, the closer to flowering, the higher the GA3 content, while the content of its antagonist, ABA, is lower before flowering. Although the contents of IAA and ZT showed dynamic changes, the pattern was not obvious.

[0058] To further investigate the changes in endogenous hormones in flower buds, the ratios of GA3, IAA, ZT, and ABA were calculated as follows: Figure 9 105 days after flower bud formation, the GA3 / ABA and IAA / ABA ratios in the treatment group increased sharply, while the ratios in the control group showed no significant difference. The ZT / ABA ratios in both the treatment and control groups showed a trend of first decreasing and then increasing, with the treatment group increasing faster than the control. This indicates that GA3 treatment increases the GA3 content in flower buds, leading to an increase in the content of IAA (which has a synergistic effect) and a decrease in the content of ABA (which has an antagonistic effect), thereby regulating flowering by adjusting the balance of endogenous plant hormones. In conclusion, high levels of GA3 / ABA and IAA / ABA, and low levels of ZT / ABA in flower buds are beneficial for flowering.

[0059] 5. Determination of soluble starch, soluble sugar, and soluble protein content in rhododendron flower buds treated with GA3.

[0060] Soluble starch was determined using the Nanjing Jiancheng Plant Starch Content Test Kit. Soluble sugar and soluble protein were determined according to Wang Xuekui's anthrone colorimetric method and Coomassie Brilliant Blue G-250 method (Plant Physiology and Biochemistry Experimental Principles and Techniques, 2015), respectively, using the corresponding wavelengths on an M200 PRO multi-functional microplate reader (Infinite, Tecan). Results are as follows: Figure 10 As shown.

[0061] Depend on Figure 10 As shown in A, after GA3 treatment, the soluble protein content of A3B2 and CK did not show a significant trend, but the soluble protein content of A3B2 was consistently higher than that of the control group. Figure 10 As shown in B and C, after GA3 treatment, the starch content of A3B2 decreased sharply 105 days after flower bud formation, while the soluble sugar content of both A3B2 and CK reached its peak at 105 days after flower bud formation and then decreased sharply. Figure 10 As shown in D, the ratio of soluble sugar to starch reached its lowest value 91 days after flower bud formation and then showed a rapid upward trend. In summary, GA3 treatment is beneficial to the accumulation of soluble protein and soluble sugar in flower buds during flower bud development, thereby providing the necessary nutrients for flowering and ensuring the quality of rhododendron flowering.

[0062] As can be seen from the above embodiments, the present invention provides a method for regulating the flowering period of azaleas, which can advance the flowering period of azaleas and prolong their peak flowering period.

[0063] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for regulating the flowering period of azaleas, characterized in that, On the 26th to 30th day after the flower bud formation rate reaches 88-92%, spray the whole plant with gibberellic acid at a concentration of 1600-1800 mg / L, spraying until the leaves are dripping wet. Spray once every 6-8 days, for 2-4 consecutive times. This method can advance the flowering period of azaleas and prolong the peak flowering period.

2. The method for regulating the flowering period of rhododendrons according to claim 1, characterized in that, The volume ratio of the cultivation substrate formula for azaleas is peat moss:vermiculite = 3:

1.

3. The method for regulating the flowering period of rhododendrons according to claim 1, characterized in that, The method regulates the endogenous hormone balance of GA3 / ABA, IAA / ABA, and ZT / ABA by increasing the content of GA3 and IAA in flower buds and decreasing the content of ABA. At the same time, it promotes the accumulation of soluble proteins and soluble sugars in flower buds, accelerates the development of stamens, pistils and ovaries in flower buds, and thus regulates the flowering period of azaleas.

4. The method according to claim 1, characterized in that, The azalea variety mentioned is 'Oyo no Ei'.

5. The application of gibberellic acid in regulating the flowering period of rhododendrons, characterized in that, Spraying at a concentration of 1600-1800 mg / L every 6-8 days for 2-4 consecutive days after the azalea flower bud formation rate reaches 88-92% can advance its flowering period and prolong its peak flowering period.

6. The application according to claim 4, characterized in that, The gibberellic acid is applied by spraying the entire plant until water drips from the leaves.

7. The application according to claim 5, characterized in that, The azalea variety mentioned is 'Oyo no Ei'.

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