Application of rosemary extract in promoting plant growth

Abstract

The invention relates to the technical field of biology, in particular to application of a rosemary extract in promoting plant growth. The invention provides application of a rosemary extract in promoting plant growth, and research shows that after the rosemary extract is applied to disease-free plants, the height of the plants and the fresh weight and dry weight of stems and roots are remarkably increased, the MDA, Pro and POD levels in host plants are also improved, and the CAT level is remarkably reduced.

Description

Technical Field

[0001] This invention relates to the field of biotechnology, specifically to the application of rosemary extract in promoting plant growth. Background Technology

[0002] Taiwan Silver Thread Orchid (Anoectochilus formosanus), also known as Taiwan Golden Thread Orchid, is a rare medicinal plant belonging to the genus Anoectochilus in the Orchidaceae family. Rich in flavonoids, polysaccharides, glycosides, and various amino acids, it enjoys a high reputation in traditional medicine and is hailed as the "King of Herbs." In recent years, with the continuous increase in its medicinal value and market demand, wild Taiwan Silver Thread Orchid resources have been depleted due to over-harvesting. Therefore, artificial cultivation to meet market demand has become an inevitable choice.

[0003] However, *Anoectochilus yunnanensis* grows extremely slowly during artificial cultivation and has very demanding requirements for environmental conditions (such as temperature, humidity, light, and soil microorganisms). This results in a long cycle from tissue culture seedlings to harvestable mature plants, high costs, and a high mortality rate, severely restricting its industrial development. To address this issue, existing technologies often use chemically synthesized plant growth regulators (such as NAA and 6-BA) to attempt to promote its growth. However, long-term or improper use of chemically synthesized plant growth regulators can easily lead to physiological deformities in plants, such as leaf curling and abnormal root development, affecting the appearance and quality of the finished medicinal material. Furthermore, the residues of chemical reagents are inconsistent with the cultivation concepts of green agriculture and organic medicinal materials, and may damage the beneficial microbial community in the cultivation substrate.

[0004] Therefore, developing and utilizing natural and safe plant-derived growth promoters to specifically promote the healthy growth of Taiwan silver thread orchid, shorten the cultivation cycle, and ensure its medicinal quality has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide the application of rosemary extract in promoting plant growth.

[0006] This invention provides the use of rosemary extract in at least one of the following (1) to (4):

[0007] (1) Promotes plant growth;

[0008] (2) Increase the content of malondialdehyde and / or proline in plants;

[0009] (3) Increase the activity of plant peroxidase;

[0010] (4) Reduce the activity of plant catalase.

[0011] In some embodiments, promoting plant growth includes increasing at least one of plant height, plant fresh weight, plant dry weight, plant root fresh weight, and plant root dry weight.

[0012] In some embodiments, the plant is a dicotyledonous or monocotyledonous plant.

[0013] In some specific embodiments, the plant is *Aglaonema taiwanensis*.

[0014] In some embodiments, the method for preparing rosemary extract includes:

[0015] Step 1: Take rosemary, dry it, and pulverize it to obtain rosemary powder;

[0016] Step 2: Take the rosemary powder from Step 1, soak it in ethanol solution, and then extract it by percolation. The resulting percolate is then distilled under reduced pressure to obtain the extract paste.

[0017] Step 3: Take the extract, dissolve it in ethanol solution, let it stand for incubation, remove the precipitate, and then obtain the rosemary extract.

[0018] In some embodiments, the rosemary includes Cyvenhey rosemary and / or pink rosemary.

[0019] In some embodiments, in steps 2 and 3, the concentration of the ethanol solution is 60 vol% to 80 vol%.

[0020] In step 2, the soaking time is 36-60 hours;

[0021] In step 3, the static culture time is 2 to 4 days.

[0022] In some specific embodiments, the concentration of the ethanol solution in steps 2 and 3 is 70 vol%.

[0023] In step 2, the soaking time is 48 hours;

[0024] In step 3, the static culture time is 3 days.

[0025] In some embodiments, the mass-to-volume ratio of the rosemary powder in step 2 to the ethanol solution in step 3 is (40~60) g: (40~60) mL.

[0026] In some specific embodiments, the mass-to-volume ratio of the rosemary powder in step 2 to the ethanol solution in step 3 is 50g:50mL.

[0027] This invention provides a culture medium for promoting plant growth, comprising rosemary extract and a basal culture medium;

[0028] The basal culture medium is PDA medium, and the concentration of the rosemary extract is 100~150mL / L.

[0029] In some embodiments, the rosemary extract is an extract of 110 mL / L of pink rosemary.

[0030] This invention provides a method for promoting plant growth, comprising applying rosemary extract to plants;

[0031] The concentration of the rosemary extract is 100~150mL / L.

[0032] In some embodiments, the plant includes Taiwan silver thread orchid.

[0033] In some embodiments, the rosemary extract is an extract of 110 mL / L of pink rosemary.

[0034] This invention provides the application of rosemary extract in promoting plant growth. Studies have shown that after applying rosemary extract to disease-free plants, the height of the plants, as well as the fresh weight and dry weight of the stems and roots, are significantly increased. The levels of MDA, Pro and POD in the host plant are also increased, while the CAT level is significantly decreased. Attached Figure Description

[0035] Figure 1 The study showed the differences in inhibitory activity of different rosemary extracts against Fusarium oxysporum, where EE was an alcohol extract and AE was a water extract.

[0036] Figure 2 The inhibitory activity of different strains of rosemary ethanol extract against Fusarium oxysporum at different concentrations was shown.

[0037] Figure 3 The differences in phenotypic characteristics of *Anoectochilus roxburghii* plants under different treatments are shown.

[0038] Figure 4 The differences in the content of anolysin were shown.

[0039] Figure 5 The study showed differences in malondialdehyde (MDA), proline (Pro), catalase (CAT), and peroxidase (POD) activity under different treatments. Detailed Implementation

[0040] This invention provides the application of rosemary extract in promoting plant growth. Those skilled in the art can refer to this document and appropriately modify the process parameters to achieve the desired results. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments. Those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to implement and apply the technology of this invention.

[0041] The test materials used in this invention are all commercially available products. The invention will be further illustrated below with reference to specific embodiments.

[0042] Example 1

[0043] This invention explores the antifungal potential of rosemary extract and ethanol extract as growth promoters for disease-free plants and against stem rot caused by Fusarium oxysporum in A. formosanus, Taiwan; (2) detects potential changes in the activity of antioxidant enzymes and the content of Anoectochilin in the treated plants.

[0044] 1. Technical solutions adopted

[0045] 1. Materials and Methods

[0046] 1.1. Sample collection, identification and preparation

[0047] 1.1.1. Fungal isolates and varieties of Anoectochilus roxburghii

[0048] Researchers isolated *Fusarium oxysporum* from the diseased part (stem base) of *Anoectochilus taiwanensis* stem rot. Following Koch's postulates, an inoculating needle covered with mycelium was reinserted into the base of sterile *Candida taiwanensis* seedlings, with a sterile needle soaked in water serving as a blank control, confirming the pathogenicity of the isolate. The pathogen is accessed in GenBank (accession number OQ244517.1) and provided by the Subtropical Crops Research Institute of the Fujian Academy of Agricultural Sciences. The strain was stored at 4°C on potato dextrose agar (PDA) slant medium for future use. *Anoectochilus taiwanensis* tissue culture seedlings used in the experiment were purchased from the Yaowanggu Traditional Chinese Medicine Planting Cooperative in Nanjing County, Zhangzhou City, Fujian Province, and were identified as suitable host plants by senior agronomist Wu Weijian.

[0049] 1.1.2. Functional Extract Raw Material Plants

[0050] The Subtropical Plant Research Institute of the Fujian Academy of Agricultural Sciences collected leaf samples from two rosemary varieties: *R. officinalis* 'SevernSea' and *R. officinalis* 'Majorca Pink'. Plant identification was conducted by the institute's Aromatic Plants Research Group.

[0051] 1.2. Preparation of water extracts and alcohol extracts

[0052] 1.2.1. Preparation of water extract

[0053] The aqueous extract of rosemary was prepared by water extraction and ethanol precipitation. The specific steps are as follows: Leaves of two types of rosemary were dried separately in an oven at 40±2℃. 50 g of the dried leaves were then extracted twice with 750 ml of distilled water at 80℃, each extraction lasting 2 h. Separation was achieved by qualitative filter paper filtration. The filtrate was then vacuum-evaporated at 60℃ to a relative density of 1.18-1.22 (measured at 40℃). Ethanol was then added to a final concentration of 70%. The solution was sealed with sealing film and allowed to stand at 26℃ for 12 hours. The supernatant was collected by filtration and concentrated under vacuum at 60℃ to obtain a dark brown residue. This residue was air-dried into crystals and stored in a dry, light-protected environment (26℃) for later use.

[0054] 1.2.2. Preparation of alcohol extract

[0055] Rosemary extract was prepared by percolation. The specific procedure is as follows: Leaves of two types of rosemary were dried in an oven at 40±2℃ and then ground into powder. 50 g of the powder was placed in 70% ethanol and soaked at 26℃ for 48 h, followed by percolation. The extract was then obtained by vacuum rotary evaporation at 60℃. The resulting paste was transferred to a 50 ml volumetric flask, diluted to 50 ml with 70% ethanol, mixed thoroughly, and incubated for 3 days. After removing the precipitate, the supernatant was stored at 4℃ for later use.

[0056] 1.3. Preparation of the mother liquor of the extract

[0057] 1.3.1. Preparation of aqueous extract-containing tablets

[0058] Weigh 500 mg of the aqueous extracts from each of the two rosemary strains and slowly add them dropwise to 500 μL of distilled water until fully dissolved. Stir continuously with a magnetic stirrer for 30 minutes until the final concentration reaches 1 mg / μL. Then, these solutions are mixed into liquid PDA medium at different concentrations for subsequent in vitro antifungal experiments.

[0059] 1.3.2. Preparation of drug-containing tablets from alcohol extract

[0060] Take 10 ml of ethanol extract from each of the two strains of rosemary and slowly add it to 1 ml of dimethyl sulfoxide (DMSO, purity 99.5%) to prepare colloidal solutions. Then, use a magnetic stirrer to continuously stir the dispersion for 30 min. Finally, add the resulting mixture to liquid PDA medium at different concentrations for in vitro antifungal experiments and artificial climate chamber experiments.

[0061] 1.4. In vitro antifungal activity test of the extract

[0062] To evaluate the antifungal activity of rosemary water extract and alcohol extract against *Fusarium oxysporum*, this study employed the mycelial growth inhibition method proposed by inventors Zhao et al. for in vitro experiments. The specific procedure was as follows: a bacterial suspension mixture was added to sterile PDA liquid medium at a concentration of 50 mL / L, and 10 mL of the medium was poured into a 90 mm culture dish. The positive control group used medium containing 0.05% fungicide (0.5 µL / mL nystatin), while the negative control group used sterile distilled water and 10 μL / mL DMSO solution as controls, respectively. A 4 mm diameter *Fusarium oxysporum* mycelial disc (taken from the edge of the PDA culture dish and cultured for 7 days) was inoculated in the center of each culture dish. Three replicates were set up for each treatment. All culture dishes were incubated at 28°C, and the colony diameter was measured on day 7.

[0063] Given that the ethanol extract of rosemary showed the strongest inhibitory effect in previous experiments, researchers dissolved it in sterile liquid PDA medium to prepare solutions with final concentrations of 50, 70, 90, 110, and 130 mL / L. 10 mL of PDA medium was poured into 90 mm Petri dishes, along with 13 mL / L DMSO solution as a negative control. A 4 mm diameter Fusarium oxysporum mycelial disc (taken from the edge of the dish) was inoculated in the center of each dish and incubated for 7 days. Three replicates were set up for each treatment. All Petri dishes were incubated at 28°C, and colony diameter was measured on day 7.

[0064] 1.5. In vivo effects of rosemary alcohol extract on stem rot of Anoectochilus taiwanensis

[0065] Prepare the cultivation substrate for *Anoectochilus taiwanensis* by mixing sterilized peat moss and perlite in a 10:1 ratio. Take healthy 5-month-old tissue culture seedlings of *Anoectochilus taiwanensis* and immerse the roots in a suspension of *Fusarium oxysporum* conidia (10:10). 6 -10 7The plants were cultured in CFU / mL medium for 1 h. Three seedlings were planted per pot, with 10 pots per treatment. They were cultured under standard conditions. Subsequently, in a climate incubator (temperature 28℃, humidity 75-80%, light intensity 60%), the plants were watered every 7 days with 20 mL / pot of 130 mL / L *Rosemaryia cerenes* and 110 mL / L *Rosemaryia pulvinata* extracts, respectively, for two weeks. On non-treatment days, the plants were watered with 20 mL / pot of sterile water. The negative control group (CK) received 13 mL / L DMSO medium without the extract, and the positive control group (F) was inoculated with *Fusarium oxysporum* only. Both groups received either 110 mL / L *Rosemaryia pulvinata* extract (P and PF groups) or 130 mL / L *Rosemaryia cerenes* extract (S and SF groups). Stem rot incidence was assessed in all pots, with 30 replicates per group. Fourteen days after infection, the disease index was assessed according to the 0-5 scoring standard: 0 (no rot), 1 (stem blackening), 2 (stem wrinkling), 3 (stem shrinkage without leaf wilting), 4 (stem shrinkage with leaf wilting), 5 (wilting of all leaves).

[0066] Use the following formulas to calculate the severity and incidence of disease:

[0067]

[0068] ×100

[0069] 1.5.1. Analysis of Plant Growth Parameters

[0070] Researchers collected samples of *Anoectochilus taiwanensis* seedlings (5 months and 14 days old) for statistical analysis of botanical traits, disease incidence, and physiological and biochemical indicators. Three plants were collected from each group, carefully removed from the cultivation substrate after being transferred to the laboratory, rinsed with tap water, and dried. The height and fresh weight of the above-ground parts and roots were measured. The samples were dried in a 40°C oven for 5 days before their dry weight was determined.

[0071] 1.5.2. Determination of Anoectochilus roxburghii glycoside content

[0072] High-performance liquid chromatography-ultraviolet (HPLC-UV) analysis was performed using a Thermo Fisher Scientific UltiMate 3000 system (USA) equipped with an autosampler (Spark Holland Alias, Netherlands). The analytical conditions were as follows: C18 column (250 mm × 4.6 mm inner diameter, 5 μm particle size), column temperature 25°C, mobile phase consisting of 5% acetonitrile, 5% methanol, and 90% deionized water, flow rate 1 mL / min for 5 minutes, and UV detection wavelength of 215 nm.

[0073] The preparation method of the roximate solution is as follows: 10 mg of roximate (HPLC ≥98%; Lameitai Pharmaceuticals, China) was slowly dissolved in 1 mL of methanol with stirring to obtain a final concentration of 10 mg / mL. This stock solution was further diluted with methanol to obtain concentration gradients of 0.5, 1, 2, 4, and 8 mg / mL for the construction of standard curves.

[0074] Taiwanese *Anoectochilus roxburghii* seedlings were dried in an oven at 40±2℃ for 72 hours. The dried powder from each treatment group was sieved through a 250±9.9 μm sieve, and 100 mg was accurately weighed and divided into two equal portions (50 mg each), transferred to 1.5 mL centrifuge tubes containing 1 mL of methanol. Due to the thermal instability of *Anoectochilus roxburghii* glycosides (e.g., easy decomposition at high temperatures), ultrasonic extraction (model KQ-300DE, made in China) was performed at 4-15℃ and power <150W for 45 minutes. After centrifugation at 10℃ and 10,000 rpm for 10 minutes, the supernatant was filtered through a 0.22 μm mM filter membrane. 20 μL of sample solution from each group was used for analysis, with three biological replicates for each treatment. Relative standard deviation (RSD = SD / mean) was used to assess method repeatability.

[0075] 1.6. Evaluation of malondialdehyde (MDA) and proline (Pro) content and antioxidant enzyme activity

[0076] Using a commercial assay kit (Solarbio Life Sciences), determine the levels of MDA and Pro, as well as the activities of catalase (CAT) and peroxidase (POD), following the manufacturer's instructions.

[0077] 1.7. Statistical Analysis

[0078] All data are expressed as mean ± standard deviation (SD). Statistical significance was assessed using one-way ANOVA (SPSS 13.0, USA), with a threshold of p < 0.05. Heatmap visualizations were generated using the R programming language. All experiments were performed in triplicate.

[0079] 2. Results

[0080] 2.1. Screening for antifungal activity of extracts

[0081] This study evaluated the antifungal activity of different extracts from two rosemary strains against Fusarium oxysporum at a concentration of 50 mL / L. Differences are shown in the table below. Figure 1 Table 1 shows the average inhibition rate of rosemary extract on Fusarium oxysporum mycelial growth.

[0082] Table 1 Effects of rosemary extract on the mycelial growth of Fusarium oxysporum

[0083]

[0084] Positive control = Potato dextrose agar (PDA) medium containing 0.5 μL / mL nystatin. Different letters indicate statistically significant differences between treatments (p≤0.05). SD = Standard deviation.

[0085] Compared with the positive control (0.5 μL / mL nystatin) and the negative control, all extracts showed varying degrees of antifungal activity. The two rosemary alcohol extracts exhibited the highest inhibition rates (66.75±0.14% and 69.96±0.36%, respectively), significantly higher than the positive control. The Cevensea rosemary water extract showed the lowest inhibition rate of active ingredients (55.64%), but it was still significantly higher than the positive control.

[0086] 2.2. Determination of the antibacterial activity of rosemary ethanol extract against Fusarium oxysporum at different concentrations

[0087] This study evaluated the antifungal activity of ethanol extracts of *Rosemaryia severens* and *Rosemaryia semperflorens* against *Fusarium oxysporum* at different concentrations (130, 110, 90, 70 and 50 mL / L). Figure 2 The average degree of inhibition of radial growth of the strain after treatment with the alcohol extract is shown.

[0088] Compared with the blank control, all treatments showed varying degrees of inhibitory effects. After 7 days of incubation at 28℃, the mycelial growth inhibition rate gradually increased over time. Among them, the 130 and 110 mL / L rosemary extracts (labeled as 93.83±0.62%, 93.17±0.84%, and 93.00±0.36%, respectively) and the 130 mL / L sévenmargren extract showed the highest inhibitory effects, with inhibition rates significantly higher than the control group. The 50 mL / L sévenmargren extract showed the lowest inhibition rate (70.04%), which was basically the same as the control group.

[0089] 2.3. Effects of alcohol extract on growth parameters and stem rot severity of *Anoectochilus taiwanensis*

[0090] When seedlings of *Anoectochilus taiwanensis* were treated with the highest concentrations (110 and 130 mL / L) of rosemary ethanol extract, the inhibitory effect on *Fusarium oxysporum* mycelial growth and the reduction of stem rot incidence were significantly better than those in the untreated control group. The disease severity of plants inoculated with *Fusarium oxysporum* was 48.89 ± 10.18%, while plants treated with 110 mL / L *Rosemaryia sericata* ethanol extract and 130 mL / L *Rosemaryia sericata* ethanol extract showed significant inhibitory effects (p ≤ 0.05), reaching 15.56% ± 7.7% and 11.11% ± 7.7%, respectively. No significant difference in disease severity was observed between the two ethanol extract treatment groups (Table 2).

[0091] Table 2. Effects of two rosemary alcohol extracts on the severity and disease index of *Anoectochilus tectorius* seedlings infected with *Fusarium oxysporum*.

[0092]

[0093] *Different letters indicate significant differences between treatments, p≤0.05. Data are expressed as mean ± standard deviation (SD) of three replicates.

[0094] Compared with the infected group, the infected group, and the negative control group, treatment with 110 mL / L rosemary extract significantly increased the height of disease-free plants as well as the fresh and dry weight of stems and roots (see Table 3). Similarly, treatment with 130 mL / L sévenh rosemary extract significantly increased plant height compared with all control groups, and increased stem and root biomass compared with the infected group and infected samples (Table 3). Notably, the plant heights treated with 110 mL / L rosemary extract and 130 mL / L sévenh rosemary extract (10.08 ± 0.92 cm and 9.41 ± 0.69 cm, respectively) were significantly higher than those of the control group (7.81 ± 0.71 cm). In contrast, the lowest plant height recorded was for the sample treated with 110 mL / L rosemary extract (6.35 ± 0.15 cm). Furthermore, treatment with 130 mL / L Cevenh rosemary extract also resulted in a significant increase in stem and root biomass compared to plants inoculated with Fusarium oxysporum. Figure 3 However, fungal infection, due to severe stem rot, significantly reduced all growth parameters. The content of *Anoectochilus roxburghii* glycosides was as follows: Figure 4 As shown, the negative control group had the highest content (24.72 ± 3.71 mg / mL), followed by the group treated with 130 mL / L cervin rosemary extract (19.78 ± 1.56 mg / mL).

[0095] Table 3. Effects of ethanol extracts of *Rosemaryia speciosa* and *Rosemaryia severans* on biomass of plants infected with stem rot disease in *Anoectochilus taiwanensis*.

[0096]

[0097] Different letters indicate significant differences between treatments, p ≤ 0.05. Data are expressed as mean ± standard deviation (SD) of three replicates.

[0098] 2.4. Malondialdehyde (MDA) and proline (Pro) content and antioxidant enzyme activity

[0099] Figure 5Data showed the effects of 110 ml / L rosemary extract and 130 ml / L rosemary sévenir extract on malondialdehyde (MDA) and proline (Pro) content and antioxidant enzyme activity in 14-day-old *Anoectochilus thunbergii* seedlings infected with stem rot. Overall, the MDA and Pro levels in the extract-treated and pathogen-infected groups were significantly higher than those in the untreated control group. However, the MDA content in the ethanol extract-treated group was significantly lower than that in the pathogen-infected group. Furthermore, the Pro content (169.12 μg / g) in the 110 ml / L rosemary ethanol extract-treated group was the highest among all groups.

[0100] Figure 5 The study also demonstrated the effects of Fusarium oxysporum infection alone, and treatment with 110 ml / L rosemary extract and 130 ml / L sévenheise rosemary extract for two weeks, on CAT and POD activities compared to the negative control group. Application of rosemary extract to healthy *Anoectochilus taiwanensis* plants reduced CAT activity, but the increase in POD levels offset this effect. Figure 5 In infected plants, treatment with rosemary alcohol extract resulted in an increase in CAT and POD activities.

[0101] In summary, in vivo experiments confirmed that *Fusarium oxysporum* significantly reduces the biomass and *Anoectochilus roxburghii* content in *Anoectochilus taiwanensis*, while significantly increasing MDA and Pro levels and POD activity in the host plant. Interestingly, we found that applying rosemary extract to disease-free plants increased fresh stem weight while simultaneously increasing MDA, Pro, and POD levels and significantly decreasing CAT levels. This suggests that the tested rosemary extract can stimulate a moderate oxidative stress response in the host, thereby activating defensive metabolic pathways. Furthermore, the enhanced POD activity helps clear excess H2O2 from the host, while Pro activation promotes cell division and proliferation, increasing biomass rather than wasting energy on antioxidant consumption. Additionally, the tested rosemary extract can reduce the ineffective decomposition of H2O2 by inhibiting CAT activity, thus allowing more energy to be used for the synthesis and accumulation of photosynthetic products.

[0102] In vivo experiments also confirmed that rosemary extract can effectively reduce the levels of MDA, POD, and CAT in diseased plants and help increase the content of Pro in plants. It also effectively reduces the disease index of diseased plants. It can be inferred that rosemary extract helps to clear free radicals in diseased plants, thereby reducing the accumulation of MDA; and inhibits the over-activated levels of POD and CAT, avoiding the waste of defense resources; and maintains the homeostasis of cells through the accumulation of Pro.

[0103] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications 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. The use of rosemary extract in at least one of the following (1) to (4): (1) Promotes plant growth; (2) Increase the content of malondialdehyde and / or proline in plants; (3) Increase the activity of plant peroxidase; (4) Reduce the activity of plant catalase.

2. The application according to claim 1, characterized in that, The promotion of plant growth includes increasing at least one of the following: plant height, plant fresh weight, plant dry weight, plant root fresh weight, and plant root dry weight.

3. The application according to claim 1 or 2, characterized in that, The plant is a dicotyledonous or monocotyledonous plant.

4. The application according to claim 1, characterized in that, Methods for preparing rosemary extract include: Step 1: Take rosemary, dry it, and pulverize it to obtain rosemary powder; Step 2: Take the rosemary powder from Step 1, soak it in ethanol solution, and then extract it by percolation. The resulting percolate is then distilled under reduced pressure to obtain the extract paste. Step 3: Take the extract, dissolve it in ethanol solution, let it stand for incubation, remove the precipitate, and then obtain the rosemary extract.

5. The application according to claim 2, characterized in that, The rosemary includes Cyvenhey rosemary and / or pink rosemary.

6. The application according to claim 2, characterized in that, In steps 2 and 3, the concentration of the ethanol solution is 60 vol% to 80 vol%. In step 2, the soaking time is 36-60 hours; In step 3, the static culture time is 2 to 4 days.

7. The application according to claim 2, characterized in that, The mass-to-volume ratio of the rosemary powder in step 2 to the ethanol solution in step 3 is (40~60) g: (40~60) mL.

8. A culture medium for promoting plant growth, characterized in that, Includes rosemary extract and basal culture medium; The basal culture medium is PDA medium, and the concentration of the rosemary extract is 100~150mL / L.

9. A method for promoting plant growth, characterized in that, This includes applying rosemary extract to plants; The concentration of the rosemary extract is 100~150mL / L.

10. The method according to claim 9, characterized in that, The plant mentioned includes Taiwan silver thread orchid.

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