A method for preserving the original color of a plant specimen based on chemical treatment

Abstract

The present application relates to the technical field of plant specimen preservation, and particularly relates to a plant specimen original color preservation method based on chemical treatment, comprising the following steps: preparing dry plant specimens; preparing a premix solution; uniformly mixing mint, clove and thunder god vine, crushing, adding into an ethanol aqueous solution, sealing and standing for soaking, adding salicylic acid for ultrasonic treatment, filtering, removing solid matters, recovering ethanol, adding the dry plant specimens into the ethanol aqueous solution, soaking at a temperature of 30-40 DEG C, adding sodium salicylate, trehalose and a color protection agent for stirring, taking out the treated plant specimens, and obtaining pretreated plant specimens; uniformly spraying the premix solution to the surface of the pretreated plant specimens, placing the plant specimens into a specimen clamp for flattening, low-temperature cold treatment, then increasing the temperature for heat preservation, decreasing the temperature for cold treatment again, and freeze-drying; the present application can basically maintain the original color of the plant specimens, improves the identification rate for specimen identification, the preservation method has good mildew-proof effect, can effectively prevent specimen damage, is convenient for classification and preservation, and has longer durability.

Description

Technical Field

[0001] This invention relates to the field of plant specimen preservation technology, and in particular to a method for preserving the original color of plant specimens based on chemical treatment. Background Technology

[0002] Plant specimens are essentially whole or processed samples of plants preserved for observation, identification, and comparison. They are processed physical samples of plants and, in the work of preserving forest and grassland germplasm resources, are one of the five essential elements (seeds and other propagation materials, specimens, DNA samples, information, and images). They serve as permanent evidence for accurate identification of the germplasm and play an important role in scientific research, teaching, and popular science. Currently, the most widely used physical specimens are herbarium specimens, preserved specimens, laminated specimens, and resin specimens.

[0003] Preservative-preserved specimens are lifelike after immersion, making them easy to observe and identify. However, the commonly used formaldehyde solution is toxic and difficult to carry and transport. Laminated specimens are made by covering herbarium specimens with plastic film and then vacuum-sealing them. They combine the ease of handling of herbarium specimens with durability. However, the film covering prevents direct contact with the details of the plant specimen for observation, hindering identification. Resin specimens are made by embedding a two-component polymer material consisting of epoxy resin and a curing agent. They are three-dimensional, aesthetically pleasing, highly transparent, and durable, but the cost and technical requirements are relatively high. They are more commonly used in decorative materials and art processing.

[0004] Currently, herbarium specimens are the most widely used due to their ease of handling, low cost, environmental friendliness, and ease of access and portability. However, due to their low protective properties, long-term exposure to the air not only makes them susceptible to damage, but also causes severe discoloration during the preparation process, especially yellowing, browning, and blackening, due to the plant's own characteristics or high water content in its stems and leaves. This results in distorted colors in the plant specimens, making it impossible to maintain their original colors.

[0005] Based on the above problems, it is particularly important to provide a method for preparing plant specimens that can improve specimen strength and color retention, which can provide realistic evidence for the accurate identification of forest and grassland germplasm resources. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a method for preserving the original color of plant specimens based on chemical treatment.

[0007] A method for preserving the original color of plant specimens based on chemical treatment includes the following steps:

[0008] S1. Collect healthy, disease-free, fresh plant specimens, remove dirt from the surface of the specimens, unfold and pre-fix the plant specimens according to the required morphology for specimen observation, pre-cool them in liquid nitrogen vapor and then immerse them in liquid nitrogen for quick freezing.

[0009] S2. Transfer the quick-frozen plant specimens into a freeze dryer pre-cooled to -40 to -50°C to freeze-dry the plant specimens until the moisture content is reduced to 5-10 wt%, thus obtaining dried plant specimens.

[0010] S3. Add polyvinyl alcohol to deionized water and stir at 85-90℃. Cool down to 30-40℃, add hydroxypropyl methylcellulose, carboxymethyl chitosan, sorbitol, sodium phytate, and gelatin and stir. Add carboxylated nanocellulose and disperse by high-speed shearing. Add transglutaminase and ethanol, adjust the pH of the system to 6.2-6.8, and pass through a 100-200 mesh sieve to obtain a premixed solution.

[0011] S4. Mix peppermint, clove, and Tripterygium wilfordii evenly, pulverize and pass through a 20-mesh sieve, add to an ethanol-water solution, seal and let stand for 5-10 hours, add salicylic acid and sonicate, filter, remove solids, recover ethanol to the system ethanol content of 8-15wt%, add dried plant specimens, soak at 30-40℃, add sodium salicylate, trehalose, and color-protecting agent and stir, take out the treated plant specimens to obtain pretreated plant specimens;

[0012] S5. Spray the premixed solution evenly onto the surface of the pretreated plant specimen, place it in the specimen holder and flatten it, perform low-temperature cold treatment, then raise the temperature to 40-50℃ and keep it warm for 20-40 minutes, cool it down again and perform freeze drying.

[0013] Preferably, in S3, the mass ratio of polyvinyl alcohol, hydroxypropyl methylcellulose, carboxymethyl chitosan, sorbitol, sodium phytate, gelatin, carboxylated nanocellulose, transglutaminase, deionized water, and ethanol is 0.8-1.2:0.02-0.08:0.01-0.03:0.1-0.2:0.01-0.03:0.2-1:0.01-0.1:0.01-0.05:8-12:0.5-1.

[0014] Preferably, in S4, the mass ratio of peppermint, clove, Tripterygium wilfordii, salicylic acid, dried plant specimen, sodium salicylate, trehalose, and color-protecting agent is 10-20:15-25:5-15:1-2:40-60:0.05-0.2:0.5-1.5:1-2.

[0015] Preferably, in S4, during the ultrasonic process, the ultrasonic temperature is 50-60℃, the ultrasonic time is 20-40min, and the ultrasonic frequency is 60-70kHz.

[0016] Preferably, in S4, the concentration of the ethanol aqueous solution is 50-70 wt%, and the material-to-liquid ratio is 1:6-8.

[0017] Preferably, in S4, the color-protecting agent is at least one of sodium ascorbate, magnesium gluconate, and sodium citrate.

[0018] Preferably, in S3, the enzyme activity of the transglutaminase is 80-120 U / g.

[0019] Preferably, in S5, during the low-temperature cooling process, the temperature is first cooled at -8 to -12°C for 10-20 minutes, and then cooled at -15 to -20°C for 20-40 minutes.

[0020] Preferably, in S5, during the cooling and re-cooling process, the temperature is lowered to -10 to -20°C for 10-20 minutes.

[0021] Preferably, in S5, during the freeze-drying process, the drying is carried out at a vacuum of 8-15 Pa and a temperature of -10 to -20 °C for 20-25 hours.

[0022] Compared with existing technologies, the present invention has the following advantages:

[0023] In this invention, after peppermint is extracted in combination with clove and Tripterygium wilfordii, it not only has excellent anti-mildew and color-protecting effects under the action of salicylic acid, but also allows the herbarium specimen to maintain its original color, effectively avoiding rot, browning and other phenomena, and the durability is longer.

[0024] In this invention, gelatin, as a cross-linking substrate for transglutaminase, is combined with polyvinyl alcohol, carboxymethyl chitosan, and carboxylated nanocellulose in a premixed solution to form a film. The film layer sprayed on the plant surface is further cured during the subsequent heating and heat preservation process, forming a transparent, flexible, and non-brittle composite protective layer. This improves the herbarium specimen's resistance to bending and tearing, and helps maintain the plant's original shape and color. This invention not only has minimal impact on the plant's skeletal structure during the processing, but also preserves the shape of the herbarium specimen as perfectly as possible, maintaining the plant's shape before and after drying. Furthermore, the herbarium specimen is less prone to breakage, and retains its original color and shape for a longer period of time.

[0025] The method of this invention preserves the colors of plant specimens well, and the colors of various organs such as flowers, leaves, stems and roots of plant specimens can be kept consistent with the original living plants to the greatest extent. It can maintain the original colors of plant specimens, improve the identification rate of specimens, and the preservation method has good anti-mold effect, can effectively prevent specimen damage, facilitate classification and preservation, and has a longer durability. Attached Figure Description

[0026] Figure 1The image shows a comparison of the color difference ΔE of the leopard specimens obtained in Examples 1-5 and Comparative Examples 1-2.

[0027] Figure 2 This is a comparison image of the original leopard specimen obtained in Example 5 and the preservation effect after 12 months.

[0028] Figure 3 This is a comparison chart showing the preservation effect of the original leopard specimen obtained in Comparative Example 1 and the specimen preserved for 12 months.

[0029] Figure 4 This is a comparison chart showing the preservation effect of the original leopard specimen and the specimen preserved for 12 months, as shown in Comparative Example 2.

[0030] Figure 5 This is a comparison image of the original and moldy leopard specimens obtained in Example 5 after 3 months.

[0031] Figure 6 This is a comparison image of the original and moldy leopard specimens obtained in Comparative Example 1 after 3 months.

[0032] Figure 7 This is a comparison image of the original and moldy leopard specimens obtained in Comparative Example 2 after 3 months. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0034] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0035] The gelatin used below was purchased from Anhui Zhonghong Bioengineering Co., Ltd. The hydroxypropyl methylcellulose used below was purchased from Jinan Zhiheng Zhiyuan Chemical Technology Co., Ltd. The carboxymethyl chitosan used below was purchased from Wuhan Shuer Biotechnology Co., Ltd., with a degree of deacetylation of 85%. The carboxylated nanocellulose used below was purchased from Nanjing Tianlu Nanotechnology Co., Ltd., model TL-001. The transglutaminase used below was purchased from Hebei Jijie Biotechnology Co., Ltd., with an enzyme activity of 100 U / g. The polyvinyl alcohol (30-70 kDa) used below was purchased from Hubei Jianchu Biomedical Co., Ltd.

[0036] Example 1

[0037] A method for preserving the original color of plant specimens based on chemical treatment includes the following steps:

[0038] S1. Collect healthy, disease-free, fresh plant specimens, remove dirt from the surface of the specimens, spread out the plant specimens according to the required morphology for specimen observation and pre-fix them, place them in liquid nitrogen vapor for 1 minute to pre-cool, and then immerse them in liquid nitrogen for 2 minutes to quick-freeze.

[0039] S2. Transfer the quick-frozen plant specimens into a freeze dryer pre-cooled to -40℃ and freeze-dry until the moisture content of the plant specimens drops to 5wt% to obtain dried plant specimens;

[0040] S3. Add 8g of polyvinyl alcohol to 80g of deionized water, stir at 85℃ for 30min, cool to 30℃, add 0.2g of hydroxypropyl methylcellulose, 0.1g of carboxymethyl chitosan, 1g of sorbitol, 0.1g of sodium phytate, and 10g of gelatin, stir for 20min, add 0.1g of carboxylated nanocellulose, shear and disperse at 5000r / min for 5min, add 0.1g of transglutaminase and 5g of ethanol, adjust the pH of the system to 6.2-6.8, pass through a 100-mesh sieve to obtain the premixed solution;

[0041] S4. Mix 100g of peppermint, 150g of clove, and 50g of Tripterygium wilfordii evenly, pulverize and pass through a 20-mesh sieve, add to a 50wt% ethanol aqueous solution with a material-to-liquid ratio of 1:6, seal and let stand for 5 hours, add 10g of salicylic acid, sonicate at 50℃ for 20 minutes at a frequency of 60kHz, filter to remove solids, recover ethanol until the ethanol content of the system is 8wt%, add 400g of dried plant specimen, soak at 30℃ for 10 minutes, add 0.5g of sodium salicylate, 5g of trehalose, and 10g of sodium ascorbate, stir at 20r / min for 10 minutes, take out the treated plant, and obtain the pretreated plant specimen;

[0042] S5. Spray the premixed solution evenly onto the surface of the pretreated plant specimen, place it in the specimen holder and flatten it, cold treat at -8℃ for 10 min, cold treat at -15℃ for 20 min, raise the temperature to 40℃ and keep it warm for 20 min, then cool it down to -10℃ and cold treat for 10 min, and dry it at a vacuum of 8 Pa and a temperature of -10℃ for 20 h.

[0043] Example 2

[0044] A method for preserving the original color of plant specimens based on chemical treatment includes the following steps:

[0045] S1. Collect healthy, disease-free, fresh plant specimens, remove dirt from the surface of the specimens, spread out the plant specimens according to the required morphology for specimen observation and pre-fix them, place them in liquid nitrogen vapor for pre-cooling for 3 minutes, and then immerse them in liquid nitrogen for quick freezing for 5 minutes.

[0046] S2. Transfer the quick-frozen plant specimens into a freeze dryer pre-cooled to -50℃ and freeze-dry until the moisture content of the plant specimens drops to 10wt% to obtain dried plant specimens;

[0047] S3. Add 12g of polyvinyl alcohol to 120g of deionized water and stir at 90℃ for 60min. Cool down to 40℃, add 0.8g of hydroxypropyl methylcellulose, 0.3g of carboxymethyl chitosan, 2g of sorbitol, 0.3g of sodium phytate, and 2g of gelatin. Stir for 40min, add 1g of carboxylated nanocellulose, and shear and disperse at 7000r / min for 10min. Add 0.5g of transglutaminase and 10g of ethanol, adjust the pH of the system to 6.2-6.8, and pass through a 200-mesh sieve to obtain the premixed solution.

[0048] S4. Mix 200g of peppermint, 250g of clove, and 150g of Tripterygium wilfordii evenly, pulverize and pass through a 20-mesh sieve, add to a 70wt% ethanol aqueous solution with a material-to-liquid ratio of 1:7, seal and let stand for 10 hours, add 20g of salicylic acid, sonicate at 60℃ for 40 minutes at a frequency of 70kHz, filter to remove solids, recover ethanol until the ethanol content of the system is 15wt%, add 600g of dried plant specimen, soak at 40℃ for 30 minutes, add 2g of sodium salicylate, 15g of trehalose, and 20g of sodium ascorbate, stir at 40r / min for 20 minutes, take out the treated plant, and obtain the pretreated plant specimen;

[0049] S5. Spray the premixed solution evenly onto the surface of the pretreated plant specimen, place it in the specimen holder and flatten it, cold treat at -12℃ for 20 min, cold treat at -20℃ for 40 min, raise the temperature to 50℃ and keep it warm for 40 min, then cool it down to -20℃ and cold treat for 20 min, and dry it at a vacuum of 15 Pa and a temperature of -20℃ for 25 h.

[0050] Example 3

[0051] A method for preserving the original color of plant specimens based on chemical treatment includes the following steps:

[0052] S1. Collect healthy, disease-free, fresh plant specimens, remove dirt from the surface of the specimens, spread out the plant specimens according to the required morphology for specimen observation and pre-fix them, place them in liquid nitrogen vapor for pre-cooling for 1.5 min, and then immerse them in liquid nitrogen for quick freezing for 3 min.

[0053] S2. Transfer the quick-frozen plant specimens into a freeze dryer pre-cooled to -42℃ and freeze-dry until the moisture content of the plant specimens drops to 6wt% to obtain dried plant specimens;

[0054] S3. Add 9g of polyvinyl alcohol to 90g of deionized water and stir at 86℃ for 35min. Cool down to 32℃, add 0.5g of hydroxypropyl methylcellulose, 0.15g of carboxymethyl chitosan, 1.2g of sorbitol, 0.15g of sodium phytate, and 5g of gelatin. Stir for 25min, add 0.21g of carboxylated nanocellulose, and shear and disperse at 6000r / min for 6min. Add 0.2g of transglutaminase and 6g of ethanol, adjust the pH of the system to 6.2-6.8, and pass through a 120-mesh sieve to obtain the premixed solution.

[0055] S4. Mix 120g of peppermint, 180g of clove, and 80g of Tripterygium wilfordii evenly, pulverize and pass through a 20-mesh sieve, add to a 55wt% ethanol aqueous solution with a material-to-liquid ratio of 1:6.5, seal and let stand for 6 hours, add 15g of salicylic acid, sonicate at 55℃ for 25 minutes at a frequency of 62kHz, filter to remove solids, recover ethanol until the ethanol content of the system is 9.2wt%, add 450g of dried plant specimen, soak at 32℃ for 15 minutes, add 1g of sodium salicylate, 8g of trehalose, and 12g of magnesium gluconate, stir at 25r / min for 12 minutes, take out the treated plant, and obtain the pretreated plant specimen;

[0056] S5. Spray the premixed solution evenly onto the surface of the pretreated plant specimen, place it in the specimen holder and flatten it, cold treat at -9℃ for 12 min, cold treat at -16℃ for 25 min, raise the temperature to 42℃ and keep it warm for 25 min, then cool it down to -12℃ and cold treat for 12 min, and dry it at a vacuum of 10 Pa and a temperature of -12℃ for 21 h.

[0057] Example 4

[0058] A method for preserving the original color of plant specimens based on chemical treatment includes the following steps:

[0059] S1. Collect healthy, disease-free, fresh plant specimens, remove dirt from the surface of the specimens, spread out the plant specimens according to the required morphology for specimen observation and pre-fix them, place them in liquid nitrogen vapor for 2 minutes to pre-cool, and then immerse them in liquid nitrogen for 4 minutes to quick-freeze.

[0060] S2. Transfer the quick-frozen plant specimens into a freeze dryer pre-cooled to -46℃ and freeze-dry until the moisture content of the plant specimens drops to 8.5wt% to obtain dried plant specimens;

[0061] S3. Add 11.5g of polyvinyl alcohol to 115g of deionized water and stir at 88℃ for 55min. Cool down to 38℃, add 0.7g of hydroxypropyl methylcellulose, 0.25g of carboxymethyl chitosan, 1.8g of sorbitol, 0.25g of sodium phytate, and 10g of gelatin. Stir for 35min, add 0.08g of carboxylated nanocellulose, and shear and disperse at 6500r / min for 8min. Add 0.4g of transglutaminase and 8g of ethanol, adjust the pH of the system to 6.2-6.8, and pass through a 150-mesh sieve to obtain the premixed solution.

[0062] S4. Mix 180g of peppermint, 200g of clove, and 120g of Tripterygium wilfordii evenly, pulverize and pass through a 20-mesh sieve, add to a 65wt% ethanol aqueous solution with a material-to-liquid ratio of 1:7.5, seal and let stand for 9 hours, add 18g of salicylic acid, sonicate at 58℃ for 35 minutes at a frequency of 68kHz, filter to remove solids, recover ethanol until the ethanol content of the system is 13wt%, add 550g of dried plant specimen, soak at 38℃ for 25 minutes, add 1.5g of sodium salicylate, 12g of trehalose, and 18g of magnesium gluconate, stir at 36r / min for 18 minutes, take out the treated plant, and obtain the pretreated plant specimen;

[0063] S5. Spray the premixed solution evenly onto the surface of the pretreated plant specimen, place it in the specimen holder and flatten it, cold treat at -11℃ for 18 min, cold treat at -18℃ for 35 min, raise the temperature to 48℃ and keep it warm for 35 min, then cool it down to -18℃ and cold treat for 18 min, and dry it at a vacuum of 12 Pa and a temperature of -18℃ for 22 h.

[0064] Example 5

[0065] A method for preserving the original color of plant specimens based on chemical treatment includes the following steps:

[0066] S1. Collect healthy, disease-free, fresh plant specimens, remove dirt from the surface of the specimens, spread out the plant specimens according to the required morphology for specimen observation and pre-fix them, place them in liquid nitrogen vapor for 2 minutes to pre-cool, and then immerse them in liquid nitrogen for 4 minutes to quick-freeze.

[0067] S2. Transfer the quick-frozen plant specimens into a freeze dryer pre-cooled to -45℃ and freeze-dry until the moisture content of the plant specimens drops to 6.5wt% to obtain dried plant specimens;

[0068] S3. Add 10g of polyvinyl alcohol to 100g of deionized water and stir at 88℃ for 40min. Cool down to 35℃, add 0.5g of hydroxypropyl methylcellulose, 0.23g of carboxymethyl chitosan, 1g of sorbitol, 0.2g of sodium phytate, and 5g of gelatin. Stir for 30min, add 0.6g of carboxylated nanocellulose, and shear and disperse at 6000r / min for 6min. Add 0.4g of transglutaminase and 6g of ethanol, adjust the pH of the system to 6.2-6.8, and pass through a 150-mesh sieve to obtain the premixed solution.

[0069] S4. Mix 180g of peppermint, 200g of clove, and 100g of Tripterygium wilfordii evenly, pulverize and pass through a 20-mesh sieve, add to a 60wt% ethanol aqueous solution with a material-to-liquid ratio of 1:7, seal and let stand for 10 hours, add 15g of salicylic acid, sonicate at 55℃ for 30 minutes at a frequency of 65kHz, filter to remove solids, recover ethanol until the ethanol content of the system is 12wt%, add 500g of dried plant specimen, soak at 35℃ for 20 minutes, add 1g of sodium salicylate, 12g of trehalose, and 15g of sodium ascorbate, stir at 30r / min for 15 minutes, take out the treated plant, and obtain the pretreated plant specimen;

[0070] S5. Spray the premixed solution evenly onto the surface of the pretreated plant specimen, place it in the specimen holder and flatten it, cold treat at -10℃ for 15 min, cold treat at -18℃ for 30 min, raise the temperature to 45℃ and keep it warm for 30 min, then lower it to -15℃ and cold treat for 15 min, and dry it at a vacuum of 10 Pa and a temperature of -15℃ for 22 h.

[0071] Comparative Example 1

[0072] A method for preserving the original color of plant specimens based on chemical treatment includes the following steps:

[0073] S1. Collect healthy, disease-free, fresh plant specimens, remove dirt from the surface of the specimens, spread out the plant specimens according to the required morphology for specimen observation and pre-fix them, place them in liquid nitrogen vapor for 2 minutes to pre-cool, and then immerse them in liquid nitrogen for 4 minutes to quick-freeze.

[0074] S2. Transfer the quick-frozen plant specimens into a freeze dryer pre-cooled to -45℃ and freeze-dry until the moisture content of the plant specimens drops to 6.5wt% to obtain dried plant specimens;

[0075] S3. Add 10g of polyvinyl alcohol to 100g of deionized water and stir at 88℃ for 40min. Cool down to 35℃, add 0.5g of hydroxypropyl methylcellulose, 0.23g of carboxymethyl chitosan, 1g of sorbitol, 0.2g of sodium phytate, and 5g of gelatin. Stir for 30min, add 0.6g of carboxylated nanocellulose, and shear and disperse at 6000r / min for 6min. Add 0.4g of transglutaminase and 6g of ethanol, adjust the pH of the system to 6.2-6.8, and pass through a 150-mesh sieve to obtain the premixed solution.

[0076] S4. Mix 230g of peppermint and 250g of clove evenly, pulverize and pass through a 20-mesh sieve, add to a 60wt% ethanol aqueous solution with a material-to-liquid ratio of 1:7, seal and let stand for 10 hours, add 15g of salicylic acid, sonicate at 55℃ for 30 minutes at a frequency of 65kHz, filter to remove solids, recover ethanol until the ethanol content of the system is 12wt%, add 500g of dried plant specimen, soak at 35℃ for 20 minutes, add 1g of sodium salicylate, 12g of trehalose and 15g of sodium ascorbate, stir at 30r / min for 15 minutes, take out the treated plant to obtain the pretreated plant specimen;

[0077] S5. Spray the premixed solution evenly onto the surface of the pretreated plant specimen, place it in the specimen holder and flatten it, cold treat at -10℃ for 15 min, cold treat at -18℃ for 30 min, raise the temperature to 45℃ and keep it warm for 30 min, then cool it down to -15℃ and cold treat for 15 min, and dry it at a vacuum of 10 Pa and a temperature of -15℃ for 22 h.

[0078] Comparative Example 2

[0079] A method for preserving the original color of plant specimens based on chemical treatment includes the following steps:

[0080] S1. Collect healthy, disease-free, fresh plant specimens, remove dirt from the surface of the specimens, spread out the plant specimens according to the required morphology for specimen observation and pre-fix them, place them in liquid nitrogen vapor for 2 minutes to pre-cool, and then immerse them in liquid nitrogen for 4 minutes to quick-freeze.

[0081] S2. Transfer the quick-frozen plant specimens into a freeze dryer pre-cooled to -45℃ and freeze-dry until the moisture content of the plant specimens drops to 6.5wt% to obtain dried plant specimens;

[0082] S3. Mix 180g of peppermint, 200g of clove, and 100g of Tripterygium wilfordii evenly, pulverize and pass through a 20-mesh sieve, add to a 60wt% ethanol aqueous solution with a material-to-liquid ratio of 1:7, seal and let stand for 10 hours, add 15g of salicylic acid, sonicate at 55℃ for 30 minutes at a frequency of 65kHz, filter to remove solids, recover ethanol until the ethanol content of the system is 12wt%, add 500g of dried plant specimen, soak at 35℃ for 20 minutes, add 1g of sodium salicylate, 5g of gelatin, 12g of trehalose, and 15g of sodium ascorbate, stir at 30r / min for 15 minutes, take out the treated plant, and obtain the pretreated plant specimen;

[0083] S4. Place the specimen in a specimen holder and flatten it. Cool it at -10℃ for 15 minutes, then at -18℃ for 30 minutes. Raise the temperature to 45℃ and hold for 30 minutes. Cool it to -15℃ for 15 minutes. Dry it at a vacuum of 10Pa and a temperature of -15℃ for 22 hours.

[0084] test

[0085] 1. Color protection effect

[0086] Healthy leopards (scientific name: *Pleurotus ostreatus*) were collected from the same time and area. Codonopsis javanica (Blume) Hook. f.), select samples that are similar in size, shape and color, and prepare herbarium specimens according to the methods of Examples 1-5, Comparative Examples 1 and 2 respectively. Each group has no less than 3 parallel samples.

[0087] The L*, a*, and b* values ​​of the prepared herbarium leaf specimens at fixed positions on the front surface were measured using a colorimeter and compared with the L*, a*, and b* values ​​of the corresponding positions on fresh leopard leaf specimens from the same batch to obtain ΔL*, Δa*, and Δb*. The color difference ΔE was then calculated using the following formula:

[0088] ΔE=[(ΔL*)²+(Δa*)²+(Δb*)²] 1 / 2

[0089] Table 1. Color difference ΔE results of leopard specimens obtained in Examples 1-5 and Comparative Examples 1-2 Example 1 2.3 Example 2 2.5 Example 3 1.9 Example 4 2.1 Example 5 1.7 Comparative Example 1 3.2 Comparative Example 2 4.9

[0090] The results of the color difference ΔE measurement are shown in Table 1. Figure 1 As shown, the color difference ΔE of the specimens obtained in Examples 1-5 is significantly smaller than that in Comparative Examples 1 and 2, indicating that the method has a good color preservation effect in leopard specimens.

[0091] 2. Preservation effect

[0092] Healthy leopards collected at the same time and in the same area were selected. Samples of similar size, shape, and color were chosen and prepared according to the methods of Examples 1-5, Comparative Examples 1, and Comparative Examples 2, respectively. The obtained specimens were stored under the same conditions, and the plant condition was observed at 1 month, 3 months, 6 months, and 12 months after storage. Quality evaluation was performed, and the evaluation results are shown in Table 2. The original plant condition and the plant condition after 12 months of storage for the specimens obtained in Example 5 and Comparative Examples 1-2 are shown in Table 2. Figure 2-4 As shown.

[0093] Quality evaluation is divided into 3 levels:

[0094] Advantages: The flowers, branches, leaves, or corresponding organs of the plants retain their original colors and shapes after preservation;

[0095] Good: The flowers, branches, leaves, or corresponding organs of the plant retain their color after preservation, but the fading is more obvious and the lifelikeness of the shape is reduced;

[0096] Poor: The original colors of the flowers, branches, leaves, or corresponding organs of the plant are basically lost after preservation, and the realism of the form is significantly reduced.

[0097] Table 2 Quality evaluation of leopard specimens in each group Example 1 excellent excellent good good Example 2 excellent excellent good good Example 3 excellent excellent good good Example 4 excellent excellent excellent good Example 5 excellent excellent excellent good Comparative Example 1 excellent good Difference Difference Comparative Example 2 good good Difference Difference

[0098] As shown in Table 2, the leopard specimens prepared in Examples 1-5 remained in good condition after 12 months of storage. Figure 2-4 It can be seen that the leopard specimen prepared in Example 5 can still maintain its original color and shape well after 12 months of storage, and the preservation effect is better than that of Comparative Example 1 and Comparative Example 2.

[0099] 3. Anti-mildew effect

[0100] Using *Pleurotus eryngii* as the experimental subject, specimens were collected from the same area at the same time. *Pleurotus eryngii* specimens with similar inflorescence or leaf size, shape, and color were selected, and specimens were prepared using the methods of Examples 1-5, Comparative Examples 1, and Comparative Examples 2, respectively. The obtained *Pleurotus eryngii* specimens were placed in a constant temperature and humidity chamber, with the temperature controlled at 30-32℃ and the relative humidity at 85-90%. The formation of mycelium and mold spots on the surface of the *Pleurotus eryngii* specimens was observed at 1 month and 3 months, and the results are shown in Table 3. The original plant state and the plant state after 3 months of mold growth for the specimens obtained in Example 5 and Comparative Examples 1-2 are shown in Table 3. Figure 5-7 As shown.

[0101] The mold severity rating is as follows:

[0102] "-" indicates that no hyphae or mold spots are visible to the naked eye on the sample surface.

[0103] A "+" indicates that a small amount of hyphae are visible on the sample surface, but no obvious mold spots have formed.

[0104] "++" indicates that a large number of mycelia are visible on the sample surface, and obvious mold spots appear.

[0105] Table 3. Evaluation of mold severity in different groups of leopard specimens Example 1 － － Example 2 － － Example 3 － － Example 4 － － Example 5 － － Comparative Example 1 － ＋ Comparative Example 2 － ＋＋

[0106] As shown in Table 3, the leopard specimens prepared in Examples 1-5 remained in a "-" state after three months of observation. Figure 5-7 It can be seen that the leopard specimen prepared in Example 5 did not show obvious mold growth after being placed under high humidity conditions for a long time, indicating that the method has a good anti-mold effect on plant specimens.

[0107] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application includes any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope of this application.

Claims

1. A method for preserving the original color of plant specimens based on chemical treatment, characterized in that, Includes the following steps: S1. Collect healthy, disease-free, fresh plant specimens, remove dirt from the surface of the specimens, unfold and pre-fix the plant specimens according to the required morphology for specimen observation, pre-cool them in liquid nitrogen vapor and then immerse them in liquid nitrogen for quick freezing. The plant in question is a golden leopard; S2. Transfer the quick-frozen plant specimens into a freeze dryer pre-cooled to -40 to -50°C to freeze-dry the plant specimens to reduce the moisture content to 5-10 wt% and obtain dried plant specimens. S3. Add polyvinyl alcohol to deionized water and stir at 85-90℃. Cool down to 30-40℃, add hydroxypropyl methylcellulose, carboxymethyl chitosan, sorbitol, sodium phytate, and gelatin, and stir. Add carboxylated nanocellulose and shear disperse at 5000-7000 r / min. Add transglutaminase and ethanol, adjust the pH of the system to 6.2-6.8, and pass through a 100-200 mesh sieve to obtain a premixed solution. The mass ratio of polyvinyl alcohol, hydroxypropyl methylcellulose, carboxymethyl chitosan, sorbitol, sodium phytate, gelatin, carboxylated nanocellulose, transglutaminase, deionized water, and ethanol is 0.8-1.2:0.02-0.08:0.01-0.03:0.1-0.2:0.01-0.03:0.2-1:0.01-0.1:0.01-0.05:8-12:0.5-1; S4. Mix peppermint, clove, and Tripterygium wilfordii evenly, pulverize and pass through a 20-mesh sieve, add to an ethanol-water solution, seal and let stand for 5-10 hours, add salicylic acid and sonicate, filter, remove solids, recover ethanol to the system ethanol content of 8-15wt%, add dried plant specimens, soak at 30-40℃, add sodium salicylate, trehalose, and color-protecting agent and stir, take out the treated plant specimens to obtain pretreated plant specimens; The mass ratio of peppermint, clove, Tripterygium wilfordii, salicylic acid, dried plant specimen, sodium salicylate, trehalose, and color-protecting agent is 10-20:15-25:5-15:1-2:40-60:0.05-0.2:0.5-1.5:1-2; S5. Spray the premixed solution evenly onto the surface of the pretreated plant specimen, place it in the specimen holder and flatten it, perform low-temperature cold treatment, then raise the temperature to 40-50℃ and keep it warm for 20-40 minutes, cool it down again and perform freeze drying.

2. The method for preserving the original color of plant specimens based on chemical treatment according to claim 1, characterized in that, In S4, during the ultrasound process, the ultrasound temperature is 50-60℃, the ultrasound time is 20-40min, and the ultrasound frequency is 60-70kHz.

3. The method for preserving the original color of plant specimens based on chemical treatment according to claim 1, characterized in that, In S4, the concentration of the ethanol-water solution is 50-70 wt%, and the material-to-liquid ratio is 1:6-8; The material-liquid ratio is the ratio of the mass of the solid material to the volume of the liquid material, with peppermint, clove, and Tripterygium wilfordii as solid materials and an aqueous ethanol solution as liquid material.

4. The method for preserving the original color of plant specimens based on chemical treatment according to claim 1, characterized in that, In S4, the color-protecting agent is at least one of sodium ascorbate, magnesium gluconate, and sodium citrate.

5. The method for preserving the original color of plant specimens based on chemical treatment according to claim 1, characterized in that, In S3, the enzyme activity of the glutamine transaminase is 80-120 U / g.

6. The method for preserving the original color of plant specimens based on chemical treatment according to claim 1, characterized in that, In S5, during the low-temperature cooling process, the temperature is first cooled at -8 to -12℃ for 10-20 minutes, and then cooled at -15 to -20℃ for 20-40 minutes.

7. The method for preserving the original color of plant specimens based on chemical treatment according to claim 1, characterized in that, In S5, during the cooling and re-cooling process, the temperature is lowered to -10 to -20℃ for 10-20 minutes.

8. The method for preserving the original color of plant specimens based on chemical treatment according to claim 1, characterized in that, In S5, during the freeze-drying process, drying is carried out at a vacuum of 8-15 Pa and a temperature of -10 to -20 °C for 20-25 hours.

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