Application of mesoporous silica nanoparticles in improving salt tolerance of Physcomitrella patens

Abstract

The present invention discloses the application of mesoporous silica nanoparticles in improving the salt tolerance of Physcomitrella patens, belonging to the technical field of plant stress resistance; wherein, the particle size of the mesoporous silica nanoparticles is 80-120 nm, and they have a negative potential. The mesoporous silica nanoparticles provided by the present invention can effectively reduce the reactive oxygen content increased by salt stress in Physcomitrella patens, alleviate salt stress by reducing the accumulation of reactive oxygen, and promote ion balance to enhance the resistance of Physcomitrella patens to salt stress. At the same time, the preparation process of the mesoporous silica nanoparticles is relatively simple, environmentally friendly, low-cost and has no toxic side effects, laying a foundation for exploring the effects of nanomaterials on plant stress resistance and physiological processes using Physcomitrella patens as a model plant.

Description

Technical Field

[0001] The invention belongs to the technical field of plant stress resistance, and particularly relates to application of mesoporous silica nanoparticles in improving the salt tolerance of Physcomitrella patens. Background Art

[0002] Excessive salt concentrations in the soil, resulting in saline-alkali soils, can severely impact plant growth and development. Salt stress is a major abiotic stress contributing to crop yield losses and quality degradation. While plants typically employ mechanisms to combat salt stress, these mechanisms are limited in their effectiveness. Safely and effectively mitigating the effects of high salt stress on plants remains an urgent challenge.

[0003] Traditional breeding and chemical methods are ineffective in improving plant resistance to salt stress and are likely to pose a threat to the environment. In recent years, artificial nanomaterials, as an emerging technology, have been increasingly applied in agricultural production, offering new approaches to alleviating the challenge of high salt stress in plants. Existing research suggests that nanomaterials play a positive role in the growth, development, and stress response of some plants, but the mechanisms of action of nanomaterials in plants require further investigation.

[0004] Physcomitrium patens is an important model plant, characterized by low morphological complexity, simple developmental patterns, and strong stress tolerance. Therefore, studying the uptake, localization, and interaction mechanisms of nanomaterials in Physcomitrium patens is crucial for uncovering the mechanisms by which nanomaterials affect plant stress tolerance and exploring plant physiological processes. However, there are currently no reports on the use of nanomaterials in enhancing stress tolerance in Physcomitrium patens. Summary of the Invention

[0005] The inventors discovered in their research that mesoporous silica nanoparticles (MSN) with a specific particle size and electric potential can effectively improve the salt tolerance of Physcomitrella patens, providing a theoretical and experimental basis for subsequent research.

[0006] Specifically, the technical solution of the present invention is as follows:

[0007] The present invention provides an application of mesoporous silica nanoparticles in improving the salt tolerance of Physcomitrella patens. The mesoporous silica nanoparticles have a particle size of 80-120 nm and exhibit a negative potential.

[0008] The present invention's research shows that negatively charged mesoporous silica nanoparticles within the aforementioned particle size range can be traced and found to be able to enter the plant's body, thereby inducing salt tolerance in the plant. Specifically, the aforementioned mesoporous silica nanoparticles exert their effects through at least the following pathways:

[0009] a) After entering the body of Physcomitrella patens, it is distributed in the intercellular spaces, cell walls and cytoplasm;

[0010] b) Increase the expression level of ROS (reactive oxygen species) related genes and reduce the accumulation of ROS;

[0011] c) Affects the expression levels of genes involved in calcium signaling and ion homeostasis.

[0012] Preferably, in the above application, the mesoporous silica nanoparticles are spherical with a relatively smooth surface. As shown in one embodiment of the present invention, when spike-like protrusions are present on the surface of the mesoporous silica nanoparticles, their salt tolerance is significantly reduced compared to spherical particles.

[0013] Preferably, in the above application, the mesoporous silica nanoparticles are modified with fluorescein isothiocyanate (FITC) to produce fluorescent mesoporous silica nanoparticles. These fluorescent mesoporous silica nanoparticles not only enhance the salt tolerance of Physcomitrella patens but can also be used to track the location and distribution of MSNs in the moss, thereby enabling studies of the absorption and localization of MSNs by the moss.

[0014] Preferably, in the above application, the method for preparing mesoporous silica nanoparticles comprises the following steps:

[0015] S1. Add cetyltrimethylammonium chloride (CTAC) and water to a reaction vessel, heat and stir thoroughly;

[0016] S2. Add triethanolamine (TEA) to the reaction system obtained in step S1, mix well, and then add tetraethyl orthosilicate (TEOS). Maintain the reaction temperature and continue stirring until the reaction is complete. Centrifuge to remove the supernatant, and wash the resulting solid with water and methanol, respectively, to obtain mesoporous silica nanoparticles composited with CTAC.

[0017] S3, dispersing the mesoporous silica nanoparticles obtained in step S2 into methanol, and then adding concentrated hydrochloric acid to react to remove CTAC;

[0018] S4. Centrifuge the reaction system obtained in step S3, wash the obtained solid with water and methanol in sequence, and continue washing with water to obtain mesoporous silica nanoparticles stored in the aqueous phase, and vacuum dry.

[0019] More preferably, in the reaction system obtained in step S1 above, the mass fraction of CTAC is 9-12%.

[0020] More preferably, in the above step S2, the mass volume ratio of triethanolamine to ethyl orthosilicate is (0.60~0.62):15.

[0021] More preferably, in the above steps S1 and S2, the heating temperature is controlled at 93-98°C.

[0022] More preferably, in the above step S3, the volume ratio of methanol to concentrated hydrochloric acid is 1:(0.05~0.06).

[0023] More preferably, the above preparation method further comprises the following steps:

[0024] S5. Mesoporous silica nanoparticles were dispersed in methanol, and amino groups were modified on the mesoporous silica nanoparticles using 3-aminopropyltriethoxysilane (APTES), and then reacted with fluorescein isothiocyanate to prepare fluorescent mesoporous silica nanoparticles.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention discovered for the first time that mesoporous silica nanoparticles under specific conditions can effectively improve the resistance of Physcomitrella patens to salt stress. By constructing fluorescent mesoporous silica nanoparticles and tracing them, it was revealed that the mesoporous silica nanoparticles enter the body of Physcomitrella patens and stimulate the occurrence of related plant immune responses, thereby promoting the salt tolerance of Physcomitrella patens. Specifically, the mesoporous silica nanoparticles provided by the present invention can enhance the salt tolerance of Physcomitrella patens by reducing the accumulation of reactive oxygen species and promoting ion balance. At the same time, the mesoporous silica nanoparticles provided by the present invention have the advantages of simple preparation, low cost, eco-friendly, safe and pollution-free, etc., which provides a basis for exploring the effects of nanomaterials on plant stress resistance and plant physiological processes using Physcomitrella patens. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Transmission electron microscopy image (A) and particle size potential map (B) of mesoporous silica nanoparticles (MSN) prepared in Example 1 of the present invention;

[0028] Figure 2 Graphs showing the effects of mesoporous silica nanoparticles on salt stress in Example 2 of the present invention are shown; A shows the growth of Physcomitrella patens after six days of salt stress and during the recovery period, and B shows the photosynthetic index (maximum photochemical efficiency Fv / Fm) of Physcomitrella patens after six days of salt stress and during the recovery period.

[0029] Figure 3 Figure 4 shows the results of the study on the location of fluorescent mesoporous silica nanoparticles in Physcomitrella patens in Example 4 of the present invention; A and B show the distribution of MSNs in Physcomitrella patens at 24 hours, with S2R representing the distance from the top leaf to the rhizome and R2S representing the distance from the rhizome to the top leaf, and the scale bar is 1 mm; C shows the distribution of MSNs in Physcomitrella patens cells at 4 hours, and the scale bar is 50 μm;

[0030] Figure 4Graphs showing the effects of mesoporous silica nanoparticles on reactive oxygen species in Physcomitrella patens under salt stress in Example 5 of the present invention; A shows the results of hydrogen peroxide detection using DAB staining, and B shows the results of superoxide detection using NBT staining. The scale bars for A and B are both 1 mm, and C shows the expression levels of reactive oxygen-related genes.

[0031] Figure 5 The results of the effect of mesoporous silica nanoparticles on calcium signal transduction and ion balance of Physcomitrella patens under salt stress in Example 6 of the present invention are shown in FIG. A shows the change in cytoplasmic calcium concentration of Physcomitrella patens under 300 mg / L MSN, and B shows the change in Ca 2+ Concentration-dependent Ca 2+ Expression profiles of sensor genes (PpCML and PpCDPK3) and genes related to ion balance (PpGORK);

[0032] Figure 6 This is a diagram showing the growth status of Arabidopsis thaliana after 7 days of salt stress in Comparative Example 1 of the present invention;

[0033] Figure 7 This is a growth state diagram of Physcomitrella patens in the recovery period after salt stress in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The term "comprise" and any variations thereof in the description and claims of the present invention are intended to cover non-exclusive inclusions.

[0035] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. It should be understood that the embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0036] If no specific techniques or conditions are specified in the following examples, the procedures were carried out in accordance with the techniques or conditions described in the literature in the field or in accordance with the product instructions; if no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0037] Example 1

[0038] This example provides a method for preparing mesoporous silica nanoparticles (MSNs) capable of promoting salt tolerance in Physcomitrella patens, comprising the following steps:

[0039] To a 500 mL flask, add 20 g of CTAC and 200 mL of water, stirring continuously. Maintain the reaction temperature at 95°C in an oil bath. Add 0.60 g of TEA to the reaction system and continue stirring for 1 hour to dissolve and thoroughly mix the solids. Then, add 15 mL of TEOS and continue stirring for another hour while maintaining the reaction temperature at 95°C in an oil bath. Remove the supernatant by centrifugation, and wash the resulting solid with water and methanol three times each. This yields mesoporous silica nanoparticles composited with CTAC, which are then dried under vacuum for quantitative determination.

[0040] 0.5 g of CTAC-compounded mesoporous silica nanoparticles was dispersed in 80 mL of methanol and stirred thoroughly. 4.5 mL of concentrated hydrochloric acid was then added to the reaction system. After vigorous stirring for 24 hours, the reaction system was maintained at 60°C in an oil bath and refluxed for 48 hours to remove the CTAC template. The supernatant was then removed by centrifugation, and the resulting solid was washed with water and methanol six times, followed by three more washes with water, to obtain the mesoporous silica nanoparticles stored in an aqueous phase. Finally, the solution was vacuum-dried to obtain a quantitative result.

[0041] The morphology and structural characteristics of the mesoporous silica nanoparticles obtained in this example were observed using a transmission electron microscope. Figure 1 As shown in Figure A, the mesoporous silica nanoparticles are relatively evenly dispersed spherical particles with good size uniformity.

[0042] At the same time, the particle size of mesoporous silica nanoparticles was measured by dynamic light scattering method, and the electrokinetic potential of mesoporous silica nanoparticles was measured by zeta potential tester. Figure 1 As shown in B, the zeta potential of the mesoporous silica nanoparticles is -7.81 mV. Figure 1 B shows that the particle size of mesoporous silica nanoparticles in the aqueous phase is about 120 nm, that is, the hydrated particle size measured by dynamic light scattering is larger than the particle size observed by transmission electron microscopy. The reason is that the -OH group on the surface of the nanoparticles in the aqueous solution binds to the H + A hydration layer will form.

[0043] Example 2

[0044] This example verifies the effect of mesoporous silica nanoparticles on the salt tolerance of Physcomitrella patens. The specific experimental process is as follows:

[0045] All plants of Physcomitrella patens were grown on BCD medium containing 1 mM CaCl2 at a temperature of 25°C and a light intensity of 60-80 μmol / m 2 / s, with a photoperiod of 16 h / 8 h. One-month-old Physcomitrella patens shoot tips (2-3 mm in length) were immersed in different concentrations of MSN (prepared in Example 1) and spiny mesoporous silica nanoparticles (VMSN) for 4 h, then washed with sterile water. The MSN and VMSN concentrations were 0.1 mg / L, 1 mg / L, 10 mg / L, 50 mg / L, 100 mg / L, and 300 mg / L (in sterile water), respectively. An equal amount of sterile water was used as a control.

[0046] Treated Physcomitrella patens were grown on BCD medium containing 500 mM NaCl and observed every five days. The maximum fluorescence yield (Fm) and maximum photochemical efficiency (Fv / Fm) of Physcomitrella patens leaves were measured using a chlorophyll fluorometer (WALZ, Germany). Plants were acclimated to darkness for 30 minutes before measurement.

[0047] The results are as follows Figure 2 As shown: The growth state of Physcomitrella patens treated with 300 mg / L MSN under salt stress was better than that of the other two groups, and its growth state in the recovery period was significantly better than that of the other two groups ( Figure 2 A); The Fv / Fm value of Physcomitrella patens leaves treated with MSN was significantly higher than that without MSN treatment. MSN and VMSN improved resistance to salt stress by affecting photosynthesis efficiency, but the effect of MSN was significantly higher than that of VMSN.

[0048] The VMSN used in this example was prepared by the following process:

[0049] To a flask, 1.0 g of hexadecyltrimethylammonium bromide (CTAB), 50 mL of water, and 0.8 mL of 0.1 M sodium hydroxide were added sequentially. Stirring was initiated and the reaction temperature was maintained at 60°C in an oil bath. After stirring for 2 h, the CTAB was completely dissolved, and the solution became colorless and transparent with no obvious bubbles. A mixture of ethyl orthosilicate and cyclohexane (1:4 by volume) was added. The reaction temperature was maintained at 60°C in an oil bath. The reaction was continued for a further 72 h, and the supernatant was removed by centrifugation. The resulting solid was washed several times with water and ethanol, respectively, to obtain CTAB-coated spike-shaped mesoporous silica nanoparticles. The CTAB-coated spike-shaped mesoporous silica nanoparticles were washed with acetone three times, and the nanoparticles were dispersed with 50 mL of acetone. The dispersed nanoparticles were then added to the flask. Stirring was initiated and the reaction temperature was maintained at 50°C in an oil bath. Condensed water was introduced and the mixture was refluxed for 48 h to remove the CTAB template. The supernatant was then removed by centrifugation, and the obtained solid was washed with ethanol, which was repeated 6 times. The obtained solid was further washed with water, which was repeated 3 times to obtain spike-shaped mesoporous silica nanoparticles stored in the aqueous phase, which were vacuum dried and quantified.

[0050] Example 3

[0051] Based on the MSN prepared in Example 1, this example provides fluorescent mesoporous silica nanoparticles that can be traced in Physcomitrella patens. The preparation process is as follows:

[0052] To a 500 mL flask, add 20 g of CTAC and 200 mL of water, stirring continuously. Maintain the reaction temperature at 95°C in an oil bath. Add 0.60 g of TEA to the reaction system and continue stirring for 1 hour to dissolve and thoroughly mix the solids. Then, add 15 mL of TEOS and continue stirring for another hour while maintaining the reaction temperature at 95°C in an oil bath. Remove the supernatant by centrifugation, and wash the resulting solid with water and methanol three times each. This yields mesoporous silica nanoparticles composited with CTAC, which are then dried under vacuum for quantitative determination.

[0053] Disperse 0.5 g of CTAC-coated mesoporous silica nanoparticles in 80 mL of methanol and stir until homogeneous. Then, add 4.5 mL of concentrated hydrochloric acid to the reaction system. After vigorous stirring for 24 hours, control the reaction temperature at 60°C in an oil bath and reflux for 48 hours to remove the CTAC template. Centrifuge to remove the supernatant, and wash the resulting solid with water and methanol six times, each for six cycles, before vacuum drying for quantitative determination.

[0054] Take 1 g of the prepared mesoporous silica nanoparticles and disperse them in 100 mL of methanol. The reaction temperature was controlled at 70°C in an oil bath and stirred evenly. Then, 2 mL of 3-aminopropyltriethoxysilane (APTES) was added dropwise while stirring. The mixture was condensed and refluxed at 70°C for 24 h. The product (denoted as MSN-NH2) was collected by centrifugation, then washed with water 3 times, ethanol 3 times, and quantified under vacuum.

[0055] Disperse 20 mg of MSN-NH2 in 10 mL of ethanol and stir evenly in the dark. Then, add 1 mg of fluorescein isothiocyanate (FITC) dropwise into the solution while stirring in the dark. Stir in the dark for 24 h and centrifuge at 11,000 rpm for 25 min to obtain fluorescent mesoporous silica nanoparticles (denoted as MSN-FITC). After removing the supernatant, wash with ethanol three times and quantify under vacuum.

[0056] Example 4

[0057] This example utilizes the tracing ability of MSN-FITC prepared in Example 3 to detect the distribution of mesoporous silica nanoparticles in Physcomitrella patens. The specific experimental process is as follows:

[0058] The rhizoids and apical leaves of Physcomitrella patens were carefully soaked in 2 µL of 9 mg / ml MSN-FITC for 4 hours. The leaves were then rinsed with sterile water and subjected to fluorescence observation. After 24 hours, the leaves were rinsed with sterile water and the migration of MSNs in vivo was observed using fluorescence. The absorption and localization of MSNs were observed under a confocal microscope. The emission wavelength of MSN-FITC is 520-541 nm.

[0059] like Figure 3 As shown in the figure, after 24 hours, a faint green fluorescence was observed in the apical leaves and rhizomes. Green fluorescence also appeared in the intercellular spaces, cell walls, and cytoplasm of the leaves, which was inconsistent with chlorophyll autofluorescence, indicating that MSNs were distributed in the intercellular spaces, cell walls, and cytoplasm but did not enter the chloroplasts. This suggests that MSNs are distributed on the cell surface, and some can enter cells and be transported in the body.

[0060] Example 5

[0061] In this study, the reactive oxygen species (ROS) in the leaves of Physcomitrella patens after MSN treatment were detected, and 3,3'-diaminobenzidine (DAB) and nitro blue tetrazolium (NBT) were used to detect the reactive oxygen species hydrogen peroxide (H2O2) and superoxide anion (O2﹒ － ) for dyeing, the specific process is as follows:

[0062] One-month-old, 2-3 mm long Physcomitrella patens stem tips were selected (culture conditions refer to Example 2) and immersed in 300 mg / L MSN (prepared in Example 1) for 4 hours, then rinsed with sterile water. The stem tips were then grown on BCD medium containing 500 mM NaCl. Fresh target leaves were immersed in 1 mg / mL nitro blue tetrazolium (dissolved in potassium dihydrogen phosphate buffer, pH 7.8) or 3,3'-diaminobenzidine (dissolved in potassium dihydrogen phosphate buffer, pH 3.8) for 2 hours, followed by bleaching with 95% ethanol.

[0063] The results of detecting hydrogen peroxide and superoxide anions in Physcomitrella patens leaves with DAB and NBT dyes are shown in the figure. Figure 4 As shown, DAB staining showed that the leaves turned dark brown under salt stress ( Figure 4 A), NBT staining showed that the leaves were dark blue under salt stress ( Figure 4 B), while leaves containing MSNs showed a lighter color than leaves in the control group in both DAB and NBT staining. These results suggest that NaCl can cause large amounts of hydrogen peroxide and superoxide anions to accumulate in leaves, while application of the MSNs prepared by the present invention can effectively reduce their accumulation.

[0064] Furthermore, the expression levels of ROS-related genes in the leaves of Physcomitrella patens were detected, and the results were as follows: Figure 4 As shown in C. Figure 4 C shows that the expression of ROS-related genes increased under salt stress, and the expression level was significantly increased after MSN treatment.

[0065] The above results indicate that the MSN in the present invention can alleviate the salt stress of Physcomitrella patens by increasing the expression level of ROS-related genes and reducing the accumulation of ROS.

[0066] Example 6

[0067] This example demonstrates the effect of MSN treatment on calcium signaling in Physcomitrella patens. The specific steps are as follows:

[0068] In this example, Rhod-2 is used as the calcium ion (Ca 2+ ) indicator, the stem tips of Physcomitrella patens in the MSN (prepared in Example 1) and sterile water treatment groups were placed in a 3 mg / L Rhod-2 solution (Thermo Fisher Scientific, R1244) and treated with a vacuum pump for 30 minutes. The cells were then cultured in an incubator at 37°C for 45 minutes and rinsed with sterile water before the Ca2+ assay was performed. 2+ Ca levels were measured using an optical mapping system (SciMedia, MiCAM02 LEX2-LZ4) as described. 2+ Level change detection.

[0069] Total RNA was extracted using TransZol reagent from Beijing Quanshijin Biotechnology, following the manufacturer's instructions. Genomic DNA was removed from RNA samples and first-strand cDNA was synthesized using MonScript™ RTIII All-in-One Mix with dsDNase from Mona Biotechnology, following the manufacturer's instructions. The samples were then analyzed for Ca-related proteins using RT-qPCR. 2+ Concentration-dependent Ca 2+ Expression of sensor genes and genes related to ion balance.

[0070] Figure 5 The results in A showed that MSN could enhance calcium signaling in Physcomitrella patens, especially under salt stress. Figure 5 The results in B showed that under salt stress, compared with the sterile water treatment group, Ca 2+ The expression level of the sensor gene PpCML was significantly reduced, while the expression level of the PpCDPK3 gene was significantly increased; in the absence of stress, MSN significantly reduced the gene expression level of PpCML, but the gene expression level of PpCDPK3 was unaffected; the expression level of the gene PpGORK related to ion balance was significantly decreased after MSN treatment under salt stress; while in the absence of salt stress, the gene expression level was significantly increased after MSN treatment.

[0071] The above results indicate that the MSN provided by the present invention can improve the salt tolerance of Physcomitrella patens by affecting calcium signal transduction and the expression level of genes involved in ion balance.

[0072] Comparative Example 1

[0073] Taking another model crop, Arabidopsis thaliana (wild type), as an example, this example explored the salt resistance effect of the MSN provided by the present invention on other plants. The specific experiments are as follows:

[0074] All Arabidopsis plants were grown on 1 / 2 MS medium supplemented with 1% sucrose and MES at 22°C, 21,000 lux of light, 60% humidity, and a 16-hour / 8-hour photoperiod. Three-day-old Arabidopsis seedlings with roots approximately 1 cm long were treated with various concentrations of MSN (prepared in Example 1) for 2 hours: 0 μg / mL, 10 μg / mL, 50 μg / mL, 100 μg / mL, 200 μg / mL, and 500 μg / mL. An equal amount of sterile water was used as a control. The treated Arabidopsis plants were then cultured for 24 hours on medium containing various concentrations of NaCl (0 mM, 100 mM, and 200 mM). After 24 hours of NaCl incubation, the seedlings were transplanted onto blank medium. After 7 days of incubation, their growth status was observed and recorded.

[0075] The results are as follows Figure 6 As shown in the data, under salt stress, the root growth of Arabidopsis was affected, the leaf surface area was smaller than that under normal conditions, the leaves turned yellow at a concentration of 200 mM NaCl, and the growth of Arabidopsis was slow. At a concentration of 100 mM NaCl, high concentration MSN treatment significantly inhibited the growth of Arabidopsis. The growth status of Arabidopsis under different salt concentrations was not significantly different from that of the water treatment group.

[0076] The above results indicate that the MSN prepared in the present invention has no significant salt-resistance effect on Arabidopsis thaliana under salt stress. This indicates that nanomaterials do not have universality in plant stress resistance, and the reasons for this remain to be revealed.

[0077] Comparative Example 2

[0078] Different from Example 2, this example uses MSN (spherical) with an average particle size of 160 nm to conduct the salt tolerance test of Physcomitrella patens. The specific process is as follows:

[0079] All plants of Physcomitrella patens were grown on BCD medium containing 1 mM CaCl2, at a temperature of 25°C and a light intensity of 60-80 μmol / m 2 / s, with a 16 h / 8 h photoperiod. One-month-old Physcomitrella patens shoot tips, 2-3 mm in length, were immersed in 300 mg / L MSN (160 nm particle size) for 4 hours and then washed with sterile water. An equal amount of sterile water was used as a control. The treated Physcomitrella patens were grown on BCD medium containing 500 mM NaCl and observed every 5 days.

[0080] The results are as follows Figure 7 As shown in the figure, there was no significant difference in leaf color and size of Physcomitrella patens in the MSN treatment group and the control group under salt stress, indicating that the same concentration of MSN with a larger particle size (160 nm) had no significant effect on improving the salt tolerance of Physcomitrella patens under salt stress.

[0081] In summary, the mesoporous silica nanoparticles with a particle size range of 80-120 nm and a negative potential prepared in the present invention can significantly improve the salt tolerance of Physcomitrella patens, and the mesoporous silica nanoparticles can enter the body of Physcomitrella patens, thereby enhancing the salt tolerance of Physcomitrella patens by reducing the accumulation of reactive oxygen species and promoting ion balance.

[0082] It should be noted that the above embodiments are only part of the embodiments of the present invention rather than all the embodiments, and are only used to illustrate the technical solutions of the present invention rather than to limit them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

Claims

1. A method for improving the salt tolerance of Physcomitrella patens by using mesoporous silica nanoparticles, characterized in that: The mesoporous silica nanoparticles are spherical, have a particle size of 80-120 nm and exhibit a negative potential. The preparation method of the mesoporous silica nanoparticles comprises the following steps: S1. Add cetyltrimethylammonium chloride (CTAC) and water to a reaction vessel, heat and stir thoroughly; S2. Add triethanolamine to the reaction system obtained in step S1, mix well, then add ethyl orthosilicate, maintain the reaction temperature and continue stirring until the reaction is complete, remove the supernatant by centrifugation, and wash the resulting solid with water and methanol, respectively, to obtain mesoporous silica nanoparticles composited with hexadecyltrimethylammonium chloride (CTAC); S3, dispersing the mesoporous silica nanoparticles obtained in step S2 into methanol, and then adding concentrated hydrochloric acid to react to remove hexadecyltrimethylammonium chloride (CTAC); S4. Centrifuge the reaction system obtained in step S3, wash the obtained solid with water and methanol in sequence, and continue washing with water to obtain mesoporous silica nanoparticles stored in the aqueous phase, and vacuum dry.

2. The use according to claim 1, characterized in that The mesoporous silica nanoparticles are modified with fluorescein isothiocyanate.

3. The use according to claim 1, characterized in that The mesoporous silica nanoparticles enter the body of Physcomitrella patens and improve the salt tolerance of Physcomitrella patens by reducing the accumulation of reactive oxygen species (ROS) and promoting ion balance.

4. The use according to claim 1, characterized in that In the reaction system obtained in step S1, the mass fraction of the hexadecyltrimethylammonium chloride (CTAC) is 9-12%.

5. The use according to claim 1, characterized in that In step S1 and step S2, the temperature is controlled at 93-98°C.

6. The use according to claim 1, characterized in that In step S3, the volume ratio of methanol to concentrated hydrochloric acid is 1:(0.05-0.06).

7. The use according to claim 2, characterized in that The method for preparing the mesoporous silica nanoparticles further comprises the following steps: S5. Dispersing mesoporous silica nanoparticles in methanol, modifying amino groups on the mesoporous silica nanoparticles using 3-aminopropyltriethoxysilane, and then reacting with fluorescein isothiocyanate to prepare fluorescent mesoporous silica nanoparticles.

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