Application of mesoporous silica nanoparticles in improvement of salt tolerance of erenchium leptosphaereum

Abstract

The invention discloses application of mesoporous silica nanoparticles to improvement of salt tolerance of strignum leptosphaereum, and belongs to the technical field of plant stress resistance. Wherein the particle size of the mesoporous silica nanoparticles is 80-120 nm, and the mesoporous silica nanoparticles are in negative potential. The mesoporous silica nanoparticles provided by the invention can effectively reduce the content of active oxygen increased due to salt stress, relieve the salt stress by reducing accumulation of the active oxygen, and also can promote ion balance to enhance the salt stress resistance of the acidichrocephalum leptosphaerocephalum, so that the salt stress resistance of the acidichrocephalum leptosphaerocephalum is improved. Meanwhile, the preparation process of the mesoporous silicon dioxide nanoparticles is relatively simple, environment-friendly, low in cost and free of toxic and side effects, and a foundation is laid for exploring the stress resistance and physiological process of a nano material on plants in the mode of phytoncigia palustris.

Description

Technical Field

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

[0002] Excessive salt concentration in the soil forms saline-alkali soil, which seriously affects plant growth and development. Salt stress is the main abiotic stress that causes crop yield loss and quality decline. Generally, plants can resist salt stress through some mechanisms, but the actual effect is limited. How to safely and effectively alleviate the impact of high salt stress on plants is an urgent problem to be solved.

[0003] Traditional breeding and chemical methods cannot improve plant resistance to salt stress economically and effectively, and are likely to pose a certain threat to the environment. In recent years, artificial nanomaterials, as an emerging technology, have been gradually applied to agricultural production, providing a new idea for alleviating the problem of high salt stress in plants. Existing studies have shown that nanomaterials play a positive role in the growth, development and stress response of some plants, but the mechanism of action of nanomaterials in plants still needs to be further studied.

[0004] Physcomitrium patens is an important model plant with low morphological complexity, simple developmental pattern, and strong stress resistance. Therefore, studying the absorption, localization, and interaction mechanism of nanomaterials in Physcomitrium patens is of great significance for revealing the mechanism of nanomaterials on plant stress resistance and exploring plant physiological processes. However, there are no reports on the use of nanomaterials in promoting stress resistance in Physcomitrium patens. Summary of the invention

[0005] The inventors found in their research that mesoporous silica nanoparticles (MSN) with 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: The invention provides an application of mesoporous silica nanoparticles in improving the salt tolerance of Physcomitrella patens. The particle size of the mesoporous silica nanoparticles is 80-120 nm and the mesoporous silica nanoparticles present a negative potential.

[0007] The present invention has shown that the negatively charged mesoporous silica nanoparticles within the above-mentioned particle size range can be traced and found to enter the body of Physcomitrella patens, thereby inducing the plant to tolerate salt; specifically, the above-mentioned mesoporous silica nanoparticles exert their effects in at least the following ways: a) After entering the body of Physcomitrella patens, it is distributed in the intercellular spaces, cell walls and cytoplasm; b) Increase the expression level of ROS (reactive oxygen species) related genes and reduce the accumulation of ROS; c) Affects the expression levels of genes involved in calcium signaling and ion homeostasis.

[0008] 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 there are spike-like protrusions on the surface of the mesoporous silica nanoparticles, their salt resistance effect is significantly reduced compared with that of spherical particles.

[0009] Preferably, in the above application, the mesoporous silica nanoparticles are modified with fluorescein isothiocyanate (FITC) to obtain fluorescent mesoporous silica nanoparticles. The fluorescent mesoporous silica nanoparticles can be used to trace the position distribution of MSN in Physcomitrella patens while enhancing the salt tolerance of Physcomitrella patens, and can further be used to study the absorption and positioning of MSN by Physcomitrella patens.

[0010] Preferably, in the above application, the method for preparing mesoporous silica nanoparticles comprises the following steps: S1. Add cetyltrimethylammonium chloride (CTAC) and water into a reaction vessel, heat and stir thoroughly; S2, adding triethanolamine (TEA) to the reaction system obtained in step S1, adding tetraethyl orthosilicate (TEOS) after mixing, maintaining the reaction temperature and continuously stirring until the reaction is completed, removing the supernatant by centrifugation, washing the obtained solid with water and methanol respectively, to obtain mesoporous silica nanoparticles composited with CTAC; S3, dispersing the mesoporous silica nanoparticles obtained in step S2 into methanol, and then adding concentrated hydrochloric acid to react to remove CTAC; S4, centrifuging the reaction system obtained in step S3, washing the obtained solid with water and methanol in turn, and continuing to wash with water to obtain mesoporous silica nanoparticles stored in the aqueous phase, and vacuum drying.

[0011] More preferably, in the reaction system obtained in the above step S1, the mass fraction of CTAC is 9-12%.

[0012] More preferably, in the above step S2, the mass volume ratio of triethanolamine to tetraethyl orthosilicate is (0.60~0.62):15.

[0013] More preferably, in the above step S1 and step S2, the heating temperature is controlled at 93-98°C.

[0014] More preferably, in the above step S3, the volume ratio of methanol to concentrated hydrochloric acid is 1:(0.05~0.06).

[0015] More preferably, in the above preparation method, the following steps are also included: S5. Disperse mesoporous silica nanoparticles in methanol, modify the amino groups on the mesoporous silica nanoparticles using 3-aminopropyltriethoxysilane (APTES), and then react with fluorescein isothiocyanate to obtain fluorescent mesoporous silica nanoparticles.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention discovers 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 is 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 active oxygen 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

[0017] Figure 1 Transmission electron microscope image (A) and particle size potential map (B) of mesoporous silica nanoparticles (MSN) prepared in Example 1 of the present invention; Figure 2 The test result diagram of the effect of mesoporous silica nanoparticles on salt stress of Physcomitrella patens in Example 2 of the present invention; wherein A is a growth state diagram of Physcomitrella patens after 6 days of salt stress and in the recovery period, and B is a photosynthetic index diagram of Physcomitrella patens after 6 days of salt stress and in the recovery period (maximum photochemical efficiency Fv / Fm); Figure 3 Figure 4 is a result of the study on the position of fluorescent mesoporous silica nanoparticles in Physcomitrella patens in Example 4 of the present invention; A and B are the distribution results of MSN in Physcomitrella patens at 24 hours, S2R refers to the distance from the top leaf to the rhizome, and R2S refers to the distance from the rhizome to the top leaf, and the scale is 1 mm; C is a distribution diagram of MSN in Physcomitrella patens cells at 4 hours, and the scale is 50 μm; Figure 4 The results of the effect of mesoporous silica nanoparticles on the active oxygen of Physcomitrella patens under salt stress in Example 5 of the present invention are shown in Figure 5; wherein A is a DAB staining result diagram for hydrogen peroxide detection, B is a NBT staining result diagram for superoxide detection, the scales of A and B are both 1 mm, and C is a diagram for the expression level of genes related to active oxygen; Figure 5Graph showing 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; wherein A is the change in cytoplasmic calcium concentration of Physcomitrella patens under 300 mg / L MSN, and B is the change in calcium signal transduction and ion balance of Physcomitrella patens under 300 mg / L MSN. 2+ Concentration-dependent Ca 2+ Expression profiles of sensor genes (PpCML and PpCDPK3) and genes related to ion balance (PpGORK); Figure 6 This is a growth state diagram of Arabidopsis thaliana after 7 days of salt stress in Comparative Example 1 of the present invention; 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

[0018] 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 belongs. The term "comprises" and any variations thereof in the specification and claims of the present invention are intended to cover non-exclusive inclusions.

[0019] The technical solution of the present invention will be described clearly and completely 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 used to limit the present invention.

[0020] If no specific techniques or conditions are specified in the following examples, the procedures are 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.

[0021] Example 1 This example provides a method for preparing mesoporous silica nanoparticles (MSN) capable of promoting salt tolerance of Physcomitrella patens, comprising the following steps: Add 20 g CTAC and 200 mL water to a 500 mL flask in sequence, start stirring, and control the reaction temperature at 95°C in an oil bath. Then add 0.60 g TEA to the reaction system and continue stirring for 1 h to dissolve and mix the solids. Then add 15 mL TEOS and continue to maintain the reaction temperature at 95°C in an oil bath and continue stirring for 1 h. Centrifuge to remove the supernatant, wash the solid with water and methanol, respectively, and repeat three times to obtain mesoporous silica nanoparticles composited with CTAC, which are then vacuum dried for quantitative determination.

[0022] 0.5 g of mesoporous silica nanoparticles composited with CTAC were dispersed in 80 mL of methanol, stirred evenly, and then 4.5 mL of concentrated hydrochloric acid was added to the reaction system. After vigorous stirring for 24 h, the temperature of the reaction system was controlled at 60 ° C using an oil bath, and condensed and refluxed for 48 h to remove the CTAC template. The supernatant was then removed by centrifugation, and the obtained solid was washed with water and methanol, and each was repeated six times, and then the obtained solid was washed with water again, and after three times, the mesoporous silica nanoparticles stored in the aqueous phase were obtained, and finally vacuum dried for quantification.

[0023] 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 A, the mesoporous silica nanoparticles are relatively evenly dispersed spherical particles with good size uniformity.

[0024] At the same time, the particle size of mesoporous silica nanoparticles was measured by dynamic light scattering method, and the electromotive force of mesoporous silica nanoparticles was measured by zeta potential tester. Figure 1 As shown in B, the zeta potential of 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 on the surface of the nanoparticles in the aqueous solution binds to H + A hydration layer will form.

[0025] Example 2 This example verifies the effect of mesoporous silica nanoparticles on the salt tolerance of Physcomitrella patens. The specific test process is as follows: All plants of Physcomitrella patens were grown in a medium containing 1 mM CaCl 2 The temperature was 25°C and the light intensity was 60-80 μmol / m 2 / s, and the photoperiod was 16 h / 8 h. The shoot tips of 2-3 mm in length on the gametophyte of Physcomitrella patens grown for one month were immersed in different concentrations of MSN (prepared in Example 1) and spike-shaped mesoporous silica nanoparticles (VMSN) for 4 h, and then washed with sterile water; wherein the concentrations of MSN and VMSN were 0.1 mg / L, 1 mg / L, 10 mg / L, 50 mg / L, 100 mg / L and 300 mg / L (with sterile water as solvent), respectively, and the same amount of sterile water treatment was used as a control.

[0026] The treated Physcomitrella patens were grown on BCD medium containing 500 mM NaCl and observed every 5 days. The maximum fluorescence yield (Fm) and maximum photochemical efficiency (Fv / Fm) of Physcomitrella patens leaves were measured using a chlorophyll fluorescence meter (WALZ, Germany); before measurement, the plants were adapted to darkness for 30 min.

[0027] 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 treated with MSN was significantly higher than that without MSN treatment. MSN and VMSN improved the resistance to salt stress by affecting the photosynthesis efficiency, but the effect of MSN was significantly higher than that of VMSN.

[0028] The VMSN used in this example was prepared by the following process: 1.0 g of hexadecyltrimethylammonium bromide (CTAB), 50 mL of water and 0.8 mL of 0.1 M sodium hydroxide were added to the flask in sequence, stirring was started, and the reaction temperature was controlled at 60°C in an oil bath. After stirring for 2 h, CTAB was completely dissolved, and the solution became colorless and transparent without obvious bubbles. A mixed solution of tetraethyl orthosilicate and cyclohexane (volume ratio of 1:4) was added, and the reaction temperature was maintained at 60°C in an oil bath. After further reaction for 72 h, the supernatant was removed by centrifugation, and the solid was washed with water and ethanol several times to obtain spike-shaped mesoporous silica nanoparticles composited with CTAB. The spike-shaped mesoporous silica nanoparticles composited with CTAB were washed with acetone, and after repeating 3 times, the nanoparticles were dispersed with 50 mL of acetone, and the dispersed nanoparticles were added to the flask, stirring was started, and the reaction temperature was controlled at 50°C in an oil bath. Condensed water was passed through, and the condensation reflux was performed for 48 h to remove the CTAB template. The supernatant was then removed by centrifugation, and the obtained solid was washed with ethanol. This was repeated 6 times, and then the obtained solid was further washed with water. This was repeated 3 times to obtain spike-shaped mesoporous silica nanoparticles stored in the aqueous phase, which were then vacuum dried for quantification.

[0029] Example 3 Based on the MSN prepared in Example 1, this example provides a fluorescent mesoporous silica nanoparticle that can be traced in Physcomitrella patens. The preparation process is as follows: Add 20 g CTAC and 200 mL water to a 500 mL flask in sequence, start stirring, and control the reaction temperature at 95°C in an oil bath. Then add 0.60 g TEA to the reaction system and continue stirring for 1 h to dissolve and mix the solids. Then add 15 mL TEOS and continue to maintain the reaction temperature at 95°C in an oil bath and continue stirring for 1 h. Centrifuge to remove the supernatant, wash the solid with water and methanol, respectively, and repeat three times to obtain mesoporous silica nanoparticles composited with CTAC, which are then vacuum dried for quantitative determination.

[0030] 0.5 g of mesoporous silica nanoparticles with CTAC were dispersed in 80 mL of methanol, stirred evenly, and then 4.5 mL of concentrated hydrochloric acid was added to the reaction system. After vigorous stirring for 24 h, the temperature of the reaction system was controlled at 60 ° C using an oil bath, and condensed and refluxed for 48 h to remove the CTAC template. The supernatant was then removed by centrifugation, and the solid was washed with water and methanol, each of which was repeated six times, and then vacuum dried for quantification.

[0031] Take 1 g of the prepared mesoporous silica nanoparticles and disperse them in 100 mL of methanol. Control the reaction temperature at 70 °C in an oil bath and stir evenly. Then, add 2 mL of 3-aminopropyltriethoxysilane (APTES) dropwise while stirring. Condensate and reflux at 70 °C for 24 h. Collect the product (denoted as MSN-NH 2 ), followed by three washes with water, three washes with ethanol, and vacuum quantification.

[0032] 20 mg MSN-NH 2 Disperse 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. Centrifuge at 11000 rpm for 25 min to obtain fluorescent mesoporous silica nanoparticles (denoted as MSN-FITC). Remove the supernatant, wash with ethanol three times, and quantify under vacuum.

[0033] Example 4 In this example, the tracing ability of MSN-FITC prepared in Example 3 was used to detect the distribution of mesoporous silica nanoparticles in Physcomitrella patens. The specific experimental process is as follows: The rhizoids and top leaves of Physcomitrella patens were carefully soaked with 2 μL of 9 mg / ml MSN-FITC for 4 h, and then the leaves were rinsed with sterile water for fluorescence observation. After 24 h, the migration of MSN in vivo was observed by fluorescence after rinsing with sterile water. The absorption and localization of MSN were observed under a confocal microscope, where the emission wavelength of MSN-FITC was 520-541 nm.

[0034] like Figure 3 As shown in the figure, weak green fluorescence can be observed in the top leaves and rhizomes after 24 hours; green fluorescence also appears in the intercellular spaces, cell walls and cytoplasm of the leaves, which is inconsistent with the chlorophyll autofluorescence, indicating that MSNs are distributed in the intercellular spaces, cell walls and cytoplasm, but have not entered the chloroplasts. This indicates that MSNs are distributed on the cell surface, and some can enter the cells and be transported in the body.

[0035] Example 5 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 (H 2 O 2 ) and superoxide anion (O 2 ﹒ － ) for dyeing, the specific process is as follows: A 2-3 mm long Physcomitrella patens stem tip grown for 1 month (culture conditions refer to Example 2) was selected and immersed in 300 mg / LMSN (prepared in Example 1) for 4 h and washed with sterile water. It was then grown on a BCD medium containing 500 mM NaCl. Fresh target leaves were selected and immersed in 1 mg / mL nitro blue tetrazolium (dissolved in potassium dihydrogen phosphate buffer at pH = 7.8) or 3,3'-diaminobenzidine (dissolved in potassium dihydrogen phosphate buffer at pH = 3.8), incubated for 2 h, and then bleached with 95% ethanol.

[0036] The results of DAB and NBT dyes for detecting hydrogen peroxide and superoxide anions in Physcomitrella patens leaves are shown in Figure 4 As shown, DAB staining showed that the leaves were dark brown under salt stress ( Figure 4 A), NBT staining shows that leaves under salt stress are dark blue ( Figure 4 B), while the leaves containing MSN in DAB staining and NBT staining were lighter in color than the leaves in the control group. These results show that NaCl can accumulate a large amount of hydrogen peroxide and superoxide anions in leaves, and the application of MSN prepared by the present invention can effectively reduce the accumulation of hydrogen peroxide and superoxide anions.

[0037] Furthermore, the expression of ROS-related genes in the leaves of Physcomitrella patens was detected, and the results were as follows: Figure 4 C. Figure 4 C shows that the expression of ROS-related genes increased under salt stress, while the expression level increased significantly after MSN treatment.

[0038] The above results show 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.

[0039] Example 6 This example shows the effect of MSN treatment on calcium signaling in Physcomitrella patens. The specific operation is as follows: 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) treatment 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 min, then cultured in an incubator at 37°C for 45 min, and then rinsed with sterile water and tested for Ca 2+ Ca levels were measured using an optical mapping system (SciMedia, MiCAM02 LEX2-LZ4) as described. 2+ Level change detection.

[0040] The total RNA was extracted using TransZol reagent from Beijing Quanshijin Biotechnology, and the specific operation was performed according to the instructions. The genome removal and first-strand cDNA synthesis in RNA samples were performed using MonScript™RTIII All-in-One Mix with dsDNase from Mona Biotechnology, and the specific operation was performed according to the manufacturer's instructions. RT-qPCR was then used to analyze the samples for Ca 2+ Concentration-dependent Ca 2+ Expression of sensor genes and genes related to ion balance.

[0041] Figure 5 The results in A show that MSN can enhance calcium signaling in Physcomitrella patens, especially under salt stress. Figure 5 The results in B show 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 not affected; 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.

[0042] 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.

[0043] Comparative Example 1 Taking another model crop Arabidopsis thaliana (wild type) as an example, this example explores the salt resistance effect of the MSN provided by the present invention on other plants. The specific experiment is as follows: All Arabidopsis plants were grown on 1 / 2 MS medium supplemented with 1% sucrose and MES, at a temperature of 22°C, a light of 21000 lux, a humidity of 60%, and a photoperiod of 16 h / 8 h. Arabidopsis seedlings with a root length of about 1 cm after growing for 3 days were treated with different concentrations of MSN (prepared in Example 1) for 2 h, wherein the MSN concentrations were 0 μg / mL, 10 μg / mL, 50 μg / mL, 100 μg / mL, 200 μg / mL and 500 μg / mL, respectively, and treated with an equal amount of sterile water as a control. The treated Arabidopsis were placed on a medium containing different concentrations of NaCl (0 mM, 100 mM, 200 mM) and cultured for 24 h. After 24 h of NaCl culture, the Arabidopsis seedlings were transplanted to a blank medium, and their growth status was observed and recorded after 7 days of culture.

[0044] The results are as follows Figure 6 As shown in the figure, 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 200 mM NaCl concentration, and the growth of Arabidopsis was slow. At 100 mM NaCl concentration, high concentration MSN treatment significantly inhibited the growth of Arabidopsis, and the growth status of Arabidopsis under different salt concentrations was not significantly different from that of the water treatment group.

[0045] The above results show that under salt stress, the MSN prepared by the present invention has no obvious salt resistance effect on Arabidopsis thaliana. It can be seen that nanomaterials do not have commonality in plant stress resistance, and the reason remains to be revealed.

[0046] Comparative Example 2 Different from Example 2, this example uses MSN (spherical) with an average particle size of 160 nm to carry out the salt tolerance test of Physcomitrella patens. The specific process is as follows: All plants of Physcomitrella patens were grown in a medium containing 1 mM CaCl 2 The temperature was 25°C and the light intensity was 60-80 μmol / m 2 / s, and the photoperiod was 16 h / 8 h. The shoot tips of 2-3 mm long on the gametophyte of Physcomitrella patens grown for one month were immersed in 300 mg / L MSN with a particle size of 160 nm for 4 h, and then washed with sterile water. The same amount of sterile water was used as the control. The treated Physcomitrella patens were placed on BCD medium containing 500 mM NaCl and observed every 5 days.

[0047] The results are as follows Figure 7 As shown, it can be seen that there is 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) has no significant effect on improving the salt tolerance of Physcomitrella patens under salt stress.

[0048] In summary, the mesoporous silica nanoparticles with a particle size range of 80-120 nm and negative potential prepared by 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 active oxygen and promoting ion balance.

[0049] 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 solution of the present invention rather than to limit it. 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. An application of mesoporous silica nanoparticles in improving the salt tolerance of Physcomitrella patens, characterized in that: The mesoporous silica nanoparticles have a particle size of 80-120 nm and have a negative potential.

2. The use according to claim 1, characterized in that: The mesoporous silica nanoparticles are spherical.

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

4. 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 ROS accumulation and promoting ion balance.

5. The use according to claim 2 or 3, characterized in that: The method for preparing the mesoporous silica nanoparticles comprises the following steps: S1. Add CTAC and water to a reaction vessel, heat and stir well; S2, adding triethanolamine to the reaction system obtained in step S1, adding tetraethyl orthosilicate after mixing, maintaining the reaction temperature and continuously stirring until the reaction is completed, removing the supernatant by centrifugation, washing the obtained solid with water and methanol respectively, to obtain mesoporous silica nanoparticles composited with CTAC; S3, dispersing the mesoporous silica nanoparticles obtained in step S2 into methanol, and then adding concentrated hydrochloric acid to react to remove CTAC; S4, centrifuging the reaction system obtained in step S3, washing the obtained solid with water and methanol in turn, and continuing to wash with water to obtain mesoporous silica nanoparticles stored in the aqueous phase, and vacuum drying.

6. The use according to claim 5, characterized in that: In the reaction system obtained in step S1, the mass fraction of CTAC is 9-12%.

7. The use according to claim 5, characterized in that: In step S2, the mass volume ratio of triethanolamine to tetraethyl orthosilicate is (0.60-0.62):

15.

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

9. The use according to claim 5, characterized in that: In step S3, the volume ratio of methanol to concentrated hydrochloric acid is 1:(0.05-0.06).

10. The use according to claim 5, characterized in that: The following steps are also included: 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 obtain fluorescent mesoporous silica nanoparticles.

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