Method for improving growth of strawberry offspring plants based on nano-cerium dioxide

Abstract

The application discloses a method for improving growth of strawberry offspring plants based on nano CeO2, and comprises the following steps: S1, culture soil preparation; S2, culture of strawberry mother plants; S3, culture of first-generation strawberry daughter plants; and S4, culture of second-generation strawberry daughter plants. The method can culture two generations of strawberry daughter plants through the method of stolon reproduction, and a higher nano CeO2 transport coefficient can be obtained in the two generations of strawberry daughter plants. The transported nano CeO2 significantly improves the underground and aboveground biomass of the first-generation / second-generation strawberry daughter plants, thereby finally improving the crop yield. Only suitable nano CeO2 needs to be applied in the culture soil of the strawberry mother plants, and no nano CeO2 needs to be applied in the culture soil of the strawberry daughter plants, so that the cost is saved, the possible side effects of the nano CeO2 can be avoided, and the method has strong practicability.

Description

Technical Field

[0001] This invention relates to the field of strawberry cultivation technology, specifically to a method for improving the growth of strawberry progeny plants based on nano-CeO2. Background Technology

[0002] Studies have shown that nano-cerium dioxide (nano-CeO2) has a certain promoting effect on plant growth. Appropriate concentrations of nano-CeO2 particles can promote the germination of seeds in some plants. Nano-CeO2 may also participate in regulating the activity of some key enzymes in photosynthesis, making the carbon fixation process more efficient, helping plants accumulate more photosynthetic products, and promoting plant growth. Nano-CeO2 can affect the absorption and transport of some nutrients by plants. For example, it can promote the absorption and utilization of macroelements such as nitrogen, phosphorus, and potassium, as well as microelements such as iron, zinc, and manganese. This may be because nano-CeO2 alters the microenvironment of plant roots or affects the activity of ion channels and transport proteins on root cell membranes, thereby facilitating the absorption of nutrients and their transport to the aboveground parts, providing sufficient nutrients for plant growth.

[0003] However, the effects of nano-CeO2 on plant growth are not always positive; its effectiveness is influenced by various factors, such as the particle size and concentration of nano-CeO2, the treatment method, and the plant species. High concentrations of nano-CeO2 may have toxic effects on plants, inhibiting their growth. Furthermore, the role of nano-CeO2 in the growth of plant offspring remains unclear, and the accumulation and transport patterns of nano-CeO2 in plants require further investigation.

[0004] During its growth, strawberries produce numerous runners. Adventitious roots and new seedlings can emerge from the nodes of these runners. These seedlings, once separated from the mother plant, can become independent new plants. Based on this, the mechanism by which nano-CeO2 enhances the growth of strawberry offspring plants has not yet been thoroughly investigated, and the methods for using nano-CeO2 to improve the growth of strawberry offspring plants also require further improvement. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for improving the growth of strawberry progeny plants based on nano-CeO2.

[0006] The technical solution of this invention is:

[0007] A method for improving the growth of strawberry progeny plants based on nano-CeO2 includes the following steps:

[0008] S1. Preparation of culture soil: Mix nano CeO2 with one part of soil evenly to obtain the first culture soil with a mass concentration of 40-60 mg / kg. Take two other parts of soil as the second and third culture soils, respectively.

[0009] S2. Strawberry mother plant culture: The strawberry mother plant is planted in the first culture soil and cultured under alternating light and dark conditions for 28 to 35 days. The rootstock of the strawberry mother plant is 1 to 4 cm long and has 5 to 8 normally developed compound leaves.

[0010] S3. Cultivation of the first generation of strawberry offspring: When the strawberry mother plant produces runners in S2, transplant it to its original location. The runners are buried in the second culture soil at a depth of 1-3cm. When the runners continue to grow to 28-32cm, guide the stems and train them to grow. This allows one adventitious root on the runner to penetrate 2-5cm into the second culture soil for cultivation. Maintain alternating light and dark conditions for 28-35 days to cultivate the first generation of strawberry offspring.

[0011] S4. Second-generation strawberry plantlet cultivation: When the first-generation strawberry plantlets in S3 produce runners, they are transplanted to their original location. The runners are buried in the third culture soil at a depth of 1-3 cm. When the runners continue to grow to 28-32 cm, the stems are trained and pressed, so that an adventitious root on the runner penetrates 2-5 cm into the third culture soil for cultivation. The plantlets are then cultivated under alternating light and dark conditions for 28-35 days.

[0012] Furthermore, the particle size of the nano CeO2 in S1 is 25±10nm, and the first culture medium is placed in a dark environment for 1 to 2 weeks to achieve equilibrium before use.

[0013] Note: The particle size of nano CeO2 is optimized to ensure uniform mixing with the soil.

[0014] Furthermore, the soil moisture content of the first, second, and third culture soils in S1 is adjusted to 60-70% of the field maximum water holding capacity.

[0015] Note: By optimizing the moisture content of the potting soil, a good growing environment is ensured for both mother and daughter strawberry plants.

[0016] Furthermore, when planting the strawberry mother plant in S2, the base of the seedling is level with the surface of the first culture soil, and the roots are spread out flat inside the first culture soil, with the depth of the first culture soil being 20-30cm.

[0017] Note: By optimizing the planting depth of the strawberry mother plants, we can ensure that they have good growing conditions.

[0018] Furthermore, in S2 to S4, during the cultivation of strawberry mother plants, the cultivation of first-generation strawberry daughter plants, and the cultivation of second-generation strawberry daughter plants, the air humidity is 75-85%, and the alternation between 16 hours of light and 8 hours of darkness is maintained. The light intensity is 600-700 Lux, and the cultivation temperature is 20±2℃.

[0019] Note: By optimizing the external conditions such as temperature and humidity during the cultivation of strawberry mother plants, first-generation strawberry daughter plants, and second-generation strawberry daughter plants, stable and rapid growth can be ensured.

[0020] Furthermore, in S3 and S4, the adventitious roots on the mother plant's stolons and the daughter plant's stolons are located at a point ±5 cm from the middle of either the mother plant's stolons or the daughter plant's stolons.

[0021] Explanation: By optimizing the rooting positions of the mother plant's runners and the daughter plant's runners, the normal growth of strawberry daughter plants can be ensured.

[0022] Furthermore, in S1, 20-40 mg / kg of biochar-based soil conditioner is added to the second culture soil, and 10-20 mg / kg of biochar-based soil conditioner is added to the third culture soil.

[0023] Furthermore, the biochar-based soil conditioner, by weight, comprises 30-40 parts of straw biochar powder or rice husk biochar powder, 10-12 parts of municipal sludge, 3-4 parts of coffee grounds, and 1-2 parts of microbial inoculant.

[0024] Note: This product uses a bio-carbon-based soil conditioner to help promote the growth of strawberry plants.

[0025] The beneficial effects of this invention are:

[0026] (1) The method of improving the growth of strawberry offspring plants based on nano CeO2 of the present invention cultivates two generations of strawberry offspring plants by stolon propagation, and a high nano CeO2 translocation coefficient can be obtained in both generations of strawberry offspring plants. The translocated nano CeO2 significantly increases the biomass of the underground and aboveground parts of the first and second generation strawberry offspring plants, thereby ultimately increasing crop yield. It is only necessary to apply appropriate nano CeO2 to the culture soil of the strawberry mother plant, without applying it to the culture soil of the strawberry offspring plants. This saves costs and avoids the possible side effects of nano CeO2, and has strong practicality.

[0027] (2) The method for improving the growth of strawberry progeny plants based on nano-CeO2 of this invention also conducts in-depth research on the mechanism of nano-CeO2 acting on strawberry progeny plants. Some key genes that have undergone significant changes, such as psaK, PHYB, COP1, and HY5, are involved in photosynthesis and diurnal rhythms. These genes interact with plant hormone genes such as AUX1, MYC2, and PIF4, providing a basis for nano-CeO2 to promote the growth of strawberry progeny plants. At the same time, nano-CeO2 alters the content of auxin, cytokinin, jasmonic acid, and salicylic acid in multiple generations of strawberry plants, thereby activating the hormone-induced regulatory network. These findings enhance our understanding of the molecular mechanisms by which nanomaterials are delivered and promote growth in asexually propagated plants and provide potential agricultural development strategies. Attached Figure Description

[0028] Figure 1 It refers to the changes in underground biomass of the strawberry mother plant, the first-generation strawberry daughter plant, and the second-generation strawberry daughter plant in the experimental examples of this invention;

[0029] Figure 2 It refers to the aboveground biomass changes of the strawberry mother plant, the first-generation strawberry daughter plant, and the second-generation strawberry daughter plant in the experimental examples of this invention;

[0030] Figure 3 The photosynthetic parameter F of the strawberry mother plant, the first-generation strawberry daughter plant, and the second-generation strawberry daughter plant in the experimental examples of this invention is... v / F0 value change;

[0031] Figure 4 It refers to the change in the photosynthetic parameter P index value of the strawberry mother plant, the first-generation strawberry daughter plant, and the second-generation strawberry daughter plant in the experimental examples of this invention;

[0032] Figure 5 These are the changes in chlorophyll content of the strawberry mother plant, the first-generation strawberry daughter plant, and the second-generation strawberry daughter plant in the experimental examples of this invention.

[0033] Figure 6 This refers to the cumulative Ce concentration of the strawberry mother plant, the first-generation strawberry daughter plant, and the second-generation strawberry daughter plant in the experimental examples of this invention;

[0034] Figure 7 This refers to the Ce translocation coefficient TF from soil to strawberry mother plant in the experimental examples of this invention;

[0035] Figure 8 The Ce transport coefficient TF is the transfer coefficient from the mother strawberry plant to the first generation strawberry plant and from the first generation strawberry plant to the second generation strawberry plant in the experimental examples of this invention.

[0036] Figure 9 This invention relates to the effects of soil conditions on the nutrient element content in the leaves of strawberry mother plants, first-generation strawberry daughter plants, and second-generation strawberry daughter plants in experimental examples.

[0037] Figure 10 This is a volcano diagram of differentially expressed genes (DEGs) in strawberry mother plants in the experimental examples of this invention;

[0038] Figure 11 This is a volcano diagram of differentially expressed genes (DEGs) in the first generation of strawberry seedlings in the experimental examples of this invention;

[0039] Figure 12 This is a volcano diagram of differentially expressed genes (DEGs) in the second-generation strawberry plants in the experimental examples of this invention;

[0040] Figure 13 This is a schematic diagram of photosynthesis in an experimental example of the present invention;

[0041] Figure 14 This is the protein interaction network of differentially expressed genes (DEGs) in the KEGG pathway related to plant hormones, photosynthesis, and diurnal rhythm in the experimental examples of this invention;

[0042] Figure 15 This invention demonstrates the direct and indirect effects of nano-CeO2, plant hormones, photosynthesis, and diurnal rhythm on strawberry biomass in experimental examples.

[0043] Figure 16 This is a schematic diagram of the method for improving the growth of strawberry progeny plants based on nano CeO2 according to the present invention. Detailed Implementation

[0044] Example 1

[0045] A method for improving the growth of strawberry progeny plants based on nano-CeO2 includes the following steps:

[0046] S1. Preparation of potting soil: Mix nano CeO2 with one part of soil evenly to obtain the first potting soil with a mass concentration of 50 mg / kg. The particle size of nano CeO2 is 25±10 nm. Before use, the first potting soil is placed in a dark environment and allowed to stand for equilibration for 1.5 weeks. Take two more parts of soil as the second and third potting soils respectively. The soil moisture content of the first, second and third potting soils is adjusted to 65% of the field capacity.

[0047] S2. Strawberry mother plant culture: Plant the strawberry mother plant in the first culture soil for cultivation. When planting the strawberry mother plant, make the base of the seedling level with the surface of the first culture soil, and spread the roots flat inside the first culture soil. The depth of the first culture soil is 25cm. Maintain alternating light and dark conditions for 30 days. The strawberry mother plant has a rootstock of 3cm and 6 normally developed compound leaves.

[0048] S3, First-generation strawberry plantlet cultivation: When the strawberry mother plant produces runners in S2, it is transplanted to its original location. The runners are buried in the second culture soil at a depth of 2cm. When the runners continue to grow to 30cm, the stems are trained and the vines are trained to grow into the second culture soil at a depth of 3cm. The plant is then cultivated under alternating light and dark conditions for 30 days to form the first-generation strawberry plantlets.

[0049] S4. Second-generation strawberry plantlet cultivation: When the first-generation strawberry plantlets in S3 produce runners, they are transplanted to their original location. The runners are buried in the third culture soil at a depth of 2cm. When the runners continue to grow to 30cm, the stems are trained and the vines are trained to grow. One adventitious root on the runner is inserted into the third culture soil to a depth of 3cm for cultivation. The plantlets are then cultivated under alternating light and dark conditions for 30 days.

[0050] In S2 to S4, the air humidity was 80% during the cultivation of strawberry mother plants, first-generation strawberry daughter plants, and second-generation strawberry daughter plants. The alternation of light and dark was maintained for 16 hours and 8 hours, the light intensity was 650 Lux, and the cultivation temperature was 20℃.

[0051] In S3 and S4, the adventitious roots on both the mother plant's stolons and the daughter plant's stolons are located in the middle of either the mother plant's stolons or the daughter plant's stolons.

[0052] Example 2

[0053] The difference between this embodiment and Embodiment 1 is that the mixing ratio of nano-CeO2 in the first culture soil to one part of soil is different.

[0054] Nano CeO2 was mixed evenly with a portion of soil to obtain the first culture soil with a mass concentration of 40 mg / kg.

[0055] Example 3

[0056] The difference between this embodiment and Embodiment 1 is that the mixing ratio of nano-CeO2 in the first culture soil to one part of soil is different.

[0057] Nano CeO2 was mixed evenly with a portion of soil to obtain the first culture soil with a mass concentration of 45 mg / kg.

[0058] Example 4

[0059] The difference between this embodiment and Embodiment 1 is that the mixing ratio of nano-CeO2 in the first culture soil to one part of soil is different.

[0060] Nano CeO2 was mixed evenly with a portion of soil to obtain the first culture soil with a mass concentration of 55 mg / kg.

[0061] Example 5

[0062] The difference between this embodiment and Embodiment 1 is that the mixing ratio of nano-CeO2 in the first culture soil to one part of soil is different.

[0063] Nano CeO2 was mixed evenly with a portion of soil to obtain the first culture soil with a mass concentration of 60 mg / kg.

[0064] Example 6

[0065] The difference between this embodiment and Embodiment 1 is that the specific parameters in S1 are different.

[0066] S1. Preparation of potting soil: Before use, the first potting soil is placed in a dark environment and allowed to stand for one week to reach equilibrium. Two other soil samples are taken as the second and third potting soils, respectively. The soil moisture content of the first, second, and third potting soils is adjusted to 60% of the field capacity.

[0067] Example 7

[0068] The difference between this embodiment and Embodiment 1 is that the specific parameters in S1 are different.

[0069] S1. Preparation of potting soil: Before use, the first potting soil is placed in a dark environment and allowed to stand for 2 weeks to reach equilibrium. Two other soil samples are taken as the second and third potting soils, respectively. The soil moisture content of the first, second, and third potting soils is adjusted to 70% of the field capacity.

[0070] Example 8

[0071] The difference between this embodiment and embodiment 1 is that the specific parameters in S2 are different.

[0072] S2. Strawberry mother plant culture: The depth of the first culture soil is 20cm. Maintain alternating light and dark conditions for 28 days. The strawberry mother plant has a rootstock of 1cm and 5 normally developed compound leaves.

[0073] Example 9

[0074] The difference between this embodiment and embodiment 1 is that the specific parameters in S2 are different.

[0075] S2. Strawberry mother plant culture: The depth of the first culture soil is 30cm. The strawberry mother plant is cultured under alternating light and dark conditions for 35 days. The rootstock of the strawberry mother plant is 4cm long and has 8 normally developed compound leaves.

[0076] Example 10

[0077] The difference between this embodiment and embodiment 1 is that the specific parameters in S3 are different.

[0078] S3, First-generation strawberry plantlet cultivation: When the strawberry mother plant produces runners in S2, it is transplanted to its original location. The runners are buried in the second culture soil at a depth of 1cm. When the runners continue to grow to 28cm, the stems are trained and the vines are trained to grow. An adventitious root on the runner is inserted into the second culture soil to a depth of 2cm for cultivation. The plant is cultivated under alternating light and dark conditions for 28 days, which are then used as the first-generation strawberry plantlets.

[0079] Example 11

[0080] The difference between this embodiment and embodiment 1 is that the specific parameters in S3 are different.

[0081] S3. Cultivation of the first generation of strawberry offspring: When the strawberry mother plant produces runners in S2, it is transplanted to its original location. The runners are buried in the second culture soil at a depth of 3cm. When the runners continue to grow to 32cm, the stems are trained and the vines are trained to grow. An adventitious root on the runner is inserted into the second culture soil to a depth of 5cm for cultivation. The plant is cultivated under alternating light and dark conditions for 35 days, which are then used as the first generation of strawberry offspring.

[0082] Example 12

[0083] The difference between this embodiment and embodiment 1 is that the specific parameters in S4 are different.

[0084] S4. Second-generation strawberry plantlet cultivation: When the first-generation strawberry plantlets in S3 produce runners, they are transplanted to their original location. The runners are buried in the third culture soil at a depth of 1cm. When the runners continue to grow to 28cm, the stems are trained and the vines are trained to grow. An adventitious root on the runner is inserted into the third culture soil to a depth of 2cm for cultivation. The plantlets are then cultivated under alternating light and dark conditions for 28 days.

[0085] Example 13

[0086] The difference between this embodiment and embodiment 1 is that the specific parameters in S4 are different.

[0087] S4. Second-generation strawberry plantlet cultivation: When the first-generation strawberry plantlets in S3 produce runners, they are transplanted to their original location. The runners are buried in the third culture soil at a depth of 3cm. When the runners continue to grow to 32cm, the stems are trained and the vines are trained to grow. One adventitious root on the runner is inserted into the third culture soil to a depth of 5cm for cultivation. The plant is then cultivated under alternating light and dark conditions for 35 days.

[0088] Example 14

[0089] The difference between this embodiment and Embodiment 1 is that:

[0090] In S2 to S4, the air humidity was 75% during the cultivation of strawberry mother plants, first-generation strawberry daughter plants, and second-generation strawberry daughter plants. The alternation of light and dark was maintained for 16 hours and 8 hours, the light intensity was 600 Lux, and the cultivation temperature was 18℃.

[0091] In S3 and S4, the adventitious roots on both the mother plant's stolons and the daughter plant's stolons are located 5 cm from the middle of either the mother plant's stolons or the daughter plant's stolons.

[0092] Example 15

[0093] The difference between this embodiment and Embodiment 1 is that:

[0094] In S2 to S4, the air humidity was 85% during the cultivation of strawberry mother plants, first-generation strawberry daughter plants, and second-generation strawberry daughter plants. The alternation of light and dark was maintained for 16 hours and 8 hours, the light intensity was 700 Lux, and the cultivation temperature was 22℃.

[0095] In S3 and S4, the adventitious roots on both the mother plant's stolons and the daughter plant's stolons are located at the midpoint +5cm of either the mother plant's stolons or the daughter plant's stolons.

[0096] Example 16

[0097] The difference between this embodiment and Embodiment 1 is that:

[0098] In S1, the second culture soil contains 30 mg / kg of biochar-based soil conditioner, and the third culture soil contains 15 mg / kg of biochar-based soil conditioner. The biochar-based soil conditioner, by weight, includes 35 parts of straw biochar powder or rice husk biochar powder, 11 parts of municipal sludge, 3.5 parts of coffee grounds, and 1.5 parts of microbial inoculant. The microbial inoculant is Bacillus subtilis with an effective viable count of >0.5 billion / mL.

[0099] Example 17

[0100] The difference between this embodiment and embodiment 16 is that:

[0101] In S1, 20 mg / kg of biochar-based soil conditioner was added to the second culture soil, and 10 mg / kg of biochar-based soil conditioner was added to the third culture soil. The biochar-based soil conditioner, by weight, includes 30 parts of straw biochar powder or rice husk biochar powder, 10 parts of municipal sludge, 3 parts of coffee grounds, and 1 part of microbial inoculant.

[0102] Example 18

[0103] The difference between this embodiment and embodiment 16 is that:

[0104] In S1, 40 mg / kg of biochar-based soil conditioner was added to the second culture soil, and 20 mg / kg of biochar-based soil conditioner was added to the third culture soil. The biochar-based soil conditioner, by weight, includes 40 parts of straw biochar powder or rice husk biochar powder, 12 parts of municipal sludge, 4 parts of coffee grounds, and 2 parts of microbial inoculant.

[0105] Experimental Example

[0106] Nano-CeO2 (purity >99.95%) used in this experiment was purchased from Sigma-Aldrich. Its particle size and morphology were characterized by transmission electron microscopy (Tecani G2 SpiritTWIN, FEI, Netherlands), with an average particle size of 24.6 ± 10.2 nm. The real soil sample was collected from a farmland, consisting of sandy loam with clay, silt, and sand content of 3.82%, 62.83%, and 33.35%, respectively. The soil pH-H2O, available phosphorus, available potassium, organic matter, and Ce concentration were 6.68, 9.77 mg / kg, 163 mg / kg, 44.4 g / kg, and 6.87 mg / kg, respectively. The soil samples were air-dried, sieved through a 2 mm sieve, and stored for pot experiments.

[0107] I. After cultivation according to the method in Example 1, the cultivation results were analyzed. The results showed that nano-CeO2 significantly increased the fresh weight of the underground and aboveground parts of the first-generation strawberry plants (by 139% and 54%, respectively) and the fresh weight of the underground and aboveground parts of the second-generation strawberry plants (by 74% and 75%, respectively). Figure 1 and 2 );

[0108] Furthermore, the photosynthetic parameters (F) of multiple generations of plants treated with nano-CeO2 were also observed. v The F0 index, P index, and chlorophyll content were 23%-24%, 82%-106%, and 10%-27% higher than the control group, respectively. Figures 3-5 Previous studies have shown that low concentrations of Ce 3+ It can enter chloroplasts and bind to chlorophyll, promoting chlorophyll synthesis and photosynthetic rate. Enhanced photosynthesis at the leaf level can directly promote plant biomass accumulation. These findings highlight the importance of nano-CeO2 in improving plant growth and development.

[0109] II. Under exposure to the mother plant, nano-CeO2 is absorbed by the roots of the strawberry mother plant and transported to the leaf and stolon tissues. Figures 6-7 Specifically, the Ce accumulation in the roots, leaves, and stolons of strawberry mother plants exposed to 50 mg / kg nano CeO2 reached 1.86 × 10⁻⁶. 3The concentrations of nano-CeO2 were 36.1 μg / kg, 36.1 μg / kg, and 366 μg / kg, respectively. The study showed that after root exposure, nano-CeO2 was mainly enriched in the roots, with only about 1.00% translocated to the aboveground parts. Similarly, the distribution of nano-CeO2 in strawberry mother plants was root > stolon > leaf. The translocation of Ce from underground to aboveground tissues occurs through the xylem, and the decrease in Ce concentration in the aboveground parts indicates radial movement. Ce accumulated in the roots may be stored in the cortical tissue due to this movement, thus preventing Ce from entering the leaves. Furthermore, the translocation factors of Ce from roots to leaves and stolons in strawberry mother plants were 0.0194 and 0.197, respectively.

[0110] After accumulating in the mother strawberry plant, nanoparticles can enter the daughter plants through the connected stolons. The distribution of Ce in the tissues of the first and second strawberry daughter plants was consistent with that of the mother strawberry plant: roots (1.13 × 10⁻⁶). 3 and 1.58×10 3 μg / kg) > stolons (273 and 234 μg / kg) > leaves (6.99 and 25.3 μg / kg) Figure 6 This result is consistent with the high proportion of Ce in the roots of multigenerational divisions. The Ce translocation factors from stolons to daughter leaves, stolons, and roots were as follows: strawberry mother plant to first-generation strawberry daughter plant: 0.0197 < 0.755 < 3.16; first-generation strawberry daughter plant to second-generation strawberry daughter plant: 0.0934 < 0.856 < 5.80. Figure 8 This indicates that the sharing of Ce among multiple generations of saplings did not decrease with increasing generations. The interaction between nano-CeO2 and plant metabolites (such as the formation, aggregation, and dissolution of biocrowsing on the nanoparticle surface) may affect its plant behavior and accumulation.

[0111] In addition to Ce analysis, it was also found that nano-CeO2 reprogrammed the nutrient element spectrum in plants. Figure 9 It is noteworthy that nano-CeO2 significantly reduced the levels of micronutrients in first-generation strawberry plants. Nano-CeO2 may compete with or substitute for elements such as Fe, thereby affecting the plant's absorption of certain nutrients and influencing plant growth and development by altering the activity of element-regulated enzymes.

[0112] III. Global Transcriptome Analysis

[0113] Transcriptome analysis further revealed the molecular initiation events of plant physiological and biochemical development. Significant differences in leaf transcriptomes were observed across multiple generations of strawberry mother plants (mother plants, first-generation strawberry daughter plants, and second-generation strawberry daughter plants) after exposure to nano-CeO2. Principal component analysis (PCA) showed a clear distinction in gene expression patterns between the nano-CeO2 treatment and the control group. The results were supported by |log2(fold change)|>2 and P... adjUsing <0.01 as the standard, 3694 (2333 upregulated and 1361 downregulated), 19101 (11395 upregulated and 7706 downregulated), and 3882 (2475 upregulated and 1407 downregulated) differentially expressed genes (DEGs) were identified in mother plants, first-generation strawberry plants, and second-generation strawberry plants, respectively. These were visualized using a volcano plot. Figures 10-12 ).

[0114] Specifically, nano-CeO2 led to the upregulation of more DEGs rather than their downregulation, indicating a positive impact on strawberry transcriptional activity. In terms of DEG quantity, first-generation strawberry offspring were more sensitive to nano-CeO2 than other plants. The phenomenon of adaptive transgenerational memory in multi-generational plants has been widely reported. This result may be related to the positive adaptive regulation of transgenerational memory in the response of offspring plants to nano-CeO2.

[0115] Furthermore, research indicates that resource sharing among connecting ramets is influenced by the ramet developmental stage. Compared to first-generation strawberry ramets, second-generation strawberry ramets, with lower biomass, are in the early stages of ramet development and have lower nutrient requirements, which may lead to lower transcriptional activity.

[0116] These DEGs were matched for their potential biological functions using the KEGG database. The significant biological functions activated by nano CeO2 are mainly related to plant hormone signal transduction, photosynthesis, and circadian rhythms, as detailed below.

[0117] Plant hormone signal transduction

[0118] Plant hormones play a central role in intercellular crosstalk and signal transduction. After strawberry mother plants were exposed to nano-CeO2, the transcriptional effect level index (TELI) values ​​of the pathways "plant hormone signal transduction," "cysteine ​​and methionine metabolism," and "phenylalanine, tyrosine, and tryptophan biosynthesis" in the leaves of first-generation strawberry daughter plants were significantly increased, indicating that nano-CeO2 induced changes in hormone transcription in both mother and daughter strawberry plants.

[0119] Consistent with the findings of this study, previous reports indicated that root exposure to 70 mg / kg CeO2 nanoparticles significantly affected the metabolic pathways of plant hormones such as auxin and jasmonic acid in pak choi. Notably, exposure of strawberry mother plants to nano-CeO2 significantly regulated the expression of genes related to these pathways (such as cysE, aroF, AOC, AUX1, JAZ, and MYC2). These genes are primarily involved in hormone biosynthesis, distribution, and signal transduction. Specifically, the aroF gene encodes a protein that catalyzes the formation of 3-dehydroquinic acid from D-erythrose-4-phosphate, a step in the biosynthesis of auxin and salicylic acid. AOC is a key enzyme in jasmonic acid biosynthesis, producing its precursors. The AUX1 gene is a major auxin influx carrier, mediating auxin transport between plant tissues. The JAZ and MYC2 genes also regulate developmental and growth-related processes in plants. Alterations in the expression of these genes may affect the levels of plant hormones in tissues.

[0120] Therefore, the hormone content in plant leaves was further examined. Data showed that nano-CeO2 reprogrammed the hormone profiles of strawberry mother plants, first-generation strawberry offspring, and second-generation strawberry offspring. Specifically, the contents of auxin, salicylic acid, jasmonic acid, and cytokinin in the treatment groups of strawberry mother plants / first-generation strawberry offspring / second-generation strawberry offspring were 0.321 / 0.705 / 0.451, 4.16 / 2.31 / 0.855, 2.47 / 1.45 / 0.897, and 1.04 / 1.11 / 1.12 times higher than those in the control group, respectively. These hormones are involved in photosynthetic processes such as stomatal and chloroplast development, further regulating photosynthetic activity. For example, reduced auxin may induce stomatal cluster formation, promoting photosynthesis. Furthermore, high levels of cytokinin positively regulate chloroplast structural and functional development. The differential changes among multiple generations of plants indicate that adaptive transgenerational memory is hormone- and offspring development-dependent, warranting further investigation.

[0121] plant photosynthesis

[0122] Photosynthesis is the process by which plants convert CO2 into organic matter. Figure 13 This treatment significantly increased the photosynthetic TELI values ​​of strawberry mother plants, first-generation strawberry daughter plants, and second-generation strawberry daughter plants in the treatment groups, reaching 9.58 times and 2.52 × 10⁻⁶ times that of the control group, respectively. 3 The ratios of 8.49 and 8.49 times indicate that the application of nano-CeO2 to strawberry mother plants positively regulates the photosynthetic potential of the plants.

[0123] This view aligns with the findings of some researchers that low concentrations of CeO2 nanoparticles (0-100 mg / kg) can stimulate photosynthetic processes in plants. Notably, thermographic analysis revealed that photosynthetic-related DEGs are mainly classified into five categories: photosystem II (PSII), cytochrome b6 / f complex, electron transport, photosystem I (PSI), and ATP synthase. Specifically, nano-CeO2 downregulated the expression of some DEGs related to PSII and PSI processes in first-generation strawberry offspring, while upregulating the expression of these genes in both mother plants and second-generation strawberry offspring. The PSII process captures electrons from H2O, providing electrons for the production of organic matter (i.e., the PSI process). This transcriptome data is inconsistent with the results on plant photosynthetic activity. Figure 1 This may be because photosynthesis is affected by transcription and post-transcriptional regulation as well as enzyme activity.

[0124] Plant diurnal rhythm

[0125] Circadian rhythm is an intrinsic timing mechanism in plants that can temporally regulate their metabolic, physiological, and behavioral characteristics. The TELI values ​​of all generations of plants in the nano-CeO2 treatment group were significantly higher than those in the control group (control group: 0.103-0.793; nano-CeO2 group: 3.52-9.92), indicating that nano-CeO2 has a positive regulatory effect on circadian rhythm.

[0126] This result is consistent with previous studies showing that metal-based nanoparticles and metal exposure alter molecules associated with circadian rhythms in plants and animals. Furthermore, nano-CeO2 reprogrammed partial DEG expression profiles related to the diurnal system, including the input pathway, central oscillator, and output pathway. Notably, two hallmark photoreceptor genes in the input pathway, PHYA and PHYB, were significantly altered in plants exposed to nano-CeO2. This study suggests that photoreceptors in the input pathway mediate plant growth and development by integrating light signals and the core oscillator. For example, the expression trends of genes related to the output pathway (such as ELF3, GI, CO, COP, and HY5) are consistent with those of genes related to the input pathway (such as PHYA, PHYB, and CRY). Previous studies have confirmed the regulatory roles of the CO and HY5 genes in flowering and photosynthesis. Therefore, the diurnal rhythm changes induced by nano-CeO2 may regulate photosynthetic processes in plants.

[0127] Molecular mechanism of strawberry seedling response to nano-CeO2 transport

[0128] By constructing a protein-protein interaction network of 136 key DEGs (containing 78 nodes and 501 interaction relationships, with an average node degree of 12.8 and a clustering coefficient of 0.692), it was found that PSI-related genes (psaB, psaK), hormone signaling genes (AUX1, PIF4, MYC2), and circadian rhythm genes (PHYB, PHYA, COP1, GI, HY5) constitute the core hub genes. Figure 14 Structural equation modeling (SEM) showed that nano-CeO2 indirectly regulates strawberry plant biomass through diurnal rhythms (total standardized effect value: -0.379) and hormone signaling networks (0.962), explaining 52% of the growth variation. Figure 15 Among them, the interaction between photoreceptor PHYB and auxin transporter AUX1 and transcription factor PIF4 promotes plant growth by regulating cell elongation and auxin signal transduction.

Claims

1. A method for improving the growth of strawberry progeny plants based on nano-CeO2, characterized in that, Includes the following steps: S1. Preparation of culture soil: Mix nano CeO2 with one part of soil evenly to obtain the first culture soil with a mass concentration of 40-60 mg / kg. Take two other parts of soil as the second and third culture soils, respectively. S2. Strawberry mother plant culture: The strawberry mother plant is planted in the first culture soil and cultured under alternating light and dark conditions for 28 to 35 days. The rootstock of the strawberry mother plant is 1 to 4 cm long and has 5 to 8 normally developed compound leaves. S3. Cultivation of the first generation of strawberry offspring: When the strawberry mother plant produces runners in S2, transplant it to its original location. The runners are buried in the second culture soil at a depth of 1-3cm. When the runners continue to grow to 28-32cm, guide the stems and train them to grow. This allows one adventitious root on the runner to penetrate 2-5cm into the second culture soil for cultivation. Maintain alternating light and dark conditions for 28-35 days to cultivate the first generation of strawberry offspring. S4. Second-generation strawberry plantlet cultivation: When the first-generation strawberry plantlets in S3 produce runners, they are transplanted to their original location. The runners are buried in the third culture soil at a depth of 1-3 cm. When the runners continue to grow to 28-32 cm, the stems are trained and pressed, so that an adventitious root on the runner penetrates 2-5 cm into the third culture soil for cultivation. The plantlets are then cultivated under alternating light and dark conditions for 28-35 days.

2. The method for improving the growth of strawberry progeny plants based on nano-CeO2 according to claim 1, characterized in that, The particle size of nano CeO2 in S1 is 25±10nm, and the first culture medium is placed in a dark environment for 1 to 2 weeks to achieve equilibrium before use.

3. The method for improving the growth of strawberry progeny plants based on nano-CeO2 according to claim 1, characterized in that, The soil moisture content of the first, second, and third culture soils in S1 is adjusted to 60-70% of the field maximum water holding capacity.

4. The method for improving the growth of strawberry progeny plants based on nano-CeO2 according to claim 1, characterized in that, When planting the strawberry mother plant in S2, the base of the seedling should be level with the surface of the first culture soil, and the roots should be spread out flat inside the first culture soil, with a depth of 20-30cm.

5. The method for improving the growth of strawberry progeny plants based on nano-CeO2 according to claim 1, characterized in that, In S2 to S4, the air humidity was 75-85% during the cultivation of strawberry mother plants, the first generation of strawberry daughter plants, and the second generation of strawberry daughter plants. The alternation of light and darkness was maintained for 16 hours and 8 hours, the light intensity was 600-700 Lux, and the cultivation temperature was 20±2℃.

6. The method for improving the growth of strawberry progeny plants based on nano-CeO2 according to claim 1, characterized in that, In S3 and S4, the adventitious roots on the mother plant's stolons and the daughter plant's stolons are located at a point ±5cm from the middle of either the mother plant's stolons or the daughter plant's stolons.

7. The method for improving the growth of strawberry progeny plants based on nano-CeO2 according to claim 1, characterized in that, The second culture soil in S1 contains 20-40 mg / kg of biochar-based soil conditioner, and the third culture soil contains 10-20 mg / kg of biochar-based soil conditioner.

8. The method for improving the growth of strawberry progeny plants based on nano-CeO2 according to claim 7, characterized in that, The biochar-based soil conditioner, by weight, comprises 30-40 parts of straw biochar powder or rice husk biochar powder, 10-12 parts of municipal sludge, 3-4 parts of coffee grounds, and 1-2 parts of microbial inoculant.

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