A method for restoring a hydro-fluctuation belt

Abstract

The application provides a drawdown zone repair method, and belongs to the technical field of ecological restoration.The method is as follows: planting mulberry grape special No.1 in the drawdown zone; the mulberry grape special No.1 is preserved in the China General Microbiological Culture Collection Center, the address is No.3, Xili Beichen, Chaoyang District, Beijing, the preservation date is February 19, 2025, and the preservation number is CGMCC No.32201.The mulberry grape special No.1 can tolerate flooding and keep a dormant state when the water level rises; after the water level drops, the mulberry grape special No.1 can quickly restore growth, form stable vegetation coverage, effectively reduce water and soil loss, improve the ecological environment of the drawdown zone, and solve the key problems of ecological restoration and reconstruction of the drawdown zone.

Description

Technical Field

[0001] This invention relates to the field of ecological restoration technology, and in particular to a method for restoring drawdown zones. Background Technology

[0002] The drawdown zone is a special area formed by the rise and fall of water levels in rivers, lakes, and reservoirs. The frequent fluctuations in water levels make the ecological environment of the drawdown zone fragile and unique. Many plants struggle to adapt to this periodic flooding and drought, resulting in low vegetation cover. Without vegetation protection, the drawdown zone suffers from severe soil erosion and is extremely difficult to restore. Currently, in drawdown zone restoration research or projects, commonly used woody plants include Metasequoia glyptostroboides, Betula platyphylla, and Pterocarya stenoptera, while herbaceous plants such as Cynodon dactylon, Xanthium sibiricum, and Cyperus rotundus are employed. However, plant selection is limited, and there is a lack of fast-growing, fully flood-tolerant woody vines suitable for drawdown zone restoration.

[0003] Grapes, woody vines belonging to the genus *Vitis* in the family Vitaceae, are among the oldest fruit tree species in the world. Wild grapes typically possess characteristics such as rapid growth, strong resistance to adverse conditions, and wide adaptability, which can expand the important gene pool of cultivated grapes. Wild grapes can be crossbred with desired cultivated varieties to cultivate a variety of resistant plant germplasm materials. This is beneficial to agricultural production and the development of local cash crops. However, in recent years, due to factors such as pollution, overexploitation of resources, and destruction of their habitats, large numbers of wild plant populations have died, including wild grape species, many of which are now facing endangerment.

[0004] Existing technologies indicate that plant responses to flooding stress include changes in root morphology and structure, increased activity of antioxidant enzymes, accumulation of osmotic regulators, and regulation of photosynthesis and respiration. Most plants undergo noticeable changes in morphology and anatomy after flooding and initiate a series of physiological and biochemical responses to adapt to the adverse environment. Studies have shown that flooded plants develop adventitious roots to enable them to grow normally in the harsh flooded environment. When many primary roots die due to flooding, the plant's root system quickly develops adventitious roots adapted to flooding. These adventitious roots can grow normally due to their unique structure. Their root tip cells have high cell division capacity and physiological activity, and well-developed aerenchyma forms in the elongation zone, significantly increasing the porosity of the root tissue. These structures enhance the plant's oxygen absorption, and the aerenchyma allows gases to diffuse rapidly over long distances within the plant, thus restoring photosynthesis and ensuring sufficient oxygen transported to the roots to sustain its life activities.

[0005] The physiological and biochemical responses of plants under flood conditions are a complex and sensitive process. First, flood stress directly affects plant roots. Due to reduced oxygen supply in the soil, roots cannot perform normal respiratory metabolism. This hypoxic state not only inhibits root growth and development but may also lead to oxidative stress in the roots. The accumulation of reactive oxygen species (ROS) causes oxidative damage to biomolecules such as cell membranes, proteins, and DNA, potentially triggering lipid peroxidation of cell membranes, protein oxidation, and DNA breakage. To cope with this oxidation, plants may increase the activity of antioxidant enzymes, such as superoxide dismutase (SOD) and catalase, to scavenge ROS and protect cells from damage. However, as flood stress persists, plants may gradually lose their ability to adapt to the environment, causing antioxidant enzyme activity to peak and then decline. This may be due to the collapse of the plant's antioxidant system or resource constraints, preventing the plant from maintaining high levels of antioxidant enzyme activity. At this point, the plant may face more severe oxidative stress and cell damage. In addition, some transcription factors and aquaporins are also involved in regulating plant stress responses.

[0006] The Three Gorges drawdown zone, located in the Three Gorges area of ​​the Yangtze River, is a very unique ecological environment. It is affected not only by fluctuations in water level but also by seasonal climate change, soil type, and vegetation cover. Providing a woody vine capable of restoring the drawdown zone, especially the Three Gorges drawdown zone, would not only provide plant germplasm resources for vegetation restoration and reconstruction in the Three Gorges Dam drawdown zone environment but also contribute to a deeper understanding of plant adaptation mechanisms and survival strategies under flood conditions, offering new ideas and methods for scientific research in related fields. Summary of the Invention

[0007] The purpose of this invention is to provide a method for repairing drawdown zones.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0009] This invention provides a method for restoring drawdown zones, which involves planting *Vitis vinifera* Species No. 1 in the drawdown zone. *Vitis vinifera* Species No. 1 is deposited at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with a deposit date of February 19, 2025 and accession number CGMCC No. 32201.

[0010] Preferably, the drawdown zone is the drawdown zone of the Three Gorges Reservoir area.

[0011] Preferably, before planting, the Mulberry Leaf Grape Specific No. 1 is propagated. The propagation is carried out in a nursery or in nutrient pots, and the propagation method is hardwood cutting or softwood full-light spray cutting.

[0012] Preferably, the time for propagation using the hardwood cutting method is February to May, June to September, or October to November, and the time for propagation using the softwood full-light spray cutting method is July to September.

[0013] Preferably, the method of hardwood cutting is as follows: after cutting the hardwood branches of Mulberry Leaf Grape Special No. 1 into cuttings with 2 to 3 buds, the morphological lower end of the cuttings is inserted into the cutting substrate in the nursery or nutrient pot.

[0014] Preferably, the hardwood branch is a one-year-old or perennial branch;

[0015] The morphological lower end of the cutting is cut obliquely, and the morphological upper end is cut horizontally;

[0016] The nutrient pot is a non-woven fabric nutrient pot, and the diameter of the non-woven fabric nutrient pot is 12-30cm;

[0017] The depth of insertion into the cutting substrate is 1 / 3 to 1 / 2 of the length of the cutting; the cutting substrate is yellow-brown soil.

[0018] Preferably, the method of full-light spray propagation of tender branches is as follows: after cutting tender branches of Mulberry Leaf Grape Special No. 1 into cuttings with 2 to 3 buds, insert the morphological lower end of the cuttings into a river sand bed, and use a full-light spray watering device for watering management. After 40 to 80 days, the rooted seedlings are transplanted into nutrient pots for cultivation.

[0019] Preferably, the upper part of the cutting has leaves, with the leaf area accounting for 1 / 3 to 1 / 2;

[0020] The nutrient pot is a non-woven fabric nutrient pot, and the diameter of the non-woven fabric nutrient pot is 12-30cm.

[0021] Preferably, the seedlings are two years old or older, using the clonal cultivar 'Mulberry Leaf Grape No. 1'; the planting spacing is 2-3m × 3-5m; and the planting hole is 15-35cm × 15-35cm × 25-35cm long × wide × deep.

[0022] Preferably, after planting Mulberry Leaf Grape Special No. 1, the rootstock of the seedlings is compacted and fixed, the planting hole is covered with weed control cloth and the weed control cloth is fixed around the perimeter.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This invention provides a method for restoring drawdown zones using *Vitis vinifera* var. *mulberry* (specific variety 1), which is planted in the drawdown zone area. *Vitis vinifera* var. *mulberry ... Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0026] Figure 1 The results of the determination of MDA content in the roots of mulberry leaves and grapes after different flooding times in Example 2;

[0027] Figure 2 The results show the determination of free proline content in the roots of mulberry leaves and grapes after different flooding times in Example 2.

[0028] Figure 3 The results show the determination of soluble sugar content in the roots of mulberry leaves and grapes after different flooding times in Example 2.

[0029] Figure 4 The results show the determination of soluble protein content in the roots of mulberry leaves and grapes after different flooding times in Example 2.

[0030] Figure 5 The results show the determination of peroxidase content in the roots of mulberry leaves and grapes after different flooding times in Example 2.

[0031] Figure 6 The results show the determination of superoxide dismutase content in the roots of mulberry leaves and grapes after different flooding times in Example 2.

[0032] Figure 7 The results show the determination of catalase content in the roots of mulberry leaves and grapes after different flooding times in Example 2.

[0033] Figure 8The figures show the morphological characteristics of various mulberry grape plants after different flooding times in Example 2. In the figures, A represents mulberry grape plants that have not been flooded, B represents mulberry grape plants that have been flooded for 3 days, C represents mulberry grape plants that have been flooded for 6 days, D represents mulberry grape plants that have been flooded for 9 days, E represents the aboveground part of mulberry grape plants that have been flooded for 12 days, F represents the underground part of mulberry grape plants that have been flooded for 12 days, G represents mulberry grape plants that have been flooded for 15 days, and H represents mulberry grape plants that have been flooded for 30 days.

[0034] Figure 9 The images show the microstructures of cross-sections of mulberry and grape root tips after different flooding times in Example 2. Specifically, A represents the microstructure of a cross-section of a mulberry and grape root tip without flooding, B represents the microstructure of a cross-section of a mulberry and grape root tip after 3 days of flooding, C represents the microstructure of a cross-section of a mulberry and grape root tip after 6 days of flooding, D represents the microstructure of a cross-section of a mulberry and grape root tip after 9 days of flooding, E represents the microstructure of a cross-section of a mulberry and grape root tip after 12 days of flooding, F represents the microstructure of a cross-section of a mulberry and grape root tip after 15 days of flooding, and G and H represent the microstructures of a cross-section of a mulberry and grape root tip after 30 days of flooding.

[0035] Figure 10 The images show magnified views of the cross-sectional microstructure of the root tips of mulberry and grape after 3d (A), 6d (B), and 9d (C) of flooding treatment in Example 2. In these images, a represents the periderm, b represents the phloem, c represents the phloem rays, d represents the wood rays, e represents the secondary xylem, f represents the primary xylem, g represents the accumulated suberin and lignin, and h represents the lysogenic aerenchyma formed by programmed cell death and dissolution.

[0036] Figure 11 This is a diagram illustrating the effect of planting Mulberry Leaf Grape Special No. 1 in the drawdown zone of the Three Gorges Reservoir area in Example 3.

[0037] Figure 12 This is a diagram illustrating the effect of planting Mulberry Leaf Grape Special No. 1 in the drawdown zone of the Three Gorges Reservoir area in Example 3.

[0038] Figure 13 This is a diagram showing the effect of planting Mulberry Leaf Grape Special No. 1 in the drawdown zone of the Three Gorges Reservoir area in Example 3. Detailed Implementation

[0039] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0040] Example 1: Obtaining Mulberry Leaf and Grape Specific No. 1

[0041] The inventor discovered a wild grape vine in the Three Gorges drawdown zone, which was identified as Vitis ficifolia. It is deposited at the China General Microbiological Culture Collection Center, located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, on February 19, 2025, with accession number CGMCC No. 32201.

[0042] Example 2: Study on the water-resistance mechanism of Mulberry Leaf Grape Specific No. 1

[0043] Artificial flooding was conducted at the Three Gorges Botanical Garden. Potted *Vitis vinifera* 'Special No. 1' grapes were selected. In early October, three-year-old two-year-old cuttings of *Vitis vinifera* 'Special No. 1' of uniform size, good growth, and similar developmental stage were selected, and three pots were grouped together. Three of these pots were selected for open-field cultivation as a control group. The remaining pots were completely submerged in a pond for 3, 6, 9, 12, 15, and 30 days. After each group reached the corresponding flooding time, the grape pots were immediately removed from the pond.

[0044] 1. Detection of physiological and biochemical indicators

[0045] The contents of MDA, osmotic regulatory factors (free proline, soluble sugar, soluble protein), and antioxidant enzymes (peroxidase, superoxide dismutase, catalase) in the roots of mulberry leaves and grapes were determined after different flooding durations using the following methods:

[0046] Malondialdehyde (MDA) content determination employs the TBA spectrophotometric method. The basic principle is that MDA undergoes a condensation reaction with TBA, producing a colored compound with a maximum absorption peak at 532 nm. The amount of this colored compound produced is proportional to the MDA content; therefore, the MDA content can be indirectly determined by measuring the absorbance at 532 nm.

[0047] The acidic ninhydrin colorimetric method is used to determine proline content. The principle is based on the characteristic that free amino acids react with ninhydrin to form colored compounds. During the reaction, amino acids react with acidic ninhydrin to produce a blue-violet compound, which exhibits maximum light absorption at a wavelength of 520 nm. The content of this compound represents the level of free proline.

[0048] The soluble sugar content was determined using the anthrone colorimetric method. A 100 μg / mL sucrose solution was used as the standard solution. Six test tubes were filled with 0 mL, 0.2 mL, 0.4 mL, 0.6 mL, 0.8 mL, and 1.0 mL of the standard sucrose solution, respectively. Distilled water was added to bring the volume to 2 mL. Then, 0.5 mL of anthrone-ethyl acetate and 5 mL of concentrated sulfuric acid were added sequentially. After thorough shaking, the test tubes were immediately placed in a boiling water bath for 1 min. After cooling to room temperature, the OD value was measured at a wavelength of 630 nm, using a blank as a reference. A standard curve for soluble sugars was plotted with the OD value on the ordinate and the concentration of each standard solution (μg / mL) on the abscissa. The soluble sugar content in the sample was then calculated.

[0049] The soluble protein content was determined using the Coomassie Brilliant Blue method. Coomassie Brilliant Blue G-250 can bind to the hydrophobic regions of proteins in an acidic environment, causing its maximum absorption peak to change from 465 nm to 595 nm, and its color development is positively correlated with the protein concentration.

[0050] Peroxidase activity was determined using the guaiacol method, which is based on the fact that peroxidase can oxidize guaiacol to a brownish-yellow product under hydrogen peroxide, with an absorption peak wavelength of 470 nm. The POD activity was determined by measuring the change in absorbance (OD) at each time step.

[0051] Superoxide dismutase (SOD) activity was measured using the nitroblue tetrazolium (NBT) method. This method is based on the fact that SOD can scavenge superoxide anion free radicals (O₂O₃). 2- The principle is to inhibit the photoreduction reaction of NBT. By measuring the degree of NBT reduction in the reaction system, the activity of SOD can be calculated.

[0052] Catalase activity was determined using the potassium permanganate titration method. The basic principle of this method is that catalase decomposes hydrogen peroxide into oxygen, and potassium permanganate oxidizes the hydrogen peroxide. Therefore, catalase activity can be measured by titrating a potassium permanganate solution.

[0053] This experiment used Excel to calculate the mean and standard deviation; SPSS 27 was used for one-way ANOVA, and a p-value < 0.05 was considered statistically significant; Origin 2021 was used for plotting.

[0054] The results of the determination of MDA, free proline, soluble sugar, soluble protein, peroxidase, superoxide dismutase and catalase contents in the roots of various mulberry leaves and grapes after different flooding time treatments are as follows: Figures 1 to 7 As shown.

[0055] Malondialdehyde (MDA) is the end product of lipid peroxidation in cell membranes, and its content reflects the degree of damage to plants under stress. Under stress, plants primarily utilize inorganic ions to resist adverse conditions, but due to Na+...+ The accumulation of elements such as malondialdehyde (MDA) leads to ion toxicity in plants. Therefore, the MDA content will increase. Figure 1 It can be seen that the malondialdehyde (MDA) content first increases, then decreases, and then increases again with the extension of flooding stress time, reaching the highest level after 9 days of flooding treatment, at which time the MDA content is 1.85 times that of the control (0 days of treatment).

[0056] Proline, an important substance for maintaining osmotic balance in plants, may increase its free proline content in the early stages of flood stress to maintain cell structure stability, thereby increasing the cells' water-retention capacity. Figure 2 It can be seen that the content of free proline increased significantly with the extension of flooding time, reaching a maximum value at 12 days, which was 2.29 times that of the control group.

[0057] Under flooded conditions, the synthesis and accumulation of soluble sugars in grape roots may be affected to maintain intracellular osmotic pressure balance and energy supply. These soluble sugars act as osmotic regulators, helping cells maintain internal water balance and preventing excessive water loss during flooding. Simultaneously, soluble sugars are also an important energy source for plants to cope with environmental stress, providing a crucial material basis for their survival and repair under adverse conditions. Figure 3 It can be seen that the soluble sugar content increases significantly with the increase of flooding time, reaching the highest level at 12 days, which is 4.71 times that of the control group. Long-term flooding stress may lead to hypoxia in the roots of mulberry leaves and grapes, affecting the absorption and utilization of nutrients by the roots, thereby limiting the synthesis and accumulation of soluble sugars. Therefore, the soluble sugar content decreases from 12 to 30 days.

[0058] Soluble proteins play important physiological functions in plant cells; their accumulation can increase the osmotic pressure of plants and mitigate the damage caused by flooding stress. Figure 4 It can be seen that the content of soluble protein in mulberry leaves and grape roots increases with the extension of water flooding treatment time, reaching the highest level at 15 days, which is 10.6 times that of the control; however, after 15 days, the content of soluble protein decreases significantly.

[0059] Peroxidases are a class of valuable antioxidant enzymes in plants. Their main function is to protect cells from oxidative damage by hydrolyzing peroxides. Figure 5 It can be seen that after flooding treatment, the peroxidase activity showed a change pattern of first increasing and then decreasing, with the maximum value at 15 days of flooding, which was 2.14 times that of the control; as the flooding time was prolonged, the peroxidase activity decreased again at 30 days of flooding stress.

[0060] Superoxide dismutase (SOD) is a key antioxidant enzyme whose main function is to catalyze the dismutation reaction of superoxide free radicals, converting them into hydrogen peroxide (H₂O₂) and oxygen (O₂), thereby protecting cells from oxidative damage. Figure 6 It was found that under flood stress, the activity of superoxide dismutase (SOD) in the roots of mulberry and grape plants first increased significantly and then decreased. Among them, the SOD activity reached its maximum value after 3 days of flooding, which was 1.19 times that of the control group, and the SOD activity continued to decline after 6 days.

[0061] Catalase is a class of antioxidant enzymes with important physiological activity. Its main function is to degrade hydrogen peroxide into water and oxygen to maintain normal plant growth and metabolism, and to reduce oxidative damage to cells. Figure 7 It was found that catalase activity was low at day 0. After water immersion stress, catalase activity first increased significantly, reaching its peak at day 3, which was 2.1 times that of the control group. After day 3, catalase activity gradually decreased over time.

[0062] The results show that within a certain period of flooding, all physiological indicators showed an upward trend, but beyond this period, they showed a downward trend. This may be because prolonged flooding stress leads to metabolic imbalance in the plant, preventing the normal synthesis and accumulation of organic matter. Furthermore, prolonged flooding stress may also alter other metabolic pathways in the plant, increasing the decomposition and consumption of proline and soluble proteins. These results indicate that the *Mulberry Leaf Grape Specific No. 1* variety adapts to flooding stress by regulating osmotic regulators and antioxidant enzyme activity, but its adaptability is limited, and long-term flooding stress will inhibit its growth.

[0063] 2. Root system tissue structure analysis

[0064] The morphological structure of *Vitis vinifera* vines after different flooding durations was observed and photographed. Simultaneously, the finest surviving roots from each vine were collected and prepared using paraffin sectioning to observe and analyze the anatomical structure of the root tissues after different flooding durations. The specific sectioning method is as follows:

[0065] (1) Material selection and fixation: Select mulberry leaves and grape root tips (about 1cm) as the slide preparation material, fix them with FAA (70% alcohol: formaldehyde: glacial acetic acid = 90: 5: 5) and remove the air, and place them for more than 24 hours.

[0066] (2) Softening: Place in a 1:1 mixture of glycerin and 95% alcohol for 7 days.

[0067] (3) Dehydration and transparency: Place the mixture in a gradient of ethanol at 50%, 70%, 85%, 95%, 100%, and 100% for 1 hour each. Then place it in a xylene: pure alcohol mixture at a ratio of 1:1 and wait for 2 hours. Finally, place it in pure xylene for 2 hours.

[0068] (4) Wax impregnation and embedding: Mix the material with a small amount of xylene and paraffin wax, pour the wax liquid into a 60°C constant temperature oven, and replace the wax every 3 hours for a total of 3 times. Then embed the material using a paraffin embedding machine.

[0069] (5) Slicing and mounting: After trimming the wax slides, place them on a microtome, set the slice thickness to 8μm, spread the slides in a water bath (40℃), and then place them in a constant temperature drying oven (40℃).

[0070] (6) Staining, mounting, and microscopic examination: Safranin-Fix Green was used for staining and observation. The staining time was first determined through preliminary experiments to be 35 minutes for Safranin and 30 seconds for Fast Green.

[0071] (7) Dewaxing: Place the material in pure xylene 1, take it out after 5 minutes and place it in pure xylene 2, then transfer it to pure xylene 3 after another 5 minutes and wait for 5 minutes.

[0072] (8) Rehydration: Place in anhydrous ethanol 1 and wait for 5 minutes. Take it out and place it in anhydrous ethanol 2. After 10 minutes, take it out and place it in alcohol with volume fractions of 95%, 95%, 85%, and 70% in turn for 3 minutes, 2 minutes, 3 minutes, and 3 minutes respectively. Finally, place it in filtered water for 2 minutes.

[0073] (9) Safranin staining: Soak in 1% safranin solution for 35 min. Then soak in filtered water for 5 min and then in filtered water for 2 min.

[0074] (10) Dehydration: Place the material in alcohol at a gradient of 70%, 85%, and 95% for 1 minute each.

[0075] (11) Fast Green counterstaining: Place the material in 1% Fast Green and stain for 30 seconds.

[0076] (12) Dehydration: Place the material into a dyeing tank containing 95% alcohol for 1 minute each, and then into a dyeing tank containing anhydrous ethanol for 2 minutes each.

[0077] (13) Transparency: Then place it in two staining tanks containing pure xylene for 2 minutes each.

[0078] (14) Covering the slide: Drip enough resin onto the wax slide, then cover the material with a coverslip and place it indoors to wait for the resin to dry.

[0079] (15) Microscopic examination: using a microscope to observe and analyze materials.

[0080] The results of morphological observation of mulberry leaf grape plants after different flooding times are as follows: Figure 8 As shown in Table 1, the roots of plants that were not subjected to waterlogging treatment were intact and dense, with a yellow root color, and the leaves were normal. Figure 8 (A) After three days of flooding stress, most of the secondary roots of the mulberry leaf grapevines survived, and the root system was yellowish-brown in color; almost all the leaves on the branches were preserved, while some leaves turned yellow. Figure 8 (Medium B). After 6 days of waterlogging stress, a small number of the absorbing roots of the mulberry-leaf grape survived, most of them turned black, and some roots with a thickness of 1 mm or more remained, showing a yellow color; most of the leaves on the branches remained, some of which turned yellow. Figure 8 (C) After being submerged for 9 days, all the absorbing roots of the mulberry and grapevines had died and turned black, while the remaining secondary roots were still alive; there were many leaves remaining on the branches. Figure 8 (D). After being submerged for 12 days, the fine absorbing roots of the mulberry and grapevines have all died and turned black, and the remaining secondary roots are partially dead; the lateral branches survive, are green, and have a few remaining leaves on them. Figure 8 (E and F). After 15 days of flooding, the absorbing roots of the mulberry leaf grapevines all died and turned black; only the secondary roots and main roots survived, which were yellowish-brown in color. All the leaves on the branches withered and fell off. Figure 8 (G). After 30 days of flooding, the absorbing roots of mulberry and grape leaves were necrotic, with some remaining on them; most of the secondary roots died, with only the main roots surviving; all lateral branches died and fell off, with no leaves remaining, and the branches were smelly and slimy. Figure 8 (H).

[0081] Table 1. Morphological changes of mulberry leaves, grape stems, leaves, and roots under different flooding treatment times.

[0082]

[0083] Microstructure of root tip cross sections of mulberry leaf grape plants after different flooding times: Figure 9 As shown, A represents the cross-sectional microstructure of mulberry and grape root tips without flooding treatment; B represents the cross-sectional microstructure of mulberry and grape root tips after 3 days of flooding treatment; C represents the cross-sectional microstructure of mulberry and grape root tips after 6 days of flooding treatment; D represents the cross-sectional microstructure of mulberry and grape root tips after 9 days of flooding treatment; E represents the cross-sectional microstructure of mulberry and grape root tips after 12 days of flooding treatment; F represents the cross-sectional microstructure of mulberry and grape root tips after 15 days of flooding treatment; and G and H represent the cross-sectional microstructure of mulberry and grape root tips after 30 days of flooding treatment. Enlarged views of the cross-sectional microstructures of mulberry and grape root tips after 3 days (A), 6 days (B), and 9 days (C) of flooding treatment are shown below. Figure 10As shown, a is the periderm, b is the phloem, c is the phloem ray, d is the wood ray, e is the secondary xylem, f is the primary xylem, g is the accumulated suberin and lignin, and h is the lysogenic aerenchyma formed by the programmed death and dissolution of living cells.

[0084] Depend on Figure 9 and Figure 10 It can be seen that the primary structure of normal mulberry and grape roots that have not undergone flooding includes the stele, endodermis, cortex, exodermis, lignified 'Φ'-shaped thickening, aerenchyma, and epidermis; the secondary structure consists of secondary xylem, secondary phloem, aerenchyma, and cork layer. After flooding stress, multiple cells in the cortex undergo 'Φ'-shaped lignification and thickening, and the exodermis deposits a large amount of cork and lignin, producing a cork cambium, and the aerenchyma becomes more developed. After 3 days of flooding stress, a small number of small cavities are produced in the cortex of mulberry and grape roots. This is mainly due to cell separation. After 6 days of flooding stress, these cavities become denser in the cortex. After 9 days of flooding stress, lysogenic air cavities caused by programmed cell death or dissolution begin to appear in the cortex. When flooding stress reaches 12 days, a large number of lysogenic air cavities appear in the cortex, and the previously produced cavities also become wider. These changes are distributed in the cortex of wild grape roots, making its parenchyma appear broad. No significant changes were observed 15 days and 30 days after flooding stress.

[0085] Example 3

[0086] A method for restoring the drawdown zone of the Three Gorges Reservoir area using the aforementioned mulberry leaf and grape-specific No. 1, comprising the following steps:

[0087] (1) Propagation of Mulberry Leaf Grape Special No. 1: Propagation is carried out in the nursery or in nutrient pots. The propagation method is hardwood cutting or softwood full-light spray cutting.

[0088] The propagation time using the hardwood cutting method is from February to May, June to September, or October to November (the cuttings used for propagation from June to September are cold-preserved cuttings). During propagation, one-year-old or multi-year-old hardwood branches of the Mulberry Leaf Grape Special No. 1 variety are cut into cuttings with 2-3 buds. The lower morphological end of the cutting is cut obliquely, and the upper morphological end is cut horizontally. The lower morphological end of the cutting is inserted into the nursery bed or into a non-woven fabric nutrient pot (yellow-brown soil) with a diameter of 12-30 cm, to a depth of 1 / 3 to 1 / 2 of the cutting length.

[0089] The propagation time using the aforementioned softwood full-light misting cutting method is from July to September. During propagation, softwood branches of *Vitis vinifera* 'Special No. 1' are cut into cuttings with 2-3 buds each. The upper morphological end of each cutting should have leaves, with the leaves covering 1 / 3 to 1 / 2 of the surface area. The lower morphological end of the cutting is inserted into a bed of river sand, and watering is managed using a full-light misting system. After two months, the rooted seedlings are transplanted into non-woven fabric nutrient pots with a diameter of 12-30 cm for further cultivation.

[0090] (2) Planting steps in the drawdown zone of the Three Gorges Reservoir: (1) Two-year-old or older clonal seedlings of the *Vitis vinifera* var. *mulioides* (planted in nutrient pots) obtained from propagation. Plant after the drawdown zone is exposed, with a spacing of 2.5m × 4m and a planting hole length × width × depth of 25cm × 25cm × 30cm. After planting, use stones around the planting hole in the drawdown zone to compact and fix the seedling roots, cover the planting hole with weed control cloth and fix the weed control cloth around the perimeter to reduce wave erosion. Appropriate fertilization can be carried out in the first and second years to promote growth. In the first year of planting, weeds such as *Cynodon dactylon* should be mowed around the planting hole to prevent weeds from growing.

[0091] The effect image of the Mulberry Leaf Grape Special No. 1 planted at an altitude of 159 meters in the drawdown zone of the Three Gorges Reservoir area is shown below. Figures 11-13 As shown. Experiments have shown that the Mulberry Leaf Grape Special No. 1 has the characteristics of good flood tolerance, high propagation rate, strong drought resistance and strong adaptability. It can adapt to a 7-month flooded environment during its dormancy period, the survival rate of cutting propagation is over 90%, it can adapt to arid and low-rainfall environments, and it does not have high requirements for soil fertility, and can grow in barren drawdown zone soils.

[0092] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for repairing drawdown zones, characterized in that, Mulberry Leaf Grape Species No. 1 was planted in the drawdown zone; the Mulberry Leaf Grape Species No. 1 is deposited at the China General Microbiological Culture Collection Center, located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with a deposit date of February 19, 2025 and a deposit number of CGMCC No. 32201; the drawdown zone is the Three Gorges Reservoir area. Before planting, the mulberry leaf grape special variety No. 1 was propagated in a nutrient pot using hardwood cuttings. The method of hardwood cutting is as follows: cut the hardwood branches of Mulberry Leaf Grape Special No. 1 into cuttings with 2 to 3 buds, and insert the morphological lower end of the cuttings into the cutting substrate in the nutrient pot. The hard branches are one-year-old or perennial branches; The morphological lower end of the cutting is cut obliquely, and the morphological upper end is cut horizontally; The nutrient pot is a non-woven fabric nutrient pot, and the diameter of the non-woven fabric nutrient pot is 12~30 cm; The cutting is inserted into the rooting medium to a depth of 1 / 3 to 1 / 2 of its length; the rooting medium is yellow-brown soil. After planting Mulberry Leaf Grape Special No. 1, the roots and stems of the seedlings were compacted and fixed, and the planting holes were covered with weed control cloth and the cloth was fixed around the perimeter.

2. The method as described in claim 1, characterized in that, The best time for propagation using the hardwood cutting method is from February to May, June to September, or October to November.

3. The method as described in claim 1, characterized in that, When planting, select 2-year-old or older clonal seedlings of Mulberry Leaf Grape No. 1; the planting spacing is 2~3 m × 3~5 m; the length × width × depth of the planting hole is 15~35 cm × 15~35 cm × 25~35 cm.

Images