Method for improving saline-alkali stress resistance of scirpus planiculmis seedlings

Abstract

The invention discloses a method for improving saline-alkali stress resistance of bolboschoenus planiculmis seedlings, which specifically comprises the following three aspects: bolboschoenus planiculmis corm treatment and seedling staged water management, saline-alkali resistant composite nutrient solution preparation and application, and soil microenvironment optimization. According to the bolboschoenus planiculmis corm treatment and seedling staged water management, a dynamic water supplementing strategy is designed according to different physiological requirements in the germination period; the salt damage is relieved and the metabolic activity is enhanced through the preparation and application of the salt and alkali resistant composite nutrient solution through an ion antagonist and an osmotic regulation substance; in soil microenvironment optimization, the surface salinity concentration is reduced by using the design of a covering material and a planting layer. According to the technical scheme, through three-dimensional regulation and control of the water-nutrient-soil microenvironment, on the premise of not depending on physical means, synergistic improvement of corm germination and stress resistance under saline-alkali stress is achieved, the technical cost is low, and large-scale application in saline-alkali wetland vegetation recovery is easy to achieve.

Description

Technical Field

[0001] The present invention relates to the technical field of saline-alkali land plant restoration, and specifically to a comprehensive method for synergistically improving the survival rate and stress resistance of Vitex sylvestris seedlings under saline-alkali stress through phased water regulation, saline-alkali adaptable nutrient formulation and soil microenvironment optimization technology. More specifically, it relates to a method for improving the saline-alkali stress resistance of Vitex sylvestris seedlings. Background Art

[0002] Saline wetlands possess unique ecological functions and value, playing an irreplaceable role in regulating the global carbon cycle. As typical ecotones, saline wetlands boast exceptionally high species diversity and productivity, providing critical habitats for numerous rare and endangered species. For example, the number of bird species recorded in the Chahan Nur Wetland in Inner Mongolia has increased from 79 to 119, making it a crucial migratory stop for migratory birds. The western Songnen Plain boasts extensive soda saline wetlands, rich in reserve land resources and considered one of the regions with the greatest potential for increasing grain production in my country. However, saline wetland ecosystems are extremely fragile, and once damaged, their ecological functions often take a long time to recover. Vegetation restoration in saline wetlands is a core component of ecological restoration, facing complex technical requirements and practical challenges. The primary goal of saline wetland vegetation restoration has shifted from simple ecological restoration to enhancing "ecological-economic synergy." This requires that vegetation restoration techniques consider not only ecological adaptability but also economic feasibility.

[0003] Tripterygium wilfordii Bolboschoenus planiculmis ) is the dominant plant in the soda saline wetlands in the western Songnen Plain, and its bulbous rhizome is also the source of the rare water bird Siberian Crane ( White-crowned crane ). In addition, the flat-stalked thorn thorn is salt-alkali tolerant, soil-fixing and slope-protecting, and water-purifying, making it a key species for the restoration of degraded wetlands. However, affected by the increasingly warming and drying climate and soil salinization, the vegetation in the flat-stalked thorn thorn wetland has seriously degraded, threatening the quality of the white crane's habitat and regional ecological security. In order to alleviate the trend of wetland vegetation degradation, it is urgent to carry out artificial assisted ecological restoration with vegetation restoration as the core. However, the survival and growth of plant seedlings are the key to vegetation restoration. They are sensitive to salt-alkali stress and have a low natural settlement rate, which has become a major obstacle to population expansion. Therefore, it is urgent to improve their stress resistance in artificial cultivation of wetland vegetation restoration. At present, the high osmotic pressure of saline-alkali land makes it difficult for seedlings to absorb water, and traditional water replenishment methods cannot balance salt leaching and water supply efficiency. Conventional fertilizers are easily fixed or induce ion antagonism (such as Na + Inhibit K +Absorption), resulting in low nutrient utilization. Salt accumulation in the soil surface directly inhibits seedling survival and growth, and there is a lack of low-cost microenvironment improvement technology. Therefore, given the important ecological value of Tripterygium wilfordii and the bottlenecks of existing restoration technologies, a method for improving the salt-alkali stress resistance of Tripterygium wilfordii seedlings based on precise water and fertilizer regulation was developed to provide a low-cost, high-survival seedling cultivation program for saline-alkali wetland ecological restoration, promote saline-alkali land vegetation restoration, and help improve the ecological functions of saline-alkali wetlands in a targeted manner. Summary of the Invention

[0004] In view of this, the present invention provides a method for improving the salt-alkali stress resistance of the flat-stalked violet trifoliate seedlings, which achieves the improvement of the salt-alkali stress resistance of the flat-stalked violet trifoliate seedlings based on precise regulation of water and fertilizer.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A method for improving the salt-alkali stress resistance of Vitex trifoliata seedlings, comprising the following steps: Step 1: Treatment of the corms of the flat-stemmed thorn thorn and water management of the seedlings in different stages (1.1) Gradient salinization infiltration: Soak the corms of Tripterygium wilfordii in a gradient saline-alkali solution, changing to the next concentration solution every 24 hours for 7 days; (1.2) Moisture control awakening: After soaking, place in an environment with a humidity of 70%-85% and a temperature of 25°C for 48 hours to activate germination metabolism; (1.3) Watering during the germination period: water intermittently after sowing, and the amount of water added each time should be 50%-60% of the soil's saturated water holding capacity; Step 2: Preparation and application of salt-alkali resistant compound nutrient solution The salt-alkali resistant compound nutrient solution uses water as the matrix and is supplemented with macroelements, ion antagonists, osmotic regulators, antioxidants and trace elements. It is applied before sowing, in the early germination stage and in the seedling stage respectively. Step 3: Soil microenvironment optimization (3.1) Cover layer design: After planting, a cover layer is set on the surface. The cover layer includes a humic acid granule layer and a straw debris layer from bottom to top; (3.2) Optimization of planting layer structure: ridge and furrow planting, laying a mixture of rice husk ash and vermiculite at the bottom of the furrow, and mixing biochar within an 8 cm radius around the bulb sowing hole.

[0006] Preferably, the saline-alkali gradient solution in step (1.1) comprises a gradually increasing 50 mM → 100 mM → 150 mM NaCl solution, pH 7.5 → 8.0 → 8.5, and the pH is adjusted using Na2CO3. Synthesis of osmoprotectants (proline, betaine) is induced.

[0007] Preferably, the interval of intermittent watering in step (1.3) is dynamically adjusted according to the soil electrical conductivity. When EC≤5 dS / m, no watering is required. When EC>5 dS / m, the watering frequency is 8 hours / time. After watering, the salt content of the 0-10 cm surface soil is controlled below 0.35%.

[0008] Preferably, the macronutrients in step 2 are nitrogen, phosphorus and potassium compound fertilizers, with a content of 900 mg / L, low nitrogen and high potassium, and reduced Na + Competition; the ion antagonists are 8-12 mM CaCl2 (to enhance membrane stability), 1-2 mM sodium silicate (to promote K + absorption); the osmotic regulator is 2-3 mM betaine and 0.5 mM proline (directly supplementing endogenous protective substances); the antioxidant is 100 μM ascorbic acid and 20 μM glutathione; the trace element is 5 μM Fe-EDTA and 1 μM ZnSO4 (alleviating the deficiency of trace elements under saline-alkali stress).

[0009] Preferably, the salt-alkali resistant composite nutrient solution in step 2 is applied by mixing with natural water, adjusting the pH to 6.0-6.5 by diluting with water, and applying until the moisture content of the 0-20 cm soil layer reaches 25%-30%.

[0010] Preferably, in step (3.1), the humic acid granule layer is 2 cm thick and has a particle size of 2-3 mm; the straw debris layer is 3 cm thick and has a length of 5-10 cm. The humic acid granules adsorb salt ions, while the straw debris reduces water evaporation.

[0011] Preferably, in step (3.2), the ridge height is 10-15 cm, the rice husk ash + vermiculite is laid to a thickness of 4 cm, and the mass ratio of rice husk ash to vermiculite is 1:1, forming a salt "buffer isolation layer".

[0012] Preferably, the amount of biochar applied in step (3.2) is 15% of the weight of the soil to improve water and fertilizer retention capacity.

[0013] Through the above technical solution, it can be seen that compared with the prior art, the present invention discloses a method for improving the salt-alkali stress resistance of Tripterygium wilfordii seedlings, which has the following beneficial effects: The technical solution of the present invention mainly adopts the following three strategies: (1) Phased water management: Design a dynamic water replenishment strategy based on the different physiological needs during the germination period; (2) Targeted nutritional supplementation: Alleviate salt damage and enhance metabolic activity through ion antagonists and osmotic regulators; (3) Soil structure optimization: Use covering materials and planting layer design to reduce surface salt concentration.

[0014] The main innovations of this invention are: (1) Synergistic enhancement of water and fertilizer: Dynamic water management matches salt leaching with the water absorption needs of bulbs, and combined with salt-resistant nutrient solution to directly alleviate ion toxicity; (2) Targeted salt control: Double-layer coverage and localized improvement zone design physically block salt migration to the rhizosphere; (3) Activation of endogenous stress resistance: Gradient salinization pretreatment induces the synthesis of the bulb's own osmotic protective substances, reducing dependence on exogenous substances. This technical solution achieves a synergistic improvement of bulb germination and stress resistance under saline-alkali stress through three-dimensional regulation of the water-nutrient-soil microenvironment without relying on physical means. The technology is low-cost and easy to apply on a large scale in saline-alkali wetland vegetation restoration. DETAILED DESCRIPTION

[0015] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0016] Example 1 Verification of the effectiveness of phased moisture management A conventional saline-alkali stress group (200 mM NaCl + pH 8.5) was set up, which is the saline-alkali stress level of moderate saline-alkali wetland water under natural conditions. The bulb germination rate and root NaCl content of the samples treated with gradient salinization (gradient concentration of 50 mM→100 mM→150 mM NaCl solution, pH 7.5→8.0→8.5, pH adjustment was performed using Na2CO3, and the concentration was changed to the next concentration every 24 hours. The three concentrations were cyclically changed for 7 days) were compared with those of the conventional saline-alkali stress group. + / K + The results are shown in Table 1.

[0017] Table 1. Comparison of bulb germination rate, root Na⁺ / K⁺ ratio, and proline content between the present invention and conventional saline-alkali stress treatments

[0018] Table 1 shows that the bulb germination rate (95.38±3.58%) of the technical solution of the present invention is significantly higher than that of the conventional saline-alkali stress group (71.92±2.69%), with an increase of 32.6%, indicating that the technology of the present invention effectively promotes germination; the root Na + / K +The ratio (2.08±0.17) was significantly lower than that of the conventional saline-alkali stress group (3.90±0.15), with a decrease of 46.7%, indicating that the present invention enhanced the ability to regulate ion homeostasis; the proline content of the technical solution of the present invention (1.826±0.076 mg / g·dw) was significantly higher than that of the conventional saline-alkali stress group (0.480±0.044 mg / g·dw), with an increase of 280.4%, confirming that the present invention enhances the osmotic protection mechanism.

[0019] Example 2 Nutrient solution ratio optimization test Response surface methodology (RSM) was used to determine the optimal concentration combination of CaCl₂, sodium silicate, and betaine (i.e., CaCl₂ 9.5 mM; sodium silicate 1.6 mM; betaine 2.4 mM) to minimize leaf relative electrical conductivity (REC) (i.e., maximize membrane stability) and maximize superoxide dismutase (SOD) activity. This combination was compared with natural wetland water without the addition of the three substances. The results are shown in Table 2.

[0020] Table 2. Comparison of relative electrical conductivity and superoxide dismutase activity of leaves treated with the present invention and natural water

[0021] Table 2 shows that the present invention significantly reduced leaf relative conductivity (-47.5%) and significantly increased superoxide dismutase activity (+107.0%), indicating that the optimization of the nutrient solution of the present invention enhances seedling resistance.

[0022] Example 3 Synergistic effect of soil microenvironment improvement The survival rate and dry weight of seedlings in the soil surface layer under the double-layer mulching (humic acid + straw) of the present invention were compared with those under single mulching (humic acid and straw alone) and no mulching. The results are shown in Table 3.

[0023] Table 3. Comparison of seedling survival rate and seedling dry weight of the embodiment of the present invention with single cover and no cover

[0024] Table 3 shows that compared with single humic acid covering, single straw covering and no covering, the survival rate of the seedlings of the present invention was significantly increased by 55.6%, 102.3% and 202.9%, respectively (Table 3), and the dry weight of the seedlings was increased by 146.3%, 179.7% and 333.1%, respectively, indicating that the present invention significantly enhances the stress resistance of the flat-stalked thorn vine seedlings.

[0025] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the present invention. Various modifications to these embodiments will be apparent to professionals and technicians in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for improving the salt-alkali stress resistance of Tripterygium wilfordii seedlings, characterized in that: The following steps are involved: Step 1: Treatment of the corms of the flat-stemmed thorn thorn and water management of the seedlings in different stages (1.1) Gradient salinization infiltration: Soak the corms of Tripterygium wilfordii in a gradient saline-alkali solution, changing to the next concentration solution every 24 hours for 7 days; (1.2) Humidity control awakening: After soaking, place in an environment with a humidity of 70%-85% and a temperature of 25°C for 48 hours; (1.3) Watering during the germination period: water intermittently after sowing, and the amount of water added each time should be 50%-60% of the soil's saturated water holding capacity; Step 2: Preparation and application of salt-alkali resistant compound nutrient solution The salt-alkali resistant compound nutrient solution uses water as the matrix and is supplemented with macroelements, ion antagonists, osmotic regulators, antioxidants and trace elements. It is applied before sowing, in the early germination stage and in the seedling stage respectively. Step 3: Soil microenvironment optimization (3.1) Cover layer design: After planting, a cover layer is set on the surface. The cover layer includes a humic acid granule layer and a straw debris layer from bottom to top; (3.2) Optimization of planting layer structure: ridge and furrow planting, laying a mixture of rice husk ash and vermiculite at the bottom of the furrow, and mixing biochar within an 8 cm radius around the bulb sowing hole.

2. The method for improving the salt-alkali stress resistance of the scutellaria baicalensis seedlings according to claim 1, wherein: The saline gradient solution in step (1.1) includes a gradually increasing 50 mM→100 mM→150 mM NaCl solution, pH 7.5→8.0→8.5, and the pH is adjusted using Na2CO3.

3. The method for improving the salt-alkali stress resistance of the scutellaria baicalensis seedlings according to claim 1, wherein: The interval time of intermittent watering in step (1.3) is dynamically adjusted according to the soil electrical conductivity. When EC≤5 dS / m, no watering is required. When EC>5dS / m, the watering frequency is 8h / time. After watering, the salt content of the 0-10 cm surface soil is controlled below 0.35%.

4. The method for improving the salt-alkali stress resistance of Tripterygium wilfordii seedlings according to claim 1, wherein: The macronutrients in step 2 are nitrogen, phosphorus and potassium compound fertilizers with a ratio of N-P2O5-K2O of 2:1:3 and a content of 900 mg / L; the ion antagonists are 8-12 mM CaCl2 and 1-2 mM sodium silicate; the osmotic regulators are 2-3 mM betaine and 0.5 mM proline; the antioxidants are 100 μM ascorbic acid and 20 μM glutathione; and the trace elements are 5 μM Fe-EDTA and 1 μM ZnSO4.

5. The method for improving the salt-alkali stress resistance of Tripterygium wilfordii seedlings according to claim 1, wherein: The salt-alkali resistant composite nutrient solution in step 2 is applied as follows: mixed with natural water, diluted with water to adjust the pH to 6.0-6.5, and applied until the moisture content of the 0-20 cm soil layer reaches 25%-30%.

6. The method for improving the salt-alkali stress resistance of Tripterygium wilfordii seedlings according to claim 1, wherein: In step (3.1), the thickness of the humic acid granule layer is 2 cm, and the particle size of the humic acid granules is 2-3 mm; the thickness of the straw debris layer is 3 cm, and the length of the straw debris is 5-10 cm.

7. The method for improving the salt-alkali stress resistance of Tripterygium wilfordii seedlings according to claim 1, characterized in that: In step (3.2), the middle ridge height is 10-15 cm, the rice husk ash + vermiculite is laid to a thickness of 4 cm, and the mass ratio of rice husk ash to vermiculite is 1:

1.

8. The method for improving the salt-alkali stress resistance of Tripterygium wilfordii seedlings according to claim 1, characterized in that: The amount of biochar applied in step (3.2) was 15% of the soil weight.

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