A method for cultivating a salt and alkaline resistant magnolia

Abstract

This invention discloses a method for cultivating salt-alkali resistant magnolias, belonging to the field of magnolia cultivation technology. The method includes the following steps: (1) Seed treatment: Magnolia seeds are treated to promote germination and then potted for seedling cultivation; (2) Preliminary screening: Na2CO3 solution is mixed with a regulator and the potted magnolia seedlings are subjected to gradient salt-alkali stress, and then robust magnolia plants are selected for secondary screening; (3) Secondary screening: Branches of robust magnolia plants are cut as cuttings for propagation, and then treated with different concentrations of alkali solution for screening of salt-alkali resistant cuttings; (4) Transplanting and planting: The selected salt-alkali resistant cuttings are transplanted and planted. By subjecting magnolias to salt-alkali stress and using regulators to ensure the absorption of salt and alkali substances by the seedlings, the salt-alkali resistance of magnolias can be better induced, effectively improving the salt-alkali resistance of magnolias and thus promoting the further development of magnolia cultivation.

Description

Technical Field

[0001] This invention relates to the field of magnolia cultivation technology, and in particular to a method for cultivating salt-tolerant magnolias. Background Technology

[0002] Magnolia (Yulania denudata (Desrousseaux) DL Fu.) is a plant of the genus Yulania in the family Magnoliaceae. It is a valuable material for studying the phylogeny and origin of angiosperms. It combines multiple economic benefits such as fragrance, medicinal use, and timber, and has extremely high scientific research value. It is one of the most important landscaping plants.

[0003] Due to various factors such as ecology and climate, the area of ​​saline-alkali land is constantly increasing, and it has now become a global concern. The normal growth of plants is inseparable from their environment, and soil salinization is a potential threat to plant growth. For acid-loving plants that are intolerant of saline-alkali soil, salinity and alkali will cause stress, affecting the absorption of water and nutrients by the roots, leading to limited plant growth, yellowing leaves, weakened plants, and even death. Cultivating salt-alkali tolerant plants is an important way to promote the widespread application of plants. Magnolia, as an acid-loving plant, is prone to poor growth and even death in saline-alkali soil, which greatly limits its development and utilization. Domestic and international research on magnolia mainly focuses on the investigation of wild magnolia germplasm resources, classification of cultivated varieties, chemical composition of essential oils, and self-compatibility; research on salt-alkali tolerant breeding of magnolia has not yet been reported. Summary of the Invention

[0004] Based on the above-mentioned technical problems, the purpose of this invention is to provide a method for cultivating salt-alkali resistant magnolias. This method involves selecting high-quality magnolia seeds for potted seedling cultivation, cutting propagation, and transplanting, and inducing salt-alkali resistance in magnolias through salt-alkali stress, thereby cultivating magnolia seedlings with strong salt-alkali resistance to promote the development and utilization of magnolias.

[0005] The present invention solves the above-mentioned technical problems through the following technical means:

[0006] A method for cultivating salt-tolerant magnolias, the method comprising the following steps:

[0007] (1) Seed treatment: Select high-quality magnolia seeds, germinate them, and then cultivate them in pots.

[0008] (2) Preliminary screening: After the seedlings in pots grow to a height of 2-3cm, the seedlings are subjected to gradient salt and alkali stress by mixing Na2CO3 solution with regulators, and then healthy magnolia plants are selected for secondary screening.

[0009] (3) Secondary screening: Cuttings of healthy magnolia plants selected in the initial screening are used as cuttings for propagation, and then the cuttings are treated with different concentrations of alkaline solution before screening for salt-tolerant cuttings.

[0010] (4) Transplanting and planting: Transplant the selected salt-tolerant cuttings to obtain salt-tolerant magnolias, and then manage them according to conventional methods.

[0011] Because magnolias grow slowly, subjecting them to salt and alkali stress from the seedling stage (when they are 2-3 cm tall) can shorten the cultivation time for salt- and alkali-resistant magnolias. Furthermore, the seedling stage is a period when magnolias are more sensitive to salt and alkali stress. At this time, gradient salt and alkali stress can better trigger the physiological response mechanism of seedlings under salt and alkali stress, thereby cultivating magnolia seedlings with better salt and alkali resistance. However, the inventors found that when a high concentration of salt and alkali solution was applied in one irrigation, a large number of seedlings died, resulting in a significant loss of seedlings. Therefore, by gradually inducing salt and alkali stress using a gradient method, the survival rate of seedlings was greatly increased.

[0012] Furthermore, the seed germination treatment in step (1) is performed as follows:

[0013] Soak the seeds in a 60% ethanol solution for 4-7 minutes, then rinse them 2-3 times with deionized water and soak them in 30℃ water for 48 hours. Then, treat them with ultrasound at a frequency of 25KHz and a power of 220W for 5-7 minutes.

[0014] Furthermore, the specific operation of potted seedling cultivation in step (1) is as follows:

[0015] After germination treatment, the seeds were sown in flowerpots filled with substrate and cultured under the following conditions: 10 h / d light, light intensity of 2000-3000 lx, temperature of 18-28℃, and humidity of 70-80%.

[0016] Furthermore, the specific operation of the gradient salt-alkali stress treatment in step (2) is as follows:

[0017] The magnolia seedlings were irrigated with Na2CO3 solutions of concentrations of 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, and 5wt% respectively, mixed with the regulator. The irrigation was carried out once every 30 days, for a total of 6 irrigations, with an irrigation amount of 120-200g per seedling.

[0018] Furthermore, the regulator comprises the following raw materials in parts by weight:

[0019] 0.5-1 part isopropanolamine, 0.3-0.6 parts p-aminoacetanilide, 0.2-0.5 parts zinc phosphate, 0.2-0.4 parts vitamin B, 0.05-0.1 parts polyvinylpyrrolidone.

[0020] Furthermore, the method for preparing the regulator is as follows:

[0021] A: Add p-aminoacetanilide to water and stir well. Then heat in a hot water bath until dissolved. Cool to room temperature, add isopropanolamine and vitamin B, mix well, and let stand overnight to obtain a mixture.

[0022] B: Add zinc phosphate to the mixture and stir evenly, then add polyvinylpyrrolidone for homogenization to obtain a regulator.

[0023] The inventors discovered that treating seedlings with gradient salt-alkali stress effectively improved their survival rate. However, when transplanted into saline-alkali soil in the wild, the survival rate remained low. This was because the gradient salt-alkali stress caused osmotic imbalance and cell membrane rupture in the seedling roots, affecting their physiological functions and inhibiting root growth. Consequently, the contact rate with and absorption of salt and alkali decreased, failing to effectively induce salt and alkali resistance. Although the seedlings showed good survival rates in the initial screening, their immediate exposure to large amounts of salt and alkali in the wild after transplanting led to their death. Therefore, further treatment of the seedlings is needed to address the problem of low survival rates of magnolia seedlings after transplanting due to changes in root physiological state during gradient salt-alkali stress cultivation.

[0024] After the growth regulator was mixed with Na2CO3 solution and applied as irrigation, Na2CO3 induced stress in the magnolia seedlings. Simultaneously, isopropanolamine in the growth regulator acted on the root cell membranes of the seedlings, enhancing the interactions between cell membrane molecules and thus maintaining the stability of the root cell membrane structure. Furthermore, p-aminoacetanilide induced the accumulation of osmotic regulators in the root cells of the magnolia seedlings and enhanced the activity of antioxidant enzymes, thereby maintaining osmotic balance between the inside and outside of cells and promptly clearing reactive oxygen species generated under salt and alkali stress, alleviating the stress of salt and alkali on the roots of the magnolia seedlings. At the same time, combined with zinc phosphate in the growth regulator, it improved root growth capacity. The various components of the growth regulator... The combined action of these components inhibits the stresses caused by saline-alkali substances on the seedling roots, such as cell membrane rupture and osmotic imbalance, allowing the roots to grow well even under gradient saline-alkali stress. This increases the root contact and absorption rate of saline-alkali substances, gradually inducing salt and alkali resistance. In turn, while ensuring the survival rate of the seedlings, it can better improve the salt and alkali resistance of the cultivated seedlings. The obtained plants are then propagated by cuttings and subjected to a second selection under the combined action of higher concentration Na2CO3 solution and regulators before being transplanted to the wild to further induce the salt and alkali resistance of magnolia and better improve the survival rate of seedlings transplanted to saline-alkali soils in the wild.

[0025] Furthermore, the specific operation of cutting propagation in step (3) is as follows:

[0026] Select healthy magnolia plants as cuttings, cut the cuttings to a length of 10-20cm, soak the lower end in rooting solution for 0.5-1h, and then insert them into sandy soil for cultivation under natural outdoor conditions.

[0027] Furthermore, the specific steps for screening salt-tolerant cuttings in step (3) are as follows:

[0028] Thirty days after cutting, the cuttings were watered with a mixture of 5wt% and 6wt% Na2CO3 solutions and a growth regulator, at a rate of 120-200g per plant, once every 20 days for a total of two waterings. Ten days after the second watering, the best-growing cuttings were selected to obtain salt-tolerant cuttings for transplanting.

[0029] Furthermore, the substrate used for potted seedling cultivation is obtained by mixing leaf mold, river sand, and well-rotted cow manure, with the mass ratio of leaf mold, river sand, and well-rotted cow manure being 20:10:1.

[0030] Beneficial effects:

[0031] This invention involves selecting high-quality magnolia seeds for potted seedling cultivation and then subjecting them to a gradient salt-alkali stress method to cultivate magnolia plants with good salt and alkali resistance. During the gradient salt and alkali stress process, a regulator is used to treat the seedlings together with a salt and alkali solution. The components of the regulator work together to inhibit the damage caused by salt and alkali to the seedling roots, such as cell membrane rupture and osmotic imbalance, thereby ensuring the normal physiological state of the seedling roots, promoting root growth to improve the absorption of salt and alkali substances, and better inducing the salt and alkali resistance of magnolias. In this way, the cultivation time is shortened, the salt and alkali resistance of seedlings is effectively improved, and the survival rate of seedlings after transplanting in the wild can be effectively improved, thus promoting the further development of magnolia cultivation. Attached Figure Description

[0032] Figure 1 : These are pictures showing the growth of seedlings during pot cultivation according to the present invention;

[0033] Figure 2 Image of cutting propagation during the secondary screening process of this invention. Detailed Implementation

[0034] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings:

[0035] Example 1: Preparation of regulator

[0036] Weigh out 0.7 kg of isopropanolamine, 0.4 kg of p-aminoacetanilide, 0.3 kg of zinc phosphate, 0.3 kg of vitamin B, and 0.07 kg of polyvinylpyrrolidone.

[0037] Preparation method:

[0038] A: Add p-aminoacetanilide to 4 kg of water and stir well. Then heat in a 75°C hot water bath until dissolved. Cool to room temperature, add isopropanolamine and vitamin B, mix well, and let stand overnight to obtain a mixture.

[0039] B: Add zinc phosphate to the mixture and stir evenly, then add polyvinylpyrrolidone and homogenize at 900 rpm for 6 minutes to obtain the regulator.

[0040] Example 2: Preparation of the regulator

[0041] Weigh out 0.5 kg of isopropanolamine, 0.3 kg of p-aminoacetanilide, 0.2 kg of zinc phosphate, 0.2 kg of vitamin B, and 0.05 kg of polyvinylpyrrolidone.

[0042] Preparation method:

[0043] A: Add p-aminoacetanilide to 3 kg of water and stir well. Then heat in a 65°C hot water bath until dissolved. Cool to room temperature, add isopropanolamine and vitamin B, mix well, and let stand overnight to obtain a mixture.

[0044] B: Add zinc phosphate to the mixture and stir evenly, then add polyvinylpyrrolidone and homogenize at 800 rpm for 5 minutes to obtain the regulator.

[0045] Example 3: Preparation of Regulator

[0046] Weigh out 1 kg of isopropanolamine, 0.6 kg of p-aminoacetanilide, 0.5 kg of zinc phosphate, 0.4 kg of vitamin B, and 0.1 kg of polyvinylpyrrolidone.

[0047] Preparation method:

[0048] A: Add p-aminoacetanilide to 6 kg of water and stir well. Then heat in an 85°C hot water bath until dissolved. Then cool to room temperature, add isopropanolamine and vitamin B, mix well, and let stand overnight to obtain a mixture.

[0049] B: Add zinc phosphate to the mixture and stir evenly, then add polyvinylpyrrolidone and homogenize at 1000 rpm for 7 minutes to obtain the regulator.

[0050] Comparative Example 1: Preparation of Regulator

[0051] In contrast to Example 1, the only difference is that isopropanolamine was not added during the preparation of the regulator in Comparative Example 1.

[0052] Comparative Example 2: Preparation of Regulator

[0053] Compared with Example 1, the only difference is that p-aminoacetanilide was not added during the preparation of the regulator in Comparative Example 2, as detailed below.

[0054] A: Add isopropanolamine and vitamin B to 4 kg of water, mix well, and let stand overnight to obtain a mixture;

[0055] B: Same as Example 1.

[0056] Comparative Example 3: Preparation of Regulator

[0057] In contrast to Example 1, the only difference is that zinc phosphate was not added during the preparation of the regulator in Comparative Example 3.

[0058] Comparative Example 4: Preparation of Regulator

[0059] In contrast to Example 1, the only difference is that vitamin B was not added during the preparation of the regulator in Comparative Example 4.

[0060] Example 4: Cultivation method of salt-tolerant magnolia

[0061] The rooting solution used in this example consists of 50 mg / L ABT + 100 mg / L IBA.

[0062] (1) Seed treatment: Select plump magnolia seeds free from pests and diseases. Soak the seeds in 60% ethanol solution for 5 minutes, then rinse them three times with deionized water and soak them in 30℃ water for 48 hours. Then, treat them with ultrasound at 25KHz and 220W for 6 minutes to obtain germinated seeds. Mix leaf mold, river sand and well-rotted cow manure in a mass ratio of 20:10:1 and put them in an autoclave. Sterilize at 121℃ for 25 minutes. After cooling, obtain the substrate and fill it into flower pots. Sow the germinated seeds in the flower pots filled with substrate at a rate of 1 seed per pot. Raise seedlings in pots under the conditions of 10h / d light, light intensity of 2200lx, temperature of 22℃ and humidity of 75%.

[0063] (2) Preliminary screening: After the seedlings in pots grow to a height of about 3cm, Na2CO3 solutions with concentrations of 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, and 5wt% are mixed with the regulator prepared in Example 1 at a mass ratio of 2:1 and then watered the magnolia seedlings in sequence. Watering is done once every 30 days, for a total of 6 waterings, with a watering amount of 150g / plant.

[0064] (3) Secondary screening: Cuttings from healthy magnolia plants selected in the initial screening were used as cuttings; the cuttings were cut to a length of 15cm, and the lower end was soaked in rooting solution for 0.6h before being inserted into sandy soil and cultivated outdoors under natural conditions; 30 days after cutting, the cuttings were watered with a 5wt% Na2CO3 solution and the regulator prepared in Example 1 at a mass ratio of 2:1, with a watering amount of 150g / plant. Then, on the 50th day, the cuttings were watered with a 6wt% Na2CO3 solution and the regulator prepared in Example 1 at a mass ratio of 2:1, with a watering amount of 150g / plant. 10 days after the second watering, the cuttings with good growth were selected to obtain salt-tolerant cuttings for transplanting.

[0065] (4) Transplanting and planting: Transplant the selected salt-tolerant cuttings to obtain salt-tolerant magnolias. Then, water, fertilize and prune according to conventional methods.

[0066] Comparative Example 5: Cultivation Methods for Salt-Resistant Magnolias

[0067] Compared with Example 4, the only difference is that in Comparative Example 5, when cultivating salt-tolerant magnolias, step (2) did not use different concentrations of Na2CO3 solution for gradient irrigation. Instead, 4wt% Na2CO3 solution was directly mixed with the regulator prepared in Example 1 at a mass ratio of 2:1 before irrigation. The remaining steps are the same as in Example 4, as follows:

[0068] (1) Same as Example 4;

[0069] (2) Preliminary screening: After the seedlings in pots grow to a height of about 3cm, the 4wt% Na2CO3 solution and the regulator prepared in Example 1 are mixed at a mass ratio of 2:1 and then watered. The seedlings are watered once every 30 days for a total of 6 times, and the watering amount is 150g / plant.

[0070] (3)-(4) are the same as in Example 4.

[0071] Comparative Example 6: Cultivation Methods for Salt-Resistant Magnolias

[0072] In contrast to Example 4, the only difference is that in Comparative Example 6, no regulator was used during the cultivation of salt-tolerant magnolias; instead, only a single Na2CO3 solution was applied, as detailed below:

[0073] (1) Same as implementation 4;

[0074] (2) Preliminary screening: After the seedlings in pots grow to a height of about 3cm, the magnolia seedlings are watered with Na2CO3 solutions of concentrations of 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, and 5wt% in sequence. The solution is watered once every 30 days, for a total of 6 waterings, with a watering amount of 100g / plant.

[0075] (3) Secondary screening: Cuttings from healthy magnolia plants selected in the initial screening are used as cuttings; the cuttings are cut to a length of 15cm, the lower end is soaked in rooting solution for 0.6h and then inserted into sandy soil and cultivated outdoors under natural conditions; 30 days after cutting, the cuttings are watered with a 5wt% Na2CO3 solution at a rate of 100g / plant, and then on the 50th day, the cuttings are watered with a 6wt% Na2CO3 solution at a rate of 100g / plant. 10 days after the second watering, the cuttings with good growth are selected to obtain salt-tolerant cuttings for transplanting.

[0076] (4) Same as Example 4.

[0077] Comparative Example 7: Cultivation method of salt-tolerant magnolia:

[0078] Compared with Example 4, the only difference is that salt stress was not applied during the second screening in step (3) of the salt-tolerant magnolia cultivation in Comparative Example 7, as detailed below:

[0079] (1)-(2) are the same as in Example 4;

[0080] (3) Secondary screening: Cut the branches of the healthy magnolia plants selected in the initial screening as cuttings; cut the cuttings to a length of 15cm, soak the lower end in rooting solution for 0.6h and then insert them into sandy soil for cultivation; after 60 days of cutting, select the well-grown cuttings to obtain salt-tolerant cuttings for transplanting.

[0081] (4) Same as Example 4.

[0082] Comparative Example 8: Cultivation Methods for Salt-Resistant Magnolias

[0083] Compared with Example 4, the only difference is that in Comparative Example 8, when cultivating salt-tolerant magnolias, step (2) was not subjected to gradient salt-alkali stress during the initial screening, as detailed below:

[0084] (1) Same as Example 4;

[0085] (2) Preliminary screening: After the seedlings have grown to a height of about 3cm in pots, they are cultivated for another 150 days before a second screening is carried out.

[0086] (3)-(4) are the same as in Example 4.

[0087] Experiment: Cultivation of Salt-Resistant Magnolia Seedlings

[0088] 1. Experimental Methods:

[0089] The regulators prepared in Example 1 and Comparative Examples 1-4 were used in a salt-tolerant Magnolia cultivation experiment. The experiment was divided into 10 groups: experimental group 1, control groups 1-8, and blank control group. The regulators and cultivation methods used in each group are as follows:

[0090] Experimental group 1: The regulator prepared in Example 1 and the culture method in Example 4 were used;

[0091] Control groups 1-4: The regulators prepared in comparative examples 1-4 and the cultivation method of example 4 were used respectively;

[0092] Control group 5: The regulator prepared in Example 1 and the cultivation method of Comparative Example 5 were used;

[0093] Control group 6: No regulators were used; the cultivation method of comparative example 6 was adopted.

[0094] Control group 7: The regulator prepared in Example 1 and the cultivation method of Comparative Example 7 were used;

[0095] Control group 8: The regulator prepared in Example 1 and the cultivation method of Comparative Example 8 were used.

[0096] Blank control group: Cultivated using conventional methods, without the use of regulators or gradient salt-alkali stress. The blank control group is as follows:

[0097] (1) Seed treatment: Select plump magnolia seeds free from pests and diseases. Soak the seeds in 60% ethanol solution for 5 minutes, then rinse them three times with deionized water and soak them in 30℃ water for 48 hours. Then, treat them with ultrasound at 25KHz and 220W for 6 minutes to obtain germinated seeds. Mix leaf mold, river sand and well-rotted cow manure in a mass ratio of 20:10:1 and put them in an autoclave. Sterilize at 121℃ for 25 minutes. After cooling, obtain the substrate and fill it into flower pots. Sow the germinated seeds in the flower pots filled with substrate at a rate of 1 seed per pot. Raise seedlings in pots under the conditions of 10h / d light, light intensity of 2200lx, temperature of 22℃ and humidity of 75%.

[0098] (2) Preliminary screening: After the seedlings have grown to a height of about 3cm, continue to cultivate them for another 150 days for a second screening.

[0099] (3) Secondary screening: Cut the branches of the healthy magnolia plants selected in the initial screening as cuttings; cut the cuttings to a length of 15cm, soak the lower end in rooting solution for 0.6h, and then insert them into sandy soil for outdoor cultivation under natural conditions; after 60 days of cutting, select the well-grown cuttings to obtain salt-tolerant cuttings for transplanting.

[0100] (4) Transplanting and planting: Transplant the selected salt-tolerant cuttings to obtain salt-tolerant magnolias. Then, water, fertilize and prune according to conventional methods.

[0101] 2. Result Detection:

[0102] After initial screening, the survival rate of potted seedlings in each group was recorded. Five days after the second Na2CO3 solution irrigation (55 days after cutting), the mean values ​​of proline content, chlorophyll content, and SOD activity in each group of Magnolia plants were measured. Then, the salt-tolerant cuttings selected in the second screening were transplanted to the Xi'an Botanical Garden in Shaanxi Province. A separate experimental area was set up within the botanical garden, with a soil pH of 8.8 and a soluble salt content of 0.5%. Each group had 50 transplanted plants, with three replicates. The survival rate of each group was recorded 30 days after transplanting. The data are shown in Table 1.

[0103] Table 1

[0104]

[0105] Based on the data analysis in Table 1, we can conclude that:

[0106] (1) The survival rate of the magnolias in experimental group 1 was high, reaching 92.4%. After being propagated by cuttings and treated with a higher concentration of alkali solution, the cuttings had the lowest malondialdehyde content, the highest proline content and SOD enzyme activity. This indicates that the salt-tolerant cuttings obtained in experimental group 1 have good resistance to salt-alkali stress. When they are transplanted into saline-alkali soil with a pH of 8.8 and a soluble salt content of 0.5%, their transplant survival rate can also reach 93.3%.

[0107] (2) In the preparation of the regulators in control group 1 and control group 2, isopropanolamine and p-aminoacetanilide were not added respectively. In control group 1, the root cell membrane stability of magnolia seedlings was poor under salt and alkali stress. In control group 2, the osmotic regulation ability of magnolia seedlings was reduced under salt and alkali stress. Under the growth-promoting effect of zinc phosphate, the roots grew and absorbed more salt and alkali substances. The lack of isopropanolamine and p-aminoacetanilide increased the degree of root damage under salt and alkali stress, resulting in the death of some seedlings due to root damage. The survival rate of the initial screening was reduced. The obtained cuttings had increased malondialdehyde content and significantly reduced proline and SOD activity under higher concentrations of salt and alkali stress. At this time, the cuttings had poor salt and alkali resistance and the survival rate was reduced after transplanting into saline-alkali soil.

[0108] (3) No zinc phosphate was added to control group 3. The root growth was poor and the amount of salt and alkali absorbed was reduced. Although the survival rate of the initial screening was relatively good, the reduced amount of salt and alkali absorbed also led to a decrease in the degree of salt and alkali resistance induction. The malondialdehyde content of the cuttings increased and the proline and SOD activities decreased. The survival rate of the cuttings was severely reduced after transplanting.

[0109] (4) In control group 5, the seedlings were directly treated with 4wt% Na2CO3 solution instead of gradient salt and alkali stress. The seedlings died under high concentrations of salt and alkali stress, resulting in a significantly low survival rate in the initial screening.

[0110] (5) No regulator was added to control group 6. The survival rate of the initial screening was significantly higher than that of control group 5, which was directly irrigated with 4wt% alkaline solution. During the experiment, it was found that the root growth of the seedlings in control group 6 was poor, indicating that the lack of inducing agent led to a decrease in the absorption of salt and alkali substances. Although the survival rate of the initial screening was relatively ideal, the high malondialdehyde content, low proline content, and low SOD enzyme activity under salt and alkali stress during the second screening indicated that its salt and alkali resistance was not good. The severe decrease in survival rate after transplanting also illustrates this point.

[0111] (6) In control group 7, no salt-alkali stress was applied during the second screening, and the magnolia resistance could not be further induced. During the cutting cultivation process, the malondialdehyde content was not high under the absence of salt-alkali stress, but the proline content and SOD enzyme activity were not ideal, and the survival rate also decreased significantly in the later stage of transplanting. In control group 8, no salt-alkali stress was applied during the initial screening, and the seedling survival rate was ideal, but the salt-alkali resistance could not be effectively induced. This shows that the regulator prepared in this invention, together with Na2CO3 solution, can induce salt-alkali stress in magnolias, which can promote root growth and absorption of more salt-alkali substances and thus better induce salt-alkali resistance. At the same time, by ensuring the normal growth state of the roots, the survival rate of cultivated seedlings can be improved, and more salt-alkali resistant magnolias with good survival rate after transplanting in the wild can be cultivated.

[0112] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention. Technical aspects, shapes, and structures not described in detail in this invention are all well-known technologies.

Claims

1. A method for cultivating salt-tolerant magnolias, characterized in that, The method includes the following steps: (1) Seed treatment: Magnolia seeds were treated to promote germination and then potted for seedling cultivation; (2) Preliminary screening: After mixing Na2CO3 solution with regulator, the magnolia seedlings in pots were subjected to gradient salt and alkali stress, and then healthy magnolia plants were selected for secondary screening. (3) Secondary screening: Cuttings of healthy magnolia plants selected in the initial screening are used as cuttings for propagation, and then treated with alkaline solutions of different concentrations for screening of salt-tolerant cuttings. (4) Transplanting and planting: Transplant the selected salt-tolerant cuttings to obtain salt-tolerant magnolias, and then manage them according to conventional methods. The regulator comprises the following raw materials in parts by weight: 0.5-1 part isopropanolamine, 0.3-0.6 parts p-aminoacetanilide, 0.2-0.5 parts zinc phosphate, 0.2-0.4 parts vitamin B, 0.05-0.1 parts polyvinylpyrrolidone.

2. The method for cultivating salt-tolerant magnolias according to claim 1, characterized in that, The seed germination treatment in step (1) is as follows: Soak the seeds in a 60% ethanol solution for 4-7 minutes, then rinse them with deionized water and soak them in 30℃ water for 48 hours, followed by ultrasonic treatment.

3. The method for cultivating salt-tolerant magnolias according to claim 2, characterized in that, The specific steps for potted seedling cultivation in step (1) are as follows: After germination treatment, the seeds were sown in pots containing substrate and cultured under the following conditions: 10 h / d light, light intensity of 2000-3000 lx, temperature of 18-28℃, and humidity of 70-80%.

4. The method for cultivating salt-tolerant magnolias according to claim 1, characterized in that, The specific operation of the gradient salt-alkali stress treatment in step (2) is as follows: The magnolia seedlings were irrigated with Na2CO3 solutions of concentrations of 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, and 5wt% respectively, mixed with the regulator, and irrigated once every 30 days for a total of 6 times. The amount of irrigation was 120-200g per seedling.

5. The method for cultivating salt-tolerant magnolias according to claim 4, characterized in that, The preparation method of the regulator is as follows: A: Add aminoacetanilide to water and stir well. Then heat in a hot water bath until dissolved. Cool to room temperature, add isopropanolamine and vitamin B, mix well, and let stand overnight to obtain a mixture. B: Add vitamin B to the mixture and stir well. Then add polyvinylpyrrolidone and homogenize to obtain a regulator.

6. The method for cultivating salt-tolerant magnolias according to claim 1, characterized in that, The specific operation of cutting propagation in step (3) is as follows: Select healthy magnolia plants and cut off branches as cuttings. After soaking them in rooting solution, insert them into sandy soil and cultivate them outdoors under natural conditions.

7. The method for cultivating salt-tolerant magnolias according to claim 6, characterized in that, The specific steps for screening salt-tolerant cuttings in step (3) are as follows: Thirty days after cutting, the cuttings were watered with a mixture of 5wt% and 6wt% Na2CO3 solutions and a growth regulator, at a rate of 120-200g per plant, once every 20 days for a total of two waterings. Ten days after the second watering, the best-growing cuttings were selected to obtain salt-tolerant cuttings for transplanting.

Images