Seed treatment method for improving drought resistance of alfalfa in seedling stage

Abstract

The invention relates to the technical field of alfalfa cultivation, in particular to a seed treatment method for improving drought resistance of alfalfa in the seedling stage. Soaking the alfalfa seeds before sowing in a paclobutrazol aqueous solution; the concentration of the paclobutrazol aqueous solution is 40-100 mg / L; the invention solves the technical problem of how to enhance the drought resistance of alfalfa in the seedling stage.

Description

Technical Field

[0001] The invention relates to the technical field of alfalfa cultivation, and in particular to a seed treatment method for improving drought resistance of alfalfa at the seedling stage. Background Art

[0002] Alfalfa (Medicago sativa L.) (abbreviated as "alfalfa") is an excellent perennial legume forage with the characteristics of high protein content and good palatability. It is an indispensable high-quality forage for the development of animal husbandry. A report released by the Food and Agriculture Organization of the United Nations in 2021 shows that drought stress accounts for 82% of the impact on the agricultural sector, and is one of the main abiotic stresses limiting the growth, development and yield of alfalfa. my country's alfalfa planting area accounts for about 1 / 8 of the world, mainly distributed in Gansu, Inner Mongolia, Xinjiang, Ningxia, Hebei, Heilongjiang, Jilin and other places. The main areas of alfalfa cultivation are arid and semi-arid areas. Severe droughts will cause large-scale death of alfalfa, seriously affecting the sustained high yield of alfalfa and causing huge losses to the alfalfa industry.

[0003] Drought stress will seriously limit the growth rate and biomass of alfalfa, especially the seedling stage, which is susceptible to drought and may even cause the alfalfa seedlings to wilt and die due to water loss.

[0004] Therefore, the problem existing in the prior art is: how to enhance the drought resistance of alfalfa in the seedling stage. Summary of the invention

[0005] The invention provides a seed treatment method for improving drought resistance of alfalfa at the seedling stage, aiming to solve the problem of how to enhance the drought resistance of alfalfa at the seedling stage.

[0006] The technical scheme used in the present invention is as follows: a seed treatment method for improving drought resistance of alfalfa at the seedling stage, comprising the following steps:

[0007] Soak the alfalfa seeds before sowing with the paclobutrazol aqueous solution; the concentration of the paclobutrazol aqueous solution is 40-100 mg / L.

[0008] Furthermore, the alfalfa seeds were soaked in the paclobutrazol aqueous solution for 12 hours at an ambient temperature of 25°C.

[0009] Furthermore, before the alfalfa seeds were soaked in the paclobutrazol aqueous solution, they were polished with sandpaper and then quickly rinsed with distilled water for 3 times.

[0010] Furthermore, the concentration of the paclobutrazol aqueous solution is preferably 70-75 mg / L.

[0011] The beneficial effects achieved by the present invention are as follows: under drought stress, the paclobutrazol aqueous solution used to soak alfalfa seeds before sowing increases the root length of the alfalfa seedlings by 10.73%-44.80% and the aboveground biomass by 1.64%-24.28%; in addition, soaking the seeds with the paclobutrazol aqueous solution increases the number of branches of the alfalfa seedlings under drought stress, but reduces the plant height.

[0012] The invention provides that the optimal concentration range of paclobutrazol aqueous solution for soaking alfalfa seeds before sowing to improve drought resistance of alfalfa seedlings is 70-75 mg / L.

[0013] The method provided by the invention has simple operation and simple procedures, and can quickly and effectively improve the drought resistance of alfalfa in the seedling stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a bar diagram showing the effect of paclobutrazol on the height of alfalfa seedlings under drought stress.

[0015] Figure 2 This is a bar diagram showing the effect of paclobutrazol on the root length of alfalfa in the seedling stage under drought stress.

[0016] Figure 3 This is a bar diagram showing the effect of paclobutrazol on the aboveground biomass of alfalfa at the seedling stage under drought stress.

[0017] Figure 4 This is a bar diagram showing the effect of paclobutrazol on the number of alfalfa branches at the seedling stage under drought stress.

[0018] Figure 5 It is a bar diagram of the comprehensive drought resistance coefficient of paclobutrazol on alfalfa seedlings under drought stress.

[0019] Figure 6 This is a real picture of the root growth of alfalfa seedlings soaked in aqueous solution of different concentrations of paclobutrazol under drought stress. DETAILED DESCRIPTION

[0020] To facilitate those skilled in the art to understand the present invention, specific implementations of the present invention are described below with reference to the accompanying drawings.

[0021] The present invention provides a seed treatment method for improving drought resistance of alfalfa at the seedling stage, comprising the following steps:

[0022] Select alfalfa seeds with full grains, grind them with sandpaper, and then quickly rinse them with distilled water for 3 times;

[0023] Sandpaper grinding alfalfa seeds can break the hardness and grind until the seed coat is slightly damaged, which increases the permeability of the seed coat and allows the paclobutrazol aqueous solution to penetrate better; distilled water is used to quickly rinse the polished impurities;

[0024] Soaking alfalfa seeds before sowing in a paclobutrazol aqueous solution; the concentration of the paclobutrazol aqueous solution is 40-100 mg / L; soaking 50 alfalfa seeds in 50 ml of paclobutrazol aqueous solution of different concentrations;

[0025] The time for soaking alfalfa seeds in paclobutrazol aqueous solution was 12 h, and the ambient temperature was 25°C;

[0026] The method provided by the invention improves the drought resistance of alfalfa at the seedling stage.

[0027] Example

[0028] Select the full-grained alfalfa seeds of Zhongcao No. 3, grind them with sandpaper, and then quickly rinse them with distilled water for 3 times;

[0029] Alfalfa seeds were placed at an ambient temperature of 25°C and soaked in 40, 50, 60, 70, 75, 85, 95, and 100 mg / L paclobutrazol aqueous solutions for 12 h.

[0030] The seeds were taken out and air-dried, sown in pots, 50 seeds per pot, 4 replicates (4 pots) per treatment, and cultured in a greenhouse;

[0031] The culture time was 40 days, the day / night temperature was 25 / 20°C, the photoperiod was 16 / 8h, and the light intensity was 20Klux;

[0032] When the alfalfa seedlings were cultured for 30 days, drought stress treatment was started until the soil moisture content dropped from 80%±5% to 15%±5%.

[0033] Comparative Example CK1

[0034] Select the full-grained alfalfa seeds of Zhongcao No. 3, grind them with sandpaper, and then quickly rinse them with distilled water for 3 times;

[0035] Alfalfa seeds were placed at an ambient temperature of 25°C and soaked in an equal volume of distilled water for 12 hours;

[0036] Take out the seeds, air dry them, and sow them in pots, 50 seeds per pot;

[0037] The culture time was 40 days, the day / night temperature was 25 / 20°C, the photoperiod was 16 / 8h, and the light intensity was 20Klux.

[0038] Alfalfa seedlings were not subjected to drought treatment.

[0039] Comparative Example CK2

[0040] Select the full-grained alfalfa seeds of Zhongcao No. 3, grind them with sandpaper, and then quickly rinse them with distilled water for 3 times;

[0041] Alfalfa seeds were placed at an ambient temperature of 25°C and soaked in an equal volume of distilled water for 12 hours;

[0042] Take out the seeds, air dry them, and sow them in pots, 50 seeds per pot;

[0043] The culture time was 40 days, the day / night temperature was 25 / 20°C, the photoperiod was 16 / 8h, and the light intensity was 20Klux;

[0044] When the alfalfa seedlings were cultured for 30 days, drought stress treatment was started until the soil moisture content dropped from 80%±5% to 15%±5%.

[0045] The processing methods of the embodiment, comparative example CK1 and comparative example CK2 are shown in Table 1 below;

[0046] Table 1 Treatment methods of Example, Comparative Example CK1 and Comparative Example CK2

[0047]

[0048] Note: The seeds are Chinese herb No. 3 alfalfa; the soaking time for alfalfa seeds is 12 hours, and the ambient temperature is 25℃.

[0050] After 40 days, the morphological indices of the alfalfa seedlings of the embodiment, comparative example CK1 and comparative example CK2 were measured and photographed.

[0051] The measurement indicators and methods are as follows:

[0052] Morphological indicators

[0053] Ten alfalfa seedlings were randomly selected from each pot for determination of morphological indicators.

[0054] Plant height: Use a ruler to measure vertically the height from the ground to the highest point of the seedling.

[0055] Root length: Place the roots of alfalfa seedlings on a flat black background cloth and use a ruler to measure from the top of the root (root tip) to the junction of the root base and the stem.

[0056] Aboveground biomass: After mowing the alfalfa seedlings in each pot at ground level, dry them in an oven at 60-80°C for 24 h to constant weight, and then weigh them.

[0057] Number of branches: Take the alfalfa seedlings out of the planting substrate, place them on a clean, flat workbench, use tweezers to comb out the alfalfa seedlings so that the primary branches are clearly visible, count the number of primary branches of each seedling, and calculate the average value.

[0058] The drought resistance evaluation method is as follows:

[0059] Based on plant height, root length, aboveground biomass and number of branches, the drought resistance coefficient was calculated respectively. The calculation formula is as follows:

[0060] Drought resistance coefficient DRC = Y d / Y CK1

[0061] In the above formula, Y d is the measured value of drought treatment, Y CK1 It is the measured value for water treatment.

[0062] The comprehensive evaluation method for drought resistance is as follows:

[0063] Based on plant height, root length, aboveground biomass and number of branches, the comprehensive drought resistance coefficient method was used for evaluation, and the calculation formula is as follows:

[0064] Comprehensive drought resistance coefficient CDRC (comprehensive drought resistance coefficient)

[0065]

[0066] In the above formula, W j is the weight coefficient of the j index, and DRC is the drought resistance coefficient.

[0067] Data analysis

[0068] The data were analyzed by one-way ANOVA using SAS software, and graphs were drawn using GraphPadprism 8.3.0 software;

[0069] Figure 1 The effect of paclobutrazol on the height of alfalfa seedlings under drought stress is shown. Figure 2 The results show the effect of paclobutrazol on the root growth of alfalfa seedlings under drought stress. Figure 3 The results show the effect of paclobutrazol on aboveground biomass of alfalfa at the seedling stage under drought stress. Figure 4 The results show the effect of paclobutrazol on the number of alfalfa branches at the seedling stage under drought stress. Figure 5 The results show the effect of paclobutrazol on the comprehensive drought resistance coefficient of alfalfa at the seedling stage under drought stress.

[0070] Table 2 shows the effects of paclobutrazol on various indicators of alfalfa seedlings under drought stress;

[0071] Table 3 shows the effects of paclobutrazol on the drought resistance coefficient of various indicators of alfalfa seedlings under drought stress;

[0072] Table 4 shows the effect of paclobutrazol on the comprehensive drought resistance coefficient of alfalfa seedlings under drought stress;

[0073] Table 2 Effects of paclobutrazol on various parameters of alfalfa seedlings under drought stress

[0074]

[0075] Note: The percentages are the increase or decrease percentages compared with CK2 treated with paclobutrazol.

[0076] Figure 1 Table 2 shows the effect of paclobutrazol seed soaking on the height of alfalfa seedlings under drought stress;

[0077] like Figure 1 As shown in Table 2, compared with CK2, paclobutrazol soaking reduced the height of alfalfa seedlings under drought stress by 5.18%-25.88%; 75 mg / L had the least reduction, by 5.18%; 70 mg / L also had a reduction, but not significantly.

[0078] Figure 2 Table 2 shows the effect of paclobutrazol seed soaking on the root length of alfalfa seedlings under drought stress;

[0079] like Figure 2 As shown in Table 2, under drought stress, compared with CK2, paclobutrazol soaking significantly increased the root length of alfalfa seedlings, increasing by 10.73%-44.80%; among them, the root length of 70 mg / L was the longest, reaching 28.33 cm, a significant increase of 44.80% (P<0.05); followed by 75 mg / L, which had the longest increase, a significant increase of 36.29% (P<0.05).

[0080] Figure 3 Table 2 shows the effect of paclobutrazol seed soaking on aboveground biomass of alfalfa seedlings under drought stress;

[0081] like Figure 3 As shown in Table 2, compared with CK2, except for 50 mg / L, the aboveground biomass of alfalfa seedlings soaked with paclobutrazol under drought stress increased by 1.64%-24.28%, with 75 mg / L increasing the most, significantly increasing by 24.28% (P<0.05); 70 mg / L also increased slightly.

[0082] Figure 4 Table 2 shows the effect of paclobutrazol seed soaking on the number of branches of alfalfa seedlings under drought stress;

[0083] like Figure 4 As shown in Table 2, compared with CK2, under drought stress, except for the 50 mg / L treatment, the number of branches of alfalfa seeds soaked with paclobutrazol increased at the seedling stage, but not significantly.

[0084] Table 3 Effects of paclobutrazol on drought resistance coefficient of various indicators of alfalfa seedlings under drought stress

[0085]

[0086] As shown in Table 3, compared with CK2, under drought stress, 75 mg / L paclobutrazol seed soaking reduced the drought resistance coefficient of alfalfa plant height the least, only by 5.24%; 70 mg / L reduced it, but not significantly.

[0087] Under drought stress, compared with CK2, 60, 70 and 75 mg / L paclobutrazol seed soaking could significantly increase the drought resistance coefficient of alfalfa root length (P<0.05), while 40, 50, 85, 95 and 100 mg / L had no significant difference; compared with CK2, under drought stress, 70 mg / L paclobutrazol seed soaking treatment increased the drought resistance coefficient of root length the most, significantly increasing by 44.66% (P<0.05); 75 mg / L significantly increased by 36.31% (P<0.05).

[0088] Compared with CK2, under drought stress, 75-100 mg / L paclobutrazol seed soaking significantly increased the drought resistance coefficient of aboveground biomass of alfalfa seedlings (P<0.05); 75 mg / L had the largest increase, significantly increasing by 24.23% (P<0.05).

[0089] Under drought stress, compared with CK2, the drought resistance coefficient of alfalfa branch number increased the most and was the same under the treatments of 70 and 75 mg / L paclobutrazol, but not significantly.

[0090] Table 4 Effect of paclobutrazol on comprehensive drought resistance coefficient of alfalfa seedlings under drought stress

[0091] Treatment (mg / L) Comprehensive drought resistance coefficient CK2 0.794 40 0.926 50 0.825 60 0.918 70 0.981 75 1.018 85 0.906 95 0.900 100 0.869

[0092] As shown in Table 4 and Figure 5 As shown, under drought stress, compared with CK2, the comprehensive drought resistance coefficient of alfalfa seedlings soaked with paclobutrazol increased significantly, except for 50 mg / L, among which 75 mg / L increased the most, increasing by 28.21%, followed by 70 mg / L (23.55%).

[0093] Conclusion: The above cases show that under drought stress, compared with CK2, soaking seeds in 75 mg / L paclobutrazol aqueous solution significantly increased the aboveground biomass of alfalfa seedlings under drought stress by 24.28% (P<0.05), and the root length significantly increased by 36.29% (P<0.05); the number of branches increased by 12.5%, and the plant height decreased slightly, but not significantly; soaking seeds in 70 mg / L paclobutrazol significantly increased the root length of alfalfa seedlings (44.80%) (P<0.05); the number of branches increased by 12.5%, and the plant height decreased, but not significantly.

[0094] Compared with CK2, under drought stress, 75-100 mg / L paclobutrazol seed soaking significantly increased the drought resistance coefficient of aboveground biomass of alfalfa seedlings, among which 75 mg / L increased the most (P<0.05); paclobutrazol seed soaking significantly increased the drought resistance coefficient of root length of alfalfa seedlings, and the optimal concentration was 70 mg / L, followed by 75 mg / L (P<0.05); paclobutrazol seed soaking reduced the drought resistance coefficient of plant height of alfalfa seedlings, and the concentration with the least reduction was 75 mg / L; paclobutrazol seed soaking increased the drought resistance coefficient of branch number of alfalfa seedlings, and the optimal concentrations were 70 and 75 mg / L.

[0095] Based on the above results, under drought stress, compared with CK2, 75 mg / L paclobutrazol soaking significantly increased the root length (P<0.05) and aboveground biomass of alfalfa seedlings (P<0.05); 70 mg / L paclobutrazol soaking significantly increased the root length of alfalfa seedlings (P<0.05); compared with CK2, under drought stress, 75 mg / L paclobutrazol soaking significantly increased the drought resistance coefficient of alfalfa seedling root length (P<0.05) and aboveground biomass (P<0.05 ); The drought resistance coefficient of the root length of alfalfa seedlings soaked with 70 mg / L paclobutrazol was significantly increased (P<0.05); According to the comprehensive drought resistance coefficient, the comprehensive drought resistance coefficient of alfalfa seedlings soaked with 75 mg / L paclobutrazol was the highest, followed by 70 mg / L; Therefore, the optimal concentration range of paclobutrazol for improving the drought resistance of alfalfa seedlings is 70-75 mg / L. It is recommended to soak alfalfa seeds planted in arid and semi-arid areas with 70-75 mg / L paclobutrazol before sowing to effectively improve their drought resistance.

[0096] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A seed treatment method for improving drought resistance of alfalfa at the seedling stage, characterized in that: The following steps are involved: Soak the alfalfa seeds before sowing with the paclobutrazol aqueous solution; the concentration of the paclobutrazol aqueous solution is 40-100 mg / L.

2. A seed treatment method for improving drought resistance of alfalfa at the seedling stage according to claim 1, characterized in that: The paclobutrazol aqueous solution was used to soak the alfalfa seeds for 12 hours at an ambient temperature of 25°C.

3. A seed treatment method for improving drought resistance of alfalfa at the seedling stage according to claim 1, characterized in that: Before the alfalfa seeds are soaked in the paclobutrazol aqueous solution, they are polished with sandpaper and then quickly rinsed with distilled water for 3 times.

4. A seed treatment method for improving drought resistance of alfalfa at the seedling stage according to claim 1, characterized in that: The concentration of the paclobutrazol aqueous solution is preferably 70-75 mg / L.

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