A method for evaluating garlic growth status and screening method for garlic rhizosphere growth-promoting bacteria

Abstract

The present invention relates to the technical field of garlic planting, and in particular to a method for evaluating garlic growth conditions and a method for screening garlic rhizosphere growth-promoting bacteria. The method for evaluating garlic growth conditions comprises the following steps: removing a garlic plant to be evaluated from the soil, washing it, and drying the surface moisture, separating the root system of the garlic plant and weighing the root system, which is recorded as W1; then peeling off the original garlic clove flesh after the garlic plant develops, weighing the original garlic clove flesh, which is recorded as W2; then weighing the remaining part of the garlic plant, which is recorded as W3; calculating the growth index according to a formula, and evaluating the garlic growth condition based on the growth index. The present invention converts the garlic growth condition into quantitative data by constructing a growth index, accurately reflecting its growth dynamics; with the help of the growth index, suitable growth conditions can be quickly determined, and a scientific basis is provided for the efficient screening of garlic rhizosphere growth-promoting bacteria.

Description

Technical Field

[0001] The present invention relates to the technical field of garlic planting, and in particular to a method for evaluating garlic growth conditions and a method for screening garlic rhizosphere growth-promoting bacteria. Background Art

[0002] Garlic is a perennial herbaceous plant of the Allium genus, Amaryllis family. Its bulbs (garlic cloves) are rich in allicin, sulfides, amino acids, and various vitamins, giving them a unique, pungent flavor. They are widely used in food seasoning, medicine, and healthcare. Garlic cultivation methods and the environment in which it grows significantly influence its yield and quality. For example, the microorganisms surrounding garlic's roots can promote its growth through mechanisms such as nutrient conversion, enhanced stress resistance, and disease suppression. Scientific analysis and evaluation of garlic growth not only accurately determine optimal growth conditions but also provide a basis for screening growth-promoting rhizosphere bacteria, aiding in the optimization of cultivation techniques.

[0003] Currently, garlic growth evaluation relies primarily on indicators such as morphology, physiology, yield, and quality, but each has its limitations. Morphologically, plant height is easily affected by environmental factors such as planting density, light, and water, lacking comparability across different growing conditions and only reflecting aboveground growth. Pseudostem diameter requires specialized tools such as vernier calipers, which is cumbersome and difficult to measure, making it difficult to assess the nutritional and physiological activity of the plant. Leaf number stabilizes in the later stages of growth, failing to dynamically reflect plant changes, and leaf damage caused by pests and diseases can interfere with data accuracy. Bulb diameter can only be measured at harvest time, preventing real-time monitoring of growth.

[0004] In terms of physiological indicators, chlorophyll content fluctuates due to leaf position, growth stage, and environmental factors such as light and temperature, and the measurement results are not stable; root activity requires high measurement technology and complex experimental conditions, and it is difficult to make horizontal comparisons under different soil environments; malondialdehyde (MDA) content measurement is easily interfered by other substances, and as a single adverse stress indicator, it needs to be combined with other data for comprehensive analysis; antioxidant enzyme activity measurement relies on professional test kits and instruments, which are costly, and the changes are complex in different growth stages and environments, making analysis difficult.

[0005] In terms of yield and quality indicators, yield, as a comprehensive result, can only be counted after harvest. It is impossible to dynamically monitor the growth process and it is difficult to locate a single influencing factor. The number and size of garlic cloves are restricted by the genetics of the variety and affected by the environment, making it difficult to accurately judge the growth status based on this. Summary of the Invention

[0006] To address the technical limitations of existing garlic growth evaluation methods, including morphological, physiological, yield, and quality indicators, the present invention provides a method for evaluating garlic growth and screening for garlic growth-promoting rhizosphere bacteria. This method constructs a growth index to convert garlic growth status into quantitative data, accurately reflecting its growth dynamics. This growth index enables rapid determination of suitable growth conditions and provides a scientific basis for the efficient screening of garlic growth-promoting rhizosphere bacteria.

[0007] The technical solutions of the present invention are as follows:

[0008] In a first aspect, the present invention provides a method for evaluating the growth status of garlic, comprising the following steps:

[0009] The garlic plant to be evaluated was removed from the soil, washed, and the surface moisture was absorbed. The root system of the garlic plant was separated and weighed, which was recorded as W1. The original garlic clove flesh after the garlic plant developed was then peeled off and weighed, which was recorded as W2. The remaining part of the garlic plant was then weighed, which was recorded as W3.

[0010] The growth index was calculated according to the following formula:

[0011] ;

[0012] Evaluate the growth status of garlic based on the growth index.

[0013] Furthermore, the growth index is compared with a preset threshold value. When the growth index is greater than or equal to the preset threshold value, it indicates that the garlic is in good growth condition.

[0014] Furthermore, the preset threshold is obtained by substituting the average or median values ​​of W1, W2 and W3 of garlic plants in the historical data of garlic planting in the early stage into the growth index formula;

[0015] Alternatively, W1, W2 and W3 of garlic plants obtained according to the currently practiced planting method can be substituted into the growth index formula to obtain the value.

[0016] Furthermore, the growth indexes of garlic plants obtained under at least two groups of different planting conditions are compared, and the growth condition of the garlic plants with a larger growth index is better than that of the garlic plants with a smaller growth index.

[0017] Furthermore, the garlic plants were evaluated within 30 days after emergence.

[0018] In a second aspect, the present invention provides a method for screening garlic rhizosphere growth-promoting bacteria, comprising the following steps:

[0019] S1: Collect garlic rhizosphere soil and isolate garlic rhizosphere bacteria;

[0020] S2: Cultivate garlic rhizosphere bacteria, inoculate the diluted bacterial solution of garlic rhizosphere bacteria into sterile soil, and plant garlic as the treatment group;

[0021] Add sterile water of the same volume as the diluted bacterial solution to another sterile soil of equal mass and plant garlic therein as a blank control group;

[0022] The garlic planting methods of the treatment group and the blank control group were consistent;

[0023] S3: The garlic plants in the treatment group and the blank control group were removed from the soil, washed, and dried, and the roots of the garlic plants were separated and weighed, which was recorded as W1. The original garlic cloves after the garlic plants developed were then peeled off and weighed, which was recorded as W2. The remaining part of the garlic plant was then weighed, which was recorded as W3.

[0024] S4: Calculate the growth index of garlic plants in the treatment group and the blank control group according to the following formula:

[0025] ;

[0026] If the growth index of the garlic plants in the treatment group is greater than the growth index of the garlic plants in the blank control group, it is judged that the garlic rhizospheric bacteria used in the treatment group have a growth-promoting effect.

[0027] Furthermore, step S1 also includes amplifying and identifying the separated garlic rhizosphere bacteria to determine the classification of the garlic rhizosphere bacteria.

[0028] Furthermore, in step S2, the diluted bacterial solution of garlic rhizosphere bacteria is obtained by the following method:

[0029] The isolated garlic rhizosphere bacteria were cultured overnight with shaking, and the obtained culture solution was then diluted 10 times, and 2 parts by volume of the diluted culture solution was mixed with 5 parts by volume of sterile water to obtain the product.

[0030] Furthermore, in step S2, the garlic planting methods for the treatment group and the blank control group are as follows:

[0031] (1) After separating the garlic cloves, peel off the skin covering the garlic cloves and select the garlic cloves with clean and undamaged surfaces for planting;

[0032] (2) Fill a plastic cup with drainage holes with soil to one-third of its volume, place the garlic cloves in the soil, and water until the soil is completely soaked;

[0033] (3) Then evenly cover the garlic cloves with a layer of soil to cover them completely, and then water them again to soak the soil completely;

[0034] (4) Finally, place the cultivated garlic at 20℃±5℃ and water it every two days until the soil is completely soaked.

[0035] Furthermore, step S3 is to sample the garlic plants within 30 days after the garlic plants emerge.

[0036] The beneficial effects of the present invention are:

[0037] The present invention constructs a growth index that aligns with observed garlic growth and reflects gradient differences. This growth index is not significantly correlated with the fresh weight of the garlic cloves used during planting, effectively preventing the influence of individual garlic clove differences on evaluation results. Validation using herbicides with known inhibitory effects on garlic growth and fertilizers with known growth-promoting effects demonstrated that the growth index is highly consistent with known patterns of action, fully confirming its authenticity and reliability for garlic growth assessment.

[0038] The garlic growth status evaluation method provided by the present invention performs quantitative calculations through a growth index formula to obtain comparable numerical indicators, cleverly avoiding the errors caused by differences in the initial weight of garlic cloves in traditional evaluations, allowing the evaluation results to focus more on the growth dynamics of the plant itself, and achieving an accurate assessment of the garlic growth status.

[0039] At the same time, the present invention also provides a method for screening garlic rhizosphere growth-promoting bacteria based on the growth index formula, which can accurately verify the actual impact of bacteria on garlic growth with the help of the growth index, thereby achieving rapid and accurate positioning of rhizosphere strains that have a significant promoting effect on garlic growth, and providing a scientific and feasible technical path for the efficient screening of garlic rhizosphere growth-promoting bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0041] Figure 1 This is a comparison chart of the growth indicators of three garlic varieties. Figure 1 (a) is a bar chart comparing the root weights of the three garlic varieties, (b) is a bar chart comparing the seedling weights of the three garlic varieties, and (c) is a bar chart comparing the root and seedling weights of the three garlic varieties. “*” indicates P < 0.05, and “****” indicates P < 0.0001.

[0042] Figure 2 This is the growth index scatter plot and trend line of Jinxiang purple garlic. Figure 2(a), (b), (c), (d), (e), and (f) represent the relationship and trend between the original weight, original clove weight, root weight, seedling weight, root-seedling weight, growth index, and original weight of Jinxiang purple garlic, respectively.

[0043] Figure 3 This is the growth index scatter plot and trend line of Cangshan white garlic. Figure 3 (a), (b), (c), (d), (e), and (f) represent the relationships and trends between the original weight, original clove weight, root weight, seedling weight, root-seedling weight, and growth index of Cangshan white garlic, respectively.

[0044] Figure 4 This is the growth index scatter plot and trend line of Yunnan purple garlic. Figure 4 (a), (b), (c), (d), (e), and (f) represent the relationship and trend between the original weight, original clove weight, root weight, seedling weight, root-seedling weight, growth index, and original weight of Yunnan purple garlic, respectively.

[0045] Figure 5 This is a similarity analysis chart of the growth indicators and original weight of Jinxiang purple garlic. Figure 5 (a), (b), (c), and (d) represent the linear relationships between root weight, seedling weight, root-seedling weight, growth index, and original weight of Jinxiang purple garlic, respectively.

[0046] Figure 6 This is a similarity analysis chart of the growth indicators and original weight of Cangshan white garlic. Figure 6 (a), (b), (c), and (d) represent the linear relationships between root weight, seedling weight, root-seedling weight, growth index, and original weight of Cangshan white garlic, respectively.

[0047] Figure 7 This is a similarity analysis chart of the growth indicators and original weight of Yunnan purple garlic. Figure 7 (a), (b), (c), and (d) represent the linear relationships between root weight, seedling weight, root-seedling weight, growth index, and original weight of Yunnan purple garlic, respectively.

[0048] Figure 8 This is the box plot of growth index of blank control group 1 and herbicide group. Figure 8 “**” indicates P<0.01.

[0049] Figure 9 This is the box plot of growth index of blank control group 1 and fertilizer group. Figure 9 “*” indicates P<0.05.

[0050] Figure 10 is a box plot of the growth index of the blank control group 2 and each treatment group in Example 4, Figure 10(a), (b), (c), (d), (e), (f), (g), (h), (i), and (j) are box plots of growth index of treatment group 1, treatment group 2, treatment group 3, treatment group 4, treatment group 5, treatment group 6, treatment group 7, treatment group 8, treatment group 9, treatment group 10 and blank control group 2, respectively. "*" indicates P < 0.05, "***" indicates P < 0.001, and NS indicates no significant difference. DETAILED DESCRIPTION

[0051] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0052] Example 1 Determination of Growth Index

[0053] To reduce the problem of inaccurate evaluation results caused by individual differences in garlic cloves, three common varieties of garlic were selected as experimental materials to screen out the growth indicators that best reflect the garlic production status. The specific method is as follows:

[0054] 1. Garlic seed cultivation

[0055] Choose three varieties of garlic: Jinxiang Purple Garlic (G01), Cangshan White Garlic (G02), and Yunnan Purple Garlic (G03). Plant 75 cloves of each variety. Separate the garlic cloves and select cloves of moderate size. Peel the skins covering the cloves and select those with clean, undamaged surfaces for planting.

[0056] During the planting process, all three garlic varieties maintained consistent growing conditions, including temperature, watering, and light exposure. The specific planting method was as follows: A plastic cup with drainage holes was filled one-third of its volume with soil. A qualified garlic clove was placed in the soil and watered until the soil was completely moistened. Then, a thin layer of soil was evenly applied over the garlic cloves, ideally covering them completely to avoid overly thick soil that would affect seed germination. Water was then applied again until the soil was completely moistened, with no excess water accumulation. Finally, the cultivated garlic was incubated at 20°C ± 5°C, watering every two days until the soil was completely moistened.

[0057] During the cultivation process, we observed that the growth conditions of the three varieties varied. Jinxiang purple garlic showed the best growth and the fastest growth rate, Yunnan purple garlic showed the worst growth and the slowest growth rate, and Cangshan white garlic showed an intermediate growth rate.

[0058] 2. Collection of Growth Indicators

[0059] Before planting, the peeled garlic cloves were weighed and recorded as the original weight W0.

[0060] After 11 days of cultivation, remove any garlic plants that unexpectedly died. Remove the remaining garlic plants from the soil, rinse with water, and clean the entire plant of soil. Use absorbent paper to dry the entire surface moisture. Use scissors to cut the roots of the garlic plants onto weighing paper and weigh them, recording W1 (root weight). Next, remove the raw garlic cloves (the portion remaining after peeling the garlic cloves and planting them) from the garlic plants and weigh them on weighing paper, recording W2 (raw garlic clove weight). Finally, place the remaining portion of the garlic plant on weighing paper and weigh it, recording W3 (seedling weight). Based on these weighing results, calculate the root and seedling weight of each garlic plant (W1 + W3) and the growth index ((W1 + W3) / W2).

[0061] 3. Preliminary Analysis of Growth Indicators

[0062] Figure 1 The root weight, shoot weight and root-shoot weight of three garlic varieties are shown. Figure 1 From (a), we can see that the root weight of Cangshan white garlic is the largest, the root weight of Jinxiang purple garlic is the second largest, and the root weight of Yunnan purple garlic is the smallest. Figure 1 From (b), we can see that the seedling weight of Jinxiang purple garlic is the largest, the seedling weight of Cangshan white garlic is the second, and the seedling weight of Yunnan purple garlic is the smallest. Figure 1 As shown in (c), Jinxiang purple garlic had the largest root and seedling weight, Cangshan white garlic had the second largest, and Yunnan purple garlic had the smallest. Overall, there were significant differences in root weight, seedling weight, and root and seedling weight among the different varieties, and each variety exhibited different advantages in different indicators, making it impossible to directly compare the growth rates of the three varieties. Therefore, the data was further processed, and after re-sorting the original weight in ascending order, a scatter plot of Jinxiang purple garlic, Cangshan white garlic, and Yunnan purple garlic was created with the garlic clove number as the horizontal axis, along with its trend line (see Figure 2). Figure 2 、 Figure 3 、 Figure 4 shown).

[0063] according to Figures 2 to 4 From the three pictures, we can see that the weight of raw garlic cloves, root weight, seedling weight and root seedling weight of Jinxiang purple garlic, Cangshan white garlic and Yunnan purple garlic have some fluctuations, and their stability and dispersion are different, but they all show an upward trend in general, that is, they increase with the increase of raw weight. Figure 2 From (a), we can see that in terms of original weight, the scattered points of Jinxiang purple garlic are distributed around the trend line, the trend line shows an upward trend, the original weight is generally on the rise, and the data fluctuation is relatively small, and the stability is good; Figure 2As shown in (b), the trend line of Jinxiang purple garlic rises in terms of raw garlic clove weight, indicating that raw garlic clove weight increases with raw weight. The scatter distribution shows that the data has some fluctuations, but the overall changes around the trend line have a certain regularity. Figure 2 As shown in (c), the trend line of Jinxiang purple garlic rises in terms of root weight, indicating that root weight increases with the increase of original weight, but the scatter points are relatively scattered, indicating that the data fluctuates greatly and is not stable. Figure 2 As shown in (d), the trend line of Jinxiang purple garlic in terms of seedling weight is rising, indicating that seedling weight increases with the increase of original weight. The scattered distribution reflects that the data fluctuates, and the growth trend and fluctuation range of seedling weight of different varieties are different. Figure 2 As shown in (e), the trend line of Jinxiang purple garlic rises in terms of root seedling weight, indicating that the root seedling weight increases with the increase of original weight. The scattered distribution reflects the fluctuation. Different varieties have different growth trends and stability in total weight. Figure 2 As shown in (f), the trend line of Jinxiang purple garlic in terms of growth index is relatively flat, indicating that the growth index does not change much with the original weight. The scattered distribution reflects certain fluctuations, but the overall change trend is not obvious.

[0064] Normal distribution tests were performed on the raw weight, raw clove weight, root weight, seedling weight, root-seedling weight, and growth index of the three garlic varieties. The results are shown in Tables 1 to 3. For data in Tables 1 and 2 with a sample size greater than 50, the Kolmogorov-Smirnov test was used; for data in Table 3 with a sample size less than 50, the Shapiro-Wilk test was used.

[0065] Table 1 Normal distribution test results of growth indicators of Jinxiang purple garlic (* p<0.05)

[0066]

[0067] As can be seen from Table 1, the p-value of the raw clove weight of Jinxiang purple garlic is less than 0.05, showing significance, indicating that this item does not have the characteristics of a normal distribution; the p-values ​​of the raw weight, root weight, seedling weight, root-seedling weight and growth index are all greater than 0.05, and none of them show significance, indicating that the above items have the characteristics of a normal distribution and can basically be accepted as a normal distribution.

[0068] Table 2 Normal distribution test results of various growth indicators of Cangshan white garlic

[0069]

[0070] As can be seen from Table 2, the p-values ​​of the original weight, original clove weight, root weight, seedling weight, root-seedling weight, and growth index of Cangshan white garlic are all greater than 0.05, and none of them show significance, indicating that the above items have normal distribution characteristics and can basically be accepted as normal distribution.

[0071] Table 3 Normal distribution test results of growth indicators of Yunnan purple garlic

[0072]

[0073] As can be seen from Table 3, the p-values ​​of the original weight, original clove weight, root weight, seedling weight, root seedling weight and growth index of Yunnan purple garlic are all greater than 0.05, and none of them show significance, indicating that the above items have normal distribution characteristics and can basically be accepted as normal distribution.

[0074] 4. Further Correlation Processing of Growth Indicators

[0075] Based on the above analysis, the root weight, seedling weight, and root-seedling weight of the three garlic varieties may have a linear relationship with the original weight and original garlic clove weight, so further correlation analysis was conducted on the data.

[0076] like Figure 5 As shown in the figure, there is a certain linear relationship between the root weight of the Jinxiang purple garlic plant and the original weight of the garlic cloves. The linear equation is: y=-0.4+0.42x(r 2 =0.438, p<0.0001), which indicates that there is a moderate linear correlation between root weight and original weight. The garlic plant seedling weight and root seedling weight of Jinxiang purple garlic also showed a similar trend, with the linear equations being y=0.46+0.95x(r 2 = 0.699, p < 0.0001) and y = 0.06 + 1.4x (r 2 =0.670, p<0.0001). This indicates that the above three parameters cannot be used as indicators for evaluating the growth status of garlic. There is no significant linear relationship between the growth index and the original weight of garlic. The linear equation is y=1.9+0.085x(r 2 =0.019, p=0.320>0.05), indicating that the growth index can be used as an indicator to evaluate the growth status of garlic.

[0077] Figure 6 、 Figure 7 The linear relationship between the growth indicators and the original weight of the garlic plants of Cangshan white garlic and Yunnan purple garlic is shown respectively. The results are similar to those of Jinxiang purple garlic. The three growth indicators of root weight, seedling weight and root-seedling weight cannot be used as indicators to evaluate the growth status of garlic, while the growth index can be used as an indicator to evaluate the growth status of garlic.

[0078] 5. Verification of Growth Index

[0079] Jinxiang purple garlic was used as the experimental material. The selected garlic cloves of appropriate size were divided into a blank control group (CK1), a herbicide group (H), and a fertilizer group (F) for planting, with 25 cloves planted in each group. During the planting process, the blank control group (CK1) followed the planting method described in "I. Garlic Seed Cultivation," with no soil or irrigation water treatment. The herbicide group added 0.1 mL of sterile water containing the herbicide to each watering. Each 10 mL of sterile water containing the herbicide was prepared by mixing 50 μL of 20% clofopyralid and 9.95 mL of purified water in a test tube. All other methods remained the same as those for the blank control group. For the fertilizer group, organic fertilizer fermented from pure sheep manure was mixed with soil at a mass ratio of 1:10. Garlic was planted in the soil containing the organic fertilizer. All other methods remained the same as those for the blank control group.

[0080] After 14 days of incubation, remove the garlic plants from the soil, rinse with water to clean the soil from the entire plant, and then use absorbent paper to dry the entire surface moisture of the garlic plant. Use scissors to cut the roots of the garlic plants onto weighing paper and weigh them, recording W1 (root weight). Next, peel the raw garlic cloves of the garlic plants and weigh them on weighing paper, recording W2 (raw garlic clove weight). Then, place the remaining part of the garlic plant on weighing paper and weigh it, recording W3 (seedling weight). Based on the weighing results, calculate the growth index of each garlic plant: (W1 + W3) / W2.

[0081] like Figure 8 、 Figure 9 As shown, the blank control group 1 showed significant differences from both the herbicide and fertilizer groups. The median growth index for the blank control group was approximately 2.9, while that for the herbicide group was approximately 2.3. This indicates that the overall growth index for the blank control group 1 was higher than that for the herbicide group, indicating that the herbicide reduced the overall growth index. The median growth index for the fertilizer group was approximately 3.2, slightly higher than that for the blank control group 1, indicating that fertilizer increased the overall growth index. This result is consistent with the known pattern that herbicides inhibit garlic growth while fertilizers promote it, demonstrating that the growth index is reliable.

[0082] In summary, the growth index constructed by the present invention is not significantly correlated with the original weight of the garlic cloves at planting time, and can be used to objectively describe the growth status of garlic plants. Actual observations show that the growth rate of Jinxiang purple garlic plants is the fastest, followed by Cangshan white garlic, and the slowest. The growth indices of these three varieties are fully consistent with the aforementioned growth status, indicating that the growth index can accurately reflect the actual growth status of garlic. Experiments to verify the effects of herbicides (known to inhibit garlic growth) and fertilizers (known to promote garlic growth) on the growth index showed that the variation pattern of the growth index is completely consistent with the known effects. Therefore, the growth index of the present invention is fully demonstrated to be reliable.

[0083] Example 2

[0084] This embodiment 2 provides an application of a growth index, specifically evaluating the growth status of garlic based on the growth index. The main method is as follows:

[0085] A method for evaluating garlic growth status comprises the following steps:

[0086] Garlic plants within 30 days of emergence were removed from the soil, washed, and dried. The roots of the garlic plants were then separated and weighed, which was recorded as W1. The original garlic cloves were then peeled off and weighed, which was recorded as W2. The remaining part of the garlic plant was then weighed, which was recorded as W3.

[0087] The growth index was calculated according to the following formula:

[0088] .

[0089] Evaluate the growth status of garlic based on the growth index.

[0090] When using the growth index to evaluate garlic growth, an evaluation standard can be set first. Specifically, a threshold value is determined by substituting the average or median values ​​of W1, W2, and W3 of garlic plants from historical garlic planting data, or the W1, W2, and W3 values ​​of garlic plants obtained according to currently used planting methods, into the growth index formula. This threshold value is then used as the evaluation standard for determining the quality of garlic growth. The growth index calculated after actual testing is then compared with the preset threshold value. If the growth index is greater than or equal to the preset threshold value, the garlic growth is considered good; if it is less than the preset threshold value, the garlic growth is considered poor, thereby achieving an accurate evaluation of the garlic growth condition.

[0091] For example, based on the statistical data of raw clove weight, root weight, and seedling weight of garlic plants (test plants) at the same cultivation stage the previous year (e.g., 15 days after emergence), the average values ​​of each indicator were calculated and substituted into the growth index formula. The resulting growth index for that year was 2.56, which was used as the preset threshold. A sample of newly planted garlic this year was surveyed on the 15th day after emergence, and the weights were recorded and averaged. Substituting this into the formula, the current growth index was 2.38. Because the measured growth index was lower than the preset threshold, this indicated that the growth of this year's garlic was poorer than the same period the previous year, and intervention measures such as fertilization were needed to optimize planting conditions.

[0092] When using the growth index to evaluate the growth condition of garlic, the growth indexes of at least two groups of garlic plants obtained under different planting conditions can also be compared. Through this comparison method, it can be clearly seen that the growth condition of garlic plants with a larger growth index is better than that of garlic plants with a smaller growth index, thereby providing an intuitive and reliable basis for judging the quality of garlic growth conditions under different planting conditions.

[0093] For example, in the "V. Verification of Growth Index" section of Example 1, the growth indexes of garlic plants in the blank control group 1, the herbicide group, and the fertilizer group were compared to determine the ranking of the growth conditions of garlic under the three different planting methods. The growth condition of garlic in the fertilizer group was the best, followed by the blank control group 1, and the herbicide group was the worst.

[0094] Example 3

[0095] This Example 3 provides an application of a growth index, specifically screening garlic rhizosphere growth-promoting bacteria based on the growth index. The main method is as follows:

[0096] A method for screening garlic rhizosphere growth-promoting bacteria comprises the following steps:

[0097] S1: Collect garlic rhizosphere soil and isolate garlic rhizosphere bacteria.

[0098] In order to clarify the biological characteristics and taxonomic status of growth-promoting bacteria, after isolating garlic rhizospheric bacteria, each strain can be amplified and identified first. This step can provide a taxonomic basis for subsequent research on the mechanism of action, strain preservation and industrial application of growth-promoting bacteria, and improve the targeted and scientific nature of the screening work.

[0099] S2: The isolated garlic rhizosphere bacteria were cultured overnight with shaking, and the resulting culture solution was diluted 10-fold. Two volumes of the diluted culture solution were then mixed with five volumes of sterile water to obtain a diluted bacterial solution of garlic rhizosphere bacteria. The diluted bacterial solution was inoculated into sterile soil, and garlic was planted as the treatment group.

[0100] Add sterile water of the same volume as the diluted bacterial solution to another sterile soil of equal mass, and plant garlic therein as a blank control group.

[0101] The garlic planting methods of the treatment group and the blank control group were consistent.

[0102] Specifically, the garlic planting method is as follows:

[0103] (1) After separating the garlic cloves, peel off the skin covering the cloves and select the cloves with clean and undamaged surfaces for planting.

[0104] (2) Fill a plastic cup with drainage holes with soil to one-third of its volume, place the garlic cloves in the soil, and water until the soil is completely soaked.

[0105] (3) Then evenly cover the garlic cloves with a layer of soil to cover them completely, and then water them again to soak the soil completely.

[0106] (4) Finally, place the cultivated garlic at 20℃±5℃ and water it regularly and quantitatively during the cultivation process.

[0107] S3: Within 30 days after the garlic plants emerged, the garlic plants in the treatment group and the blank control group were removed from the soil, washed and dried, and the roots of the garlic plants were separated and weighed, recorded as W1; the original garlic cloves after the garlic plants developed were peeled off and weighed, recorded as W2; and the remaining part of the garlic plants was weighed, recorded as W3.

[0108] S4: Calculate the growth index of garlic plants in the treatment group and the blank control group according to the following formula:

[0109] .

[0110] If the growth index of the garlic plants in the treatment group is greater than the growth index of the garlic plants in the blank control group, it is judged that the garlic rhizospheric bacteria used in the treatment group have a growth-promoting effect.

[0111] Example 4

[0112] This Example 4 provides a specific case of screening garlic rhizosphere growth-promoting bacteria based on growth index.

[0113] (1) Obtaining garlic rhizosphere soil

[0114] Soil was collected from Fan Town, Tai'an City, Shandong Province at a depth of 5-10 cm. Large particles of impurities such as stones and plant roots were removed from the soil. After natural air drying, the soil was passed through a 20-mesh sieve.

[0115] Fill a plastic cup with drainage holes with sieved soil, filling it one-third of the cup. Remove the skin from Jinxiang purple garlic cloves and place them in the soil. Water until the soil is completely moistened. Then, evenly cover the cloves with a thin layer of soil, ensuring they completely cover the cloves. Avoid excessive soil coverage that could affect seed germination. Water again until the soil is completely moistened, with no excess water accumulation. Finally, incubate the cultivated garlic at 20°C ± 5°C, watering every two days until the soil is completely moistened. After seven days of incubation, use tweezers to insert a needle into the soil at the base of the garlic plant and remove the plant, including its roots. Gently shake off any large clumps of soil from the root surface in a clean bench. Use a sterile brush to gently remove the soil tightly attached to the root surface (approximately 2 mm thick). This soil is the rhizosphere soil and is stored in a refrigerator at 4°C until further use.

[0116] 2. Isolation of garlic rhizosphere bacteria

[0117] All isolation operations of garlic rhizosphere bacteria were completed in a clean bench using the dilution plate method. The specific steps are as follows:

[0118] First, weigh 1 g of rhizosphere soil sample and place it in a 50 mL sterile centrifuge tube filled with 9 mL of sterile water. Place the centrifuge tube on a vortex shaker and oscillate for 1 min to fully disperse the soil particles and promote the release of bacteria from the surface of the soil particles into the solution to form a soil stock solution. Pipette 100 μL of the soil stock solution into a 1.5 mL sterile centrifuge tube filled with 900 μL of sterile water and oscillate thoroughly to prepare 10 -1 Then take 100 μL of the soil suspension into another 1.5 mL sterile centrifuge tube containing 900 μL of sterile water, shake and mix to obtain 10 -2 dilution of soil suspension; and so on, to obtain 10 -3 , 10 -4 , 10 -5 and 10 -6 Soil suspensions of different dilutions.

[0119] Pipette 50 μL of 10 -2 -10 -6 Inoculate the diluted soil suspension onto the surface of a bacterial isolation medium (LB medium) and spread evenly using a sterile L-shaped spreader. Spread the suspension onto three plates for each dilution to ensure experimental accuracy. After spreading, number the plates, seal them with sterile sealing film, and invert them in a 28°C incubator to observe bacterial growth.

[0120] When a single colony grows on the plate, purification operation is carried out. According to the morphological characteristics of the colony, such as shape, size, color and surface characteristics, typical single colonies are selected from different culture media. Before selection, use a marker to mark the position of the strain to be purified on the bottom of the culture dish, and assign a unique number to each strain. Use an inoculation needle to transfer the selected single colonies to a new plate one by one, use the three-zone streak method for purification, and culture them in a constant temperature incubator at 28°C. After three plate streak purifications, the colony grows stably on the new plate and shows consistent morphological characteristics, which is considered a successful purification. After morphological classification and grouping, a total of 10 bacterial strains were purified, and the purified strains were inoculated into the culture medium and stored at 4°C for use.

[0121] (III) Identification of garlic rhizosphere bacteria

[0122] After amplification and identification of bacterial 16S rDNA gene sequences, the taxonomic information of the ten bacterial strains is shown in Table 4 below.

[0123] Table 4 Identification results of garlic rhizosphere bacteria

[0124]

[0125] 4. Effect of garlic rhizosphere bacteria on growth index

[0126] Ten strains were cultured overnight with shaking. The resulting bacterial solution was diluted 10-fold, and 2 parts by volume was mixed with 5 parts by volume of sterile water to obtain a diluted bacterial solution for later use. Garlic cloves from Jinxiang purple garlic were disinfected using conventional disinfection methods and aliquoted with sterile soil.

[0127] The experiment set up one blank control group and ten treatment groups, with 8 replicates in each group.

[0128] Blank control group 2 (CK2) was prepared by adding 7 mL of sterile water to sterile soil;

[0129] Treatment group 1 (T1) was to add 7 mL of diluted bacterial solution of sandy soil microbacterium GR1 to sterile soil;

[0130] Treatment group 2 (T2) was to add 7 mL of diluted bacterial solution of Brachybaculum GR2 into sterile soil;

[0131] Treatment group 3 (T3) was to add 7 mL of diluted bacterial solution of Gaia GR3 to sterile soil;

[0132] Treatment group 4 (T4) was to add 7 mL of diluted bacterial solution of Acidovorax GR4 to sterile soil;

[0133] Treatment group 5 (T5) was to add 7 mL of the diluted bacterial solution of Chryseobacterium GR5 to the sterile soil;

[0134] Treatment group 6 (T6) was to add 7 mL of diluted bacterial solution of Hyalaria microtubules GR6 into sterile soil;

[0135] Treatment group 7 (T7) was to add 7 mL of diluted Agrobacterium GR7 solution to sterile soil;

[0136] Treatment group 8 (T8) was to add 7 mL of diluted bacterial solution of Pseudomonas aeruginosa GR8 into sterile soil;

[0137] Treatment group 9 (T9) was to add 7 mL of diluted bacterial solution of Pseudomonas aeruginosa GR9 into sterile soil;

[0138] Treatment group 10 (T10) was prepared by adding 7 mL of diluted bacterial solution of Oligotrophic Bacillus GR10 to sterile soil.

[0139] The blank control group 2 used the same sterile soil quality as the treatment group, and the planting method was consistent, and both were carried out according to the following steps:

[0140] (1) After separating the garlic cloves, peel off the skin covering the cloves and select the cloves with clean and undamaged surfaces for planting.

[0141] (2) Fill a plastic cup with drainage holes with soil to one-third of its volume, place the garlic cloves in the soil, and water until the soil is completely soaked.

[0142] (3) Then evenly cover the garlic cloves with a layer of soil to cover them completely, and then water them again to soak the soil completely.

[0143] (4) Finally, place the cultivated garlic at 20℃±5℃ and water it every two days until the soil is completely soaked.

[0144] After 14 days of cultivation, the garlic plants of the treatment group and the blank control group 2 were removed from the soil, washed and dried, and the roots of the garlic plants were separated and weighed, recorded as W1; the original garlic cloves after the garlic plants developed were peeled off and weighed, recorded as W2; and the remaining part of the garlic plant was weighed, recorded as W3.

[0145] The growth index of garlic plants in the treatment group and the blank control group was calculated according to the formula:

[0146] .

[0147] The growth index box plots of each treatment group and the blank control group 2 are shown in Figure 10As shown, the average growth index of each treatment group was higher than that of the blank control group 2, indicating that all ten isolated and purified strains promoted garlic growth. Independent sample t-test analysis revealed that the growth indices of treatment groups 5 (Chryseobacterium septicum) and 8 (Phenybacterium septicum) were significantly different from those of blank control group 2, indicating that these two strains had a more pronounced growth-promoting effect on garlic plants. Specific data are as follows: the average growth index of blank control group 2 was 0.2415, the average growth index of treatment group 5 was 0.3246 (t=2.478, p=0.0266), and the average growth index of treatment group 8 was 0.4697 (t=4.871, p=0.0002), all significantly higher than that of blank control group 2. This clearly demonstrates that Chryseobacterium septicum and Phenybacterium septicum significantly promote garlic growth. Therefore, Chryseobacterium septicum and Phenybacterium septicum can be screened as garlic rhizosphere growth-promoting strains for further research.

[0148] Although the present invention has been described in detail with reference to the accompanying drawings and in conjunction with preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, persons of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall be within the scope of the present invention. Any changes or substitutions that can be easily conceived by persons skilled in the art within the technical scope disclosed in the present invention shall be within the scope of protection of the present invention.

Claims

1. A method for evaluating garlic growth status, characterized in that: The steps include: The garlic plant to be evaluated was removed from the soil, washed, and the surface moisture was absorbed. The root system of the garlic plant was separated and weighed, which was recorded as W1. The original garlic clove flesh after the garlic plant developed was then peeled off and weighed, which was recorded as W2. The remaining part of the garlic plant was then weighed, which was recorded as W3. The growth index was calculated according to the following formula: ； Evaluate the growth status of garlic based on the growth index.

2. A method for evaluating garlic growth status according to claim 1, characterized in that: Compare the growth index with the preset threshold. When the growth index is ≥ the preset threshold, it indicates that the garlic is growing well.

3. A method for evaluating garlic growth status as claimed in claim 2, characterized in that: The preset threshold is obtained by substituting the average or median values ​​of W1, W2 and W3 of garlic plants in the historical data of previous garlic planting into the growth index formula; Alternatively, W1, W2 and W3 of garlic plants obtained according to the currently practiced planting method can be substituted into the growth index formula to obtain the value.

4. A method for evaluating garlic growth status as claimed in claim 1, characterized in that: The growth indexes of garlic plants obtained under at least two groups of different planting conditions are compared. The growth condition of the garlic plant with a larger growth index is better than that of the garlic plant with a smaller growth index.

5. A method for evaluating garlic growth status according to any one of claims 1 to 4, characterized in that: Garlic plants were evaluated within 30 days of emergence.

6. A method for screening garlic rhizosphere growth-promoting bacteria, characterized in that: The steps include: S1: Collect garlic rhizosphere soil and isolate garlic rhizosphere bacteria; S2: Cultivate garlic rhizosphere bacteria, inoculate the diluted bacterial solution of garlic rhizosphere bacteria into sterile soil, and plant garlic as the treatment group; Add sterile water of the same volume as the diluted bacterial solution to another sterile soil of equal mass and plant garlic therein as a blank control group; The garlic planting methods of the treatment group and the blank control group were consistent; S3: The garlic plants in the treatment group and the blank control group were removed from the soil, washed, and dried, and the roots of the garlic plants were separated and weighed, which was recorded as W1. The original garlic cloves after the garlic plants developed were then peeled off and weighed, which was recorded as W2. The remaining part of the garlic plant was then weighed, which was recorded as W3. S4: Calculate the growth index of garlic plants in the treatment group and the blank control group according to the following formula: ； If the growth index of the garlic plants in the treatment group is greater than the growth index of the garlic plants in the blank control group, it is judged that the garlic rhizospheric bacteria used in the treatment group have a growth-promoting effect.

7. The method for screening garlic rhizosphere growth-promoting bacteria according to claim 6, characterized in that: Step S1 also includes amplifying and identifying the separated garlic rhizosphere bacteria to determine the classification of the garlic rhizosphere bacteria.

8. The method for screening garlic rhizosphere growth-promoting bacteria according to claim 6, wherein: In step S2, the diluted bacterial solution of garlic rhizosphere bacteria is obtained by the following method: The isolated garlic rhizosphere bacteria were cultured overnight with shaking, and the obtained culture solution was then diluted 10 times, and 2 parts by volume of the diluted culture solution was mixed with 5 parts by volume of sterile water to obtain the product.

9. A method for screening garlic rhizosphere growth-promoting bacteria according to claim 6 or 8, characterized in that: In step S2, the garlic planting method for the treatment group and the blank control group is as follows: (1) After separating the garlic cloves, peel off the skin covering the garlic cloves and select the garlic cloves with clean and undamaged surfaces for planting; (2) Fill a plastic cup with drainage holes with soil to one-third of its volume, place the garlic cloves in the soil, and water until the soil is completely soaked; (3) Then evenly cover the garlic cloves with a layer of soil to cover them completely, and then water them again to soak the soil completely; (4) Finally, place the cultivated garlic at 20℃±5℃ and water it every two days until the soil is completely soaked.

10. The method for screening garlic rhizosphere growth-promoting bacteria according to claim 6, characterized in that: Step S3 is sampling the garlic plants within 30 days after the garlic plants emerge.

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