Comprehensive evaluation method for no-top flooding resistance of Chinese cabbage for seedlings and application of comprehensive evaluation method

Abstract

The invention provides a comprehensive evaluation method for no-top flooding resistance of Chinese cabbage for seedlings and application of the comprehensive evaluation method, and belongs to the technical field of agriculture. According to the method, a comprehensive membership function evaluation model D for the top flooding waterlogging damage resistance of the seedling cabbages is constructed through a method of combining main agronomic investigation, in-vivo enzyme activity determination and membership function and principal component analysis, namely D = a1 sigma (U (Xi) PC1) + a2 sigma (U (Xi) PC2) +... + an sigma (U (Xi) PCn), the top flooding waterlogging damage resistance of the seedling cabbages can be judged through the numerical value of D, and the higher the numerical value is, the better the stress resistance is. According to the method, the waterlogging-resistant seedling Chinese cabbage variety can be rapidly screened, the objectivity and accuracy of the identification result are improved, and the method has further popularization value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of agricultural technology, in particular to a comprehensive evaluation method for top-flooded waterlogging resistance of seedling Chinese cabbage and application thereof. BACKGROUND

[0002] Seedling Chinese cabbage, also known as fast Chinese cabbage, is a special type of Chinese cabbage, which has the characteristics of short growth cycle and fast growth, and can be harvested 20-45 days after sowing, thus being able to quickly supply the market, improve land utilization rate and multiple cropping index, and serve as an emergency and supply guarantee under sudden natural disasters and special weather conditions, thereby playing an important role in guaranteeing the supply of "vegetable basket". Seedling Chinese cabbage has a fresh and tender taste, a sweet taste, and rich nutrients such as vitamins, niacin, carotene, calcium, phosphorus, iron, protein, fat, and crude fiber, and is thus deeply loved by growers and consumers.

[0003] At present, there are still many problems in the production of seedling Chinese cabbage, such as the lack of high-quality and strong-resistance varieties. The market demand for seedling Chinese cabbage is strong in summer, but the rainfall is large and typhoon weather occurs frequently in summer, so the seedling Chinese cabbage is often subjected to extreme waterlogging such as top-flooded waterlogging during planting, which causes plant leaf rot, plant type collapse, and whole plant death, and seriously affects the yield and quality of seedling Chinese cabbage, causing immeasurable economic losses. Therefore, it is urgent to screen excellent seedling Chinese cabbage varieties with strong waterlogging resistance. However, there is currently a lack of a unified, rapid and accurate evaluation method for the identification and screening of waterlogging resistance of seedling Chinese cabbage, and it is necessary to establish a simple and easy-to-use evaluation method for the top-flooded waterlogging resistance of seedling Chinese cabbage, which has a short identification time and accurate identification results. SUMMARY

[0004] The present application aims to provide a comprehensive evaluation method for the top-flooded waterlogging resistance of seedling Chinese cabbage and application thereof, which can shorten the identification time of seedling Chinese cabbage and improve the objectivity and accuracy of the identification results.

[0005] In order to achieve the above-mentioned application purpose, the present application provides the following technical solutions:

[0006] The present application provides a comprehensive evaluation method for the top-flooded waterlogging resistance of seedling Chinese cabbage, comprising the following steps:

[0007] (1) adopting pot-flooded water identification, and cultivating seedling Chinese cabbage into the same waterlogging environment;

[0008] (2) taking the SOD activity, POD activity, CAT activity, MDA content, PROT content, plant height, development degree 1, development degree 2, maximum leaf length, maximum leaf width, chlorophyll, fresh weight, dry weight, and water content of seedling Chinese cabbage before and after waterlogging as detection indexes, and quantifying the above indexes and extracting principal components by principal component analysis;

[0009] (3) Evaluate the resistance of different seedling Chinese cabbage varieties to no-top flooding by the comprehensive membership function score.

[0010] Preferably, the comprehensive membership function is composed of the following functions:

[0011] Membership function: U (Xi) = (X i - X min ) / (X max - X min );

[0012] Weight coefficient: a i = PC i / (PC1+PC2+…+PC n );

[0013] Wherein, U (Xi) is the size of the membership function; X i is the measured value of the specific index; X min , X max are the highest and lowest points of the corresponding index of all participating subjects, and U (Xi) value range [0,1];

[0014] a i is the weight coefficient, PC i is the contribution rate of the principal component i, (PC1+PC2+…+PC n ) is the sum of the contribution rates of all principal components with eigenvalues greater than 1, i=1,2,……,n;

[0015] Comprehensive membership function evaluation model:

[0016] D = a1∑(U (Xi) PC1) + a2∑(U (Xi) PC2) +…+a n ∑(U (Xi) PC n );

[0017] Wherein ∑ is the sum, ∑(U (Xi) PC1) represents the sum of the values calculated by the membership function after the principal component proportion of all measured indexes in PC1.

[0018] Preferably, the greater the D value of the comprehensive evaluation model, the better the waterlogging resistance characteristics.

[0019] Preferably, step (2) further comprises taking three days of no-top flooding as the optimal time node for detecting no-top waterlogging of different seedling Chinese cabbage varieties.

[0020] Preferably, in step (2), the principal components are indices whose eigenvalues ​​are greater than 1 obtained from principal component analysis.

[0021] This invention also provides a comprehensive evaluation method for the resistance of seedling Chinese cabbage to waterlogging, which is applied to the screening of waterlogging-resistant varieties of seedling Chinese cabbage.

[0022] The beneficial effects of this invention compared to the prior art are as follows:

[0023] (1) This invention constructs a comprehensive membership function evaluation model D for the resistance of seedling Chinese cabbage to flooding by combining membership function and principal component analysis, based on the investigation of major agronomical properties and the determination of in vivo enzyme activity. D = a1∑(U (Xi) PC1)+a2∑(U (Xi) PC2)+……+a n ∑(U (Xi) PC n The resistance of seedling Chinese cabbage to flooding damage can be judged by the value of D; the higher the value, the better the resistance. For the eight seedling Chinese cabbage varieties of this invention, the comprehensive membership function evaluation model is D = 0.550∑(U (Xi) PC1)+0.230∑(U (Xi) PC2)+0.134∑(U (Xi) PC3)+0.086∑(U (Xi) PC4).

[0024] (2) This invention can screen candidate varieties that are resistant to waterlogging, which has further promotion value. It can also shorten the identification time of waterlogging-resistant varieties of Chinese cabbage seedlings and improve the objectivity and accuracy of the identification results. Attached Figure Description

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

[0026] Figure 1 This refers to the changes in physiological indicators of Chinese cabbage seedlings without variety after being subjected to submersion flooding treatment in Example 1 of the present invention.

[0027] Figure 2 The main agronomical changes of Chinese cabbage seedlings without variety seedlings after the top-flooding treatment in Example 1 of the present invention;

[0028] Figure 3 The scores represent the waterlogging resistance characteristics of different Chinese cabbage seedling varieties in Example 1 of this invention. DETAILED DESCRIPTION

[0029] Various exemplary embodiments of the present application will now be described in detail, with reference to the drawings, which are not to be construed as limiting the application, but rather as illustrating certain aspects, features and embodiments thereof.

[0030] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Additionally, the use of the term "about" in relation to a value or a range of values is intended to include each individual intermediate value and each smaller range that falls within the range of values. The upper and lower limits of these smaller ranges can be included or excluded from the range.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, preferred methods and materials are described. All publications mentioned in this specification are herein incorporated by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. The citation of any reference in this specification is not intended as an admission that the reference is prior art, but rather that the reference is part of the technical literature that is relevant to the disclosure.

[0032] Many modifications and variations of this application can be made in the light of the above teachings without departing from the spirit and scope thereof. Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples given are exemplary only.

[0033] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", or variations thereof, are intended to be open-ended terms that mean including, but not limited to.

[0034] The present application provides a method for evaluating the submergence tolerance of seedling Chinese cabbage, comprising the following steps:

[0035] (1) using pot submergence identification, seedling Chinese cabbage is cultivated in the same submergence environment;

[0036] (2) taking the SOD activity, POD activity, CAT activity, MDA content, PROT content, plant height, development degree 1, development degree 2, maximum leaf length, maximum leaf width, chlorophyll, fresh weight, dry weight, water content of seedling Chinese cabbage before and after submergence as detection indexes, using principal component analysis to quantify the above indexes and extract principal components;

[0037] (3) The different seed Chinese cabbage varieties are evaluated for the no-top flooding resistance characteristics by the comprehensive membership function score.

[0038] The comprehensive membership function is constructed by the following functions:

[0039] Membership function: U (Xi) = (X i -X min ) / (X max -X min );

[0040] Weight coefficient: a i = PC i / (PC1+PC2+……+PC n );

[0041] Wherein, U (Xi) is the size of the membership function; X i is the measured condition of a specific item index; X min , X max are the highest point and the lowest point of the corresponding index of all participating subjects, and the value range of U (Xi) is [0, 1];

[0042] a i is the weight coefficient, PC i is the contribution rate of the principal component i, (PC1+PC2+……+PC n ) is the sum of the contribution rates of all principal components with eigenvalues greater than 1, i=1, 2,..., n;

[0043] The comprehensive membership function evaluation model is:

[0044] D=a1∑(U (Xi) PC1)+a2∑(U (Xi) PC2)+……+a n ∑(U (Xi) PC n );

[0045] Wherein ∑ is summation, and ∑(U (Xi) PC1) represents the summation of the values calculated by the membership function after the principal component proportion of all measured indexes in PC1.

[0046] Example 1

[0047] In the present embodiment, eight seed Chinese cabbage varieties (see Table 1) are subjected to a seed Chinese cabbage flooding damage resistance experiment, and the specific steps are as follows:

[0048] Table 1 Different seed Chinese cabbage varieties and origin information

[0049]

[0050] (1) Waterlogging experiment

[0051] 20-day-old seedlings with consistent growth and health were used for waterlogging tolerance test at seedling stage.

[0052] The control group was placed on the seedbed without any treatment, and the three experimental groups for waterlogging treatment were placed in square water tanks. The three experimental groups were root submersion, water level submerging the center of the plant, and whole plant submerging, respectively. Other growth conditions and management methods were kept consistent. The growth status of each variety of seedling Chinese cabbage under different experimental conditions was observed.

[0053] There was no obvious difference in the root of seedling Chinese cabbage submerged by water level. After a week of water level submerging the center of the plant, the plants began to show waterlogging phenotypes, but there was little difference between varieties. After a day of whole plant submerging, some varieties of seedling Chinese cabbage began to show waterlogging performance, and the difference between varieties was not obvious. After three days, the difference in waterlogging tolerance between varieties was obvious, and all plants died after prolonged submerging.

[0054] Therefore, three days of submerging the center of the plant can be used as the best time node for identifying waterlogging tolerance of different varieties. After three days of submerging the center of the plant, plants with good waterlogging tolerance characteristics had local leaf rot, upright plant type, and could recover after removing the waterlogging condition. Plants with poor waterlogging tolerance characteristics showed leaf rot, plant type collapse, and whole plant death, and gradually died without recovery after removing the waterlogging condition.

[0055] (2) Measurement of agronomic trait indicators and enzyme activity

[0056] Seedling Chinese cabbage was treated by submerging the center of the plant, and enzyme activity and main agronomic traits of the plants were measured and recorded after 0 days, 1 day, and 3 days of waterlogging treatment

[0057] Biochemical indicators were measured by Suzhou Gexi Si Biological Technology Co., Ltd. Fresh leaves of plants treated for 0 days, 1 day, and 3 days were used to measure SOD (superoxide dismutase) activity, POD (peroxidase) activity, CAT (catalase) activity, MDA (malondialdehyde) content, and PROT (soluble protein) content. SOD, POD, CAT, and MDA were measured using corresponding assay kits, and PROT was measured using a Coomassie Brilliant Blue method assay kit. All index measurements were performed in triplicate biological replicates, and the results are shown in Table 1. Figure 1

[0058] After submerging the center of the plant, the activity of various antioxidant enzymes in the plant increased, but due to the different waterlogging tolerance abilities of different varieties, the changes in enzyme activity and related reaction products were different, which was an important reference index for identifying the waterlogging tolerance characteristics of different varieties of seedling Chinese cabbage.​

[0059] Figure 1 It is shown that the SOD activity, POD activity, CAT activity, MDA content and PROT content of the plant leaves treated by submerging for 1 day are determined, taking 0 day as a control to remove background noise. The MDA content and PROT content of the 8 tested varieties change little; the CAT activity of the 5 varieties of serial numbers 1, 3, 4, 7 and 8 decreases obviously; the CAT activity of 2 and 6 increases, especially that of 6 changes most obviously; the CAT activity of 5 changes little; the SOD has great difference in different seedling Chinese cabbage varieties, in which the SOD activity in 7 increases, that in 3, 4, 5 and 8 decreases obviously, and that in 1, 2 and 6 changes little; the POD activity in the tested varieties all increases, and the increasing range is large. According to the above results, it is preliminarily considered that 2, 6 and 7 can better respond to waterlogging stress.

[0060] Further, the main biological characteristics (plant height, development degree 1, development degree 2, maximum leaf length, maximum leaf width, chlorophyll, fresh weight, dry weight, water content) of the material treated by submerging for 3 days are investigated, the development degree is measured by diagonal line measurement method, that is, when the plant is viewed from above, the two maximum development degree values are determined by drawing a cross, and the smaller diagonal line value is named as development degree 1, and the larger diagonal line value is named as development degree 2. The noise interference caused by plant growth is reduced by removing the data of 0 day treatment, and the results are shown in Table 2. Figure 2 Figure 2 It is shown that the longitudinal coordinate is positive value, indicating that the plant treated by submerging for 3 days shows the increase of the index, indicating that it has better waterlogging resistance, such as 2, 5 and 7; the longitudinal coordinate is negative value, indicating that the plant treated by submerging for 3 days shows the decrease of the index, indicating that it has poor waterlogging resistance, especially 8, all the indexes of which are negative values.

[0061] (3) Membership function and principal component analysis

[0062] The above 14 factors affecting the waterlogging resistance of seedling Chinese cabbage are quantified by using the method of combining membership function and principal component analysis, and the principal components are extracted, and the waterlogging resistance of different seedling Chinese cabbage varieties is evaluated by comprehensive membership function scores.

[0063] Membership function: U (Xi) = (X i - X min ) / (X max - X min );

[0064] Weight coefficient: a i = PC i / (PC1 + PC2 + … + PC n );

[0065] ​Wherein, U (Xi) is the size of membership function; X i is the determination of specific item index; X min , X max is the highest point and the lowest point of the corresponding index of all participants, U (Xi) value range [0, 1];

[0066] a i is the weight coefficient, PC i is the contribution rate of principal component i (variance explanation rate %), (PC1+PC2+……+PC n ) is the contribution rate of all eigenvalues greater than 1 principal component sum;

[0067] Comprehensive evaluation model:

[0068] D=a1∑(U (Xi) PC1)+a2∑(U (Xi) PC2)+……+a n ∑(U (Xi) PC n );

[0069] Wherein ∑ is the sum, ∑(U (Xi) PC1) represents the sum of the values of the principal component proportion of all measured indexes in PC1 after the calculation of the membership function.

[0070] Table 2 principal component extraction results

[0071]

[0072] In order to better quantify the waterlogging tolerance characteristics of seedling Chinese cabbage, according to the above results, through the membership function formula and the weight of four principal components, after calculation, the comprehensive membership function value (D) is used as the evaluation standard of the waterlogging resistance of eight varieties of seedling Chinese cabbage. The D value is calculated by the formula D=0.550∑(U (Xi) PC1)+0.230∑(U (Xi) PC2)+0.134∑(U (Xi) PC3)+0.086∑(U (Xi) PC4), through the calculation of D value, the higher the value, the better the resistance.

[0073] The final quantitative score is shown in Figure 3The results show that No. 6 (22K-5) has the highest score, good waterlogging resistance, and the best recovery state after waterlogging treatment; No. 2 (21K-64) also has good waterlogging resistance; No. 1 (21K-10), No. 4 (22K-1) and No. 7 (22K-22) have relatively good waterlogging resistance; No. 3 (21K-96), No. 5 (22K-2) and No. 8 (22K-41) have poor resistance to top submergence, and the plants have more rotten leaves and death.

[0074] The above merely describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for evaluating the submergence tolerance of seedlings of Brassica rapa L. var. Pekinensis Tsen et Lee, characterized by, It comprises the following steps: (1) Using potted waterlogging identification, multiple different varieties of seedlings are cultivated into the same waterlogging environment; (2) Taking the SOD activity, POD activity, CAT activity, MDA content, PROT content, plant height, development degree 1, development degree 2, maximum leaf length, maximum leaf width, chlorophyll, fresh weight, dry weight, water content of the seedling Chinese cabbage before and after waterlogging as detection indexes, the above indexes are quantified and principal components are extracted through principal component analysis; (3) The waterlogging resistance of different seedling Chinese cabbage varieties is evaluated through comprehensive membership function score.

2. The method for evaluating the submergence tolerance of the seedling of Chinese cabbage according to claim 1, wherein, The comprehensive membership function is composed of the following functions: Membership function: U (Xi) = ( X i - X min ) / ( X max - X min ); Weighting factor: a i = PC i / ( PC 1 +PC 2 +……+PC n ); wherein U (Xi) is the size of the membership function; X i is the measurement of the 14 detection indexes in step (2); X min , X max is the highest point and the lowest point corresponding to the detection index, U (Xi) the numerical range [0, 1]; a i PCi is a weight coefficient, i = 1, 2,..., n i PCi is a contribution rate of a principal component i, i = 1, 2,..., n n PCi is a contribution rate of a principal component i, i = 1, 2,..., n The comprehensive membership function evaluation model: D = a 1 ∑( U (Xi) PC1)+ a 2 ∑( U (Xi) PC2)+ …… + a n ∑( U (Xi) PC n ); where ∑ is the summation, ∑ U (Xi) PC1) represents the summation of the values of the principal component proportion of all the measured indexes in PC1 after membership function calculation.

3. The method for evaluating the submergence tolerance of the seedling of Brassica rapa L. according to claim 2, wherein, The greater the D value of the comprehensive membership function evaluation model, the better the waterlogging resistance characteristics.

4. The method for evaluating the submergence tolerance of the seedling of Chinese cabbage according to claim 1, wherein, Step (2) further comprises taking three days of top waterlogging as the optimal time node for detecting the top waterlogging resistance of different varieties of seedling Chinese cabbage.

5. The method for evaluating the resistance to waterlogging of the seedling Chinese cabbage according to claim 1, wherein, In step (2), the principal components are indexes with eigenvalues greater than 1 obtained through principal component analysis.

6. Application of the comprehensive evaluation method of the top waterlogging resistance of the seedling Chinese cabbage according to any one of claims 1-5 in screening waterlogging-resistant varieties of seedling Chinese cabbage.

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