Evaluation method and application of anti-shedding capability of kelp

Abstract

The invention relates to a method for evaluating the anti-shedding capability of kelp and application thereof, and belongs to the technical field of seawater algae culture, the method comprises the following steps: 1) sample collection and preparation: collecting kelp samples, dividing the samples into two groups of samples, and counting the seedling shedding condition on a culture seedling rope at the same time; 2) mechanical property testing: applying a tensile load to a group of samples until the samples are fractured to obtain a stress-strain curve; 3) morphological characteristic detection: after softening the other group of samples in a low-specific-gravity seawater culture solution, expanding the rhizoid into a planar form, and measuring and analyzing the morphological characteristics of the rhizoid; and 4) data analysis and model construction: performing principal component analysis on the mechanical and morphological characteristic parameters, constructing a multiple regression model in combination with the seedling storage rate of the culture seedling rope, and calculating the comprehensive score of the anti-shedding ability of the kelp. Based on the comprehensive score, evaluating the anti-shedding capability of leaves of different kelp strains, and providing a theoretical basis for breeding of anti-shedding kelp varieties.

Description

Technical Field

[0001] The invention belongs to the technical field of seawater algae cultivation, and in particular relates to a method for evaluating the anti-falling ability of kelp and its application. Background Art

[0002] Seaweed is an important marine biological resource and a key component of coastal ecosystems. As one of the most economically valuable large brown algae in the world, kelp (Saccharina japonica) has long been ranked first in the aquaculture output of economic algae. my country's kelp production accounts for more than 80% of the world's total production. In recent years, the density of nearshore aquaculture has increased significantly, and the pressure of global climate change, seawater pollution and coastal engineering has gradually increased. At the same time, with the advancement of marine ecological civilization construction, the protection and utilization policies of offshore waters have become increasingly stringent. Some traditional nearshore aquaculture areas (including seaweed aquaculture areas) have been reduced or withdrawn, prompting seaweed aquaculture to gradually expand to offshore deep waters.

[0003] Kelp production adopts raft culture method, which refers to the method of setting up a raft frame composed of floating ropes, pier cables, piers, buoys and seedling ropes at sea, and the kelp is clamped / attached to the seedling ropes and suspended on the surface of the seawater for culture. Offshore deep water culture has certain advantages, but also faces significant challenges. The water flow exchange in deep waters is faster, which helps to enhance photosynthesis and other metabolic activities, thereby increasing the yield of kelp. However, offshore culture areas often encounter high sea conditions of level 3-4 (may reach level 5 during storm surges), with wave heights of 0.5 to 2.5 meters and flow rates of 0.3 to 1.5 meters per second. This high sea condition not only poses a severe test to the stability of the culture equipment, but also imposes greater mechanical pressure on the kelp itself (such as stretching, bending, twisting), which can easily cause the kelp to fall off or the leaves to be damaged. At the edge of some offshore culture areas, the rate of kelp falling off or damage exceeds 50%.

[0004] The morphology and anchoring performance of kelp rhizomes may be significantly affected by the genetic factors of the species. Breeding new kelp varieties with high wind and wave resistance (including resistance to shedding and damage) is crucial to promoting the development of kelp aquaculture in offshore deep waters. The kelp algae is divided into three parts: rhizomes, petioles and leaves (see Figure 1 ), the leaves and petioles are relatively simple in shape, while the rhizomes in the growing period present a complex morphology of tangled roots (see Figure 2). The anti-falling ability of kelp mainly depends on the development of its rhizoids, anchoring performance, and the mechanical strength and flexibility of the rhizoids and stalks. In addition, the anchoring effect of the rhizoids on the seedling rope is not only related to the mechanical properties of the rhizoids themselves, but also closely related to the interaction force between the rhizoids and the seedling rope (such as friction resistance and root tip adhesion). The magnitude of this interaction force usually depends on the morphological characteristics of the rhizoids (such as configuration, root diameter, number of root tips, number of root branches and root surface area, etc.). The thickness of the stalk also has a significant effect on the characteristics of the root system. Thicker stalks usually produce primary rhizoids with larger diameters, and these thick primary branches will produce more branches, thereby increasing the probability of kelp attaching to the seedling rope.

[0005] At present, there is still a lack of research on the development and anchoring performance of cultured kelp rhizomes, as well as the measurement of their mechanical strength and flexibility. The lack of a systematic and scientific evaluation method to quantify the kelp's resistance to shedding has become one of the key technical bottlenecks restricting the breeding of high-quality kelp varieties that are resistant to wind and waves. Summary of the invention

[0006] The present invention aims at the problem that there is a lack of scientific and systematic evaluation method for the anti-shedding ability of kelp in the prior art, and provides an evaluation method and application of the anti-shedding ability of kelp. The method scientifically evaluates the anti-shedding ability of kelp by comprehensively analyzing the key morphological parameters of rhizoids and stalks (such as rhizoid fresh weight, number of root branches, number of root tips, stalk cross-sectional area, etc.) and mechanical parameters (such as maximum tensile force, tensile strength, elongation at break, elastic modulus, etc.) of kelp. Specifically, principal component analysis was first performed on the morphological and mechanical parameters, and the principal components that comprehensively reflected the characteristics of the rhizoid and petiole were extracted to obtain the morphological comprehensive score and mechanical comprehensive score, respectively; further combined with the seedling shedding situation of different kelp strains in the breeding experiment, a multivariate linear regression model was constructed, with the morphological comprehensive score and mechanical comprehensive score as independent variables, and the seedling survival rate as the dependent variable; the model coefficients were calculated through regression analysis to quantify the relative contribution weights of morphological and mechanical characteristics to the kelp's anti-shedding ability; finally, the comprehensive score of the anti-shedding ability of each kelp sample was calculated through the regression model, and different kelp strains were evaluated and ranked based on the score, providing a theoretical basis for the breeding of wind and wave resistant kelp varieties.

[0007] The present invention is achieved through the following technical solutions:

[0008] A method for evaluating the anti-shedding ability of kelp comprises the following steps: 1) sample collection and preparation: kelp samples are collected and divided into two groups of samples, and the kelp shedding conditions on the culture seedling rope are counted at the same time; 2) mechanical property test: a tensile load is applied to one group of samples until the samples break, and a stress-strain curve is obtained; 3) morphological feature detection: after another group of samples are softened in a low-density seawater culture solution, the rhizomes are unfolded into a plane shape, and their morphological features are measured and analyzed; 4) data analysis and model construction: principal component analysis is performed on mechanical and morphological feature parameters, and a multivariate regression model is constructed in combination with the survival rate of the culture seedling rope to quantify the relative contribution of morphological and mechanical features to the anti-shedding ability, and calculate the comprehensive score of the anti-shedding ability of kelp.

[0009] Furthermore, the step 1) sample collection and preparation; specifically, kelp samples are collected at the same growth stage, and each group of samples is divided into at least two groups; from one of the groups, the stalk and single rhizoid of the kelp are directly cut off, and they are used for tensile load experiments respectively; for the other group, the kelp algae with leaves removed and only rhizoids and stipes left and the attached seedling rope segments are cut, and the attached objects are removed for the morphological characteristics detection experiment of rhizoids and stipes; during the sampling period, at least 30 seedling ropes with kelp cultured are randomly taken from each group at the breeding site, and the kelp shedding on the breeding seedling ropes is counted, and the kelp that is completely missing or only has rhizoids and stipes left is regarded as shedding; according to the initial number of clamped seedlings, the kelp seedling shedding rate or seedling survival rate is calculated.

[0010] The step 2) mechanical property test; measuring the diameter of the stalk and single rhizoid of the kelp (the long diameter and short diameter of the elliptical cross-section need to be measured at the same time); wrapping the two ends of the sample with anti-slip material and fixing it on the clamp of the tensile testing machine, axially stretching it at a stretching rate of 20-40mm / min until it breaks, recording the changes in the tension F and elongation △L, and fitting to generate a stress-strain curve; calculating the tensile elastic modulus, maximum tensile force, elongation at break and tensile strength; the tensile strength calculation formula is: P = 4F max / πD 2 , where P is the tensile strength, F max is the maximum tensile strength, D is the diameter at the fracture; the specimens that broke at the clamp were considered invalid specimens. At least 30 valid specimens of rhizoids and stalks were required for each group of kelp, and there was no significant difference in specimen diameters between different groups.

[0011] The step 3) morphological feature detection is as follows: specifically, the sample is placed in a low-density seawater culture medium with a specific gravity of 1.025-1.027 and cultured for 3-5 days to soften the rhizoids, so that they are easy to separate and unfold from the seedling rope; the length and cross-sectional area of ​​the stalk are measured, and the number of primary roots is counted, and then the primary branches of the rhizoids and the stalk are separated one by one from each "root-stalk connection point"; the fresh weight of the rhizoids is weighed, the entangled roots are straightened and flattened, and then photographed or scanned; finally, the number of root branches, the number of root tips, the average root diameter, the total root length and the total root surface area are counted and analyzed; each group of experiments is repeated at least 30 times.

[0012] The step 4) data analysis and model building is as follows: (1) data sorting: sorting the average values ​​of each group of mechanical and morphological characteristic indicators into a matrix form, with sample numbers as rows and characteristic parameters as columns, to construct an analysis data matrix;

[0013] (2) Data standardization: The data matrix is ​​subjected to Z-score standardization to eliminate the dimensional differences between different feature parameters;

[0014] (3) Principal component analysis: Using the standardized data matrix, perform “dimensionality reduction-factor analysis-principal component analysis” in the statistical analysis software to determine the number of principal components and select the principal components with a cumulative variance explanation rate of more than 90%; calculate the weight of each indicator based on the variance explanation rate of the principal component; calculate the morphological comprehensive score (S) of each sample based on the principal component weight coefficient and the sample score. 形态 ) and mechanical comprehensive score (S 力学 );

[0015] (4) Regression model construction: The survival rate of different kelp strains in the actual aquaculture experiment was used as the dependent variable, S 形态 and S 力学 As independent variables, construct a multiple linear regression model:

[0016] Y 存苗 =β0+β1*S 形态 +β2*S 力学

[0017] The model coefficients were calculated through regression analysis to determine the relative contribution weights of morphological and mechanical characteristics to the anti-shedding ability of kelp; the comprehensive score of the anti-shedding ability of each variety was calculated based on the regression model.

[0018] The present invention also provides a method for breeding kelp varieties resistant to wind and waves based on the above-mentioned evaluation method. The evaluation method is used to evaluate the anti-shedding ability of different kelp strains, and they are ranked from high to low according to the comprehensive scores, and the top-ranked strain groups are selected as breeding parents, providing a scientific basis for the breeding of new kelp varieties resistant to wind and waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Overall morphology of kelp; 1. blade, 2. stalk, 3. root, 4. root-stalk connection point;

[0020] Figure 2 The morphology of kelp rhizomes on the culture rope;

[0021] Figure 3 This is a morphological diagram of the kelp stalk and its rhizoids attached to the kelp seedling rope;

[0022] Figure 4 This is a morphological diagram of kelp rhizoid branches, where the positions of the numbers 1-9 represent the positions of the 1st to 9th level root branches, respectively, and the end of the 9th level root branch is the root tip. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further explained below by examples, but the protection scope of the present invention is not limited in any form by the examples.

[0024] Example 1

[0025] 1. Sample collection and preparation

[0026] In mid-May, four kelp strains (A, B, C, and D) were collected from the high, middle, and low sea areas of Rongcheng Sea. 100 strains of each strain were collected from each sea area. The morphological characteristics of the kelp are as follows: Figure 1 As shown. Samples of the same strain in each sea area were grouped together. For example, samples of strain A in high, medium and low sea areas were named A-1, A-2 and A-3 respectively. Each group of samples was divided into two subgroups: the first subgroup directly cut off the stalk and single rhizoid of the kelp for tensile load test; the second subgroup cut off the kelp algae with only rhizoids and stipes removed from the leaves and the attached seedling rope segments, which were carefully rinsed with seawater to remove mud, algae and other attachments for the morphological characteristics detection experiment of rhizoids and stipes. During the sampling period, 30 culture seedling ropes were randomly selected for each kelp strain in each sea area, and the kelp shedding on the seedling ropes was counted. The kelp that was completely missing or only had rhizoids and stipes was considered to be shedding. According to the initial number of clamped seedlings, the kelp seedling shedding rate or seedling survival rate was calculated.

[0027] 2 Mechanical properties test

[0028] For the first group of kelp samples, the diameters of the cut stalks and single rhizomes were measured (the long diameter and short diameter of the elliptical cross-section need to be measured at the same time). The average diameter of the stalk samples ranged from 9.27 to 10.25 mm, and the average diameter of the single rhizomes ranged from 3.36 to 3.72 mm. Wrap both ends of the sample with double-layer gauze and fix it on the clamp of the tensile testing machine. You can choose any stretching rate from 20 to 40 mm / min for axial stretching. The stretching rate selected in this embodiment is 20 mm / min. Until it breaks, record the changes in the tension F and elongation △L, and fit to generate a stress-strain curve; calculate the tensile elastic modulus, maximum tensile force, elongation at break, and tensile strength. Among them, the elastic modulus reflects the strength of the elastic deformation ability. The smaller the value, the stronger the elastic deformation ability of the sample and the better the softness of the internal tissue. The tensile strength calculation formula is: P = 4F max / πD 2 Where P is the tensile strength (MPa), F max is the maximum tensile strength (N), and D is the diameter of the fracture (mm). The samples that broke at the fixture were considered invalid samples. In this example, 30 valid samples of rhizoids and stalks were obtained for each group of kelp samples, and there was no significant difference in sample diameter between different groups.

[0029] 3. Morphological feature detection

[0030] The sample was cultured in a low-density seawater culture medium with a specific gravity of 1.026 for 3 days to soften the rhizoids, making it easier to separate and unfold them from the seedling rope. After measuring the length and cross-sectional area of ​​the stalk (the long diameter and short diameter of the elliptical cross-section need to be measured at the same time), and counting the number of primary roots, the primary branches of the rhizoids and the stalks were separated one by one from each "root-stalk connection point". The fresh weight of the rhizoids was weighed, the entangled roots were straightened out and flattened, and a desktop scanner was used to obtain a high-definition two-dimensional image of them. The root configuration analysis software (RhizoVision Explorer) was used to analyze the images to obtain the morphological index values ​​of the kelp rhizoids, such as the number of root branches, the number of root tips, the average root diameter, the total root length, and the total root surface area. Figure 3 and Figure 4 In this embodiment, parallel measurement data of 30 valid samples of rhizoids were obtained for each group of kelp samples.

[0031] 4. Data Analysis and Model Building

[0032] 4.1 Mechanical characteristics

[0033] 4.1.1 Mechanical characteristic data preparation

[0034] The average values ​​of the mechanical characteristic indexes of each sample were organized into a matrix form, with sample numbers as rows and characteristic parameters as columns, as shown in Table 1;

[0035] Table 1 Mechanical characteristics data of kelp samples

[0036]

[0037] The greater the elongation at break, the greater the ductility that the algae can withstand when stretched, and the higher the flexibility; the greater the tensile strength and maximum tensile force, the higher the mechanical strength. The smaller the elastic modulus value, the easier it is for the sample to produce elastic deformation, and the higher the flexibility. For the subsequent calculation and ranking of the comprehensive score, the elastic modulus was adjusted to a negative value, and the results in Table 2 were obtained;

[0038] Table 2 Mechanical characteristics data of kelp samples after adjustment

[0039]

[0040]

[0041] .

[0042] 4.1.2 Data Standardization

[0043] The adjusted data is Z-score normalized to eliminate the dimensional differences between different feature parameters. The normalization method is to subtract the mean (μ j ), and then divided by its standard deviation (σ j ), so that the data are within the same dimension range and dimensionless units, the calculation formula is: Z ij =(X ij -μ j ) / σ j Among them, Z ij is the standardized data, X ij is the original data, μ j is the mean value of the jth characteristic parameter, σ j is the standard deviation of the jth characteristic parameter. The standardized data matrix is ​​shown in Table 3;

[0044] Table 3 Data matrix after standardization of mechanical characteristics test values ​​of kelp samples

[0045]

[0046] 4.1.3 Principal Component Analysis

[0047] Using the standardized data matrix, "dimensionality reduction-factor analysis-principal component analysis" was performed in the statistical analysis software to select the principal components with a cumulative variance explanation rate of more than 90%. This embodiment extracts three principal components of mechanical characteristic parameters, among which the variance explanation rates of principal component 1, principal component 2 and principal component 3 are 84.297%, 7.080% and 6.271%, respectively, and the cumulative variance explanation rate of these three principal components is 97.647%, as shown in Table 4. The weight coefficients (variance explanation rate / cumulative variance explanation rate 97.647%) of principal component 1, principal component 2 and principal component 3 calculated using the variance explanation rate values ​​are 86.328%, 7.250% and 6.422%, respectively, as shown in Table 5;

[0048] Table 4 Explanation of variance of mechanical characteristics of kelp samples

[0049] Element Variance explained (%) Cumulative variance explained (%) 1 84.297 84.297 2 7.080 91.376 3 6.271 97.647 4 1.563 99.210 5 0.790 100

[0050] Table 5 Weight coefficients of the principal components of mechanical characteristics of kelp samples

[0051] name Variance explained (%) Cumulative variance explained (%) Weight (%) Principal component 1 84.297 84.297 86.328 Principal component 2 7.080 91.376 7.250 Principal component 3 6.271 97.647 6.422 .

[0052] The principal component score and comprehensive score (Table 7) of the mechanical characteristics of each sample were calculated using the standardized data matrix (Table 3), the weight coefficient of the principal component (Table 5) and the component score coefficient matrix (Table 6), thereby calculating the comprehensive score of the mechanical characteristics of each strain (the average of the comprehensive scores of the three parallel samples).

[0053] Table 6 Principal component score coefficient matrix of mechanical characteristics of kelp samples

[0054] name Principal component 1 Principal component 2 Principal component 3 Maximum root tensile strength 0.216 0.62 0.986 Root tensile strength 0.225 -0.078 0.789 Root elongation at break 0.203 1.084 -1.114 Root elastic modulus -0.229 0.544 0.192 Handle elastic modulus -0.216 0.982 0.563

[0055] Table 7 Principal component scores, comprehensive scores and rankings of mechanical characteristics of kelp samples

[0056]

[0057]

[0058] 4.2 Morphological characteristics

[0059] 4.2.1 Morphological feature data preparation

[0060] The average values ​​of the morphological indices of the rhizoids and stalks of each sample were compiled into a matrix form, with the sample number as the row and the characteristic parameters as the column, as shown in Table 8;

[0061] Table 8 Morphological characteristics of kelp samples

[0062]

[0063] 4.2.2 Data Standardization

[0064] The adjusted data is Z-score normalized to eliminate the dimensional differences between different feature parameters. The normalization method is to subtract the mean (μ j ), and then divided by its standard deviation (σ j ), so that the data are within the same dimension range and dimensionless units, the calculation formula is: Z ij =(X ij -μ j ) / σ j Among them, Z ij is the standardized data, X ij is the original data, μ j is the mean value of the jth characteristic parameter, σ j is the standard deviation of the jth characteristic parameter. The standardized data matrix is ​​shown in Table 9;

[0065] Table 9 Data matrix after standardization of morphological characteristics of kelp samples

[0066]

[0067]

[0068] 4.2.3 Principal Component Analysis

[0069] Using the standardized data matrix, "dimensionality reduction-factor analysis-principal component analysis" was performed in the statistical analysis software to select the principal components with a cumulative variance explanation rate of more than 90%. This embodiment extracts three principal components of the sample morphological characteristics, among which the variance explanation rates of principal component 1, principal component 2 and principal component 3 are 70.273%, 13.884% and 7.508% respectively, and the cumulative variance explanation rate of these three principal components is 91.665%, as shown in Table 10. The weight coefficients (variance explanation rate / cumulative variance explanation rate 91.665%) of principal component 1, principal component 2 and principal component 3 calculated using the variance explanation rate values ​​are 76.663%, 15.147% and 8.190% respectively, as shown in Table 11;

[0070] Table 10 Variance explanation of morphological characteristics of kelp samples

[0071] Element Variance explained (%) Cumulative variance explained (%) 1 70.273 70.273 2 13.884 84.157 3 7.508 91.665 4 3.976 95.641 5 2.217 97.858 6 1.185 99.043 7 0.756 99.799 8 0.151 99.950 9 0.05 100

[0072] Table 11 Weight coefficients of principal components of morphological characteristics of kelp samples

[0073]

[0074]

[0075] The principal component score and comprehensive score (Table 13) of each sample's morphological characteristics were calculated using the standardized data matrix (Table 9), the weight coefficient of the principal component (Table 11), and the component score coefficient matrix (Table 12), thereby calculating the comprehensive score of the root stalk morphology of each strain (the average of the comprehensive scores of the three parallel samples);

[0076] Table 12 Principal component score coefficient matrix of kelp sample morphological characteristics

[0077] name Principal component 1 Principal component 2 Principal component 3 Fresh weight of rhizoid 0.138 -0.215 0.370 Number of primary roots 0.140 0.206 -0.320 Number of root branches 0.135 -0.287 -0.326 Number of root tips 0.105 -0.364 0.749 Average root diameter 0.111 0.501 0.057 Total root length 0.142 -0.290 -0.315 Total root surface area 0.139 -0.091 -0.552 Cross-sectional area of ​​handle 0.142 0.244 0.178 Handle length 0.134 0.306 0.365

[0078] Table 13 Principal component scores, comprehensive scores and rankings of morphological characteristics of kelp samples

[0079] Ranking Sample No. Comprehensive score Principal component 1 Principal component 2 Principal component 3 1 C-2 1.202 1.995 -0.966 -2.215 2 A-1 0.857 0.618 2.772 -0.456 3 C-1 0.554 0.568 0.104 1.263 4 A-2 0.429 0.610 -0.788 0.985 5 C-3 0.346 0.530 -0.926 0.978 6 A-3 0.195 0.096 0.401 0.745 7 D-1 0.053 0.015 0.008 0.491 8 D-3 0.045 0.033 -0.092 0.410 9 B-2 -0.603 -0.805 0.374 -0.528 10 D-2 -0.679 -0.802 -0.285 -0.251 11 B-1 -0.854 -1.074 0.100 -0.567 12 B-3 -1.545 -1.785 -0.702 -0.855 .

[0080] 4.3 Regression model construction

[0081] Based on the above analysis, the comprehensive scores of root stalk morphology and mechanical properties were obtained (respectively S 形态 and S 力学 The survival rate of different kelp strains in the actual aquaculture area (Y 存苗 ) See Table 14. 形态 and S 力学 is the independent variable, Y 存苗 As the dependent variable, construct a multiple linear regression model:

[0082] Y 存苗 =β0+β1*S 形态 +β2*S 力学 ;

[0083] Table 14 Root stalk morphology index (S 形态 ) and the comprehensive score of mechanical indicators (S 力学 ) and seedling survival rate (Y 存苗 )

[0084] serial number <![CDATA[S 形态 ]]> <![CDATA[S 力学 ]]> <![CDATA[Y 存苗 (%)]]> A-1 1.513 0.857 88.5 A-2 -0.271 0.429 75.7 A-3 0.344 0.195 78.4 B-1 -0.903 -0.854 64.2 B-2 -0.016 -0.603 71.3 B-3 -1.486 -1.545 61.5 C-1 0.135 0.554 80.2 C-2 1.203 1.202 86.1 C-3 0.740 0.346 82.6 D-1 -0.123 0.053 74.5 D-2 -0.834 -0.679 69.2 D-3 -0.304 0.045 70.8 .

[0085] The constant term (β0) is 75.25 through analysis, S 形态 The coefficient (β1) is 6.10, S 力学 The coefficient (β2) is 3.96. Then, the regression equation is:

[0086] Y 存苗 =75.25+6.10*S 形态 +3.96*S 力学

[0087] The goodness of fit is R2 =0.96, that is, the model can explain 96.4% of the variation in seedling survival rate, and the fitting effect is good.

[0088] According to the regression coefficient, the relative contribution weights of morphological and mechanical indicators to the seedling survival rate were calculated:

[0089] Form weight: W 形态 =|β1| / (|β1|+|β2|)=6.10 / (6.10+3.96)=0.61

[0090] Mechanical weight: W 力学 =|β2| / (|β1|+|β2|)=3.96 / (6.10+3.96)=0.39.

[0091] The results show that the weight of morphological characteristics is 61%, and the weight of mechanical characteristics is 39%. The score of each group of kelp's anti-shedding ability was calculated (see Table 15), thereby obtaining the comprehensive score (the average of the scores of the three groups of samples) and ranking (Table 16) of each kelp strain. The final analysis showed that the ranking of the anti-shedding ability of kelp leaves of different strains was: strain C> strain A> strain D> strain B. The deep-water aquaculture test verified that the kelp strain C had a significantly lower seedling shedding rate, which further confirmed that the evaluation results of this method have high reliability;

[0092] Table 15 S 形态 and S 力学 Calculate the anti-falling ability score of each group of samples

[0093] serial number <![CDATA[S 形态 ]]> <![CDATA[S 力学 ]]> Anti-fall ability score A-1 1.513 0.857 1.257 A-2 -0.271 0.429 0.002 A-3 0.344 0.195 0.286 B-1 -0.903 -0.854 -0.884 B-2 -0.016 -0.603 -0.245 B-3 -1.486 -1.545 -1.509 C-1 0.135 0.554 0.298 C-2 1.203 1.202 1.203 C-3 0.740 0.346 0.586 D-1 -0.123 0.053 -0.054 D-2 -0.834 -0.679 -0.774 D-3 -0.304 0.045 -0.168

[0094] Table 16 Comprehensive scores and rankings of kelp strains’ anti-shedding ability

[0095] Ranking serial number Comprehensive score of anti-falling ability 1 C 0.696 2 A 0.515 3 D -0.332 4 B -0.879 .

[0096] Based on the above results, strains with high comprehensive scores can be used for the breeding of wind and wave resistant varieties. For example, in this embodiment, strain C with the highest comprehensive score is selected as the breeding parent, and subsequent hybridization or breeding experiments are carried out in combination with its advantages in morphological characteristics and mechanical properties.

Claims

1. A method for evaluating the anti-shedding ability of kelp, characterized in that: The method comprises the following steps: 1) sample collection and preparation: collecting kelp samples and dividing them into at least two groups of samples, and at the same time counting the survival rate of seedlings on the culture seedling rope; 2) mechanical property test: applying a tensile load to one group of samples until the sample breaks, and obtaining a stress-strain curve; 3) morphological feature detection: counting and analyzing the number of root branches, the number of root tips, the average root diameter, the total root length and the total root surface area of ​​another group of samples; 4) data analysis and model construction: performing principal component analysis on mechanical and morphological feature parameters, and combining the survival rate of the culture seedling rope to construct a multivariate regression model, quantify the relative contribution of morphological and mechanical features to the anti-shedding ability, and calculate the comprehensive score of the anti-shedding ability of kelp.

2. The method for evaluating the anti-shedding ability of kelp according to claim 1, characterized in that: The step 1) sample collection and preparation is as follows: specifically, kelp samples at the same growth stage are collected, and each group of samples is divided into at least two groups; one of the groups is taken, and the stalk and single root of the kelp are directly cut off, and the stalk and single root are used for tensile load experiments respectively; the other group is taken, and the kelp algae and the seedling rope segments attached to it with only the rhizoids and stipes left after the leaves have been removed, and the attached objects are removed for the morphological characteristics detection experiment of the rhizoids and stipes; during the sampling period, at least 30 kelp culture seedling ropes are observed in each group, and the kelp seedling shedding rate or seedling survival rate on the culture seedling ropes is counted according to the initial number of seedlings clamped, and the algae that are completely missing or only have rhizoids and stipes left are regarded as falling off.

3. The evaluation method and application of the anti-shedding ability of kelp according to claim 1, characterized in that: The step 2) mechanical property test: measuring the diameter of the stem and the single root of the kelp; wrapping the stem and the two ends of the single root with anti-slip material, and fixing them on the clamp of the tensile testing machine, axially stretching at a stretching rate of 20-40mm / min until it breaks, recording the changes in the tension F and the elongation △L, and fitting to generate a stress-strain curve; calculating the tensile elastic modulus, maximum tensile force, elongation at break and tensile strength; the tensile strength calculation formula is: P = 4F max / πD 2 , where P is the tensile strength, F max is the maximum tensile strength, D is the diameter at the fracture; the specimens that broke at the clamp were considered invalid specimens. At least 30 valid specimens of rhizoids and stalks were required for each group of kelp, and there was no significant difference in specimen diameters between different groups.

4. The method for evaluating the anti-shedding ability of kelp and its application according to claim 1, characterized in that: The step 3) morphological feature detection is as follows: specifically, the culture rope sample with only kelp stalk and rhizoid is placed in a low-density seawater culture solution with a specific gravity of 1.025-1.027 for 3-5 days to soften the rhizoid and separate it from the seedling rope; the length and cross-sectional area of ​​the stalk are measured, and the number of primary roots is counted, and then the primary branches of the rhizoid and the stalk are separated one by one from each "root stalk connection point"; the fresh weight of the rhizoid is weighed, the entangled root system is straightened and flattened, and then photographed or scanned; finally, the number of root branches, the number of root tips, the average root diameter, the total root length and the total root surface area are counted and analyzed; each group of experiments is repeated at least 30 times.

5. The method for evaluating the anti-shedding ability of kelp and its application according to claim 1, characterized in that: The step 4) data analysis and model building is as follows: (1) data sorting: sorting the average values ​​of each group of mechanical and morphological characteristic indicators into a matrix form, with sample numbers as rows and characteristic parameters as columns, to construct an analysis data matrix; (2) Data standardization: Z-score standardization is performed on the data matrix to eliminate the dimensional differences between different feature parameters; (3) Principal component analysis: Using the standardized data matrix, perform "dimensionality reduction-factor analysis-principal component analysis" in the statistical analysis software to determine the number of principal components and select the principal components with a cumulative variance explanation rate of more than 90%; calculate the weight of each indicator based on the variance explanation rate of the principal component; calculate the morphological comprehensive score S of each sample based on the principal component weight coefficient and the sample score 形态 and mechanical comprehensive score S 力学 ; (4) Regression model construction: The survival rate of different kelp strains in the actual aquaculture experiment was used as the dependent variable, S 形态 and S 力学 As independent variables, construct a multiple linear regression model: Y 存苗 =β0+β1*S 形态 +β2*S 力学 The model coefficients were calculated through regression analysis to determine the relative contribution weights of morphological and mechanical characteristics to the anti-shedding ability of kelp; the comprehensive score of the anti-shedding ability of each variety was calculated based on the regression model.

6. A method for breeding kelp varieties resistant to wind and waves using the evaluation method described in any one of claims 1 to 5, characterized in that: The evaluation method is used to evaluate the anti-shedding ability of different kelp strains, and the strains are ranked from high to low according to the comprehensive scores, and the strain groups with high rankings are selected as breeding parents.

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