CN111487291A - Method for efficiently evaluating cooling capacity required by peach blossom buds based on electronic nose detection technology - Google Patents

Abstract

The invention discloses a method for efficiently evaluating the cooling capacity of peach blossom buds based on an electronic nose detection technology. The method uses electronic nose detection technology and data analysis system to detect the odor of flower bud volatile substances in different stages of cold accumulation in the process of physiological dormancy and release of flower buds of peach cultivar resources with known cooling requirements in a certain climate region. Then use principal component and linear discriminant method for data analysis and differentiation, use partial least squares method for quantification, and use Euclidean distance and Mahalanobis distance clustering methods for clustering. This method can estimate the cooling requirements of flower buds and predict the stage of cooling accumulation for peach varieties with unknown cooling requirements. The results of the evaluation method for the cooling requirement of peach blossom buds are accurate, fast and efficient, and have high application value in the evaluation of the cooling requirement of peach in the future, and have great reference significance for the innovation of the evaluation method for the cooling requirement of other deciduous fruit trees or plants.

Description

An efficient method for evaluating the cooling requirement of peach blossom buds based on electronic nose detection technology

technical field

The invention relates to a method for efficiently evaluating the cooling capacity of peach blossom buds based on an electronic nose detection technology.

Background technique

Chilling requirement is an important agronomic trait of peach and other deciduous fruit trees, and it is a quantitative indicator of physiological dormancy and its release in low temperature environment. The cooling requirement is directly related to the success or failure of fruit tree cultivation and the distribution area. Therefore, the cooling requirement evaluation is an important prerequisite for the targeted selection of varieties with different cooling requirements and the optimal allocation of planting areas.

There are three existing methods for evaluating the cooling demand of peach and other deciduous fruit trees and plants at home and abroad. The first method is to conduct field observation statistics in a more general way. This method is applied to the establishment of cooling demand estimation models. It is hardly used in quantitative evaluation. The second is the artificial control experiment, that is, for 3 to 5 consecutive years, during the cold accumulation process, the branches are continuously collected, and the light, temperature and humidity are manually controlled for cultivation; in order to ensure the vitality of the branches during the cultivation process, every 3 ～5 days to replace the culture medium and prune new stubble, cultivate for 10 days, or up to 3 weeks; then carry out grading statistics based on flower bud weight or morphological changes, until the flower bud weight, or germination rate, or flowering number reaches a certain value or proportion. The collection time of the branches is sufficient to meet the cooling demand; then combined with the temperature statistics during the cold accumulation process, the cooling demand estimation model, such as 0-7.2℃, 7.2℃, Utah and dynamic models, is used to estimate the cooling demand; this method It is the most commonly used method all the time, but its defects are also very obvious, that is, harsh training conditions, complicated and cumbersome procedures, heavy workload, complicated statistics, too many environmental and human factors affecting the results in the evaluation process, and it is difficult to control. The third is the partial least squares regression analysis proposed in recent years based on long-term (at least 15 years) and reliable meteorological and phenological data to estimate cooling demand. This method requires strict basic data and requires at least 15 years of accurate and complete data The meteorological and phenological data are not suitable for new varieties without phenological records, and are rarely used. Therefore, the shortcomings of the existing evaluation methods greatly limit the process of cooling demand evaluation. Based on this, there is an urgent need to explore and establish technologies and methods to efficiently evaluate cooling demand.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for efficiently evaluating the cooling capacity of peach blossom buds based on the electronic nose detection technology.

The technical scheme adopted in the present invention is:

A method for efficiently evaluating the cooling capacity of peach blossom buds based on electronic nose detection technology, the steps of which include:

(1) Method establishment: Use several representative peach cultivars with known cooling requirements in the agroclimatic region to be tested ^[1,2] , and collect flower buds; collect flower buds at different cooling accumulation stages The odors of volatile substances were measured by electronic nose after being placed in a sealed container for a period of time; the odors of flower buds at each stage were analyzed and distinguished, and a quantitative model was established to establish the physiological dormancy and release of flower buds of peach variety resources. Corresponding relationship between the odor of volatile substances and the ratio of real-time cooling to required cooling during the process;

(2) Method application: odor detection of volatile substances is carried out on the flower buds in the physiological dormancy and release process of the peach variety resources with unknown cooling demand in the agroclimatic region at any cold accumulation period, using the established in step (1) Quantitative analysis was carried out with the quantitative model to estimate the ratio of real-time cooling capacity to cooling capacity during the cooling capacity accumulation period; according to the temperature data and the effective low temperature accumulation starting point date, the physiological dormancy of flower buds of peach variety resources with unknown cooling capacity and the corresponding cooling capacity during the release process were calculated. The real-time cooling capacity of any cooling capacity accumulation period; the calculation of the estimated cooling capacity, the formula is: estimated cooling capacity=real-time cooling capacity/the ratio of real-time cooling capacity to cooling capacity, that is, the peach variety resource with the unknown cooling capacity is obtained The estimated cooling demand.

In step (1), according to the ratio of real-time cooling to required cooling in the process of physiological dormancy and release of flower buds, several cold accumulation stages are set, and the odor of volatile substances in the process of physiological dormancy and release of flower buds of peach variety resources is established. Corresponding relationship between the ratio of real-time cooling capacity to required cooling capacity in different cooling capacity accumulation stages; in step (2), the quantitative model established in step (1) is also used for cluster analysis, and the real-time cooling capacity in this cooling capacity accumulation period is estimated. in the cold accumulation stage. Among them, the setting of the ratio in step (1) is to avoid the factor of large variation in the cooling capacity of peach varieties, and to achieve the purpose of unifying the cold accumulation stages of resources of different cold-demanding varieties.

Preferably, in step (2), cluster analysis is also performed using the quantitative model established in step (1) to estimate the cooling capacity accumulation stage of the real-time cooling capacity during the cooling capacity accumulation period.

Preferably, the representative peach variety resources with known cooling demand in step (1) are evaluated for 3 to 5 years, the cooling demand is relatively stable between years, and the standard deviation of the cooling demand in consecutive years is 10% on average. % of the variety resources below.

Preferably, the representative peach variety resources in step (1) at least cover the variety resources that require extremely short, short, medium and long cooling capacity, and the definition standard refers to "Peach Germplasm Resources Description Specifications and Data Standards" published by China Agricultural Press. Page 83 of the book.

Preferably, the real-time cooling capacity is the actual cooling capacity accumulated from the effective low temperature accumulation starting date to the sampling date after the leaves fall in autumn. The estimation model (such as 0-7.2°C model, 7.2°C model, Utah model, dynamic model, etc.)

Preferably, in step (1), the method for stage setting and flower bud collection time is as follows: the cooling requirement of each representative known peach variety resource is set as 1, and after the leaves fall in autumn, each variety is determined according to the flower bud physiological The ratio of the real-time cooling capacity to the required cooling capacity during the dormancy and release process is set in stages from small to large. The ratio ranges from 0 to 1.2. The number and density of the stages are random. According to the real-time cooling capacity, the real-time cooling capacity and the The ratio of the required cooling capacity, and the time when the ratio reaches each set ratio is determined as the flower bud collection time at each stage.

Preferably, when collecting flower buds at each stage, select the flower buds on the annual branches that have mixed buds or flower buds and the buds are full and full, and the whole tree is randomly collected.

Preferably, the sealed container is placed in an environment of 20 to 30° C., the period of time is 0.5 to 2 hours, and the temperature and time selected by the method in the same method are consistent.

Preferably, the electronic nose detects that the flow rate is 300-400ml/min, the time is 45-60s, and the stable signals at 3-10 time points are taken. The value of each sensor at the stable signal can comprehensively characterize the different cold accumulation stages of peach blossom buds. Odor of volatile substances.

The distinction described in the step (1) is to use the electronic nose data analysis system to carry out the import of the selected stable signal data in stages according to the ratio of the real-time cooling capacity and the cooling capacity of the different cooling capacity accumulation stages that are set, and carry out Principal component and discriminant analysis;

Described quantification is to use electronic nose data analysis system, assign the ratio of setting to the selected stable signal data of each cold energy accumulation stage respectively, use partial least squares method to establish quantitative model;

The clustering is to use the established partial least squares method to establish a quantitative model, and use the Euclidean distance and Mahalanobis distance clustering methods to perform cluster analysis;

The inference is to use the established quantitative model to calculate the ratio of the real-time cooling capacity to the cooling capacity of the flower bud samples at any cold accumulation period during the physiological dormancy and release process of the unknown cold-demanding variety resources and the cold accumulation stage. presumption.

Preferably, the units of the cooling demand, the real-time cooling demand, and the estimated cooling demand are the same, and depend on the cooling demand estimation model used.

The invention uses the electronic nose detection technology to correlate the smell of volatile substances in the process of physiological dormancy and release of flower buds with the actual cold energy accumulation value of flower buds, and establishes the process of volatile material smell and cold energy accumulation of flower buds in the process of physiological dormancy and release of flower buds The relationship between the ratio of real-time cooling capacity to cooling capacity at different stages in the middle of the year, this method can be used to determine the volatile substances of flower bud samples at any cold accumulation period during the process of one-time determination of physiological dormancy of flower buds of unknown cooling demand and release process. Smell, estimate the ratio of the actual cooling capacity accumulation value (real-time cooling capacity) of the sample to the cooling capacity, combine the real-time cooling capacity of the flower bud sample calculated by using the cooling capacity estimation model and air temperature data, and use the real-time cooling capacity In addition, the method can also estimate the stage of the actual cooling capacity, which achieves the purpose of efficiently and conveniently evaluating the cooling capacity of peach variety resources, and overcomes the In addition, the method established by the present invention is based on the odor of volatile substances in different accumulation stages of flower buds, that is, the physiological indicators in the process of physiological dormancy and release of flower buds as basic data, which overcomes the problem of The results of the existing methods are vulnerable to the defects of artificially controlled experimental conditions, multi-factors, inter-annual weather, etc. The invention innovatively adopts the odor detection based on the volatile substances of the flower buds in the process of physiological dormancy and release of peach flower buds, establishes the corresponding relationship between the odor and the accumulation of cold energy, and evaluates the cooling demand, and is applied in the evaluation of the cooling demand of peach. It has high value and is of great reference to the innovation of other deciduous fruit trees or plant cooling requirements evaluation methods.

Description of drawings

Figure 1 is the response diagram of the electronic nose sensor to volatile substances in peach blossom buds ('Xiahui No. 8' 20190109) (the abscissa is time, and the ordinate is the response value).

Figure 2 shows the principal component analysis of the odors of volatile substances in flower buds of nine known cold-demanding peach cultivars at different cold accumulation stages (the abscissa is the first principal component, and the ordinate is the second principal component).

Figure 3 is a linear discriminant analysis of the odors of volatile substances in flower buds of nine known cold-demanding peach varieties at different cold-accumulation stages (the abscissa is the first discriminant, and the ordinate is the second discriminant).

Figure 4 shows the quality judgment results of the partial least squares quantitative model of the odor of volatile substances in flower buds of 9 known cooling-demanding peach cultivars at different cooling-accumulation stages.

Figure 5 shows the results of the ratio of real-time cooling capacity to cooling capacity obtained from the quantitative model of the flower bud sample of peach cultivar resource with unknown cooling demand (‘Xinjiang Huangrou’ 20200123).

Figure 6 shows the results of the cold accumulation stage obtained from the Euclidean distance and Mahalanobis distance analysis of the flower bud sample of the peach variety resource with unknown cooling demand (‘Xinjiang Huangrou’ 20200123).

The present invention will be further described below in conjunction with specific embodiments.

Detailed ways

Example 1

The electronic nose adopted in this embodiment is the PEN3.5 electronic nose of German AIRSENSE company.

From 2018 to 2019, the resources of 9 peach varieties with known cooling demand in Nanjing area (the artificial control test method was used to continuously evaluate the cooling demand for 3 years in the early stage, and the cooling demand was relatively stable, ranging from 208±20 to 1040±55h). , covering very short, short, medium and long types) flower buds as materials, taken from the adult trees of the National Peach Resource Garden of Jiangsu Academy of Agricultural Sciences, and unified management in the field. The flower bud cooling requirement of each variety resource is defined as 1, and each variety resource is set to 5 stages according to the ratio of real-time cooling capacity to its respective cooling capacity, namely I (0), II (0.4), III ( 0.8), Ⅳ(1), and Ⅴ(1.2), according to the estimation model of 0～7.2℃ (this model is widely used and is more suitable for this agro-climatic region) to determine the starting time of cold accumulation, that is, the daily average temperature in autumn passes through stably. The date of 7.2°C is the starting point of effective low temperature accumulation (December 6, 2018). According to this starting point, combined with the temperature data, the real-time cooling capacity and the ratio of real-time cooling capacity to the cooling demand of each variety of resources are calculated. When the ratio of the amount to the cooling demand of each variety resource reaches the set ratio of each stage, namely 0, 0.4, 0.8, 1, 1.2, determine the flower bud collection date of each variety resource at each stage and collect flower buds at different stages. The name of each variety resource, the required cooling capacity, and the real-time cooling capacity and sampling time of flower buds at each stage are shown in Table 1. According to this table 1, flower buds were collected (repeated 3 times) for electronic nose detection. The detection flow rate was 300ml/min, and the time was 50s. The stable signal at 8 time points from 28s to 35s of each sample is divided according to the ratio of real-time cooling capacity and cooling capacity in different cooling capacity accumulation stages, namely 0, 0.4, 0.8, 1, and 1.2. Import the selected stable signal data in each stage, perform principal component and discriminant analysis, and can clearly distinguish each cooling accumulation stage as a better quantitative model, and assign the selected stable signal data to each cooling accumulation stage respectively. The set ratios, i.e. 0, 0.4, 0.8, 1, 1.2, establish a partial least squares quantitative model, and based on the F test and subsequent probability (P value) estimates, the model quality (Quality in Figure 5) is 100%, That is, it means that the P value is 1.0, and the quantitative model is judged to be a good model.

Table 1 The real-time cold amount and collection date of flower buds in different stages of cold accumulation of 9 known cold-demanding peach cultivars

Fig. 1 The electronic nose has an obvious response to the volatile substances in peach blossom buds, and the resistance ratio is lower at the beginning. As the volatile substances are enriched on the sensor surface, the sensor resistance ratio increases continuously, and finally tends to be flat, at 28- The 42s interval reaches a very stable state, and each sensor has a different response to the volatiles of peach blossom buds. W1S (methane), W1W (hydrogen sulfide), W2W (aromatic components, organic sulfides), and W5S (nitrogen oxides) have higher relative resistivity values than other sensors.

The principal component analysis in Fig. 2 shows that the discrimination value of peach blossom buds in different cold accumulation stages is above 0.998 (the discrimination value is shown in Table 2), and the contribution rates of the first and second principal components are 84.76% and 12.90%, respectively. The contribution rate of 97.66%, and the two principal components play a role in the differentiation of different accumulation stages of peach blossom buds.

Figure 3 shows the linear discriminant analysis. The total contribution rate of the two discriminants is 80.49%, and the contribution rates of discriminant one and discriminant two are 64.69% and 15.80%, respectively. With the increase of discriminant 1, the cumulative degree of cooling capacity of peach blossom buds also gradually increased, except that the third stage and the fourth and fifth stages (that is, the ratio of real-time cooling capacity to cooling capacity is 0.8 and 1 and 1.2) have extremely high Slightly crossed, stage I and stage II (that is, the ratio of real-time cooling capacity to cooling demand is 0 and 0.4, respectively) can be clearly distinguished from each other, and can be clearly distinguished from stages III, IV and V. The results indicated that the linear discriminant analysis could distinguish different stages of cold accumulation in the process of physiological dormancy and release of peach blossom buds.

Figure 4 shows the quality judgment results of the quantitative model established by the partial least squares method. Based on the F test and the subsequent probability (P value) estimation, the model quality (Quality in Figure 5) is 100%, which means that the P value is 1.0. A quantitative model is a good model.

Table 2 Discrimination value of flower bud coldness in different accumulation stages of peach cultivar resources

Application and verification: Collect 14 varieties of resources with unknown cooling requirements (in order to achieve the comprehensive and optimal verification effect of the above-established method based on the electronic nose detection technology to efficiently evaluate the cooling requirements of peach blossom buds, the shorter the general cooling requirements , the earlier the blooming period, the longer the required cooling, and the later the blooming period is. This example verifies that the blooming period of the selected variety resources varies greatly, and the blooming period covers the very early, early, middle, late and extremely late as much as possible. In 2019-2020, combined with the 0-7.2 ℃ cooling demand estimation model (this model is widely used and is more suitable for this agro-climatic region), using the above-established electronic nose-based The method of efficiently evaluating the cooling capacity of peach blossom buds with detection technology estimated the cooling capacity, and at the same time estimated the cooling capacity by using the existing manual control test, and compared the cooling capacity results obtained by the two methods. Collect flower bud samples (repeated 3 times) of flower buds in any cold accumulation period during the process of physiological dormancy and release for electronic nose detection, and use the method established above to detect volatile substances; the real-time cold amount in any cold accumulation period is 0 The starting point time of cold accumulation determined by the ～7.2℃ estimation model (November 27, 2019) is calculated based on the temperature data; the quantitative analysis is carried out using the method established above, and the ratio of real-time cold capacity to required cold capacity is calculated; finally According to the formula: estimated cooling demand = real-time cooling capacity/the ratio of real-time cooling capacity to cooling demand, the estimated cooling demand is obtained; finally, the estimated cooling demand is compared with the cooling demand estimated by the manual control test, and the results are shown in Table 3, utilizes the paired sample T test of SPSS statistical software to obtain that the estimated cooling demand obtained by the method established by the present invention is not significantly different from the estimated cooling demand obtained by the manual control test (significance level 0.05); Explain the method established by the present invention It is feasible to evaluate the cooling demand of unknown peach varieties. The two clustering methods estimated the cold accumulation stage of 23 samples in different sampling periods, among which 18 were consistent, and only 5 were different, indicating that the method established in the present invention can estimate the physiological dormancy and release process of flower buds. The stage of cold accumulation in any sample adds weight to the accuracy of the method. In addition, when the method established by the present invention is applied to the evaluation of the cooling capacity of an unknown peach variety resource, multiple evaluations can be made during the physiological dormancy and release process of flower buds, such as 'Jinling Huanglu', For 'Xiacui' and 'Xinjiang Huangrou', taking the mean value of each estimated cooling demand as the cooling demand evaluation result can achieve better evaluation results.

Table 3 Model validation results

references:

1. Qiu Baojian, Lu Qiyao. Agro-climatic zoning and its methods [M]. Science Press, 1987.

2. Qi Laifu. Agroclimatic regionalization methods at home and abroad [J]. Meteorological Science and Technology, 1980(02):34-37.

Claims (10)

1. a method for efficiently evaluating the cooling capacity of peach blossom buds based on electronic nose detection technology, the steps of which include: (1) Method establishment: Several representative peach cultivars with known cooling requirements in the agroclimatic region to be tested were used, and flower buds were collected; After being placed in a sealed container for a period of time, the odor of volatile substances was measured by electronic nose; the odor of flower buds at each stage was analyzed and distinguished, and a quantitative model was established, so as to establish the physiological dormancy of peach variety resources and volatile substances in the process of releasing flower buds Corresponding relationship between smell and the ratio of real-time cooling to required cooling; (2) Method application: odor detection of volatile substances is carried out on the flower buds in the physiological dormancy and release process of the peach variety resources with unknown cooling demand in the agroclimatic region at any cold accumulation period, using the established in step (1) Quantitative analysis was carried out with the quantitative model to estimate the ratio of real-time cooling capacity to cooling capacity during the cooling capacity accumulation period; according to the temperature data and the effective low temperature accumulation starting point date, the physiological dormancy of flower buds of peach variety resources with unknown cooling capacity and the corresponding cooling capacity during the release process were calculated. The real-time cooling capacity of any cooling capacity accumulation period; the calculation of the estimated cooling capacity, the formula is: estimated cooling capacity=real-time cooling capacity/the ratio of real-time cooling capacity to cooling capacity, that is, the peach variety resource with the unknown cooling capacity is obtained The estimated cooling demand. 2. the method for efficiently evaluating the cooling capacity of peach blossom buds based on electronic nose detection technology according to claim 1, is characterized in that: in step (1) according to the ratio of real-time cooling capacity accounting for cooling capacity in the physiological dormancy of flower buds and lifting process Set as several cold accumulation stages, and establish the corresponding relationship between the volatile matter odor in the process of physiological dormancy and release of flower buds of peach variety resources and the ratio of real-time cold capacity to cold capacity in different cold accumulation stages; step (2) ), the quantitative model established in step (1) is used to perform cluster analysis, and the real-time cooling capacity during the cooling capacity accumulation period is estimated to be in the cooling capacity accumulation stage. 3. the method for efficiently evaluating the cooling capacity of peach blossom buds based on the electronic nose detection technology according to claim 1 and 2, is characterized in that: in step (1), the representative peach variety resource of known cooling capacity is obtained through 3 to 5 years evaluation, the cooling demand is relatively stable between years, and the standard deviation of the cooling demand in consecutive years is less than 10% of the average. 4. the method for efficiently evaluating the cooling capacity of peach blossom buds based on electronic nose detection technology according to claim 1 and 2, is characterized in that: in step (1), the representative peach variety resource of known cooling capacity at least covers Variety resources that require extremely short, short, medium and long cooling capacity. 5. the method for efficiently evaluating the cooling capacity of peach blossom buds based on electronic nose detection technology according to claim 1 and 2, it is characterized in that: described real-time cooling capacity is after falling leaves in autumn, from the effective low temperature accumulation starting date, to The actual accumulated cooling value until the sampling date. 6. the method for efficiently evaluating the cooling capacity of peach blossom buds based on electronic nose detection technology according to claim 2, is characterized in that: the method of stage setting in step (1) is: by representative each known peach The cooling requirement of the variety resource is set as 1. After the leaves fall in autumn, each variety resource is set in stages according to the ratio of the real-time cooling capacity and the cooling capacity during the physiological dormancy and release process of flower buds from small to large. The value range of the ratio is From 0 to 1.2, the number and density of stages are random. According to the real-time cooling capacity, the ratio of real-time cooling capacity and required cooling capacity is calculated, and the time when the ratio reaches each set ratio is determined as the flower bud collection time of each stage. 7. the method for efficiently evaluating the cooling capacity of peach blossom buds based on electronic nose detection technology according to claim 6, it is characterized in that: when collecting flower buds at each stage, select the annual branches that have mixed buds or flower buds and the buds are full and full On the flower buds, the whole tree is randomly collected. 8. The method for efficiently evaluating the cooling capacity of peach blossom buds based on electronic nose detection technology according to claim 6, characterized in that: the sealed container is placed under the environment of 20～30 ℃, and the described period of time is 0.5～2h, and the same The temperature and time chosen in one method are consistent. 9. the method for efficiently evaluating the cooling capacity of peach blossom buds based on electronic nose detection technology according to claim 6, is characterized in that: described electronic nose detection flow rate is 300～400ml/min, time is 45～60s, takes 3～400ml/min The stable signal at 10 time points, the value of each sensor at the stable signal is a comprehensive characterization of the odor of volatile substances in flower buds of peach in different cold accumulation stages. 10. the method for efficiently evaluating the cooling capacity of peach blossom buds based on electronic nose detection technology according to claim 6, is characterized in that: the units of described cooling capacity, real-time cooling capacity, and estimated cooling capacity are consistent, and the cooling capacity used is the same as the required cooling capacity. quantity estimation model.

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