Method and system for predicting plant photosynthetic ability by using plant leaf traits

Abstract

The invention discloses a method and system for predicting plant photosynthetic ability by using plant leaf traits, and the method comprises the following steps: obtaining fresh weight, actual leaf area, specific leaf weight and relative water content of leaves, measuring leaf nitrogen content and leaf carbon content of the leaves, obtaining unit area leaf nitrogen content, unit area leaf carbon content and leaf carbon nitrogen ratio of the leaves, and determining the plant photosynthetic ability according to the unit area leaf nitrogen content, the unit area leaf carbon content and the leaf carbon nitrogen ratio of the leaves. And calculating the photosynthetic capability index of the plant to which the leaf belongs based on the obtained leaf character data and the prediction linear model of the leaf character photosynthetic capability parameter. By adopting the scheme, in-situ determination work does not need to be carried out in the field, the workload of technicians is greatly reduced, the working process and the operation difficulty of field operation are simplified, meanwhile, the measurement precision and the accuracy of a measurement result are considered, a large number of samples can be synchronously processed and determined, and the measurement efficiency is improved. The photosynthetic capacity parameters of various plants can be obtained in the same time period, and meanwhile, the dependence on the number of photosynthetic instruments in the photosynthetic in-situ determination process is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of plant photosynthetic capacity determination, and in particular relates to a method and system for predicting plant photosynthetic capacity by using plant leaf traits. Background Art

[0002] The maximum carbon assimilation rate, maximum carboxylation rate, maximum electron transfer rate and apparent quantum efficiency in the photosynthetic gas exchange parameters are all independent physiological indicators that characterize the photosynthetic capacity of plants. However, these core physiological indicators require the use of a photosynthetic instrument to measure the light response curve and the carbon dioxide response curve in situ (under plant growth conditions), and then calculate them through a photosynthetic model. In general, this method of direct measurement and calculation of photosynthetic capacity has relatively high labor and time costs, and exhibits obvious methodological disadvantages when evaluating the photosynthetic capacity of a large number of plant species. Therefore, it is necessary to establish a more convenient alternative method for obtaining plant photosynthetic capacity.

[0003] In the prior art, for example, the high-throughput determination method of rice leaf photosynthetic capacity disclosed in document CN115032179A measures the leaf photosynthetic capacity of rice tillers, achieving a measurement flux of multiple light response curves per hour on average. In addition, the linear model of chlorophyll fluorescence parameters and photosynthetic capacity parameters can be used to predict photosynthetic capacity parameters (such as document CN112561209A), but the determination of chlorophyll fluorescence parameters also requires in-situ measurement with the aid of a chlorophyll fluorescence instrument. In essence, this method still has great limitations in improving the benefits of photosynthetic capacity prediction.

[0004] More importantly, whether it is based on the traditional light response curve (AQ) and CO2 response curve (ACi), or other new measurement methods, at least the accuracy and convenience of the measurement results must be guaranteed before they can be promoted and applied. Therefore, how to measure in a low-cost, low-operation-difficulty, and convenient way while ensuring measurement accuracy is a problem that needs to be solved. Summary of the invention

[0005] At least in order to solve the technical problems mentioned in the background technology, the present invention aims to provide a method and system for predicting plant photosynthetic capacity by using plant leaf traits.

[0006] The present invention adopts the following technical solution.

[0007] A method for predicting plant photosynthetic capacity using plant leaf traits, comprising the following steps: Step 1, collecting leaves of the target plant and obtaining the fresh weight of the leaves; Step 2, taking a photo of the obtained leaf to obtain the actual leaf area of ​​the leaf; Step 3, obtaining the dry mass of the obtained leaves, which is defined as the leaf dry weight; obtaining the specific leaf weight of the obtained leaves, which is leaf specific weight = leaf dry weight / actual leaf area; Step 4, obtaining the relative water content of the obtained leaves, relative water content of leaves = (fresh weight of leaves - dry weight of leaves) / (saturated fresh weight of leaves - dry weight of leaves); Step 5, determining the leaf nitrogen content and leaf carbon content of the obtained leaves; Step 6, obtaining the leaf nitrogen content per unit area, the leaf carbon content per unit area and the leaf carbon-nitrogen ratio of the obtained leaves, the leaf nitrogen content per unit area=leaf nitrogen content*specific leaf weight, the leaf carbon content per unit area=leaf carbon content*specific leaf weight, the leaf carbon-nitrogen ratio=leaf carbon content / leaf nitrogen content; Step 7, based on the obtained leaf trait data and the prediction linear model of leaf trait photosynthetic capacity parameters, calculate the photosynthetic capacity index of the plant to which the leaf belongs, as shown in the following formula: Y=aX1+bX2+cX3+i Where X1 represents leaf nitrogen content, X2 represents leaf relative water content, X3 represents leaf carbon-nitrogen ratio, a, b, c represent regression coefficients, and i represents the intercept term.

[0008] As a preferred embodiment, the step of obtaining the dry mass of the leaves obtained in step 2 is: first, soak the collected fresh leaves in water for at least 3 hours in a light-proof environment to allow the fresh leaves to fully absorb water, remove the leaves and absorb the water attached to the surface of the leaves, and then weigh the wet weight of the leaves, that is, the saturated fresh weight of the leaves; finally, place the leaves in an environment of 80±2°C and dry them to constant weight, and finally weigh the dry mass of the leaves to obtain the dry weight of the leaves.

[0009] As a more preferred solution, during the leaf drying process, the leaves are always placed in a flame retardant paper bag, and a ventilation port or ventilation holes are provided on the flame retardant paper bag.

[0010] As a preferred embodiment, in step 5, an elemental analyzer is used to determine the leaf nitrogen content and leaf carbon content of the leaves.

[0011] The present invention also provides a system for measuring photosynthetic capacity of plants, comprising a memory, a processor, and a program stored in the memory and executable on the processor, wherein the processor implements the following steps when executing the program: S1, read the input leaf dry weight and actual leaf area, and calculate specific leaf weight = leaf dry weight / actual leaf area; S2, read the input leaf fresh weight and leaf saturated fresh weight, and calculate the leaf relative water content = (leaf fresh weight - leaf dry weight) / (leaf saturated fresh weight - leaf dry weight); S3, reading the input leaf nitrogen content and leaf carbon content, and calculating the leaf nitrogen content per unit area, the leaf carbon content per unit area and the leaf carbon-nitrogen ratio of the leaves, the leaf nitrogen content per unit area = leaf nitrogen content * specific leaf weight, the leaf carbon content per unit area = leaf carbon content * specific leaf weight, the leaf carbon-nitrogen ratio = leaf carbon content / leaf nitrogen content; S4, calculating the photosynthetic capacity index of the plant to which the leaf belongs based on the obtained leaf trait data and the prediction linear model of the leaf trait photosynthetic capacity parameter, as shown in the following formula: Y=aX1+bX2+cX3+i In the formula, X1 represents leaf nitrogen content, X2 represents leaf relative water content, X3 represents leaf carbon-nitrogen ratio, a, b, c represent regression coefficients, and i represents the intercept term; S5, output the calculation results.

[0012] Beneficial effects: By adopting the scheme of the present invention, there is no need to carry out in-situ measurement work in the field, and the single operation time of technicians in the field is shortened to less than one hour, which greatly reduces the workload of technicians, simplifies the workflow and operation difficulty of field operations, and takes into account the measurement accuracy and accuracy of the measurement results; the measurement operation process is simple, which significantly reduces the technical threshold and implementation (measurement) cost of obtaining photosynthetic capacity parameters, and can simultaneously process and measure a large number of samples, and can achieve the acquisition of photosynthetic capacity parameters of multiple plants in the same time period, while avoiding the dependence on the number of photosynthetic instruments during the photosynthetic in-situ measurement process; it is also convenient to predict the photosynthetic capacity of plants with different life forms (shrubs, shrubs) and leaf habits (evergreen, deciduous), and has good predictability for the photosynthetic capacity parameters of each type of plant, which expands the application scenarios of the technology of the present invention and is convenient for popularization and application. DETAILED DESCRIPTION

[0013] The technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0014] A method for predicting plant photosynthetic capacity using plant leaf traits, comprising the following steps: Step 1, collecting leaves of target plants (26 woody plants planted in Tongluo Mountain, Yubei District, Chongqing), generally collecting 10 to 20 leaves from each plant, and obtaining the fresh weight of each leaf (i.e., leaf fresh weight); Step 2, laying the leaves flat on background paper, taking photos of the leaves, and using Image J software to obtain the actual leaf area of ​​these leaves; Step 3, obtaining the dry mass of the obtained leaves, that is, the dry weight of the leaves; obtaining the specific leaf weight of the obtained leaves, specific leaf weight = dry weight of the leaves / actual leaf area; The specific steps for obtaining the dry weight of the leaves are as follows: first, soak the collected fresh leaves (fresh leaves after taking photos) in water for 5 hours in a light-proof environment to allow the fresh leaves to fully absorb water, remove the leaves and use absorbent paper to absorb the water attached to the surface of the leaves, then put the leaves into a flame-retardant paper bag (the flame-retardant paper bag is provided with a vent or vent hole) and weigh the wet weight, i.e., the saturated fresh weight of the leaves; finally, place the leaves in an environment of 80±2°C (oven) and dry them to constant weight, and finally weigh the dry weight of the leaves to obtain the dry weight of the leaves; Step 4, obtaining the relative water content of the obtained leaves, relative water content of leaves = (fresh weight of leaves - dry weight of leaves) / (saturated fresh weight of leaves - dry weight of leaves); Step 5, using an element analyzer to determine the leaf nitrogen content and leaf carbon content of the obtained leaves; Step 6, obtaining the leaf nitrogen content per unit area, the leaf carbon content per unit area and the leaf carbon-nitrogen ratio of the obtained leaves, the leaf nitrogen content per unit area=leaf nitrogen content*specific leaf weight, the leaf carbon content per unit area=leaf carbon content*specific leaf weight, the leaf carbon-nitrogen ratio=leaf carbon content / leaf nitrogen content; Step 7, based on the obtained leaf trait data and the prediction linear model of leaf trait photosynthetic capacity parameters, calculate the photosynthetic capacity index of the plant to which the leaf belongs, as shown in the following formula: Y=aX1+bX2+cX3+i Where X1 represents leaf nitrogen content, X2 represents leaf relative water content, X3 represents leaf carbon-nitrogen ratio, a, b, c represent regression coefficients, and i represents the intercept term.

[0015] In this embodiment, according to the aforementioned method and the obtained data such as leaf fresh weight, actual leaf area, leaf dry weight, relative water content of leaves, etc., a multiple linear regression model of photosynthetic capacity parameters based on leaf nitrogen content per unit area, leaf relative water content and leaf carbon-nitrogen ratio was determined in combination with 26 plant categories, as shown in Table 1. Table 1 Multiple linear regression models of photosynthetic capacity parameters based on leaf nitrogen content per unit area, leaf relative water content and leaf carbon-nitrogen ratio

[0016] After determining the predicted plant species, the optimal prediction model parameters were selected according to the vegetation types provided in Table 1 for prediction. The results are shown in Table 2. Table 2 Photosynthetic capacity index of the plant to which the leaves belong

[0017] Compared with the measured values ​​of existing plant photosynthetic capacity indicators, the above prediction results are all within the allowable deviation range and meet the relevant technical requirements. Example 2

[0018] This embodiment provides a system for measuring photosynthetic capacity of plants, including a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, the following steps are implemented: S1, read the input leaf dry weight and actual leaf area, and calculate the specific leaf weight = leaf dry weight / actual leaf area; wherein, the actual leaf area of ​​the leaf is obtained using Image J software; The specific steps for obtaining the dry weight of the obtained leaves are: first, soak the collected fresh leaves (fresh leaves after taking photos) in water for 5 hours in a light-proof environment to allow the fresh leaves to fully absorb water, remove the leaves and use absorbent paper to absorb the water attached to the surface of the leaves, then put the leaves into a flame-retardant paper bag (the flame-retardant paper bag is provided with a vent or vent hole) and weigh the wet weight, i.e., the saturated fresh weight of the leaves; finally, place the leaves in an environment of 80±2°C (oven) and dry them to constant weight, and finally weigh the dry mass of the leaves, i.e., the dry weight of the leaves; S2, read the input leaf fresh weight and leaf saturated fresh weight, and calculate the leaf relative water content = (leaf fresh weight - leaf dry weight) / (leaf saturated fresh weight - leaf dry weight); S3, reading the input leaf nitrogen content and leaf carbon content, and calculating the leaf nitrogen content per unit area, the leaf carbon content per unit area and the leaf carbon-nitrogen ratio of the leaves, the leaf nitrogen content per unit area = leaf nitrogen content * specific leaf weight, the leaf carbon content per unit area = leaf carbon content * specific leaf weight, the leaf carbon-nitrogen ratio = leaf carbon content / leaf nitrogen content; S4, calculating the photosynthetic capacity index of the plant to which the leaf belongs based on the obtained leaf trait data and the prediction linear model of the leaf trait photosynthetic capacity parameter, as shown in the following formula: Y=aX1+bX2+cX3+i In the formula, X1 represents leaf nitrogen content, X2 represents leaf relative water content, X3 represents leaf carbon-nitrogen ratio, a, b, c represent regression coefficients, and i represents the intercept term; S5, output the calculation results.

Claims

1. A method for predicting plant photosynthetic capacity using plant leaf traits, characterized in that the steps include: Step 1, collecting leaves of the target plant and obtaining the fresh weight of the leaves; Step 2, taking a photo of the obtained leaf to obtain the actual leaf area of ​​the leaf; Step 3, obtaining the dry mass of the obtained leaves, which is defined as the leaf dry weight; obtaining the specific leaf weight of the obtained leaves, which is specific leaf weight = leaf dry weight / actual leaf area; Step 4, obtaining the relative water content of the obtained leaves, relative water content of leaves=(fresh weight of leaves-dry weight of leaves) / (saturated fresh weight of leaves-dry weight of leaves); Step 5, determining the leaf nitrogen content and leaf carbon content of the obtained leaves; Step 6, obtaining the leaf nitrogen content per unit area, the leaf carbon content per unit area and the leaf carbon-nitrogen ratio of the obtained leaves, the leaf nitrogen content per unit area = leaf nitrogen content * specific leaf weight, the leaf carbon content per unit area = leaf carbon content * specific leaf weight, the leaf carbon-nitrogen ratio = leaf carbon content / leaf nitrogen content; Step 7, based on the obtained leaf trait data and the prediction linear model of leaf trait photosynthetic capacity parameters, calculate the photosynthetic capacity index of the plant to which the leaf belongs, as shown in the following formula: Y=aX1+bX2+cX3+i Where X1 represents leaf nitrogen content, X2 represents leaf relative water content, X3 represents leaf carbon-nitrogen ratio, a, b, c represent regression coefficients, and i represents the intercept term.

2. The method for predicting plant photosynthetic capacity according to claim 1, characterized in that: The step of obtaining the dry mass of the leaves obtained in step 2 is: first, soak the collected fresh leaves in water for at least 3 hours in a light-proof environment to allow the fresh leaves to fully absorb water, remove the leaves and absorb the water attached to the surface of the leaves, and then weigh the wet weight of the leaves, that is, the saturated fresh weight of the leaves; finally, place the leaves in an environment of 80±2°C and dry them to constant weight, and finally weigh the dry mass of the leaves to obtain the dry weight of the leaves.

3. The method for predicting plant photosynthetic capacity according to claim 2, characterized in that: During the leaf drying process, the leaves are always placed in a flame retardant paper bag, which is provided with ventilation openings or holes.

4. The method for predicting plant photosynthetic capacity according to claim 2, characterized in that: In step 5, an elemental analyzer is used to determine the leaf nitrogen content and leaf carbon content of the leaves.

5. A system for measuring photosynthetic capacity of plants, comprising a memory, a processor, and a program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the following steps are implemented: S1, read the input leaf dry weight and actual leaf area, and calculate specific leaf weight = leaf dry weight / actual leaf area; S2, read the input leaf fresh weight, relative water content, and leaf saturated fresh weight, and calculate the leaf relative water content = (leaf fresh weight - leaf dry weight) / (leaf saturated fresh weight - leaf dry weight); S3, read the input leaf nitrogen content and leaf carbon content, and calculate the leaf nitrogen content per unit area, leaf carbon content per unit area and leaf carbon-nitrogen ratio of the leaves, leaf nitrogen content per unit area = leaf nitrogen content*leaf weight, leaf carbon content per unit area = leaf carbon content*leaf weight, leaf carbon-nitrogen ratio = leaf carbon content / leaf nitrogen content; S4, based on the leaf trait data obtained and The linear model for predicting the photosynthetic capacity parameters of leaf traits is used to calculate the plant to which the leaf belongs. The photosynthetic capacity index is as follows: Y=aX1+bX2+cX3+i In the formula, X1 represents the leaf nitrogen content, X2 represents the leaf relative water content, X3 represents the leaf carbon-nitrogen ratio, a, b, and c represent the regression coefficients. Number, i represents the intercept term; S5, output the calculation results.

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