Methods for determining the photosynthetic rate and light response characteristics of plant organisms

Abstract

This invention discloses a method for measuring the light response characteristics of plant canopy photosynthetic rate. The method includes placing the plant population under test in an isolation container to maintain a stable CO2 concentration; adjusting the light intensity to a set value to induce light induction in the plant population; then performing closed-loop monitoring of the plant population's photosynthesis; plotting trend graphs of CO2 concentration changes over time under various light intensities and fitting trend lines; selecting several data points on the trend lines for differentiation; calculating the canopy photosynthetic rate; and plotting the light response curve of the canopy photosynthetic rate based on the canopy photosynthetic rate and the corresponding light intensity. This method for measuring the light response characteristics of plant canopy photosynthetic rate can accurately determine the relationship between plant canopy photosynthetic rate and light intensity. In plant variety breeding, measuring the light response curve of plant canopy photosynthetic rate can yield the canopy photosynthetic characteristics and light energy utilization efficiency of plants under different light intensities, which is beneficial for selecting high-light-efficiency crop germplasm resources or varieties.

Description

Technical Field

[0001] This invention relates to the field of photosynthesis technology, and in particular to a method for measuring the light response characteristics of photosynthetic rate in plant populations. Background Technology

[0002] The photosynthesis of a single plant or a group of plants is called canopy photosynthesis. The canopy photosynthetic rate measures the collective photosynthetic carbon assimilation capacity per unit area of ​​land or per unit area of ​​plant leaves. Compared to an individual leaf, the canopy photosynthetic rate more accurately reflects the photosynthetic capacity of a plant and has a more direct and significant regulatory effect on plant yield. While plant photosynthesis requires light, the relationship between canopy photosynthetic rate and light intensity requires further investigation. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a method for measuring the light response characteristics of plant canopy photosynthetic rate, so as to solve the technical problem of accurately measuring the relationship between plant canopy photosynthetic rate and light intensity.

[0004] The method for measuring the light response characteristics of plant canopy photosynthetic rate in this invention includes the following steps:

[0005] 1) Place the plant population in an isolated container with an artificial light source that simulates natural light;

[0006] 2) Introduce outside air into the isolation container while simultaneously expelling the gas inside the isolation container to the outside environment, thereby creating a stable intake and exhaust system within the isolation container. This will maintain stable CO2 concentration, temperature, and pressure within the isolation container, and record these parameters.

[0007] 3) Maintain stable air intake and exhaust in the isolation container as described in step 2, and adjust the light intensity of the artificial simulated natural light source to the set value to induce light in the plant community in the isolation container until the CO2 concentration in the isolation container tends to stabilize.

[0008] 4) Close the air intake and exhaust of the isolation container to form a sealed space; then conduct closed-loop circulation detection of the photosynthesis of the plant community in the isolation container for a period of time: use an air pump to extract the gas from the isolation container and send it into the photosynthesis detector, send the gas discharged from the photosynthesis detector back into the isolation container, and record the corresponding detection time points, CO2 concentration values, pressure and temperature in the isolation container during the detection process of the photosynthesis detector;

[0009] 5) Change the light intensity of the artificial simulated natural light source, and repeat steps 2) to 4);

[0010] 6) Based on the CO2 concentration and corresponding time obtained in step 4), plot the trend of CO2 concentration change over time under various light intensities, and fit the trend line of the CO2 concentration change under each light intensity.

[0011] 7) Select several data points on the fitted trend line and differentiate them to calculate the slope k of the trend line at the selected points. The absolute value of the slope k is the rate of decrease of CO2 per unit time.

[0012] 8) Import the slope k of the corresponding data points, the pressure inside the isolation container, the volume of the isolation container, and the plant area into the population photosynthesis calculation model to calculate the population photosynthetic rate; the plant area is the actual area occupied by the plant population or the sum of the areas of all leaves of the plant population;

[0013] 9) Plot the light response curve of the plant population photosynthetic rate based on the calculated population photosynthetic rate and the corresponding light intensity, thus obtaining the relationship between the plant population photosynthetic rate and light intensity.

[0014] Furthermore, the closed-loop detection time in step 4) is 40 to 60 seconds.

[0015] The beneficial effects of this invention are:

[0016] The present invention provides a method for measuring the light response characteristics of plant canopy photosynthetic rate, which can accurately measure the relationship between plant canopy photosynthetic rate and light intensity. In plant variety breeding, measuring the light response curve of plant canopy photosynthetic rate can yield the canopy photosynthetic characteristics and light energy utilization efficiency of plants under different light intensities, which is beneficial for breeding high light-efficiency crop germplasm resources or varieties. Attached Figure Description

[0017] Figure 1 This is a trend graph showing the change of CO2 concentration values ​​over time after the experiment was conducted according to the method described in the examples;

[0018] Figure 2 To Figure 1 A schematic diagram of taking the derivative of data points on the fitted trend line;

[0019] Figure 3 The graph shows the light response curve of the photosynthetic rate of a plant population. In the graph, PPFD represents photosynthetically active radiation, i.e., light intensity.

[0020] Figure 4 Light compensation and light saturation plots for the light response curves of photosynthetic rate in plant populations.

[0021] Figure 5 This is a light response curve of the photosynthetic light energy utilization efficiency of a plant community. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] The method for measuring the light response characteristics of plant canal photosynthetic rate in this embodiment includes the following steps:

[0024] 1) The plant population to be tested is placed in an isolation container equipped with an artificial simulated natural light source. The isolation container can be the detection box disclosed in the inventor's utility model patent application number 202120876723.3, entitled "Detection Box and Detection System for Gas Exchange of Plant Population under Artificial Simulated Natural Light"; of course, other forms of isolation containers can also be used in different embodiments.

[0025] 2) Introduce outside air into the isolation container while simultaneously expelling the gas inside the isolation container to the outside environment, thus creating a stable intake and exhaust system within the isolation container. This ensures that the CO2 concentration, temperature, and pressure inside the isolation container remain stable, and the CO2 concentration, temperature, and pressure inside the isolation container are recorded.

[0026] 3) Maintain stable air intake and exhaust in the isolation container as described in step 2, and adjust the light intensity of the artificial simulated natural light source to the set value to induce light in the plant community in the isolation container until the CO2 concentration in the isolation container tends to stabilize.

[0027] 4) Close the air intake and exhaust of the isolation container to create a sealed space. Then, perform a closed-loop circulation test on the photosynthesis of the plant population inside the isolation container for 40-60 seconds: use an air pump to extract the gas from the isolation container and send it into a photosynthesis detector, then return the gas discharged from the detector to the isolation container. During the detection process, record the corresponding detection time points, CO2 concentration values, pressure, and temperature inside the isolation container. Of course, in different embodiments, the closed-loop circulation test time can be adjusted as needed.

[0028] 5) Change the light intensity of the artificially simulated natural light source and repeat steps 2) to 4). In practice, the light intensity setting can be "medium light intensity - high light intensity - medium light intensity - low light intensity - darkness", such as: 50%, 70%, 90%, 50%, 30%, 15%, 0; or it can be "high light intensity - medium light intensity - low light intensity - darkness", such as: 90%, 70%, 50%, 30%, 15%, 0; and the measurements are performed sequentially according to the corresponding light intensities.

[0029] 6) Based on the CO2 concentration and corresponding time obtained in step 4), plot the trend of CO2 concentration change over time under various light intensities, and fit the trend line of the CO2 concentration change under each light intensity.

[0030] 7) Select several data points on the fitted trend line and differentiate them to calculate the slope k of the trend line at the selected points. The absolute value of the slope k is the rate of decrease of CO2 per unit time.

[0031] 8) Import the slope k of the corresponding data points, the pressure inside the isolation container, the volume of the isolation container, and the plant area into the population photosynthesis calculation model to calculate the population photosynthetic rate; the plant area is the actual area occupied by the plant population or the sum of the areas of all leaves of the plant population.

[0032] 9) Plot the light response curve of the plant population photosynthetic rate based on the calculated population photosynthetic rate and the corresponding light intensity, thus obtaining the relationship between the plant population photosynthetic rate and light intensity.

[0033] The light response curve of the canopy photosynthetic rate was measured according to the method described in the above embodiments. The specific results showed that as the light intensity increased, the plant canopy photosynthetic rate (CAP) exhibited a trend of "rapid increase - slow growth - gradual stabilization". Figure 3 As shown). By measuring the light response curve of the canopy photosynthetic rate, the light compensation point (light intensity at which the canopy photosynthetic rate is 0) and the light saturation point (light intensity at which the canopy photosynthetic rate no longer increases significantly with increasing light intensity) of canopy photosynthetic rate can be obtained. Figure 4 (As shown). In variety selection, plant varieties with low light compensation point and high maximum canopy photosynthetic rate are considered high light efficiency varieties.

[0034] Furthermore, based on the light response curve of the canopy photosynthetic rate, the canopy photosynthetic light energy utilization efficiency can be calculated, and the canopy photosynthetic light energy utilization efficiency light response curve can be fitted. Figure 5 As shown in the figure, this method is used to study the differences in photosynthetic light energy utilization efficiency among different plant populations, thereby enabling the selection of high-light-efficiency crops in variety breeding. In variety breeding, plant varieties with high population photosynthetic light energy utilization efficiency are considered high-light-efficiency varieties.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for determining the light response characteristics of the photosynthetic rate of a population of plants, characterised in that: The method comprises the following steps: 1) placing the plant population in an isolated container with artificial simulated natural light sources; 2) sending outside air into the isolated container while letting the gas in the isolated container be discharged to the outside environment, so that the isolated container forms stable air intake and discharge, the CO2 concentration, temperature and pressure in the isolated container are kept stable, and the CO2 concentration, temperature and pressure in the isolated container are recorded; 3) keeping the stable air intake and discharge of the isolated container as described in step 2, adjusting the light intensity of the artificial simulated natural light source to a set value to induce the plant population in the isolated container, until the CO2 concentration in the isolated container tends to be stable; 4) closing the air intake and discharge of the isolated container to form a closed space, and then detecting the closed-loop circulation of the photosynthesis of the plant population in the isolated container for a period of time: the gas in the isolated container is pumped out and sent into the photosynthesis detector, the gas discharged from the photosynthesis detector is sent back into the isolated container, and the corresponding detection time point, CO2 concentration value, pressure and temperature in the isolated container are recorded during the detection of the photosynthesis detector; 5) changing the light intensity of the artificial simulated natural light source, and repeating steps 2) to 4); 6) according to the CO2 concentration and the corresponding time obtained in step 4), drawing a trend graph of the change of CO2 concentration with time under various light intensities, and performing trend line fitting on the change part of CO2 concentration under each light intensity; 7) selecting several data points on the fitted trend line to derive, and calculating the slope k of the selected points, and the absolute value of the obtained slope k is the CO2 decline rate per unit time; 8) introducing the slope k of the corresponding data points, the pressure in the isolated container, the volume of the isolated container and the plant area into the population photosynthesis calculation model to calculate the population photosynthesis rate; the plant area is the actual occupied area of the plant population or the sum of the areas of all leaves of the plant population; 9) according to the calculated population photosynthesis rate and the corresponding light intensity, drawing the light response curve of the population photosynthesis rate, that is, obtaining the response relationship between the plant population photosynthesis rate and the light intensity.

2. The method of claim 1, wherein the method is performed on a population of plants. The closed-loop detection time in step 4) is 40-60 seconds.

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