A seed germination radicle stress detection device and method based on polarized light principle

Abstract

This invention discloses a seed germination radicle stress detection device and method based on the principle of polarized light. The seed germination radicle stress detection device includes a culture module, a polarized light imaging system, an adjustment and driving mechanism, and a data processing unit. The culture module includes a transparent culture chamber and a seed fixing support set inside the transparent culture chamber. The advantages of this invention are: utilizing the birefringence effect generated by light passing through the radicle sheath, continuous observation of the entire process from the initial germination to radicle breakthrough can be achieved without contacting or damaging the sample; by acquiring images through a multi-angle rotating analyzer and combining it with a phase delay algorithm, weak birefringence signals can be effectively extracted, realizing quantitative calculation and visualization of stress; the core components are general-purpose optical elements and imaging modules, with a simple structure, controllable cost, and easy to popularize in agricultural research and teaching.

Description

Technical Field

[0001] This invention relates to the field of optical testing equipment technology, specifically to a seed germination radicle stress detection device based on the principle of polarized light. Background Technology

[0002] The stress experienced by the radicle breaking through the radicle sheath during seed germination is a key indicator for assessing seed vigor and stress resistance. However, current measurement methods mainly include micro-force sensor measurements and destructive mechanical testing, which have significant drawbacks, such as: Firstly, destructive sampling: usually requires peeling off the radicle sheath or cutting the radicle, making it impossible to monitor the complete growth process in real time while the organism is alive; Secondly, the cost is high and the operation is complicated: precision mechanical sensors are expensive and require operation in a professional laboratory environment, making them difficult to popularize in field or teaching scenarios; Third, there is a lack of visual distribution information: traditional point measurements cannot reflect the overall stress distribution on the surface of the embryonic root sheath.

[0003] While existing optical detection technologies (such as laser speckle) can achieve non-contact measurement, they have low sensitivity to semi-transparent biological tissues such as seed radicles and root sheaths, and the devices are complex.

[0004] Therefore, to address the aforementioned technical problems, it is necessary to provide a seed germination radicle stress detection device based on the principle of polarized light. Summary of the Invention

[0005] To address the shortcomings of the existing technologies, the present invention aims to provide a seed germination radicle stress detection device based on the principle of polarized light, thereby solving the problems of destructiveness, high cost, complex operation, and insufficient sensitivity to transparent tissues in seed germination stress detection technology.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: This invention provides a seed germination radicle stress detection device based on the principle of polarized light, comprising a culture module, a polarized light imaging system, an adjustment and drive mechanism, and a data processing unit. The culture module includes a transparent culture chamber and a seed fixing support disposed within the transparent culture chamber. The transparent culture chamber is used to contain the seed to be tested and an optically isotropic culture substrate to eliminate the interference of matrix birefringence on the measurement. The polarized light imaging system is arranged sequentially along the optical path direction, including a light source assembly, a polarizer, the transparent culture chamber, an analyzer, and an imaging unit. The light emitted by the light source assembly is converted into polarized light by the polarizer and passes through the transparent culture chamber. The light carrying the birefringence information of the seed to be tested is projected onto the imaging unit by the analyzer. The adjustment and drive mechanism is connected to the analyzer and is used to drive the analyzer to rotate around the optical axis to a preset angle. The data processing unit is electrically connected to both the imaging unit and the adjustment and drive mechanism, and is used to control the action of the adjustment and drive mechanism, receive image data collected by the imaging unit, and perform stress calculation.

[0007] In one or more embodiments of the present invention, an angle adjustment mechanism is connected to the seed fixing bracket. The angle adjustment mechanism is used to adjust the three-dimensional angle of the seed to be tested relative to the optical axis so that the radicle sheath region of the seed to be tested is perpendicular to the optical path.

[0008] In one or more embodiments of the present invention, an environmental monitoring sensor is also provided inside the transparent culture chamber. The environmental monitoring sensor is connected to a data processing unit and is used to monitor the temperature and humidity data inside the chamber in real time. The environmental monitoring sensor can simulate and monitor the soil microenvironment to ensure the stability of seed germination conditions.

[0009] In one or more embodiments of the present invention, the light source assembly is a brightness-adjustable white LED array; a narrow-band filter is also provided between the imaging unit and the analyzer, the narrow-band filter being used to extract light of a specific wavelength to reduce the interference of dispersion on birefringence measurement.

[0010] A method for detecting radicle stress during seed germination includes the following steps: S1. Fix the seeds to be tested in a transparent culture chamber and cover the radicle sheath of the seeds with culture medium; S2. Control the adjustment drive mechanism to drive the analyzer to rotate sequentially to multiple preset polarization angles; S3. At each preset polarization angle, the imaging unit synchronously acquires the light intensity image transmitted through the analyzer; S4. The data processing unit calculates the phase delay of pixels in the image based on the multi-angle light intensity images; S5. Based on the preset stress-optics law, the phase delay is converted into a stress value, and a stress distribution map of the seed germination process is generated.

[0011] In one or more embodiments of the present invention, the preset polarization angle in step S2.

[0012] In one or more embodiments of the present invention, the formula for calculating the phase delay δ in step S4 is as follows: ,in, These correspond to the light intensity values ​​at different polarization angles.

[0013] In one or more embodiments of the present invention, the formula for converting the phase delay into a stress value in step S5 is as follows: ,in, This is the stress value. The stress optical coefficient of the root sheath material. The equivalent thickness of light passing through the radicle sheath.

[0014] The beneficial effects of this invention are as follows: 1. Utilizing the birefringence effect produced by light passing through the radicle sheath, continuous observation of the entire process from the initial germination to radicle breakthrough can be achieved without contacting or damaging the sample. 2. By acquiring images through a multi-angle rotating analyzer and combining it with a phase delay algorithm, weak birefringence signals can be effectively extracted, enabling quantitative calculation and visualization of stress. 3. The core components are general-purpose optical elements and imaging modules, which are simple in structure, controllable in cost, and easy to popularize in agricultural scientific research and teaching. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a logic flowchart of a seed germination radicle stress detection device based on the principle of polarized light in one embodiment of the present invention; Figure 2 This is a flowchart of a seed germination radicle stress detection method based on the principle of polarized light in one embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures: 100. Cultivation module; 101. Transparent cultivation chamber; 102. Seed fixing bracket; 103. Angle adjustment mechanism; 104. Environmental monitoring sensor; 200. Polarized light imaging system; 201. Light source assembly; 202. Polarizer; 203. Analyzer; 204. Imaging unit; 205. Narrow band filter; 300. Adjustment drive mechanism; 400. Data processing unit. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] like Figure 1 and 2 As shown, a seed germination radicle stress detection device based on the principle of polarized light in one embodiment of the present invention includes a culture module 100, a polarized light imaging system 200, an adjustment drive mechanism 300, and a data processing unit 400.

[0020] The cultivation module 100 includes a transparent cultivation chamber 101 and a seed fixing bracket 102 disposed within the transparent cultivation chamber 101. The transparent cultivation chamber 101 is used to contain the seeds to be tested and the culture medium. The transparent cultivation chamber 101 is made of a material with a light transmittance ≥90%. In this embodiment, optically isotropic polyacrylamide hydrogel is used as the culture medium, with a birefringence of less than 0.001 nm / cm, ensuring that it does not interfere with the measurement of radicle sheath stress. An angle adjustment mechanism 103 is connected to the seed fixing bracket 102. The angle adjustment mechanism 103 adopts a screw adjustment structure or a ball head adjustment structure to adjust the three-dimensional angle of the seed to be tested relative to the optical axis, ensuring that the radicle sheath region is perpendicular to the optical path. An environmental monitoring sensor 104 is also installed inside the transparent cultivation chamber 101. The environmental monitoring sensor 104 is connected to the data processing unit 400 to monitor the temperature and humidity data in the chamber in real time (accuracy up to ±2%RH) to ensure the uniformity of the seed germination environment.

[0021] The polarized light imaging system 200 comprises, sequentially along the optical path, a light source assembly 201, a polarizer 202, a transparent culture chamber 101, an analyzer 203, and an imaging unit 204. The light source assembly 201 uses a brightness-adjustable white LED array with a color temperature of 5500K. The polarizer 202 is a linear polarizer with a high extinction ratio (>300:1). The light emitted from the light source assembly 201 is converted into polarized light by the polarizer 202 and passes through the transparent culture chamber 101. Due to the photoelastic effect of the seed radicle sheath, birefringence occurs, and the light carrying the stress information of the seed being measured is projected onto the imaging unit 204 via the analyzer 203. The imaging unit 204 is a CMOS camera, and a narrowband filter 205 with a center wavelength of 550nm is also disposed between it and the analyzer 203.

[0022] The adjustment drive mechanism 300 is connected to the analyzer 203 and is used to drive the analyzer 203 to rotate around the optical axis to a preset angle. The adjustment drive mechanism 300 includes a stepper motor and transmission gears, with a control accuracy of ≤0.5°. The data processing unit 400 is electrically connected to the imaging unit 204, the adjustment drive mechanism 300, and the environmental monitoring sensor 104. The data processing unit 400 includes a microcontroller and a wireless transmission module, used to control the light source switch, the rotation of the adjustment drive mechanism 300, and to receive image data collected by the imaging unit 204 for stress calculation (including correcting the stress optical coefficient and equivalent thickness based on environmental parameters).

[0023] Before conducting live specimen testing, the system needs to pre-calibrate the stress optical coefficient. An detached radicle sheath sample of the same species is taken, and a known stress (range 0-50 kPa) is applied using a miniature tensile tester under constant temperature and humidity (e.g., 25°C, 80% RH). Simultaneously, the phase retardation is measured using this device, and the stress optical coefficient value for the species at a specific moisture content is obtained through linear fitting. A humidity relationship database is then constructed. During live specimen testing, the data processing unit uses real-time humidity data from the environmental monitoring sensor 104 to interpolate from the database to obtain the stress optical coefficient value at the current specific moisture content.

[0024] Wherein, the phase delay is The stress optical coefficient at a specific moisture content is _____. Humidity relation database is -

[0025] A method for detecting radicle stress during seed germination includes the following steps: S1. Fix the seed to be tested in the transparent culture chamber 101 and cover the radicle sheath of the seed with culture medium; S2. Control the adjustment drive mechanism 300 to drive the polarizer 203 to rotate sequentially to multiple preset polarization angles; S3. At each preset polarization angle, the imaging unit 204 synchronously acquires the light intensity image transmitted through the analyzer 203; S4. The data processing unit 400 calculates the phase delay of pixels in the image based on the light intensity images from multiple angles; S5. Based on the preset stress-optics law, the phase delay is converted into a stress value, and a stress distribution map of the seed germination process is generated.

[0026] Specifically, the preset polarization angle in step S2; and the formula for calculating the phase delay δ in step S4 are as follows: .

[0027] in, The corresponding light intensity values ​​are at different polarization angles; the formula for converting the phase retardation into stress value in step S5 is as follows: .

[0028] in, This is the stress value. The stress optical coefficient of the root sheath material. The equivalent thickness of light passing through the radicle sheath.

[0029] Obviously, the above-described embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A seed germination radicle stress detection device based on the principle of polarized light, characterized in that, include: The culture module (100) includes a transparent culture chamber (101) and a seed fixing bracket (102) disposed in the transparent culture chamber (101). The transparent culture chamber (101) is used to contain the seeds to be tested and the optically isotropic culture substrate to eliminate the interference of matrix birefringence on the measurement. A polarized light imaging system (200) is provided with a light source assembly (201), a polarizer (202), a transparent culture chamber (101), an analyzer (203), and an imaging unit (204) arranged sequentially along the optical path. The light emitted by the light source assembly (201) is converted into polarized light by the polarizer (202) and passes through the transparent culture chamber (101). The light carrying the birefringence information of the seed to be tested is projected onto the imaging unit (204) by the analyzer (203). An adjustment drive mechanism (300) is connected to an analyzer (203) and is used to drive the analyzer (203) to rotate around the optical axis to a preset angle. The data processing unit (400) is electrically connected to the imaging unit (204) and the adjustment drive mechanism (300) respectively, and is used to control the action of the adjustment drive mechanism (300), receive image data collected by the imaging unit (204) and perform stress calculation.

2. The apparatus for detecting the radicle stress of seed germination based on the principle of polarized light according to claim 1, wherein, An angle adjustment mechanism (103) is connected to the seed fixing bracket (102). The angle adjustment mechanism (103) is used to adjust the three-dimensional angle of the seed to be tested relative to the optical axis so that the radicle sheath region of the seed to be tested is perpendicular to the optical path.

3. The apparatus for detecting the radicle stress of seed germination based on the principle of polarized light according to claim 1, wherein, An environmental monitoring sensor (104) is also installed inside the transparent culture chamber (101). The environmental monitoring sensor (104) is connected to the data processing unit (400) and is used to monitor the temperature and humidity data inside the chamber in real time. The environmental monitoring sensor (104) can simulate and monitor the soil microenvironment to ensure the stability of seed germination conditions.

4. The apparatus for detecting the radicle stress of seed germination based on the principle of polarized light according to claim 1, wherein, The light source component (201) is a white LED array with adjustable brightness; A narrowband filter (205) is also provided between the imaging unit (204) and the analyzer (203). The narrowband filter (205) is used to extract light of a specific wavelength to reduce the interference of dispersion on birefringence measurement.

5. A method for detecting seed radicle stress during germination, utilizing the seed radicle stress detection device based on the principle of polarized light according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Fix the seed to be tested in a transparent culture chamber (101) and cover the radicle sheath of the seed with culture medium; S2. Control the adjustment drive mechanism (300) to drive the analyzer (203) to rotate sequentially to multiple preset polarization angles; S3. At each preset polarization angle, the imaging unit (204) synchronously acquires the light intensity image transmitted through the analyzer (203); S4. The data processing unit (400) calculates the phase delay of pixels in the image based on the multi-angle light intensity image; S5. Based on the preset stress-optics law, the phase delay is converted into a stress value, and a stress distribution map of the seed germination process is generated.

6. The method for detecting radicle stress during seed germination as described in claim 5, characterized in that, The preset polarization angle in step S2.

7. The method for detecting seed radicle stress during germination as described in claim 5, characterized in that, In step S4, the formula for calculating the phase delay δ is as follows: ,in, These correspond to the light intensity values ​​at different polarization angles.

8. The method for detecting seed radicle stress during seed germination as described in claim 5, characterized in that, The formula for converting the phase delay into a stress value in step S5 is as follows: ,in, This is the stress value. The stress optical coefficient of the root sheath material. The equivalent thickness of light passing through the radicle sheath.

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