Accurate and pollution-free corn seed minimally invasive sampling method

Abstract

The invention discloses an accurate and pollution-free corn seed minimally invasive sampling method, and relates to a corn seed minimally invasive sampling method. The invention aims to solve the problems of gene pollution and section carbonization in the existing corn sampling method. Related parameters of pulse laser are set, the mobile platform is used for achieving switching of laser acting point positions, key holes are formed in the seeds one by one, and preparation of the corn seed slices can be achieved. Compared with a punching method, a punching method, a broaching method and continuous laser for slicing and sampling the corn seeds, the slice preparation method provided by the invention has the advantages that the process is easy to control, and the problems of gene pollution and loss of biological activity of the sampled seeds in a seed minimally invasive sampling technology can be effectively solved. The invention belongs to the technical field of seed slicing.

Description

Technical Field

[0001] The invention relates to a minimally invasive sampling method for corn seeds, belonging to the technical field of seed slicing. Background Art

[0002] As an important industrial raw material and feed crop, corn plays a crucial role in my country's economic development. However, my country's corn seed industry faces challenges such as homogeneity and a lack of specialized corn varieties. Automated corn seed slicing for molecular marker-assisted breeding can reduce the size of planted populations and significantly accelerate the corn breeding process. Seed slicing involves extracting small tissue samples from seeds for genetic analysis. Because the embryo is extremely sensitive to any damage, its integrity and vitality are crucial for successful germination and plant growth. Therefore, the sampling process requires obtaining high-quality slices without damaging the embryo.

[0003] Several methods are currently available for corn seed sampling, primarily categorized by the sampling method: punching, drilling, broaching, and laser sampling. The first three methods pose genetic contamination concerns due to contact cutting, while the laser method, currently commonly used, suffers from significant thermal effects from the continuous laser, resulting in carbonization of the slices and, in severe cases, seed inactivation. Therefore, a low-damage, pollution-free corn seed sampling method was developed to address the genetic contamination and loss of seed viability issues currently encountered in existing techniques, a critical technical challenge in slice sampling. Summary of the Invention

[0004] The present invention aims to solve the problems of gene contamination and loss of seed activity in existing corn sampling methods, and further proposes an accurate and pollution-free minimally invasive corn seed sampling method.

[0005] The technical solution adopted by the present invention to solve the above problems is: the steps of the present invention include: Step 1: Clamp the corn seeds on the fixture, and fix the fixture on the mobile platform; Step 2: Turn on the nanosecond pulse laser to preheat, adjust the cutting position, and measure the laser spot size; Step 3: Set the process parameters of nanosecond pulse laser cutting according to the seed thickness, cutting position width and spot size; Step 4: Drive the nanosecond pulse laser and program the mobile platform to penetrate the point and move one unit step length as one task. After completing the set number of task cycles, the corn seed slice preparation is completed.

[0006] Furthermore, the cutting position in step 2 is 1.5 mm away from the top of the corn embryo.

[0007] Furthermore, in step 3, the number of breakdown pulses and the number of task cycles at each laser action point are set according to the thickness of the corn seeds and the width of the cutting position.

[0008] Furthermore, when the seed thickness is 3 mm, the number of breakdown pulses at a single laser action point is 140±30 times; When the seed thickness is 4 mm, the number of breakdown pulses at a single laser action point is 170±30 times; When the seed thickness is 5 mm, the number of breakdown pulses at a single laser action point is 220±40 times; When the seed thickness is 6 mm, the number of breakdown pulses at a single laser action point is 350±50 times.

[0009] Furthermore, the unit step length, cutting position width, spot size and the number of task cycles satisfy the following relationship:

[0010] in, L is the width of corn seeds at the cutting position, r is the laser spot radius, s is the unit moving step length, n is the number of laser action points, that is, the number of task cycles.

[0011] Furthermore, the process parameters of nanosecond pulse laser cutting include: pulse width 3~18ns, pulse frequency 10Hz, energy density 5~20 J·cm -2 , the unit moving step value is based on the laser spot radius.

[0012] Furthermore, the wavelength of the nanosecond pulse laser is 355 nm.

[0013] Furthermore, the thickness of the corn seeds used in step 1 is 3-6 mm and the moisture content is 13%.

[0014] Furthermore, after the nanosecond pulse laser penetrates the seed at a single action point, the platform is translated by a unit step to the next action position, and so on to the end position of the seed cutting.

[0015] Furthermore, the unit movement step s The value is equal to the laser spot radius.

[0016] The beneficial effects of the present invention are: 1. This invention creates corn seed slices by setting pulsed laser parameters and switching the laser's action point using a mobile platform. This creates keyholes in the seeds one by one. Compared to punching, drilling, broaching, and continuous laser slicing of corn seeds, the slicing method provided by this invention offers easier process control and effectively addresses the genetic contamination and seed carbonization issues associated with breeding slicing techniques.

[0017] 2. In the interaction between the laser and corn seeds of the present invention, the laser energy accumulates rapidly locally to form a local high-temperature zone, triggering the pyrolysis of starch granules to generate a variety of gaseous, liquid and solid products. When the temperature rises to the phase transition temperature, water and organic matter vaporize into steam and overflow. The thermal stress will drive the decomposed solid products to splash, thereby achieving the breakdown of the seed at a single action point, and then coordinating with the movement of the action point to complete the seed slicing.

[0018] 3. This invention provides a method for sampling corn seed slices using nanosecond pulsed lasers. Compared to existing sampling techniques, this method offers simplified and convenient operation, easy control of the preparation process, minimal negative impact on seed viability, and a germination rate of over 90% after laser treatment. Most importantly, it effectively addresses the genetic contamination and seed carbonization issues associated with seed slice sampling in breeding techniques. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the point-by-point penetration method in Example 1 of the present invention, wherein L is the width of corn seeds at the cutting position, r is the laser spot radius, s is the unit moving step length, is the laser action point; Figure 2 Schematic diagram of the surface morphology of the slices and seeds after nanosecond pulse laser cutting of corn seeds in Example 1 of the present invention; Figure 3 Schematic diagram of the cross-sectional morphology of the seed after nanosecond pulse laser cutting in Example 1 of the present invention; Figure 4 Schematic diagram of the growth state of seeds after nanosecond pulse laser cutting at room temperature for 7 days in Example 1 of the present invention; Figure 5 Schematic diagram of the statistical results of germination rate before and after seed cutting and sampling in Example 1 of the present invention.

[0020] Example Example 1 The method for sampling corn seed slices using pulsed laser comprises the following steps: Step 1: Clamp the corn seeds on a fixture, and fix the fixture on a mobile platform; Step 2: Turn on the nanosecond pulse laser to preheat, adjust the cutting position, and measure the laser spot; Step 3: According to the seed thickness and cutting position width, the process parameters of nanosecond pulse laser cutting are set as follows: pulse width 9ns, pulse frequency 10Hz, energy density 9J·cm -2 , driving the pulsed laser, the laser energy is absorbed by the seeds to form a local high-temperature area, the endosperm at the action location is decomposed and vaporized, and the corn seed slices are prepared by the point-by-point penetration method; Step 4: Observe and evaluate the cut and cross-sectional morphology of the cut seeds. The cutting effect is good and the seeds can germinate normally.

[0021] like Figure 2 As shown, the surface morphology of the seeds and slices after nanosecond pulse laser cutting. It can be seen that the cutting seams of the slices and seeds are smooth and neat, indicating that the nanosecond pulse laser cutting process is stable and can effectively control the range of the heat-affected zone.

[0022] like Figure 3 As shown, the cross-sectional morphology of the seed after nanosecond pulse laser cutting can be seen. The cutting lines are clear, the cut surface is very smooth, and there is no trace of carbonization on the cut surface, indicating that nanosecond pulse laser cutting can effectively solve the carbonization problem in the laser cutting process.

[0023] like Figure 4 As shown, the growth status of seeds after nanosecond pulse laser cutting at room temperature after 7 days, which shows that the seeds treated with nanosecond pulse laser cutting can still germinate normally.

[0024] like Figure 5 The figure shows the statistical results of germination rate before and after seed cutting and sampling. The statistical results show that the germination rate of corn seeds after slicing sampling remains above 90%, indicating that nanosecond pulse laser has little damage to seeds and low negative impact on activity.

[0025] How it works Nanosecond pulse laser was used to cut the endosperm of corn seeds point by point, dividing the corn seeds into two parts at the endosperm to achieve seed slice sampling. The process parameters of the nanosecond pulse laser cutting included: pulse width 9 ns, pulse frequency 10 Hz, energy density 9 J·cm -2 The unit moving step size is based on the laser spot radius. At the same time, the germination rate of seeds after laser treatment remains above 90%.

[0026] Nanosecond pulse laser cutting technology is a high-precision processing method that uses a nanosecond pulse laser beam as a tool to finely cut materials through the laser's focused energy. During the corn seed cutting process, the laser beam irradiates the surface of the corn seed at an extremely high speed, instantly heating and vaporizing the target area, achieving precise segmentation. Because the nanosecond pulse laser has an extremely short pulse duration, the cutting process produces almost no heat-affected zone, effectively maintaining the integrity and quality of the endosperm. Through computer numerical control technology, the cutting path and laser parameters can be flexibly adjusted to achieve precise cutting of the corn seed endosperm, ensuring efficient and fine processing results. In addition, the laser cutting process does not require contact with the workpiece, avoiding the friction and damage caused by mechanical cutting, making corn seed endosperm processing more gentle and pollution-free.

[0027] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement of the above embodiments made according to the technical essence of the present invention, within the spirit and principles of the present invention, without departing from the content of the technical solution of the present invention, shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A precise and pollution-free minimally invasive sampling method for corn seeds, characterized in that: The specific steps include: Step 1: Clamp the corn seeds on the fixture, and fix the fixture on the mobile platform; Step 2: Turn on the nanosecond pulse laser to preheat, adjust the cutting position, and measure the laser spot size; Step 3: Set the process parameters of nanosecond pulse laser cutting according to the seed thickness, cutting position width and spot size; Step 4: Drive the nanosecond pulse laser and program the mobile platform to penetrate the point and move one unit step length as one task. After completing the set number of task cycles, the corn seed slice preparation is completed.

2. The precise and pollution-free minimally invasive corn seed sampling method according to claim 1, characterized in that: The cutting position in step 2 is 1.5 mm away from the top of the corn embryo.

3. The precise and pollution-free minimally invasive corn seed sampling method according to claim 1, characterized in that: In step 3, the number of breakdown pulses and the number of task cycles at each laser action point are set according to the thickness of the corn seeds and the width of the cutting position.

4. The precise and pollution-free minimally invasive corn seed sampling method according to claim 3, characterized in that: When the seed thickness is 3 mm, the number of breakdown pulses at a single laser action point is 140±30 times; When the seed thickness is 4 mm, the number of breakdown pulses at a single laser action point is 170±30 times; When the seed thickness is 5 mm, the number of breakdown pulses at a single laser action point is 220±40 times; When the seed thickness is 6 mm, the number of breakdown pulses at a single laser action point is 350±50 times.

5. The precise and pollution-free minimally invasive corn seed sampling method according to claim 3, characterized in that: The unit step length, cutting position width, spot size and the number of task cycles satisfy the following relationship: in, L is the width of corn seeds at the cutting position, r is the laser spot radius, s is the unit moving step length, n is the number of laser action points, that is, the number of task cycles.

6. The precise and pollution-free minimally invasive corn seed sampling method according to claim 1, characterized in that: The process parameters of nanosecond pulse laser cutting include: pulse width 3~18ns, pulse frequency 10Hz, energy density 5~20 J·cm -2 , the unit moving step size is based on the laser spot radius.

7. The precise, pollution-free, minimally invasive corn seed sampling method according to claim 1, characterized in that: The wavelength of the nanosecond pulse laser is 355 nm.

8. The precise, pollution-free, minimally invasive corn seed sampling method according to claim 1, characterized in that: The thickness of the corn seeds used in step 1 is 3-6 mm and the moisture content is 13%.

9. The precise, pollution-free, minimally invasive corn seed sampling method according to claim 1, characterized in that: After the nanosecond pulse laser penetrates the seed at a single action point, the platform is translated one unit step to the next action position, and so on to the end position of the seed cutting.

10. The precise, pollution-free, minimally invasive corn seed sampling method according to claim 9, characterized in that: Unit movement step s The value is equal to the laser spot radius.

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