A method for determining plant root activity using capacitance
By measuring the capacitance value of distilled water to determine plant root activity, this method solves the problems of time-consuming and inaccurate root activity measurement in existing technologies, and achieves rapid, accurate, and high-throughput root activity measurement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHIJIAZHUANG INST OF AGRI MODERNIZATION CHINESE ACAD OF SCI
- Filing Date
- 2023-12-27
- Publication Date
- 2026-07-17
AI Technical Summary
Existing root vigor measurement methods, such as staining methods, are time-consuming and have limited measurement capabilities, making it difficult to quickly measure large batches of samples. They also have measurement errors and cannot accurately reflect the true vigor of plant roots.
Plant root activity was determined by measuring the capacitance value of distilled water and using the formula: root activity = capacitance value × electrode spacing × distilled water volume / (electrode area × root fresh weight). A digital bridge was used to measure the capacitance value, and regression analysis was performed at different frequencies to determine the optimal frequency.
It achieves high-throughput measurement of root activity, is simple and fast to operate, and provides accurate measurement results. It can effectively distinguish root activity under different growth conditions and avoid measurement errors caused by changes in cell membrane permeability and ion exchange.
Smart Images
Figure CN117871618B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of plant root activity measurement technology, specifically relating to a method for determining plant root activity using capacitance. Background Technology
[0002] Root activity directly affects a plant’s ability to absorb water and nutrients. High-throughput measurement of root activity helps to understand plant responses to stresses (such as frost, salt stress, drought stress, and flooding stress), which is of great significance to research in ecology, agronomy, geography, and other fields. Therefore, high-throughput measurement of root activity is becoming increasingly important.
[0003] The commonly used method for measuring root vitality is the staining method. This involves first obtaining root samples, then measuring dehydrogenase activity through staining. However, this method is time-consuming and the amount of root samples that can be measured is limited, making it difficult to quickly measure large batches of samples. Furthermore, as plant roots age, they naturally contain a certain amount of pigment, and the precipitation of this pigment can introduce measurement errors into the staining method, failing to accurately reflect the true vitality of the plant's root system. Summary of the Invention
[0004] To address the problems existing in the prior art, this invention provides a method for determining plant root activity using capacitance. This invention determines plant root activity by measuring the capacitance value of distilled water. According to the formula: Root activity = Capacitance value × Electrode spacing × Distilled water volume / (Electrode area × Fresh weight of roots), by substituting the measured capacitance value and correlation coefficient, the root activity of the measured root sample can be characterized, thereby comparing root activity under different growth conditions.
[0005] The specific technical solution adopted in this invention is as follows:
[0006] A method for determining plant root activity using capacitance includes the following steps:
[0007] S1. Place the cleaned plant root sample into a plastic box containing distilled water.
[0008] S2. Measure the capacitance of distilled water using a digital bridge. Root activity = capacitance × electrode spacing × distilled water volume / (electrode area × fresh root weight).
[0009] Furthermore, the root sample described in step S1 is completely immersed in distilled water.
[0010] Furthermore, in step S2, a digital bridge is used to measure the capacitance value of the distilled water. The two electrodes of the digital bridge are located at both ends of the plastic box and are in contact with the distilled water in the plastic box. The test clips of the digital bridge clamp the electrodes at both ends.
[0011] Furthermore, the optimal measurement frequency in step S2 is determined as follows: prepare root samples with relatively consistent color and different activities in advance, measure the capacitance of distilled water containing roots at different frequencies (20Hz-500kHz), and perform regression analysis with the root activity determined by the staining method. The measurement frequency at which the correlation coefficient between the two reaches the maximum is the optimal measurement frequency.
[0012] The beneficial effects of this invention are:
[0013] 1. Since cell membrane permeability is directly related to root activity, higher permeability indicates greater cell membrane damage and lower root activity. Simultaneously, cell membrane damage leads to reduced charge accumulation, resulting in a lower root dielectric constant and consequently a smaller measured capacitance value. Therefore, this invention determines plant root activity by measuring the capacitance value of distilled water. Using the formula: Root Activity = Capacitance × Electrode Spacing × Distilled Water Volume / (Electrode Area × Root Fresh Weight), the measured capacitance value and correlation coefficient can be used to characterize the root activity of the tested root sample, allowing for comparison of root activity under different growth conditions. From a measurement efficiency perspective, this invention features simple operation, fast measurement speed, and high-throughput measurement of root activity.
[0014] 2. The capacitance method in this invention is more accurate than the resistance method. Although increased permeability of root cell membranes and the amount of cell sap exudation lead to a decrease in the resistivity of distilled water, thus allowing the measurement of root activity by measuring the resistance of the solution soaking the roots, root cells in the field, damaged or aged due to environmental stresses, exchange ions with the surrounding soil. Furthermore, rinsing the roots causes ions to be washed out of the cells, resulting in significant uncertainty in the method of reflecting root activity by measuring the ionic resistance of the solution. The capacitance method for measuring root activity, however, is based on the root polarization mechanism and measures the dielectric constant. The root dielectric constant is closely related to cell membrane permeability; higher cell membrane permeability corresponds to a lower root dielectric constant, indicating lower root activity. Moreover, the permeability of root cell membranes and the root dielectric constant are unaffected by rinsing and ion exchange during root washing. Therefore, using the capacitance of distilled water containing roots to reflect root activity is more accurate. Attached Figure Description
[0015] Figure 1 The capacitance of distilled water containing winter wheat roots and the capacitance of distilled water without roots are shown as a function of frequency.
[0016] Figure 2 The resistance of distilled water containing winter wheat roots and the resistance of distilled water without roots are shown as a function of frequency.
[0017] Figure 3 The relationship between the capacitance of distilled water containing summer maize roots and the absorbance measured by staining method;
[0018] Figure 4 The effects of different active summer maize root systems on capacitance and absorbance values by staining method;
[0019] Figure 5 The effect of winter maize root system on distilled water capacitance under different temperature stresses;
[0020] Figure 6 The effect of different irrigation treatments on the capacitance of distilled water in winter wheat roots;
[0021] Figure 7 The effect of different irrigation treatments on the root system of winter wheat on the resistivity of distilled water. Detailed Implementation
[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. I. Specific Implementation Methods
[0024] Example 1
[0025] S1. Prepare winter wheat roots, wash them and put them into a plastic box that is 120mm long, 86mm wide and 50mm high, and then fill the plastic box with distilled water.
[0026] S2. A digital bridge was used to measure the capacitance and resistance of the distilled water in the plastic container. The electrodes of the digital bridge were made of stainless steel, with the two ends of the electrodes located at both ends of the plastic container and in contact with the distilled water. The test clips of the digital bridge held the electrodes at both ends. The measurement frequency was 20Hz-500kHz. The test results are shown in [reference needed]. Figure 1 and Figure 2 .
[0027] Comparative Example 1
[0028] S1. Prepare four groups of winter wheat root systems and four plastic boxes with a length of 120mm, a width of 86mm, and a height of 50mm. Then fill the four plastic boxes with distilled water.
[0029] S2. First, measure the capacitance and resistance of the distilled water in four sets of plastic boxes. Then, place the prepared root system into each of the four sets of plastic boxes and measure the capacitance and resistance of the distilled water containing the roots. After the measurement, remove the roots and freeze them in a refrigerator for 2 hours. Then, place them in distilled water and let them stand for 10 minutes before measuring their capacitance and resistance again (keeping the plastic box numbers consistent with those before freezing, without changing the water). After the measurement, freeze them again for 2 hours and repeat the above steps. Three sets of roots were frozen for a total of 8 hours, and one set of roots was frozen for 10 hours. After the final measurement of the capacitance and resistance of the distilled water containing the frozen roots, remove the roots and replace the distilled water. Then, place the frozen roots back into fresh distilled water and measure the capacitance and resistance. The test results are shown below. Figure 1 and Figure 2 .
[0030] Comparative Example 1 simulated the frost stress on winter wheat roots by freezing multiple groups of winter wheat roots at different low temperatures. Figure 1 It can be seen that the capacitance value measured for the normally growing winter wheat roots in Example 1 is relatively large, while the capacitance value measured for the frozen winter wheat roots is significantly reduced, and the capacitance value gradually decreases with increasing freezing time. This indicates that the capacitance method can be used to measure the effect of freezing on root activity. Figure 2 The decrease in resistance after freezing indicates that substances inside the cells leak into the water after freezing, thus proving the rationality of the capacitance method proposed in this invention, which is based on measuring the permeability of the cell membrane to characterize root activity.
[0031] Comparative Example 2
[0032] S1. Take 32 groups of 2.5g summer maize roots at the tasseling stage, and take a plastic box with a length of 56mm, a width of 56mm, and a height of 60mm. Fill the plastic box with distilled water.
[0033] S2. Thirty-two groups of summer maize root systems were sequentially placed in plastic boxes, and the capacitance of distilled water was measured. After the measurement, 0.06g of root system was taken from each group, and the absorbance of the root soaking solution was measured using a staining method (30℃ water bath for 3 hours). The test results are shown below. Figure 3 .
[0034] Comparative Example 2 demonstrates, by comparing the correlation between the staining method and the capacitance method of this invention, that root activity can be accurately measured using capacitance values. Figure 3 This demonstrates the relationship between the capacitance and absorbance value of distilled water containing normally growing, viable roots from the field. Figure 3 The equation in the middle represents the relationship between the two, and the gray area indicates that the equation has a 95% confidence interval. This proves that there is a significant linear correlation between the capacitance value of distilled water containing roots and the absorbance value of distilled water containing roots. Since the staining method is a classic method for measuring root activity, it proves that root activity can be measured through capacitance value.
[0035] Comparative Example 3
[0036] S1. Take 2.5g of summer maize root system from 4 groups. The 4 groups of summer maize roots are in the following states: senescent dead roots, roots dehydrated for 10 hours, roots frozen for 2 hours, and roots in the normal growth and grain filling stage. Then, immerse them in 4 plastic boxes with a length of 56mm, a width of 56mm, and a height of 60mm and fill them with distilled water.
[0037] S2. The root activity of four groups of summer maize was measured using both the staining method and the capacitance method of this invention. The measurement results are shown in [the table below]. Figure 4 .
[0038] Comparative Example 3 demonstrates the limitations of the staining method in measuring the root activity of summer maize under different conditions. Figure 4 It can be seen that, where 'a' represents the root activity of summer maize measured by the capacitance method, and 'b' represents the root activity of summer maize measured by the staining method. The results presented in 'b' show no significant difference in root activity across different activity states, indicating that the root activity measured by the staining method is inconsistent with reality. However, the results measured by the capacitance method in this invention are: root activity of normally growing roots > root activity after 10 hours of dehydration > root activity after 2 hours of freezing > dead root activity, which is consistent with reality. Therefore, Figure 4 This indicates that the classical staining method also has certain limitations, and cannot effectively distinguish the activity of roots after freezing, aging dead roots, and dehydrated roots. In contrast, the capacitance method can effectively distinguish the differences in root activity, indicating that the capacitance method is more accurate than the staining method in measuring root activity, at least in these scenarios.
[0039] Comparative Example 4
[0040] Take 2.5g of winter wheat seedling roots and place them in a plastic box (56mm long, 56mm wide, and 60mm high). Fill the box with distilled water at 20℃. Place the roots in the box and measure the capacitance. After measurement, bathe the roots in a 30℃ water bath for 1 hour. Then remove the roots and place them in 20℃ distilled water for 10 minutes. Measure the capacitance of the distilled water. Repeat the above steps at water bath temperatures of 40℃, 50℃, 55℃, and 60℃. The measurement results are shown below. Figure 5 .
[0041] Comparative Example 4 simulated different levels of high-temperature stress on winter wheat roots using different water bath temperatures. Figure 5 It can be seen that the measured capacitance value decreases significantly as the water bath temperature increases, indicating that root activity gradually decreases with increasing temperature. This demonstrates that the capacitance method can effectively measure the effect of high temperature stress on root activity.
[0042] Comparative Example 5
[0043] S1. Prepare six groups of winter wheat roots in the late grain-filling stage: W0, W1, W2, W3, W4, and W5. W0, W1, W2, W3, W4, and W5 represent the following stages of winter wheat growth: dryland (W0), irrigation once at the jointing stage (W1), irrigation once at the jointing and heading stages (W2), irrigation once at the overwintering, jointing, heading, and grain-filling stages (W3), irrigation once at the overwintering, jointing, heading, and grain-filling stages (W4), and irrigation once at the overwintering, jointing, booting, heading, and grain-filling stages (W5). Take 10g of each group of winter wheat roots, wash them, and place them in multiple plastic boxes with a length of 120mm, a width of 86mm, and a height of 50mm. Then fill the plastic boxes with water.
[0044] S2. The resistance and capacitance of water in different plastic boxes were measured using a digital bridge at measurement frequencies of 30.08kHz, 60.14kHz, and 100.22kHz. The test results are shown in [Figure 1]. Figure 6-7 .
[0045] Comparative Example 5 simulated the effects of drought stress on the root system of winter wheat under different irrigation conditions, among which... Figure 7 The effect of root system on electrical resistance under different irrigation conditions. Figure 7 The differences in root activity measured under different irrigation conditions were small, proving that water resistance cannot effectively distinguish root activity under different irrigation conditions.
[0046] and Figure 6 The effect of root system on capacitance under different irrigation conditions shows that the more frequent the irrigation (under the treatment of sufficient water supply and less impact from drought stress), the larger the measured capacitance value of the root system. This indicates that capacitance value can distinguish root activity under different irrigation conditions. Figure 6 and Figure 7 The comparison shows that water capacitance is better than water resistance for measuring root vitality.
Claims
1. A method for determining plant root activity using capacitance, characterized in that, Includes the following steps: S1. Place the cleaned plant root sample into a plastic box containing distilled water. S2. Measure the capacitance of distilled water containing roots using a digital bridge. Root activity = capacitance × electrode spacing × distilled water volume / (electrode area × fresh weight of roots).
2. The method for determining plant root activity using capacitance according to claim 1, characterized in that, The root sample described in step S1 is completely immersed in distilled water.
3. The method for determining plant root activity using capacitance according to claim 1, characterized in that, In step S2, a digital bridge is used to measure the capacitance value of the distilled water containing the root system. The two electrodes of the digital bridge are located at both ends of the plastic box and are in contact with the distilled water in the plastic box. The test clips of the digital bridge hold the electrodes at both ends respectively.
4. The method for determining plant root activity using capacitance according to claim 1, characterized in that, The optimal measurement frequency in step S2 is determined as follows: Prepare root samples with relatively consistent color and different activities in advance, measure the capacitance of distilled water containing roots at different frequencies (20Hz-500kHz), and perform regression analysis with the root activity measured by the staining method. The measurement frequency at which the correlation coefficient between the two reaches the maximum is the optimal measurement frequency.