A method for characterizing the salt resistance of mangrove plants

Abstract

The present invention provides a method for characterizing the salt resistance of mangrove plants. By measuring the physiological capacitance, physiological resistance and physiological impedance of plant leaves under different clamping forces, the physiological capacitance and physiological inductance are calculated, and the physiological capacitance, physiological capacitance, physiological inductance, physiological resistance and physiological impedance of plant leaves are respectively constructed with clamping force change models. The parameters of the above models are used to calculate the relative water holding capacity of intracellular water in mangrove plant leaves, the leaf intracellular water utilization efficiency, the relative water holding time of intracellular water, and the plant leaf salt transfer rate, the relative salt flux per unit area and the salt transport capacity, and then calculate the plant salt discharge capacity, plant salt dilution capacity, plant ultrafiltration capacity and plant total salt resistance. The present invention realizes rapid, real-time, online, non-destructive and dynamic monitoring of the salt resistance of mangrove plants, and provides technical support for species selection, configuration and mangrove management for afforestation in a timely and appropriate manner according to local conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of afforestation and ecological restoration, and specifically relates to a method for characterizing the salt resistance of mangrove plants by using electrophysiological information. Background Art

[0002] The growth and development of plants and their entire life activities, such as salt tolerance, material metabolism, water status and signal transduction, involve the transmission and separation of protons and dielectric charges. Various changes in plant physiological processes, such as photosynthesis, respiration, transpiration, material flow, energy metabolism and plant growth, are directly or indirectly related to electrical signals. Leaves are the most important functional organs of plants. They are most sensitive to processes such as light energy utilization and energy metabolism, and play a vital role in the growth and development of plants. The leaves of fully expanded leaves are all mature leaves. Their cells all have central vacuoles. In mesophyll cells, vacuoles and cytoplasm occupy most of the space in the cells, and their water absorption method is mainly osmotic absorption. Whether it is a cell or an organelle, their exterior is covered with a cell membrane, and the phospholipid bilayer is the basic support of the cell membrane. Under an electron microscope, it can be divided into three layers, namely, there is an electron-dense band (hydrophilic part) about 2.5nm thick on both sides of the membrane, and a transparent band (hydrophobic part) 2.5nm thick is sandwiched in the middle. Therefore, the cell (organelle) can be regarded as a concentric spherical capacitor, except that this capacitor becomes a complex capacitor with both inductor and resistor functions due to the peripheral proteins and intrinsic proteins on the membrane. Therefore, the electrophysiological characteristics of plant leaf cells are closely related to the energy metabolism of plant leaves. In addition, the cell membrane plays a vital role in stabilizing the intracellular environment. The energy consumed by cell metabolism accounts for almost 60% of the total energy consumed by the cell. The surface proteins and binding proteins in the cell membrane are most closely related to the salt transport capacity. Therefore, the salt transport capacity of the cell is reflected in the composition and content of membrane proteins.

[0003] Plants dissipate about 95% of water through transpiration of leaves, and the remaining 5% of water in leaf cells can be used to support their growth. This precious 5% of intracellular water used by plants plays an important role in physiological processes. When plant cells are subjected to abiotic or biotic stress, their structure and composition will change, and their ion permeability will also change accordingly, and electrical parameters will also change accordingly. Therefore, the water metabolism of intracellular water affected by the environment is obviously also reflected in the changes in electrophysiological parameters.

[0004] Mangroves have extensive economic and ecological benefits and play an important role in controlling soil salinity in coastal areas and reducing seawater intrusion. Different mangrove plants have different salt resistance and mechanisms. Although the salt resistance of mangroves can be reflected by detecting plant growth, photosynthesis, and antioxidant capacity, these methods either require a long time and complicated steps, or are destructive and not dynamic and real-time. Therefore, the development of a rapid, online quantitative method for detecting the salt resistance of different plants under different environments is of great significance to the afforestation and management of mangroves.

[0005] The salt tolerance of mangrove plants depends on the ability of plants to regulate internal salt concentrations and prevent ions from reaching toxic levels under high salinity conditions. Therefore, the salt excretion capacity of plants to expel salt out of cells, the ability to dilute high concentrations into low concentrations, and the ultrafiltration capacity of plants will determine the salt tolerance of mangrove plants. The prior art does not have good parameters to describe the differences between different plants in the salt excretion capacity, salt dilution capacity, and ultrafiltration capacity of plants, even common photosynthetic parameters are no exception.

[0006] LCR can measure electrophysiological indicators such as physiological resistance, physiological capacitance, and physiological impedance of leaves. Electrophysiological parameters may characterize the salt excretion capacity, salt dilution capacity, ultrafiltration capacity, and total salt resistance of mangrove plants. Summary of the invention

[0007] In view of this, the present invention provides a method for characterizing the salt resistance of mangrove plants using electrophysiological information, and using biophysical indicators to characterize the salt excretion capacity, salt dilution capacity, ultrafiltration capacity and total salt resistance of mangrove plants, so as to achieve rapid, real-time, online, non-destructive and dynamic monitoring of the salt resistance of mangrove plants.

[0008] The present invention achieves the above technical objectives through the following technical means.

[0009] A method for characterizing the salt resistance of mangrove plants:

[0010] The salt discharge capacity C1 of plant leaves is obtained from the inherent physiological capacitive reactance IXC, inherent physiological inductive reactance IXL, inherent physiological resistance IR and inherent physiological impedance IZ of plant leaves, where C1 = a1IR N +b1IXC N +c1IXL N +d1IZ N , where a1, b1, c1 and d1 are all constants, and a1+b1+c1+d1=1, IR N IXC N 、IXL N and IZ NThey are normalized by 1 / IR, 1 / IXC, 1 / IXL and 1 / IZ respectively;

[0011] The plant salt dilution capacity C2 is obtained according to the plant leaf intrinsic physiological capacitance ICP, the plant leaf specific effective thickness d, the plant leaf intracellular relative water holding capacity IWHC and the plant leaf salt transport capacity STC, wherein C2=a2ICP N +b2d N +c2IW N +d2STC N , where a2, b2, c2 and d2 are all constants, and a2+b2+c2+d2=1, ICP N d N 、IWHC N and STC N They are normalized by ICP, d, IWHC and STC respectively;

[0012] The plant ultrafiltration capacity C3 is obtained from the plant leaf intracellular water use efficiency IWUE, the plant intracellular water relative water holding time IWHT, the relative salt flux per unit area USF and the plant leaf salt transfer rate STR, where C3 = a3IWUE N +b30.25 IWHT N +c3USF N +d3STR N , where a3, b3, c3 and d3 are all constants, and a3+b3+c3+d3=1, IWUE N 、IWHT N 、USF N and STR N They were normalized by 1 / IWUE, IWHT, 1 / USF and STR respectively;

[0013] Then, based on C1, C2 and C3, the total salt resistance of the plant T is obtained: Where l, m, and n are all constants.

[0014] A further technical solution is that the IXC=y1+k1, wherein y1 and k1 are parameters in the model of changes in the physiological capacitive reactance of plant leaves with the clamping force; the IXL=y2+k2, wherein y2 and k2 are parameters in the model of changes in the physiological inductive reactance of plant leaves with the clamping force; the IR=y3+k3, wherein y3 and k3 are parameters in the model of changes in the physiological resistance of plant leaves with the clamping force; the IZ=y4+k4, wherein y4 and k4 are parameters in the model of changes in the physiological impedance of plant leaves with the clamping force.

[0015] A further technical solution, the Where f is the test frequency, π is the circumference of a circle;

[0016] A further technical solution, the U is the test voltage, h is the model parameter of the physiological capacitance of plant leaves changing with the clamping force; The STC=USF×STR, where USF is the relative salt flux per unit area of ​​plant leaves.

[0017] A further technical solution, the IWHT=ICP×IZ; Wherein: IR is the inherent physiological resistance of the plant, IXC is the inherent physiological capacitive reactance of the plant, and IXL is the inherent physiological inductive reactance of the plant; VT is the rate of water transfer within plant leaves.

[0018] In a further technical solution, the plant leaf salt discharge capacity C1 = 0.25*IR N +0.25*IXC N +0.25*IXL N +0.25*IZ N .

[0019] In a further technical solution, the plant salt dilution capacity C2 = 0.25*IC N +0.25*d N +0.25*IWHC N +0.25*STC N .

[0020] A further technical solution is that the plant ultrafiltration capacity C3 = 0.25*IWUE N +0.25*IWHT N +0.25*USF N +0.25*STR N .

[0021] A further technical solution is that the total salt resistance of the plant

[0022] According to a further technical solution, the models of changes in physiological capacitance, physiological inductance, physiological resistance and physiological impedance with clamping force are constructed according to the physiological capacitance, physiological resistance and physiological impedance of the leaf to be tested under different clamping forces.

[0023] According to a further technical solution, the physiological capacitance, physiological resistance and physiological impedance of the leaves to be tested under different clamping forces are measured by selecting leaves to be tested at different leaf positions on the plants to be tested during the growth period and then subjecting them to saturation treatment.

[0024] The beneficial effects of the present invention are:

[0025] The present invention can not only characterize the salt excretion capacity of mangrove plants by electrophysiological indicators, but also characterize the salt dilution capacity and ultrafiltration capacity of mangrove plants by electrophysiological indicators, thus providing a unique technical means for studying the salt resistance mechanism of mangrove plants, providing technical support for species selection, configuration and mangrove management for afforestation in accordance with local conditions and at the right time and in the right place, and providing convenience for the classification and management of mangroves. Compared with the traditional detection method of plant salt resistance, the present invention can quickly, in real time, online, non-destructively and dynamically quantitatively monitor the comprehensive salt resistance of mangrove plants, and the measurement results are comparable; the present invention is simple, fast and has wide applicability. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0027] The basic principle of the present invention is:

[0028] The model of the physiological capacitance C of plant leaves changing with the clamping force F is:

[0029]

[0030] Where: U is the test voltage, ΔH is the internal energy of the system (the plant leaf system composed of cells), d is the specific effective thickness of the plant leaf, and F is the clamping force; The formula can be transformed into:

[0031] C=x0+hF (2)

[0032] Here x0 and h are model parameters, so

[0033] The models of the physiological capacitance, physiological inductance, physiological resistance and physiological impedance of plant leaves changing with clamping force can be derived based on the existing technology and will not be repeated here. The models of the physiological capacitance, physiological inductance, physiological resistance and physiological impedance of plant leaves changing with clamping force can be expressed as:

[0034] Model of the physiological capacitive reactance of plant leaves changing with clamping force:

[0035]

[0036] Among them, y1, k1 and b1 are the parameters of the model;

[0037] The model of the physiological reactance of plant leaves changing with the clamping force is:

[0038]

[0039] Among them, y2, k2 and b2 are the parameters of the model;

[0040] The model of the physiological resistance of plant leaves changing with the clamping force is:

[0041]

[0042] Among them, y3, k3 and b3 are the parameters of the model;

[0043] The model of the physiological impedance of plant leaves changing with the clamping force is:

[0044]

[0045] Among them, y4, k4 and b4 are the parameters of the model.

[0046] When the clamping force F=0, the inherent physiological capacitive reactance IXC of the plant leaves can be expressed as: IXC=y1+k1, the inherent physiological inductive reactance IXL of the plant leaves can be expressed as: IXL=y2+k2, the inherent physiological resistance IR of the plant leaves can be expressed as: IR=y3+k3, and the inherent physiological impedance IZ of the plant leaves can be expressed as: IZ=y4+k4.

[0047] The method for calculating the inherent physiological capacitance ICP based on the inherent physiological capacitive reactance IXC is: Wherein, f is the test frequency, π is the pi, and in this embodiment, π is 3.1416.

[0048] Since cells (organelles) are spherical structures, the growth of cells is closely related to the growth of their volume. For the same plant organ, especially leaves, the volume of cells is positively correlated with the volume of their vacuoles, and the main component of vacuoles is water; therefore, the capacitance of plant cells can be calculated using the formula of concentric spherical capacitors:

[0049]

[0050] Among them, π is the ratio of the circle to 3.1416, C is the capacitance of the concentric spherical capacitor, ε is the dielectric constant of the electrolyte, R1 and R2 are the radii of the outer and inner spheres, respectively. In cells (organelles), R2-R1 can be used as the thickness of the membrane, R1≈R2, the same type of cells (organelles) in the same plant tissue and organ, the membrane thickness is constant, ε is constant, so the volume of the cell (organelle) and the capacitance C of the cell have the following relationship:

[0051]

[0052] (8) In the formula, α is a constant, and for the same type of cells (organelles) in the same plant tissue and organ, the value of α is constant. In addition, the volume of cells (organelles), especially those in unfolded leaves, is proportional to their water holding capacity, that is, the water holding capacity of cells is proportional to is proportional to, so we can use Characterizing the water holding capacity of plant leaves, the method for calculating the relative water holding capacity of plant leaf cells IWHC based on the inherent physiological capacitance ICP is:

[0053] The specific effective thickness d of plant leaves represents the growth of cells. The relative water holding capacity IWHC of intracellular water supports the growth of plant cells, which can be characterized as the intracellular water use efficiency IWUE of leaves. The calculation method is:

[0054] According to Ohm's law, the current I Z =U / Z, where U is the measured voltage, I Z is the physiological current, Z is the impedance; at the same time, the current is equal to the capacitance multiplied by the differential of the voltage in time. After integral transformation, the time t is the product of the capacitance and the impedance. Therefore, based on the inherent physiological capacitance ICP and the inherent physiological impedance IZ of the plant leaves, the calculation formula for the relative water holding time IWHT of the plant intracellular water based on electrophysiological parameters is: IWHT=ICP×IZ. Based on the relative water holding capacity IWHC of the leaf cells and the relative water holding time IWHT of the plant cells, the intracellular water transfer rate can be calculated, and the calculation formula is:

[0055] The intracellular water transfer rate and the salt transfer rate STR are conceptually the same; therefore, the plant leaf salt transfer rate STR is equal to the plant leaf intracellular water transfer rate VT.

[0056] Cell membrane proteins include proteins that cause biological tissue resistance-binding proteins (intrinsic proteins) and proteins that cause biological tissue resistance, especially surface proteins (peripheral proteins). They are most closely related to salt transport; therefore, the relative salt flux per unit area of ​​plant leaves, USF, can be expressed as (9):

[0057]

[0058] Among them: IR is the inherent physiological resistance of the plant, IXC is the inherent physiological capacitive reactance of the plant, and IXL is the inherent physiological inductive reactance of the plant;

[0059] Plant leaf salt transport capacity STC: STC = USF × STR.

[0060] The salt outflow capacity is related to the bioelectric current. The greater the bioelectric current, the more cations such as sodium ions that are opposite to electrons flow out. Therefore, the salt outflow capacity I based on resistance R =U / IR, salt outflow capacity based on capacitive reactance I Xc =U / IXC, salt outflow capacity based on inductive reactance I XL =U / IXL, salt outflow capacity based on impedance IIZ =U / IZ, where U represents the voltage applied during the measurement. Since the physiological capacitance, resistance and impedance of plant leaves are measured in parallel, U is the same. Therefore, 1 / IR, 1 / IXC, 1 / IXL and 1 / IZ are defined as the absolute salt outflow capacity of each electrical component (resistance, capacitance, inductance and impedance) in plant cells, and the values ​​of 1 / IR, 1 / IXC, 1 / IXL and 1 / IZ are normalized to (0,1) and defined as IR N IXC N 、IXL N and IZ N ; The salt discharge capacity of plant leaves C1 is: C1 = a1IR N +b1IXC N +c1IXL N +d1IZ N , where a1, b1, c1 and d1 are all constants, and a1+b1+c1+d1=1. In this embodiment, the values ​​of a1, b1, c1 and d1 are all 0.25.

[0061] Increasing the volume of cells and organelles can dilute the intracellular salt. This increase in the volume of cells and organelles and the ability to maintain intracellular salt holding capacity can be defined as the plant salt dilution capacity, which can be determined by ICP, d, IWHC and STC. ICP, d, IWHC and STC are normalized to (0, 1) and defined as ICP N d N 、IWHC N and STC N ; The plant salt dilution capacity C2 is: C2 = a2ICP N +b2d N +c2IW N +d2STC N , where a2, b2, c2 and d2 are all constants, and a2+b2+c2+d2=1. In this embodiment, the values ​​of a2, b2, c2 and d2 are all 0.25.

[0062] Mangrove plants have ultrafiltration capacity, so that most salts are not transferred into the body with transpiration. Ultrafiltration capacity is related to the flow rate and flow time of salt in the cell membrane. 1 / IWUE represents the salt solution flux, IWHT represents the relative water holding time of plant intracellular water, 1 / USF represents the solute flux, and STR represents the salt transfer rate. Therefore, the ultrafiltration capacity of mangrove plants can be defined by 1 / IWUE, IWHT, 1 / USF and STR. The values ​​of 1 / IWUE, IWHT, 1 / USF and STR are normalized to (0,1) and defined as IWUE N 、IWHT N、USF N and STR N ; The ultrafiltration capacity of plants C3 is: C3 = a3IWUE N +b3IWHT N +c3USF N +d3STR N , where a3, b3, c3 and d3 are all constants, and a3+b3+c3+d3=1. In this embodiment, the values ​​of a3, b3, c3 and d3 are all 0.25.

[0063] The total salt resistance of plants is: Where l, m, and n are all constants; in this embodiment, the weights of C1, C2, and C3 are the same (i.e., l = m = n), then the total salt resistance of the plant T is:

[0064] Example

[0065] Two different mangrove species, Tung tree and Kandelia candel seedlings, were selected from Quanzhou Tongqing Mangrove Technology Co., Ltd. in the greenhouse of the College of Agricultural Engineering of Jiangsu University. The plants to be tested were cultivated under the test environment, and the plants in the growth period were used as the test materials. These plants were subjected to the following salt stress treatments for 30 days:

[0066] During the salt stress stage (Ss), different NaCl and sodium nitroprusside (SNP) treatments were used, namely, T1, NaCl (100 mM); T2, SNP (0.01 mM) + NaCl (100 mM); T3, NaCl (200 mM); T4, SNP (0.01 mM) + NaCl (200 mM); T5, NaCl (400 mM); T6, SNP (0.01 mM) + NaCl (400 mM).

[0067] Subsequently, rehydration treatment (Rw) was carried out for 30 days, and the treatment settings were as follows: T1, NaCl (100 mM); T2, SNP (0.01 mM) + NaCl (100 mM); T3, NaCl (100 mM); T4, SNP (0.01 mM) + NaCl (100 mM); T5, NaCl (200 mM); T6, SNP (0.01 mM) + NaCl (200 mM).

[0068] The fourth and fifth leaves were selected from fresh branches of different mangrove plants as experimental materials, and soaked in distilled water for 30 minutes. The water on the surface of the leaves was dried, and the leaves to be tested were immediately clamped between the parallel electrode plates of the measuring device. The measuring voltage and frequency were set, and different clamping forces were set by changing the mass of the iron block. The physiological capacitance, physiological resistance, and physiological impedance of the plant leaves under different clamping forces were measured in parallel mode, and the physiological capacitive reactance and physiological inductive reactance were calculated. The physiological capacitive reactance was calculated based on the physiological capacitance of the mangrove plant leaves. Where Xc is the physiological capacitive reactance of plant leaves, C is the physiological capacitance of plant leaves, f is the test frequency, π is the circumference of a circle, and in this embodiment, π is 3.1416; Based on the physiological impedance, physiological resistance and physiological capacitive reactance of mangrove plant leaves, the physiological inductive reactance of plant leaves is calculated: Among them, Xl is the physiological inductive reactance of plant leaves, Xc is the physiological capacitive reactance of plant leaves, Z is the physiological impedance of plant leaves, and R is the physiological resistance of plant leaves; then, a model of the change of physiological capacitance, physiological capacitive reactance, physiological inductive reactance, physiological resistance, and physiological impedance of mangrove plant leaves with clamping force is constructed to obtain the various parameters of each model; Tables 1-5 are models constructed with random sample data of Paulownia and Kandelia ovata; other data models are omitted.

[0069] Table 1 Physiological capacitance (C) variation model (CF) and parameters constructed from random sample data of Tung Blossom Tree and Kandelia candel

[0070]

[0071] Table 2 Physiological capacitive reactance (Xc) versus clamping force (F) model (Xc-F) and parameters constructed from random sample data of Tung tree and Kandelia candel

[0072]

[0073] Table 3 Physiological reactance (Xl) variation model (Xl-F) and parameters constructed from random sample data of Tung tree and Kandelia candel

[0074]

[0075] Table 4 Physiological resistance (R) variation model (RF) and parameters constructed from random sample data of Aegiceras corniculata and Kandelia candel

[0076]

[0077] Table 5 Physiological impedance (Z) variation model (ZF) and parameters constructed from random sample data of Aegiceras corniculata and Kandelia candel

[0078]

[0079]

[0080] Based on the parameters in the model of changes in physiological capacitance with clamping force, the specific effective thickness d of mangrove plant leaves is obtained; based on the model of changes in physiological capacitive reactance, physiological inductive reactance, physiological resistance and physiological impedance with clamping force, the inherent physiological capacitive reactance IXC, inherent physiological inductive reactance IXL, inherent physiological resistance IR and inherent physiological impedance IZ of mangrove plant leaves are obtained; based on the inherent physiological capacitive reactance IXC of mangrove plant leaves, the inherent physiological capacitance ICP of plant leaves is calculated, as shown in Table 6-7.

[0081] Table 6 The specific effective thickness d, intrinsic physiological resistance (IR), intrinsic physiological capacitance (IXC), intrinsic physiological inductance (IXL), intrinsic physiological impedance (IZ) and intrinsic physiological capacitance (ICP) of mangrove leaves under different treatments of Paulownia

[0082]

[0083] In the table, the values ​​represent mean ± standard deviation, n = 8. Different lowercase letters in the same column indicate significant differences by Duncan test (p < 0.05).

[0084] Table 7 The specific effective thickness d, inherent physiological resistance (IR), inherent physiological capacitance (IXC), inherent physiological inductance (IXL), inherent physiological impedance (IZ) and inherent physiological capacitance (ICP) of mangrove leaves under different treatments of Kandelia candel

[0085]

[0086]

[0087] In the table, the values ​​represent mean ± standard deviation, n = 8. Different lowercase letters in the same column indicate significant differences by Duncan test (p < 0.05).

[0088] According to the specific effective thickness d, the inherent physiological capacitance ICP and the inherent physiological impedance IZ of the plant leaves of different mangrove plants, the relative water holding capacity IWHC, the intracellular water use efficiency IWUE and the relative water holding time IWHT of the plant leaves were calculated, as shown in Table 8-9; the intracellular water transfer rate VT of the leaves of different mangrove plants was also calculated, and the plant leaf salt transfer rate STR was obtained, as shown in Table 10-11. According to the inherent physiological capacitance IXC, the inherent physiological inductance IXL, the inherent physiological resistance IR and the salt transfer rate STR of the plant leaves, the relative salt flux USF per unit area of ​​the plant leaves and the salt transport capacity STC of the plant leaves were obtained; as shown in Table 10-11.

[0089] Table 8 Relative water holding capacity (IWHC) of leaf intracellular water, intracellular water use efficiency (IWUE) of leaf intracellular water and relative water holding time (IWHT) of plant intracellular water under different treatments of Tung tree

[0090]

[0091] In the table, the values ​​represent mean ± standard deviation, n = 8. Different lowercase letters in the same column indicate significant differences by Duncan test (p < 0.05).

[0092] Table 9 Relative water holding capacity (IWHC) of leaf intracellular water, intracellular water use efficiency (IWUE) of leaf intracellular water and relative water holding time (IWHT) of plant intracellular water under different treatments of Kandelia candel

[0093]

[0094] In the table, the values ​​represent mean ± standard deviation, n = 8. Different lowercase letters in the same column indicate significant differences by Duncan test (p < 0.05).

[0095] Table 10 Relative salt flux per unit area of ​​mangrove leaves USF, salt transfer rate STR and leaf salt transport rate of mangrove plants under different treatments of Tung tree

[0096]

[0097] In the table, the values ​​represent mean ± standard deviation, n = 8. Different lowercase letters in the same column indicate significant differences by Duncan test (p < 0.05).

[0098] Table 11 Relative salt flux per unit area of ​​leaves USF, leaf salt transfer rate STR and leaf salt transport capacity STC of mangrove plants under different treatments of Kandelia candel

[0099]

[0100] In the table, the values ​​represent mean ± standard deviation, n = 8. Different lowercase letters in the same column indicate significant differences by Duncan test (p < 0.05).

[0101] Based on the inherent physiological capacitive reactance IXC of plant leaves, the inherent physiological inductive reactance IXL of plant leaves, the inherent physiological resistance IR of plant leaves and the inherent physiological impedance IZ of plant leaves, the salt excretion capacity C1 of plant leaves is obtained, as shown in Table 12-13; based on the inherent physiological capacitance IC of plant leaves, the specific effective thickness d of plant leaves, the relative water holding capacity of intracellular water of plant leaves IWHC and the salt transport capacity STC of plant leaves, the salt dilution capacity C2 of plants is obtained, as shown in Table 12-13; based on the intracellular water use efficiency IWUE of plant leaves, the relative water holding time IWHT of intracellular water of plants, the relative salt flux USF per unit area and the salt transfer rate STR, the ultrafiltration capacity C3 of plants is obtained, as shown in Table 12-13; based on the salt excretion capacity C1 of plant leaves, the salt dilution capacity C2 of plants and the ultrafiltration capacity C3 of plants, the total salt resistance T of plants is obtained, as shown in Table 12-13.

[0102] Table 12 The total salt resistance of mangrove plants under different treatments of Tung tree was obtained by the salt discharge capacity C1, plant salt dilution capacity C2 and plant ultrafiltration capacity C3

[0103]

[0104]

[0105] Table 13 The total salt resistance of mangrove plants under different treatments of Kandelia candel was obtained by the salt excretion capacity C1, plant salt dilution capacity C2 and plant ultrafiltration capacity C3

[0106]

[0107] The implementation effects of the present invention are as follows:

[0108] It can be seen from Tables 12 and 13 that the salt discharge capacity C1, plant salt dilution capacity C2, plant ultrafiltration capacity C3 and total salt resistance of Tung Blossom Tree and Kandelia candel are significantly different. At low salt levels, sodium nitroprusside (SNP) can significantly improve the salt discharge capacity C1, plant salt dilution capacity C2, plant ultrafiltration capacity C3 and total salt resistance of Tung Blossom Tree and Kandelia candel. At medium salt levels, sodium nitroprusside (SNP) has a promoting effect on the salt discharge capacity C1, plant salt dilution capacity C2, plant ultrafiltration capacity C3 and total salt resistance of Tung Blossom Tree, but has little effect on the salt discharge capacity C1, plant salt dilution capacity C2, plant ultrafiltration capacity C3 and total salt resistance of Kandelia candel. Under high salt levels, sodium nitroprusside (SNP) can significantly improve the salt excretion capacity C1, plant salt dilution capacity C2, plant ultrafiltration capacity C3 and total salt resistance of Tung tree, but has little effect on the salt excretion capacity C1, plant salt dilution capacity C2, plant ultrafiltration capacity C3 and total salt resistance of Kandelia candel.

[0109] Under medium salt level, rehydration with medium to low salt reduced the salt discharge capacity C1, plant salt dilution capacity C2, plant ultrafiltration capacity C3 and total salt resistance of Aegiceras corniculata and Kandelia candel. Under high salt level, rehydration with high to medium salt slightly improved the plant salt dilution capacity C2, plant ultrafiltration capacity C3 and total salt resistance of Aegiceras corniculata, but rehydration with high to medium salt greatly improved the salt discharge capacity C1 of Kandelia candel, and also had a significant promoting effect on the plant salt dilution capacity C2, plant ultrafiltration capacity C3 and total salt resistance of Kandelia candel.

[0110] In the presence of sodium nitroprusside (SNP), rehydration from medium to low salt reduced the salt excretion capacity C1, plant ultrafiltration capacity C3 and total salt resistance of Aegiceras corniculata, but rehydration from medium to low salt significantly promoted the plant ultrafiltration capacity C3 of Kandelia candel, had a negative effect on the salt excretion capacity C1 and plant salt dilution capacity C2 of Kandelia candel, and had no significant effect on the total salt resistance of Kandelia candel.

[0111] In the presence of sodium nitroprusside (SNP), rehydration from high to medium salt only reduced the salt excretion capacity C1 of Aegiceras corniculata, and had little effect on the plant salt dilution capacity C2 and total salt resistance. However, rehydration from high to medium salt reduced the plant ultrafiltration capacity C3 and total salt resistance of Kandelia candel, and had little effect on the salt excretion capacity C1 and plant salt dilution capacity C2 of Kandelia candel.

[0112] In conclusion, sodium nitroprusside (SNP) greatly promoted the salt resistance of mangrove plants at low salt levels; at medium and high salt levels, sodium nitroprusside (SNP) only helped to improve the salt resistance of Aegiceras corniculata, but could not improve the salt resistance of Kandelia candel, and even reversed the rehydration effect from high to medium salt. In addition, rehydration from high to medium salt greatly improved the salt resistance of Kandelia candel, but had little effect on the salt resistance of Aegiceras corniculata.

[0113] The above results show that the salt tolerance mechanisms and adaptation strategies of the two mangrove species are different under different salt levels. Sodium nitroprusside promotes the salt resistance of Tung Blossom Tree at different salt levels, which is related to the fact that sodium nitroprusside can enhance the antioxidant capacity of plants and the biological salt secretion characteristics of Tung Blossom Tree. Under high-salt to medium-salt rehydration conditions, sodium nitroprusside has an inhibitory effect on the salt resistance of Kandelia ovata, which is the result of the strong antioxidant capacity inhibiting the physical discharge of salt to offset the physical discharge of salt increased by rehydration of high-salt to medium-salt. These are consistent with the actual situation. At the same time, we can see that Tung Blossom Tree has a strong biological salt secretion characteristic, and Kandelia ovata also has a corresponding strong physical salt secretion characteristic. The biological and physical salt secretion work together to improve the adaptability of mangrove plants to salt.

[0114] The embodiments are preferred implementations of the present invention, but the present invention is not limited to the above-mentioned implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.

Claims

1. A method for characterizing the salt resistance of mangrove plants, characterized in that: The salt discharge capacity C1 of plant leaves is obtained from the inherent physiological capacitive reactance IXC, inherent physiological inductive reactance IXL, inherent physiological resistance IR and inherent physiological impedance IZ of plant leaves, where C1 = a1IR N +b1IXC N +c1IXL N +d1IZ N , where a1, b1, c1 and d1 are all constants, and a1+b1+c1+d1=1, IR N IXC N 、IXL N and IZ N They are normalized by 1 / IR, 1 / IXC, 1 / IXL and 1 / IZ respectively; The plant salt dilution capacity C2 is obtained from the plant leaf intrinsic physiological capacitance ICP, the plant leaf specific effective thickness d, the plant leaf intracellular relative water holding capacity IWHC and the plant leaf salt transport capacity STC, where C2 = a2ICP N +b2d N +c2IW N +d2STC N , where a2, b2, c2 and d2 are all constants, and a2+b2+c2+d2=1, ICP N d N 、IWHC N and STC N They are normalized by ICP, d, IWHC and STC respectively; The plant ultrafiltration capacity C3 is obtained from the plant leaf intracellular water use efficiency IWUE, the plant intracellular water relative water holding time IWHT, the relative salt flux per unit area USF and the plant leaf salt transfer rate STR, where C3 = a3IWUE N +b3IWHT N +c3USF N +d3STR N , where a3, b3, c3 and d3 are all constants, and a3+b3+c3+d3=1, IWUE N 、IWHT N 、USF N and STR N They were normalized by 1 / IWUE, IWHT, 1 / USF and STR respectively; Then, based on C1, C2 and C3, the total salt resistance of the plant T is obtained: Where l, m, and n are all constants; Said Where f is the test frequency, π is the circumference of a circle; Said U is the test voltage, h is the model parameter of the physiological capacitance of plant leaves changing with the clamping force; Said The STC=USF×STR, USF is the relative salt flux per unit area of ​​plant leaves; Said IWHT=ICP×IZ; Said Among them: IR is the inherent physiological resistance of the plant, IXC is the inherent physiological capacitive reactance of the plant, and IXL is the inherent physiological inductive reactance of the plant; Said VT is the rate of water transfer within plant leaves.

2. The method for characterizing the salt resistance of mangrove plants according to claim 1, characterized in that: The IXC=y1+k1, wherein y1 and k1 are parameters in the model of the change of the physiological capacitive reactance of the plant leaves with the clamping force; the IXL=y2+k2, wherein y2 and k2 are parameters in the model of the change of the physiological inductive reactance of the plant leaves with the clamping force; the IR=y3+k3, wherein y3 and k3 are parameters in the model of the change of the physiological resistance of the plant leaves with the clamping force; the IZ=y4+k4, wherein y4 and k4 are parameters in the model of the change of the physiological impedance of the plant leaves with the clamping force.

3. The method for characterizing the salt resistance of mangrove plants according to claim 1, characterized in that: The plant leaf salt discharge capacity C1 = 0.25*IR N +0.25*IXC N +0.25*IXL N +0.25*IZ N .

4. The method for characterizing the salt resistance of mangrove plants according to claim 3, characterized in that: The plant salt dilution capacity C2 = 0.25*IC N +0.25*d N +0.25*IWHC N +0.25*STC N .

5. The method for characterizing the salt resistance of mangrove plants according to claim 4, characterized in that: The plant ultrafiltration capacity C3 = 0.25*IWUE N +0.25*IWHT N +0.25*USF N +0.25*STR N .

6. The method for characterizing the salt resistance of mangrove plants according to claim 5, characterized in that: The total salt resistance of the plant 7. The method for characterizing the salt resistance of mangrove plants according to claim 2, characterized in that: The models of physiological capacitance, physiological inductance, physiological resistance and physiological impedance changing with clamping force are constructed according to the physiological capacitance, physiological resistance and physiological impedance of the leaf to be tested under different clamping forces.

8. The method for characterizing the salt resistance of mangrove plants according to claim 7, characterized in that: The determination of the physiological capacitance, physiological resistance and physiological impedance of the leaves to be tested under different clamping forces is carried out by selecting leaves to be tested at different leaf positions on the plants to be tested in the growth period and then subjecting them to saturated water treatment.

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