How to Analyze Plant Stress Metabolic Networks? Integrated Evaluation of GABA, Proline, Soluble Sugars, and the Antioxidant System
How to Analyze Plant Stress Metabolic Networks? Integrated Evaluation of GABA, Proline, Soluble Sugars, and the Antioxidant System
When plants are exposed to drought, salt stress, low temperature, high temperature, heavy metals, or oxidative stress, GABA, proline, soluble sugars, and the antioxidant system jointly participate in osmotic regulation, carbon-nitrogen allocation, ROS scavenging, and cellular homeostasis maintenance. Analysis of plant stress metabolic networks should not rely only on changes in a single indicator, but should integrate osmoprotective metabolites, antioxidant enzyme activities, oxidative damage markers, and reducing capacity.
Keywords: plant stress; GABA detection; proline detection; soluble sugar detection; antioxidant system; SOD; POD; CAT; APX; MDA; ROS; osmotic regulation; plant stress response
1 Analytical Framework of Plant Stress Metabolic Networks
1.1 Osmotic regulation and carbon-nitrogen redistribution
Plant stress responses first involve changes in cellular water status, ion balance, and the redox environment. Proline, GABA, and soluble sugars can act as osmotic regulators, carbon-nitrogen buffering pools, and stress signal-related metabolites, helping cells maintain water potential, protect proteins and membrane structures, and participate in metabolic recovery after stress.
(1) Proline accumulation
Proline usually increases under drought, salt stress, low temperature, and heavy metal stress. It can participate in osmotic regulation, protein stabilization, membrane protection, and ROS buffering. If proline increases while MDA and relative electrical conductivity decrease, its protective effect is relatively evident. If proline increases markedly but membrane damage still intensifies, it more likely reflects increased stress severity or insufficient protective capacity.
(2) Activation of the GABA branch
GABA enters the GABA shunt through glutamate decarboxylation and is associated with carbon-nitrogen metabolism, the TCA cycle, pH regulation, and stress signaling. Under salt stress, hypoxia, mechanical injury, and low-temperature conditions, increased GABA often indicates enhanced glutamate diversion. If this is accompanied by increased GAD activity, changes in TCA intermediates, and decreased ROS, it can support the involvement of GABA in metabolic buffering and stress adaptation.
(3) Soluble sugar regulation
Soluble sugars include glucose, fructose, sucrose, and some soluble oligosaccharides. They participate not only in osmotic regulation but also in energy supply, signaling, and carbon storage. If soluble sugars increase while photosynthetic capacity decreases, the increase may result from starch degradation or restricted transport. If sugar levels rise together with enhanced antioxidant capacity, this suggests that carbon sources may support reducing power supply and repair processes.
1.2 ROS production and antioxidant defense
Stress enhances ROS production associated with chloroplasts, mitochondria, peroxisomes, and the plasma membrane. SOD, POD, CAT, APX, GR, GPX, and the AsA-GSH cycle form the antioxidant defense network. Antioxidant system analysis should include four categories of readouts: ROS level, enzyme activity changes, membrane lipid peroxidation, and non-enzymatic antioxidants.
Table 1 Core Indicators and Interpretation Directions in Plant Stress Metabolic Networks
Indicator Module | Key Indicators | Main Functions | Interpretation Focus |
GABA metabolism | GABA, GAD, GABA-T, glutamate | GABA shunt, carbon-nitrogen buffering, pH regulation | Determine whether glutamate is diverted into the GABA branch |
Proline metabolism | Proline, P5CS, ProDH | Osmoprotection, protein stabilization, stress recovery | Distinguish protective accumulation from damage-associated accumulation |
Soluble sugars | Total soluble sugars, sucrose, glucose, fructose | Osmotic regulation, carbon source supply, signaling regulation | Interpret together with starch, photosynthetic indicators, and reducing power |
ROS levels | H₂O₂, O₂·⁻, total ROS | Stress signals and sources of oxidative damage | Must be interpreted together with antioxidant enzymes and MDA |
Antioxidant enzymes | SOD, POD, CAT, APX, GR, GPX | Scavenging of superoxide anion and hydrogen peroxide | Determine whether antioxidant responses are effective |
Membrane damage | MDA, relative electrical conductivity, membrane permeability | Lipid peroxidation and membrane integrity | Reflects the degree of stress injury |
Non-enzymatic antioxidants | GSH/GSSG, AsA/DHA, total phenols, flavonoids | Reducing power buffering and ROS scavenging | Evaluates antioxidant reserves and redox status |
2 GABA Metabolism: A Node for Stress Signaling and Carbon-Nitrogen Buffering
2.1 Mechanism of GABA accumulation
GABA is mainly generated from glutamate by glutamate decarboxylase and can subsequently enter the GABA shunt through GABA transaminase and succinic semialdehyde dehydrogenase, linking it to the TCA cycle. Under stress conditions, cytosolic acidification, Ca²⁺ signaling, and changes in glutamate supply can promote GABA production, making it a connecting node between carbon-nitrogen metabolism and stress signaling.
2.2 GABA responses under different stress types
(1) Salt stress
Under salt stress, increased GABA is often associated with ion toxicity, osmotic stress, and ROS accumulation. If increased GABA is accompanied by improved Na⁺/K⁺ balance, reduced MDA, and enhanced antioxidant enzyme activity, this suggests that GABA participates in salt stress buffering. If GABA increases while oxidative damage worsens, it may indicate that stress intensity exceeds regulatory capacity.
(2) Low-temperature and hypoxic stress
Low temperature or hypoxia can restrict mitochondrial metabolism, and the GABA shunt may serve as a TCA bypass to maintain carbon flow and redox status. If GABA increases together with changes in succinate, malate, or ATP, its energy-buffering significance should be interpreted in the context of TCA metabolism.
(3) Mechanical injury and pathogen stimulation
Under injury- or pathogen-induced conditions, GABA may be associated with defense signaling, nitrogen metabolism, and ROS burst. Detection should be combined with H₂O₂, POD, total phenols, flavonoids, and defense-related enzyme activities to avoid interpreting increased GABA only as osmotic regulation.
2.3 GABA detection and interpretation
GABA can be detected by the phenol-sodium hypochlorite colorimetric method, micro method, HPLC, or LC-MS/MS. Colorimetric methods are suitable for rapid screening, whereas HPLC and LC-MS/MS are more suitable for combined analysis with glutamate, proline, organic acids, and amino acid profiles. If the research focuses on the GABA shunt, GAD, GABA-T, glutamate, succinate, and ATP status should be detected simultaneously.
3 Proline Metabolism: Osmoprotection and a Readout of Stress Intensity
3.1 Proline accumulation pathways
Proline is mainly synthesized from glutamate through P5CS and related steps and can also be supplemented through the ornithine pathway. Under stress, proline accumulation can reduce cellular osmotic potential, stabilize proteins, protect membrane structures, and participate in ROS buffering. During the recovery phase, proline can be degraded by ProDH to provide carbon and nitrogen sources for mitochondrial metabolism.
3.2 Significance of proline under different stresses
(1) Drought stress
Under drought conditions, increased proline is usually associated with water deficit and osmotic regulation. If proline accumulation is accompanied by maintained relative water content, reduced chlorophyll decline, and decreased MDA, this indicates adaptive significance. If proline increases while leaf wilting and membrane damage remain evident, it more likely serves as an indicator of stress injury.
(2) Salt stress
Under salt stress, proline can buffer osmotic pressure and reduce oxidative damage caused by ion toxicity. Detection should be combined with Na⁺, K⁺, Na⁺/K⁺ ratio, SOD/CAT/APX activities, and MDA level to determine whether proline accumulation is associated with salt tolerance.
(3) Heavy metal stress
Under heavy metal stress, proline can participate in buffering metal-induced oxidative injury. If proline increases together with enhanced GSH, phytochelatins, or antioxidant enzymes, it may be related to detoxification and antioxidant responses. However, proline elevation alone cannot directly prove enhanced tolerance.
3.3 Proline detection and interpretation
Proline is commonly detected by the acidic ninhydrin colorimetric method or micro method, and it can also be quantified by HPLC/LC-MS/MS. Results should be normalized by fresh weight, dry weight, protein amount, or tissue type. Baseline proline levels differ substantially among young leaves, mature leaves, roots, and seeds, so absolute values should not be directly compared across organs.
4 Soluble Sugars: Osmotic Regulation, Carbon Storage, and Signaling Control
4.1 Composition and metabolic significance of soluble sugars
Soluble sugars include sucrose, glucose, fructose, and some soluble oligosaccharides. Under stress, sugar metabolism is jointly affected by photosynthesis, starch degradation, sucrose transport, respiratory consumption, and cell wall metabolism. Increased total soluble sugars may indicate enhanced osmotic regulation, but may also reflect blocked sugar transport or carbon metabolic redistribution.
4.2 Interpretation boundaries of different sugar indicators
(1) Total soluble sugars
Total soluble sugars are suitable for rapid evaluation of osmotic regulation and changes in carbon storage. If they increase together with maintained relative water content, moderate proline elevation, and decreased MDA, this supports enhanced osmoprotection. If sugar accumulation occurs with a marked decrease in starch and reduced photosynthetic indicators, it indicates carbon reserve mobilization or inhibited photosynthesis.
(2) Reducing sugars
Reducing sugars such as glucose and fructose can reflect sucrose breakdown, starch degradation, and energy supply changes. Increased reducing sugars together with enhanced respiration may indicate increased energy demand under stress. If reducing sugars accumulate while ATP decreases, mitochondrial functional limitation should be considered.
(3) Sucrose
Sucrose is an important sugar for long-distance transport and stress signaling regulation. Under salt stress, drought, and low temperature, sucrose changes can reflect source-sink relationships, phloem transport, and osmoprotection. If sucrose accumulation occurs together with decreased photosynthesis, enhanced synthesis, transport restriction, and reduced consumption should be distinguished.
4.3 Methods for soluble sugar detection
Total soluble sugars are commonly detected by the anthrone colorimetric method or phenol-sulfuric acid method. Reducing sugars can be detected by the DNS method. Composition analysis of monosaccharides, disaccharides, and oligosaccharides is more suitable for HPLC, ion chromatography, or LC-MS/MS. If the study focuses on metabolic networks, starch, sucrose, glucose, fructose, and related enzyme activities such as sucrose synthase, sucrose phosphate synthase, and invertase should be detected together.
Table 2 Comparison of Detection Methods for GABA, Proline, and Soluble Sugars
Indicator | Common Methods | Suitable Samples | Advantages | Notes |
GABA | Phenol-sodium hypochlorite method, HPLC, LC-MS/MS | Leaves, roots, fruits, cultured cells | Evaluates GABA shunt activation | Colorimetric specificity is limited; mechanistic studies require combined detection of glutamate and GAD |
Proline | Acidic ninhydrin colorimetric method, micro method, HPLC | Leaves, roots, seeds, embryogenic tissues | Suitable for rapid screening under drought and salt stress | Must be normalized by tissue type and water content |
Total soluble sugars | Anthrone method, phenol-sulfuric acid method | Leaves, roots, stems, fruits | Suitable for overall evaluation of osmotic regulation | Cannot distinguish sugar composition |
Reducing sugars | DNS method, HPLC | Leaves, roots, fruits | Reflects sugar breakdown and energy supply | Susceptible to interference from reducing substances |
Sucrose/monosaccharide profile | HPLC, ion chromatography, LC-MS/MS | Tissue extracts, phloem sap | Can distinguish sugar metabolic direction | Requires higher standards for sample preparation and reference materials |
5 Antioxidant System: ROS Scavenging Capacity and Oxidative Damage Evaluation
5.1 ROS and oxidative damage indicators
H₂O₂ and O₂·⁻ are both stress signaling molecules and sources of oxidative damage. Mild ROS increases can induce defense responses, whereas excessive ROS can cause membrane lipid peroxidation, protein oxidation, and photosystem damage. MDA, relative electrical conductivity, and protein carbonylation can serve as damage readouts and should be interpreted together with ROS and antioxidant enzyme activities.
5.2 Antioxidant enzyme system
(1) SOD
SOD converts O₂·⁻ into H₂O₂ and is the upstream enzyme in the ROS scavenging chain. If SOD increases but CAT/APX is insufficient, H₂O₂ may continue to accumulate. If SOD, CAT, and APX increase coordinately and MDA decreases, this more strongly supports effective enhancement of antioxidant defense.
(2) CAT
CAT mainly scavenges high concentrations of H₂O₂ and is often associated with peroxisomes and rapid H₂O₂ removal. Under drought, high temperature, and salt stress, CAT activity changes can reflect H₂O₂ scavenging capacity. When CAT decreases while H₂O₂ increases, APX and POD should be considered to determine whether alternative scavenging pathways exist.
(3) POD
POD participates in H₂O₂ removal, cell wall reinforcement, lignification, and defense responses. Increased POD does not only represent enhanced antioxidant activity; it may also reflect cell wall remodeling or pathogen defense activation. POD should be interpreted together with lignin, total phenols, H₂O₂, and tissue developmental stage.
(4) APX, GR, and the AsA-GSH cycle
APX uses ascorbate to scavenge H₂O₂, and GR maintains GSH regeneration. Together, they maintain cellular reducing status. If APX, GR, GSH/GSSG, and AsA/DHA improve coordinately, the AsA-GSH cycle is effectively activated. If enzyme activities increase but GSH/GSSG decreases, reducing power supply is likely insufficient.
5.3 Non-enzymatic antioxidant system
GSH, AsA, total phenols, flavonoids, carotenoids, and anthocyanins are important components of the non-enzymatic antioxidant network. Increased non-enzymatic antioxidants under stress can enhance free radical scavenging and stabilize membrane structures. If total phenols and flavonoids increase together with POD changes, their role in secondary metabolism and defense-related structural reinforcement should also be considered.
Table 3 Antioxidant System Indicators and Result Interpretation
Indicator | Main Role | Recommended Combined Indicators | Interpretation Focus |
H₂O₂ | ROS signal and oxidative pressure readout | CAT, APX, MDA | Distinguish signaling-related increase from damage-associated accumulation |
O₂·⁻ | Early ROS production readout | SOD, NBT staining, MDA | Determine superoxide scavenging pressure |
SOD | Dismutation of O₂·⁻ | CAT, APX, H₂O₂ | Assess whether downstream H₂O₂ clearance is matched |
CAT | High-capacity H₂O₂ scavenging | H₂O₂, APX, POD | Suitable for evaluating rapid H₂O₂ clearance capacity |
POD | H₂O₂ scavenging and cell wall-related responses | Lignin, total phenols, H₂O₂ | Should not be interpreted only as an antioxidant enzyme |
APX | AsA-dependent H₂O₂ scavenging | AsA/DHA, GR, GSH/GSSG | Reflects fine H₂O₂ scavenging capacity |
GR | GSH cycle regeneration | GSH/GSSG, NADPH | Determines reducing power maintenance capacity |
MDA | Membrane lipid peroxidation product | Electrical conductivity, ROS, antioxidant enzymes | Reflects the degree of oxidative damage |
GSH/GSSG | Redox status | APX, GR, ROS | More informative than GSH alone for redox status |
6 Metabolic Network Interpretation under Different Stress Scenarios
6.1 Drought stress
Under drought stress, proline and soluble sugars usually participate in osmotic regulation, while the antioxidant system controls ROS accumulation. If proline and soluble sugars increase moderately, SOD/CAT/APX activities are enhanced, and MDA and electrical conductivity decrease, this indicates strong drought adaptation. If these protective indicators increase but MDA continues to rise, stress intensity has exceeded the metabolic protection threshold.
6.2 Salt stress
Salt stress simultaneously causes osmotic stress, ion toxicity, and oxidative stress. GABA, proline, and soluble sugars can buffer osmotic pressure, while the antioxidant system reduces ROS damage. Salt stress studies should detect Na⁺, K⁺, Na⁺/K⁺ ratio, proline, GABA, soluble sugars, SOD, CAT, APX, and MDA together to distinguish whether salt tolerance arises from ion homeostasis, osmotic regulation, or enhanced antioxidant capacity.
6.3 Low-temperature stress
Low temperature restricts membrane fluidity, photosynthesis, and mitochondrial metabolism. GABA, soluble sugars, and the antioxidant system often respond together. Increased soluble sugars can protect membranes and protein structures, the GABA shunt may participate in carbon flow buffering, and antioxidant enzymes reduce low-temperature-induced ROS accumulation. If soluble sugars increase after low-temperature treatment while MDA decreases and chlorophyll is better maintained, carbon metabolic protection may be associated with membrane stability.
6.4 Heavy metal stress
Heavy metal stress often induces ROS accumulation, membrane damage, and glutathione-related detoxification responses. Changes in proline, GSH, POD, APX, and CAT can reflect plant antioxidant and detoxification capacity. If GSH/GSSG decreases, MDA increases, and antioxidant enzyme activities decline, this indicates insufficient reducing power and aggravated oxidative damage. If GSH, total phenols, POD, and APX are enhanced, detoxification and defense metabolism may be activated.
Table 4 Recommended Detection Combinations for Different Stress Types
Stress Type | Recommended Detection Combination | Core Interpretation |
Drought stress | Proline, soluble sugars, RWC, SOD/CAT/APX, MDA | Evaluate osmotic regulation and membrane protection capacity |
Salt stress | Na⁺/K⁺, GABA, proline, soluble sugars, ROS, antioxidant enzymes | Distinguish ion homeostasis, osmotic regulation, and antioxidant response |
Low-temperature stress | Soluble sugars, GABA, MDA, chlorophyll, CAT/APX | Evaluate membrane stability, carbon flow buffering, and ROS scavenging capacity |
High-temperature stress | Soluble sugars, proline, H₂O₂, SOD/POD/CAT, protein damage | Evaluate heat injury and antioxidant protection |
Heavy metal stress | Proline, GSH/GSSG, POD/APX, MDA, metal content | Determine detoxification capacity and oxidative damage level |
Pathogen stress | GABA, POD, total phenols, flavonoids, H₂O₂, MDA | Analyze the balance between defense signaling and oxidative burst |
7 Product Selection for Plant Stress Metabolic Networks
Table 5 Product Selection for Detection Kits and Enzyme Activity Analysis in Plant Stress Metabolic Networks
Application Module | Cat. No. | Product Name | Grade/Specification | Method/System | Application Positioning |
GABA content detection | γ-Aminobutyric Acid (GABA) Content Detection Kit (Phenol-sodium hypochlorite, Micro Method) | BioReagent | Phenol-sodium hypochlorite, micro method | Used for detecting GABA content in plant leaves, roots, or stress-treated samples and evaluating the degree of GABA branch activation | |
GABA content detection | γ-Aminobutyric Acid (GABA) Content Assay Kit (Phenol-Sodium Hypochlorite, Colorimetric Method) | BioReagent | Phenol-sodium hypochlorite, colorimetric method | Used for routine colorimetric detection of GABA content; suitable for comparison among multiple plant stress treatment groups | |
GABA-producing enzyme activity | Glutamate Decarboxylase (GAD) Activity Assay Kit (GABA, Micro Method) | BioReagent | GABA production detection, micro method | Used to evaluate key enzyme activity for glutamate diversion into GABA | |
GABA catabolic enzyme activity | GABA Transaminase Activity Assay Kit (Micro Method) | BioReagent | Micro method | Used to detect the metabolic capacity of GABA to further enter TCA-related branches | |
GABA catabolic enzyme activity | GABA Transaminase Activity Assay Kit (Colorimetric Method) | BioReagent | Colorimetric method | Used for routine detection of GABA transaminase activity and auxiliary determination of GABA branch metabolic fate | |
Proline content detection | Proline (PRO) Content Assay Kit (Ninhydrin, Micro Method) | BioReagent | Ninhydrin, micro method | Used for analyzing proline accumulation under drought, salt stress, low temperature, and heavy metal stress | |
Proline content detection | Proline (PRO) Content Assay Kit (Ninhydrin, Colorimetric Method) | BioReagent | Ninhydrin, colorimetric method | Used for routine proline content detection and evaluation of plant osmotic regulation and stress response intensity | |
Proline catabolic enzyme activity | Proline Dehydrogenase (ProDH) Activity Assay Kit (UV Micro Method) | BioReagent | UV micro method | Used to evaluate proline degradation and carbon-nitrogen reutilization capacity during stress recovery | |
Proline catabolic enzyme activity | Proline Dehydrogenase (ProDH) Activity Assay Kit (UV Colorimetric Method) | BioReagent | UV colorimetric method | Used for routine ProDH activity detection and auxiliary determination of the balance between proline accumulation and degradation | |
Soluble sugar detection | Plant Soluble Sugar Content Assay Kit (Phenol, Micro Method) | BioReagent | Phenol method, micro method | Used for total soluble sugar detection under plant stress and evaluation of osmotic regulation and carbon reserve changes | |
Soluble sugar detection | Plant Soluble Sugar Content Assay Kit (Phenol, Colorimetric Method) | BioReagent | Phenol method, colorimetric method | Used for routine colorimetric detection of soluble sugars, suitable for comparison of leaves, roots, and fruit samples | |
Soluble sugar detection | Plant Soluble Sugar Content Assay Kit (Anthrone, Micro Method) | BioReagent | Anthrone method, micro method | Used for soluble sugar detection in small plant tissue samples, suitable for multi-time-point stress experiments | |
Soluble sugar detection | Plant Soluble Sugar Content Assay Kit (Anthrone, Colorimetric Method) | BioReagent | Anthrone method, colorimetric method | Used for total soluble sugar colorimetric detection and auxiliary analysis of osmoprotection and carbon metabolic redistribution | |
Starch reserve detection | Starch Assay Kit (Anthrone, Micro Method) | BioReagent | Anthrone method, micro method | Used to analyze starch degradation and the source of soluble sugars under plant stress | |
Starch reserve detection | Starch Content Assay Kit (Anthrone, Colorimetric Method) | BioReagent | Anthrone method, colorimetric method | Used for routine starch content detection and auxiliary determination of carbon reserve mobilization | |
Starch composition analysis | Branched Chain/Amylose/Total Starch Content Assay Kit (Micro Method) | BioReagent | Micro method | Used to distinguish changes in amylose, amylopectin, and total starch; suitable for structural analysis of carbon reserves | |
Starch composition analysis | Branched Chain/Amylose/Total Starch Content Assay Kit (Colorimetric Method) | BioReagent | Colorimetric method | Used for routine detection of starch composition and auxiliary analysis of starch remodeling under stress | |
Amylose detection | Amylose Content Assay Kit (Micro Method) | BioReagent | Micro method | Used to evaluate changes in amylose content and carbon reserve structural adjustment under stress | |
Amylose detection | Amylose Content Assay Kit (Colorimetric Method) | BioReagent | Colorimetric method | Used for routine amylose detection, suitable for carbon reserve analysis in plant tissues | |
Amylopectin detection | Branched Chain Starch Content Assay Kit (Micro Method) | BioReagent | Micro method | Used for amylopectin content detection and auxiliary analysis of starch component changes under stress | |
Amylopectin detection | Branched Chain Starch Content Assay Kit (Colorimetric Method) | BioReagent | Colorimetric method | Used for routine amylopectin detection, suitable for coupled analysis of carbon reserves and sugar metabolism | |
Resistant starch detection | Resistant Starch Content Assay Kit (Micro Method) | BioReagent | Micro method | Used for resistant starch content detection, suitable for analyzing carbon reserve stability in specific plant materials | |
Resistant starch detection | Resistant Starch Content Assay Kit (Colorimetric Method) | BioReagent | Colorimetric method | Used for routine resistant starch detection and auxiliary evaluation of starch utilization characteristics under stress | |
H₂O₂ detection | Hydrogen Peroxide (H₂O₂) Content Assay Kit (TTS, Micro Method) |
| Titanium sulfate method, micro method | Used to detect H₂O₂ accumulation under plant stress and evaluate oxidative pressure and ROS signaling intensity | |
H₂O₂ detection | Hydrogen Peroxide (H₂O₂) Content Assay Kit (TTS, Colorimetric Method) | BioReagent | Titanium sulfate method, colorimetric method | Used for routine H₂O₂ detection and can be interpreted together with CAT, APX, and MDA | |
Superoxide anion detection | Micro Superoxide Anion Assay Kit (Griess, Micro Method) | BioReagent | Griess method, micro method | Used to evaluate the intensity of superoxide anion production under stress | |
Superoxide anion detection | Superoxide Anion Content Assay Kit (Sulfanilamide, Micro Method) | BioReagent | Sulfanilamide method, micro method | Used for O₂·⁻ content detection in small plant tissue samples | |
Superoxide anion detection | Superoxide Anion Content Assay Kit (Sulfanilamide, Colorimetric Method) | BioReagent | Sulfanilamide method, colorimetric method | Used for routine colorimetric detection of O₂·⁻ content and auxiliary evaluation of ROS production | |
Superoxide anion scavenging capacity | Superoxide Anion Scavenging Capacity Assay Kit (NBT, Micro Method) | BioReagent | NBT method, micro method | Used to evaluate the scavenging capacity of plant tissues or extracts toward superoxide anion | |
Superoxide anion scavenging capacity | Superoxide Anion Scavenging Capacity Assay Kit (NBT, Colorimetric Method) | BioReagent | NBT method, colorimetric method | Used for routine detection of superoxide anion scavenging capacity and antioxidant capacity comparison | |
Superoxide anion scavenging capacity | Superoxide anion Scavenging Capacity Assay Kit (WST-8, Micro Method) | BioReagent | WST-8 method, micro method | Used for high-sensitivity evaluation of O₂·⁻ scavenging capacity, suitable for micro plant samples | |
Superoxide anion scavenging capacity | Superoxide Anion Scavenging Capacity Assay Kit (Pyrogallol, Micro Method) | BioReagent | Pyrogallol method, micro method | Used for small-sample antioxidant scavenging capacity analysis | |
Superoxide anion scavenging capacity | Superoxide Anion Scavenging Capacity Assay Kit (Pyrogallol, Colorimetric Method) | BioReagent | Pyrogallol method, colorimetric method | Used for routine detection of superoxide anion scavenging capacity | |
MDA membrane lipid peroxidation detection | Plant Malondialdehyde (MDA) Content Assay Kit (TBA, Colorimetric Method) | BioReagent | TBA method, colorimetric method | Used for detecting plant membrane lipid peroxidation and evaluating stress injury level | |
MDA membrane lipid peroxidation detection | Malondialdehyde (MDA) Content Assay Kit (TBA, Colorimetric Method) | BioReagent | TBA method, colorimetric method | Used for routine MDA detection as an indicator of oxidative damage and membrane stability | |
MDA membrane lipid peroxidation detection | Malondialdehyde (MDA) Content Assay Kit (TBA, Fluorometric Method) | BioReagent | TBA method, fluorometric method | Used for low-abundance or high-sensitivity MDA detection, suitable for auxiliary validation in complex samples | |
SOD activity detection | Total Superoxide Dismutase (SOD) Assay Kit (NBT Riboflavin Microplate Method) | BioReagent | NBT riboflavin microplate method | Used to detect total SOD activity in plant samples and evaluate upstream O₂·⁻ scavenging capacity | |
SOD activity detection | Total Superoxide Dismutase (SOD) Assay Kit (NBT Riboflavin Colorimetric Method) | BioReagent | NBT riboflavin colorimetric method | Used for routine colorimetric detection of SOD activity and comparison among stress treatment groups | |
SOD activity detection | Total Superoxide Dismutase (T-SOD) Activity Assay Kit (WST-8, Micro Method) | BioReagent | WST-8 method, micro method | Used for SOD activity detection in small plant tissue samples | |
SOD activity detection | Total Superoxide Dismutase (SOD) Activity Assay Kit (Pyrogallol, UV Colorimetric Method) | BioReagent | Pyrogallol, UV colorimetric method | Used for SOD activity detection and auxiliary evaluation of superoxide anion scavenging capacity | |
CAT activity detection | Catalase (CAT) Activity Assay Kit (UV Micro Method) | BioReagent | UV micro method | Used to evaluate rapid H₂O₂ scavenging capacity in plant tissues | |
CAT activity detection | Catalase (CAT) Activity Assay Kit (UV Colorimetric Method) | BioReagent | UV colorimetric method | Used for routine CAT activity detection, suitable for drought, salt stress, and high-temperature stress analysis | |
CAT activity detection | Catalase (CAT) Activity Assay Kit (AHM, Micro Method) | BioReagent | Ammonium molybdate method, micro method | Used for CAT activity detection in small samples and can be combined with H₂O₂ content analysis | |
CAT activity detection | Catalase (CAT) Activity Assay Kit (AHM, Colorimetric Method) | BioReagent | Ammonium molybdate method, colorimetric method | Used for colorimetric detection of CAT activity and auxiliary evaluation of H₂O₂ scavenging capacity | |
CAT activity detection | Catalase Assay Kit（UV absorption method） | 100T/96S | UV absorbance method | Used for CAT activity detection, suitable for microplate or conventional spectrophotometric systems | |
CAT activity detection | Catalase (CAT) Activity Assay Kit (Peroxidase Method) | BioReagent | Peroxidase method | Used for CAT-related detection and combined analysis with H₂O₂ scavenging indicators | |
APX activity detection | Ascorbate Peroxidase (APX) Activity Assay Kit (UV Micro Method) | BioReagent | UV micro method | Used to evaluate AsA-dependent H₂O₂ scavenging capacity and AsA-GSH cycle activity | |
APX activity detection | Ascorbate Peroxidase (APX) Activity Assay Kit (UV Colorimetric Method) | BioReagent | UV colorimetric method | Used for routine APX activity detection and auxiliary evaluation of fine H₂O₂ scavenging capacity | |
POD activity detection | Plant Peroxidase (POD) Activity Assay Kit (Guaiacol, Micro Method) | BioReagent | Guaiacol method, micro method | Used for plant POD activity detection and evaluation of H₂O₂ scavenging, cell wall reinforcement, and defense responses | |
POD activity detection | Plant Peroxidase (POD) Activity Assay Kit (Guaiacol, Colorimetric Method) | BioReagent | Guaiacol method, colorimetric method | Used for colorimetric detection of plant POD activity, suitable for evaluating stress-induced antioxidant responses | |
POD activity detection | Peroxidase (POD) Activity Assay Kit (Guaiacol, Micro Method) | BioReagent | Guaiacol method, micro method | Used for POD activity detection, suitable for linked antioxidant enzyme analysis in plant samples | |
POD activity detection | Peroxidase (POD) Activity Assay Kit (Colorimetric Method) | BioReagent | Colorimetric method | Used for routine POD activity detection and auxiliary evaluation of H₂O₂ scavenging capacity | |
GSH-Px activity detection | Glutathione Peroxidase (GSH-Px) Activity Assay Kit (DTNB, Micro Method) | BioReagent | DTNB method, micro method | Used to detect glutathione-dependent peroxide scavenging capacity | |
GSH-Px activity detection | Glutathione Peroxidase (GSH-Px) Activity Assay Kit (DTNB, Colorimetric Method) | BioReagent | DTNB method, colorimetric method | Used for routine detection of GSH-Px activity and auxiliary evaluation of the GSH-related antioxidant system | |
TPX activity detection | Thioredoxin Peroxidase (TPX) Assay Kit (UV Micro Method) | BioReagent | UV micro method | Used to analyze thioredoxin system-related peroxide scavenging capacity | |
Lignin peroxidase detection | Lignin Peroxidase (Lip) Activity Assay Kit (Veratryl Alcohol, Micro Method) | BioReagent | Veratryl alcohol method, micro method | Used to detect lignin-related peroxidase activity, suitable for stress-induced cell wall defense and lignification research | |
Lignin peroxidase detection | Lignin Peroxidase (Lip) Activity Assay Kit (Veratryl Alcohol, Colorimetric Method) | BioReagent | Veratryl alcohol method, colorimetric method | Used for routine LiP activity detection and auxiliary analysis of cell wall reinforcement-related defense responses | |
Manganese peroxidase detection | Manganese Peroxidase (Mnp) Activity Assay Kit (Guaiacol, Micro Method) | BioReagent | Guaiacol method, micro method | Used to detect manganese peroxidase activity, suitable for specific plant or rhizosphere-related peroxidase research | |
Manganese peroxidase detection | Manganese Peroxidase (Mnp) Activity Assay Kit (Guaiacol, Colorimetric Method) | BioReagent | Guaiacol method, colorimetric method | Used for routine MnP activity detection and auxiliary evaluation of peroxidase-related defense responses |
8 Common Questions
8.1 Does increased GABA always indicate enhanced plant stress tolerance?
No. Increased GABA may indicate activation of the GABA shunt, enhanced glutamate diversion, or increased stress severity. If increased GABA is accompanied by decreased ROS and MDA and reduced growth inhibition, it more strongly supports a relationship with stress tolerance. If damage indicators still increase, it only indicates activation of the stress response.
8.2 Does higher proline content mean stronger drought tolerance?
No. Increased proline may represent protective osmotic regulation, but it may also be a consequence of severe stress. Relative water content, MDA, electrical conductivity, chlorophyll, and growth phenotype should be considered together.
8.3 Can total soluble sugars represent the full picture of sugar metabolism?
No. Total soluble sugars only reflect the overall soluble sugar pool and cannot distinguish sucrose, glucose, fructose, and oligosaccharides. To determine carbon flow direction, monosaccharide/sucrose composition, starch, and sugar metabolism enzyme activities should be further detected.
8.4 Why do antioxidant enzyme activities increase while MDA still increases?
This usually indicates that ROS production exceeds scavenging capacity, or that the non-enzymatic antioxidant system and reducing power are insufficient. H₂O₂, O₂·⁻, GSH/GSSG, AsA/DHA, and treatment time gradients should be added for analysis.
Plant stress metabolic network analysis should be built around “osmotic regulation-carbon and nitrogen branching-ROS scavenging-membrane damage.” GABA, proline, and soluble sugars reflect metabolic adaptation, while the antioxidant system and MDA reflect defense effectiveness and damage severity. Only by analyzing these indicators together can the metabolic basis of plant stress tolerance be interpreted more accurately.
For more related articles, please see below:
[1] Determination of the degree of adversity injury to plant tissues
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