Although oxidative stress biomarkers are great tools there is none that is exclusive from a specific kind of stress. There is always a chain of anti-oxidative mechanisms that most of the times gathers almost all the anti-oxidant defences from the cell.

Hi, Rishikesh, you are right, different "stressor" may lead to damage in different compartments, according to sites of ROS accumulations in plants. In green part of the plants mature choloroplasts are the main source of ROS generation, therefore can be consider as main potentail site of ROS accumulation under phoinhibition, cold stress under moderate light, etc. Under such conditions choloplast have been damage at the first. The other type of stress ma yrelated with effect of repisratoion (mitochondrial) electron transport. That's why plants have a different anti-oxdiative machinery, specific for each compartments: stroma and thylakoid APX, peroxsisomal catalase, cell wall peroxidase etc..

Hi, Rishikesh, the answer is yes, different endogenous and external stimuli trigger the accumulation of ROS in plants. Whilst low concentrations of ROS like hydrogen peroxide and superoxide anion could serve the plant in signaling events, high ROS concentration could lead to membrane or protein damage. I strongly recommend you to read the article "The Language of Reactive Oxygen Species Signaling in Plants" (Bhattacharjee 2012) that is attached here for a complete review.

Good luck!

Hi, Rishikesh, the answer is yes, different endogenous and external stimuli trigger the accumulation of ROS in plants. Whilst low concentrations of ROS like hydrogen peroxide and superoxide anion could serve the plant in signaling events, high ROS concentration could lead to membrane or protein damage at the first.

Hi Rishikesh, one of determinant features in oxidative burst is the intensity and duration of the stress causing it, which also determine the amount of of ROS produced that will serve, as Ayadi Malika said, as signaling molecules or to inflict direct damage to the cell.

Despite is commonly known that ROS or free-radical compounds generate damage in different cellular compartments.... you should take into account that if the stress condition that generate ROS is not so "intense", that could be a signal for protective response against an stressful environment. Free-radicals are not only simple reactive molecules, also participate in many signalling pathways.

I agree with Facundo, ROS generation is have a very important signalling function in plant development. That's why it is very important to measure ROS balance (differences between production and scavenger) during different stress conditions.

In many case under stress conditions plants "decide" to reduce ROS production instead of increasing scavenger. Such situation occurred in specific cells types and may lead to temporary dormancy in plant development.

You can find more information in some of my papers.

While it is true that there are different types of plant oxidative stresses and that they all similarly induce an imbalance in ROS homeostasis, each abiotic stress differ in their mechanism of inducing oxidative stress in the plants.

Many abiotic (drought, salinity, high temp., nutrient depletion) and biotic stresses (pathogen attack) causes directly or indirectly generation of free radicals and ROS as bye main or bye product that causes ultimately membrane and protein damage. so different types of stresses causes oxidative stress.

Abiotic and biotic factors alike could directly or indirectly induce production of reactive oxygen species (ROS) and even reactive nitrogen species (RNS). These species could give rise to oxidative and/or nitrosative stress in plant leading to oxidative modification of some macromolecules including protein, lipid, DNA, etc.and membrane damage. The abilty of the plant to respond timely to these modifications forms a basis for their adaptation. This marks these danger molecules also as part of the signalling pathway.

yes, i do agree with these views that ROS act as a signalling messenger under low intensity but cause cellular ( oxidation) damage when produced at high level of production under different kinds of oxidative stresses.

oxidative stress affects productivity, reduces crop yeild, alters plant metabolism, reduces water potential, ion imbalance, toxicity this leads to oxidative stress due to Reactive oxygen species ROS damages cellular functions this ultimately leads to cell death.

Environmental stimuli that affects cellular homeostasis in a negative way can cause production of ROS. Type and site of damage can change with the different types of stressors. For example if there is high light stress, or low temperatures under mid-high light singlet oxygen can be produced in chloroplasts (which is known to be the major cause of lipid peroxidation) damaging lipids and other bio-molecules in this organelle. If there is high ozone ROS is produced in apoplast and damage occurs in that compartment. If electron transport chains in mitochondria are overloaded this may cause production of superoxide anion radical therefore causing damage in mitochondria.

Overall, different types of stress can cause i) production of different ROS, ii) cause production in different organnelles, iii) can cause different extend of ROS production.

Damage can be done to lipids (generally measured by TBARS assays), proteins (can be measured by protein carbonyl assay) or other important molecules such as DNA or RNA.

Yes, indeed, there are different types of oxidative stresses that can occur in plants, however, oxidative damages all occur mainly as the result of ROS production which will result in cell membrane damage.

Any prevalence of the formation over elimination of reactive species (they don't have to be only ROS), which results in a substantial damage of the host's tissue is considered to be oxidative stress, no matter of the nature of the triggering factor. If the OS occurs in the voids between the cells, it is extra-cellular, if occurs inside of the cells it is intracellular, and if occurs both within and inside of the cells, it is inter&extracellular. There are diseases, associated with each of these types of OS. Of course, it is convenient to name the OS by the triggering factor (heat-induced, cold-induced, pesticide-induced, heavy metal-induced, etc), or it may be named by the pathology that is being associated with (disease-induced). But whatever the label, it has to correspond to the same general definition.