Table 1: The important ROS in plant tissues and their basic properties (half life-in biological system, migration capacity-Distance traveled in one half-life time, if the diffusion coefficient is assumed to be 10−9 m−2s−1).

ROSHalf lifeMigration capacitySourceReacts withReferences
DNAProteinLipid, carbohydrate

Superoxide ( O 2 )1–4 μs30 nmMembranes, chloroplast (Mehler reaction), mitochondriaNoYes (Fe-centre)Hardly[2, 5, 9]
Hydrogen peroxide (H2O2)1 ms1 μmMembranes, chloroplast, mitochondria, peroxysomeNoYes (Cysteine)Hardly[2, 8]
Hydroxyl radical ( O H )1 μs1 nmChloroplast, membranes, mitochondriaRapidlyRapidlyRapidly[2, 8]
Singlet oxygen (|O2)1–4 μs30 nmChloroplast, membranes, mitochondriaYes (Guanine)Trp, His, Tyr, Met, Cys.PUFA[8, 10]
Alkoxy radicals ( R O )?1 nmMembrane lipid peroxydationNoYesPUFA[2, 8]
Peroxy radicals ( R O O )?1 nmMembrane lipid peroxydationNoYesPUFA[8, 10]