The Language of Reactive Oxygen Species Signaling in Plants

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 10⁻⁹m⁻²s⁻¹).

ROS	Half life	Migration capacity	Source	Reacts with			References
				DNA	Protein	Lipid, carbohydrate
Superoxide (O2•−)	1–4 μs	30 nm	Membranes, chloroplast (Mehler reaction), mitochondria	No	Yes (Fe-centre)	Hardly	[2, 5, 9]
Hydrogen peroxide (H2O2)	1 ms	1 μm	Membranes, chloroplast, mitochondria, peroxysome	No	Yes (Cysteine)	Hardly	[2, 8]
Hydroxyl radical (OH^•)	1 μs	1 nm	Chloroplast, membranes, mitochondria	Rapidly	Rapidly	Rapidly	[2, 8]
Singlet oxygen (^|O2)	1–4 μs	30 nm	Chloroplast, membranes, mitochondria	Yes (Guanine)	Trp, His, Tyr, Met, Cys.	PUFA	[8, 10]
Alkoxy radicals (RO^•)	?	1 nm	Membrane lipid peroxydation	No	Yes	PUFA	[2, 8]
Peroxy radicals (ROO^•)	?	1 nm	Membrane lipid peroxydation	No	Yes	PUFA	[8, 10]