Table 1.

Main reactive oxygen species (ROS) and reactive nitrogen species (RNS) found in plant cells (adapted from Rahman et al., 2012).

Free radicals	Non-radicals
Reactive oxygen species
Superoxide, ${\mathrm{O}}_{\mathrm{2}}^{\mathrm{•-}}$	Hydrogen peroxide, H2O2
Alkoxyl, RO•	Hypochlorous acid, HOCl
Hydroxyl, OH-	Ozone, O3
Peroxyl, ROO•	Peroxynitrite, ONOO-
Hydroperoxyl, HO2•	Singlet oxygen, 1O2
Reactive nitrogen species
Nitric oxide, NO•	Nitrous acid, HNO2
Nitric dioxide, NO2•	Nitrosonium cation, NO+
Nitrate radical, NO3•	Nitrosyl anion, NO-
	Peroxynitrite, ONOO-
	Alkylperoxynitrites: ROONO
	Dinitrogen trioxide, N2O3