Reactive oxygen forms and Ca ions as possible intermediaries under the induction of heat resistance of plant cells

Signal Mediators in the Implementation of Jasmonic Acid’s Protective Effect on Plants under Abiotic Stresses

“…The stress-protective effect of exogenous JA seems, in many cases, to be realized with the participation of calcium entering the cytosol from different pools. Thus, the increase in heat resistance of wheat coleoptile cells caused by exogenous JA was almost completely eliminated by both the calcium channel blocker lanthanum chloride and the extracellular calcium chelator EGTA [ 66 ]. It is possible that the physiological effects of JA are realized through the joint participation of calcium and ROS (see below).…”

“…Exogenous JA increases NADPH oxidase-dependent superoxide anion radicals and hydrogen peroxide generation. In turn, the effect of NADPH oxidase activation was eliminated by calcium antagonists [ 66 ]. NADPH oxidase is known to be both directly and indirectly activated by calcium ions [ 67 , 68 ].…”

“…It is likely that ROS, as mediators, are also involved in JA induction of plant defense responses to abiotic stresses. As mentioned above, the increase in heat resistance of wheat coleoptiles by exogenous JA was accompanied by a calcium-dependent increase in ROS generation [ 66 ]. The ROS scavenger ionol, NADPH-oxidase inhibitor imidazole, and peroxidase inhibitor salicylhydroxamic acid eliminated the JA-induced effect of increased superoxide anion radical formation by the coleoptile cell surface and the subsequent increase in their resistance to heating.…”

“…The ROS scavenger ionol, NADPH-oxidase inhibitor imidazole, and peroxidase inhibitor salicylhydroxamic acid eliminated the JA-induced effect of increased superoxide anion radical formation by the coleoptile cell surface and the subsequent increase in their resistance to heating. In this case, at least two enzymes are thought to be involved in the formation of ROS signaling pool: NADPH oxidase and cell wall peroxidase [ 66 ]. As already noted, plant extracellular peroxidases have the ability to generate O 2 •− ; it is particularly evident in the presence of excess reducing agents [ 81 ].…”