抄録
Salicylic acid (SA) is the first molecule connecting the reactive oxygen species (ROS) and calcium signaling in plant defense mechanism. It has been shown that SA induces the production of ROS such as superoxide in tobacco cell culture through extracellular peroxidase reaction. Interestingly the SA-induced ROS eventually stimulates the movement of extracellular free calcium ion into the cells in a channel blocker-sensitive manner. Similarly, some elicitors added to tobacco cells stimulate the generation of ROS followed by calcium influx. Abscisic acid and aluminum ion were shown to stimulate the ROS-generating plant NADPH oxidase in Arabidopsis and tobacco cells, respectively. Such NADPH oxidase-dependent ROS production reportedly results in induction of calcium influx too. Recent advances in the search for the ROS-responsive calcium channels in plants and the possible use of novel selective channel blockers in the study of plant responses to pathogen attacks and environmental stresses will be discussed.
