Polyamines are water-soluble aliphatic polyanionic substances containing several amine groups and available in all plant cells [1, 2]. Diamine putrescine NH2-(СH2)4-NH2, triamine spermidine NH2-(СH2)4-NH-(СH2)3-NH2 and tetramine spermine NH2-(СH2)3-NH-(СH2)4-NH-(СH2)3-NH2 are the most abundant polyamines in plants [3, 4]. They have a fundamental importance for DNA stability in nucleus, where they act as low molecular weight chaperons [5]. Polyamines are also involved in plant stress responses [6]. The detected concentration of polyamines in plants varies from 1 to 10 mM and increases in response to abiotic stresses [1-4, 6, 7]. The symptoms of oxidative stress in plants decrease, when enzymes of polyamine biosynthesis are over-expressed [8]. Surprisingly, polyamines also play the role of substrate for ROS production in the apoplast by polyamine oxidase [8, 9]. Here, we demonstrate that polyamines decrease the intensity of NaCl- and ROS-induced Ca2+ signals, diminish loss of K+ via ROS-activated K+ efflux channel GORK and act as hydroxyl radical scavengers. At the same time, we show that they stimulate superoxide production and trigger programmed cell death (PCD).