PEA RESPONSE TO SALT AND THERMAL STRESSES IN DEPENDENCE ON PRELIMINARY IONIZING RADIATION IMPACT

T is important to find specific and non-specific aspects of plant response reactions during adaptation, to understand the pathways of signaling systems crossing and their interaction. To detect the points of signaling systems interaction a set of experiments was suggested. The pea seedlings were irradiated by X-ray. Additionally, some seedlings after irradiation were exposed to hyper thermal stress or to the osmotic stress. The aim of research was to study the modifying effect of ionizing radiation on other abiotic stress factors impact such as salinity and temperature. Morphometric measurements were used to estimate plant's response on stresses. These data can integrally characterize molecular, genetic, structural and metabolic changes in pea seedlings on their initial growth phase. For this purpose, the average growth rate of roots was compared with the theoretically expected growth rate that was calculated as an additive interaction of stress factors. “Crosstalk” means the growth of organism's resistance to one stress factor as a result of adaptation to another stressor. It is a result of interconnection and “dialogue” of various signal systems of plant. The time frame of the modifying influence of one stressor had the greatest impact on the appearance of another was found. The level of deviation from additive to synergistic or antagonistic model of stressors interaction may indicate the crosstalk effect. It was shown that crosstalk is most pronounced on second and eighth days after treatments impact. Preliminary ionizing irradiation of seedlings could modify and increase the resistance to subsequently osmotic or thermal stress impact but this phenomenon was short-term. At other phases of experiment the expected growth rates and empirical average growth rates nearly matched. It may be explained by crosstalk pathways switching.