The eff ects of natural factors (temperatures +34°C and +20°C) and anthropogenic xenobiotics (1,2,4-TriH; 1-(CH3 SO2 )-1H-1,2,4-Tri; 4-(PhSO2 )-4H-1,2,4-Tri; 4-(TolSO2 )-4H-1,2,4-Tri) on watercress Lepidium sativum L. was studied. For this, 4 series of experiments were carried out. In the fi rst two series, the eff ect of concentrations was studied: 0.001, 0.01, 0.1 mg/ml during germination at diff erent temperatures for three days. It was found that the ability of the triazole compounds to inhibit the germination of watercress seeds increased with increasing concentration of the solutions. The magnitude of lipophilicity was the determining factor in their toxicity. Diff erences between the infl uence of the studied temperatures on the energy of seed germination weren’t revealed. The ability of the synthesized triazoles to inhibit the growth of watercress roots and stems increased with increasing their concentration. At the same time, their toxicity was signifi cantly higher at the higher of the studied temperatures. The next two series examined the ability of Lepidium sativum to adapt to the toxicity of triazoles. To do this, the seeds were germinated during the day at contrasting temperatures in solutions with a concentration of 0.001 mg/ml, then they were germinated in solutions of 0.1 mg/ml for two days. It turned out that triazoles had signifi cantly diff erent eff ects on the development of the adaptive response in plants. Only 4-(PhSO2 )-4H-1,2,4-Tri; 4-(TolSO2 )-4H-1,2,4-Tri caused a signifi cant development of an adaptive response, the magnitude of which also depended on the cultivation temperature. We found that the value of lipophilicity of the studied triazoles was of signifi cant importance during their direct action, and the values of their molecular weight and molecular volume were important for the development of preadaptation.