The influence of heat shock (HS) with different temperatures on wheat seeds, cv. Odesskaia 267, was determined. For analysis were selected wheat seeds, germination of which was manifested by the appearance of 2-3 mm length rootlet. In accordance with the induced effects, the HS temperatures, applied during 10 minutes, were distributed into three zones: 1. the zone of temperatures which does not substantially change the physiological state of the seeds (zone of tolerance - limit temperature 43oC); 2. the zone of temperatures inducing moderate stress (zone of moderate stress - HS temperatures between 43 and 49oC); 3. the zone of temperatures inducing acute stress (zone of acute stress – HS temperatures exceeding 49oC). Validity of separation HS temperatures in these zones is based on the analysis of distribution of seedlings with different number of roots in the second and fifth day after the application of HS. Linear dependencies of the percentage of seedlings that in the second and fifth day after application of HS have inhibited the apparition of seminal roots, or reduced the average number of seedling roots depending of HS temperature, supports the vision of the existence of mentioned zones. Taking into account the literature data, we can conclude that by distribution of HS temperatures in zones we can characterize the specific processes characteristics for each zone and to determine HS temperatures retaining, or stopping division of the roots initials of root meristems. The zone of critical temperatures approximately extends between 51and 54oC.