Abstract: The aim of the present study was to follow the early growth of wheat seedlings at different temperatures regimes and to assess the threshold of sensitivity of the wheat seedlings to heat constraints during the early stage of development. Obtained results showed that solely temperatures 15° and 25 °C allow early growth of wheat seedlings, while this growth was inhibited at all other temperatures 5°, 35° and 45 °C. The following of the mineral ionic content in K+ and Ca2+ as function of time showed, after 2, 4 and 6 days of germination at 25°C, a decrease in the amount of potassium and calcium in both roots (R) and aerial parts (AP) or shoots of the young wheat seedlings. The drop in the content of Ca2+ is more pronounced, particularly, in the shoots of the seedlings. The temperature 15 °C caused a significant decrease of the ionic contents (K+ and Ca2+) of roots and shoots of seedlings obtained in the 6th day with regard to those obtained in the 4th day of early growth. After 6 days of growth at 25 °C, we obtained content in Ca2+ more important in the roots than that in the shoots, whereas at 15 °C the opposite was observed. The peroxidasic activity in roots and AP (shoots) of wheat seedlings obtained from seeds have germinated either at 15 ° or at 25 °C, decreases as function of time. After 4 days of the early growth at 15 °C, the activity of the total soluble peroxidases of R and AP is higher than that of R and AP of seedlings grown at 25 °C. After 6 days, this enzymatic activity increased solely in the R of seedlings grown at 25 °C if compared to those (R) obtained from seedlings established at 15 °C.