Plants are always exposed to vast aspects of either environmental biotic or abiotic stresses and those stresses affecting the plant growth and therefore crop production. Molecular and physiological mechanisms influence plant resistance to environmental stresses, therefore the identification of these mechanisms can be an important step in challenging the damages. In this study, plant physiological responses of two cold sensitive bread wheat cultivars, namely: Bayat and Darab1 vs. two cold resistant cultivars named Alvand and Shahi were studied. The amount of relative water content, chlorophylls, carotenoids as well as free proline amino acids were assessed. In addition, partial of the gene responsible for the responses to cold stress in the four wheat cultivars were isolated. The results indicated that the relative water content and the level of chlorophylls as well as carotenoids were significantly reduced in response to the stress. This reduction was more pronounced in the case of the sensitive cultivars. Furthermore, cold stress increased the free proline content. Bioinformatical analysis of the translation of 500 nucleotide sequences revealed that they contained a conserved 57 amino acid region with three ?-sheet and one ?-helix, as well as a valine amino acid at position 14 along with a glutamic acid at position 19. The sequences were recorded in NCBI GenBank.