Journal of Plant Process and Function

Drought is the cause of adverse environmental impacts on plant growth and crop yield. In this study, the effects of water deficit on plant molecular and physiological responses were investigated using two cultivars (namely, Sardari and Zarin) of bread wheat selected based on the results of a three-year research. For the purposes of this study, they were grown in plastic pots containing field soil and maintained in growth chambers (30/20 °C, 14/10 h day/night, 60% R.H). The cultivars had been The experiment was conducted in a completely randomized design with three replications. Plant response to water stress was evaluated at the physiological level by determining the relative water content (RWC) as well as chlorophyll, free proline, and total protein contents following the drought treatment with subsequent re-irrigation. All the physiological parameters were found to be affected by drought stress. The Zarin cultivar exhibited a significant decrease in its RWC. Chlorophyll a and total chlorophyll in both the cultivars showed significant decreases but chlorophyll b did not exhibit any significant variation in either cultivar. The free proline content increased significantly in both cultivars such that they were both restored their normal proline contents life when irrigation was resumed after a short-term experimental drought stress. SDS-PAGE electrophoresis of leaf proteins in both control and experimental samples revealed regulating adjustments in protein contents. Modification in the expression level of the dehydrin (DHN) gene (that is, Rab17) was also analyzed by reverse transcription–polymerase chain reaction (RT-PCR). This gene was expressed slightly in the well watered plants of the two cultivars, but the gene expression in the Sardari cultivar increased significantly after the long-term experimental drought.