Abstract: Water deficit led to a rise in abscisic acid levels and then to the induction of lignin synthesis as a survival mechanism in three different wheat cultivars grown under unfavorable environmental conditions. Photosynthets liberated through reduction of internode length were used in production of multiple layers of mesophyll tissue (thick leaf) and cell wall thickening. Plant growth reduction under drought was caused primarily by reduction in leaf area ratio. Cell sizes were reduced under higher temperature and late sown conditions due to the increased rate of cell division of the cells with different cell wall composition. Drought tolerant cultivar synthesized lignin during rehydration around vascular bundle in order to avoid cavitations. ABA enhanced programmed cell death under unfavorable growth conditions.