Morphological Changes in Response to Drought Stress in Cultivated and Wild Almond Species

This study was undertaken to identify morphological changes in young seedlings of 5 Iranian almond species (Prunus dulcis, P. eburnea, P. eleagnifolia, P. haussknechti, and P. scoparia) under polyethylene glycol-induced drought stress. Drought stress caused a significant reduction in plant growth parameters such as fresh and dry weights of plant organs, leaf number, total leaf area, and leaf relative water content in all almond species. Specific leaf weight also increased significantly in drought-treated plants compared to control. No significant changes in shoot length, individual leaf area, leaf dimension (length and width), or stomatal size and frequency were observed in response to drought treatments. P. eburnea had the highest relative water content among the species and showed the smallest decrease in fresh and dry weights of organs and greatest decrease in leaf number and total leaf area (the most reduction in transpiration area) as an adaptive mechanism to drought stress.