Water Stress-induced Changes of Morphological, Physiological and Essential Oil Compounds in Thymus eriocalyx from Iran

Thymus eriocalyx is one of the most important medicinal plants in Iran, which has extensive pharmaceutical uses due to the biosynthesis of secondary metabolites such as thymol and carvacrol. Given the fact that drought stress is one of the factors limiting the growth and yield of plants in many regions of the world, the aim of this study was to investigate different drought stress treatments on morpho-physiological features and chemical compounds of Thymus eriocalyx essential oil. A factorial experiment was conducted with three replications in a completely randomized design with five levels of drought stress (20, 40, 60, 80, and 100 % of field capacity). The results showed significant decreases in both the fresh and dry weights, plant height, crop growth rate (CGR), relative growth rate (RGR), chlorophyll a content, total chlorophyll content, and soluble leaf protein content with increasing drought stress. The contents of proline and carbohydrate in the leaf solution were significantly affected by...