Effects of Drought Stress on Morphophysiological and Biochemical Characteristics of Thymus vulgaris L.

Thymus vulgaris L. is an aromatic plant belonging to the Lamiaceae family, known for its valuable medicinal and nutritional properties. Drought stress, as one of the most significant abiotic stresses, can have adverse effects on the growth and performance of medicinal plants. To investigate the effect of drought stress on some morphological, physiological, and biochemical traits of thyme, an experiment was conducted in a completely randomized design with four levels of drought stress (۱۰۰%, ۷۵%, ۵۰%, and ۲۵% of field capacity) with three replications in ۲۰۲۱ in the greenhouse of Hormozgan University. The results showed that drought stress (۲۵% of field capacity) significantly reduced leaf length (۶۴%), leaf width (۳۳%), plant height (۵۱.۱۳%), root length (۴۹.۴%), fresh weight of aerial parts (۴.۰۴%) and dry weight of aerial parts (۷.۵%), dry weight of roots (۹.۷%), relative water content (۵۴.۲۳%), chlorophyll a (۳۱.۴۵%), chlorophyll b (۳۱.۲۹%), total chlorophyll (۳۱.۳۸%), and carotenoids (۲۲.۳۵%). The highest levels of electrolyte leakage (۳۴.۵۶%), proline (۵۳.۱۲%), catalase (۶۸.۴۷%), polyphenol oxidase (۵۱.۵۲%), malondialdehyde (۵۵.۸۴%), flavonoids (۵۹.۲۳%), and anthocyanins (۶۱.۲۹%) were observed in the ۲۵% field capacity drought stress treatment. The medicinal plant thyme responds to drought stress by employing various defense mechanisms. These mechanisms include reducing certain morphological characteristics to conserve energy, rapidly accumulating osmotic regulatory organic compounds to maintain cellular water balance, and increasing antioxidant enzyme activities to combat oxidative stress. Through these responses, thyme can continue to grow and absorb the necessary nutrients with higher efficiency. The primary objective of this research was to evaluate the drought tolerance of thyme and determine the most suitable conditions (۷۵% and ۵۰% of field capacity) for cultivating this plant in Hormozgan Province. Given that thyme is not widely cultivated in this region, examining the plant's response to drought stress could provide valuable information for expanding its cultivation in similar areas.

کلیدواژه ها:

Antioxidant enzymes ، Biochemical parameters ، Drought stress ، Thymus vulgaris ، آنزیم های آنتی اکسیدانی ، آویشن باغی ، پارامتر های بیوشیمیایی ، تنش خشکی