Selenium- and Silicon-Mediated Recovery of Satureja (Satureja mutica Fisch. & C. A. Mey.) Chemotypes Subjected to Drought Stress Followed by Rewatering

Little is known about the potential role of selenium and silicon post drought in plants, and the physiological mechanisms involved are yet to be explored. Medicinal plant cultivation in existing crop systems is of great importance for sustainable production of active ingredients. The first step in this process is to grow the plants under natural field conditions. For this purpose, the effects of drought stress (moderate stress: 25 days without irrigation and severe stress: 40 days without irrigation) and rewatering on physiological traits and photosynthetic pigments of two forest Satureja chemotypes of carvacrol/thymol/p-cymene (Darkesh chemotype) and thymol/p-cymene/carvacrol (Pono chemotype) were assessed in two separate experiments under foliar application of two drought protectants: selenium (0, 5, and 20 mg/l) and silicon (0, 1, and 5 mM). The results showed that at least in one experiment, the proline content of Darkesh and Pono increased by 33.48 and 16.76% following water stress, respectively. A significant enhancement was observed in proline level only in the Darkesh chemotype by rewatering. In both chemotypes, the sugar content increased (by 11.59 and 27.41%) as water stress increased, respectively. On the other hand, by rewatering, a reduction in sugar content was observed only in the Pono chemotype. Ionic leakage increased in both chemotypes during the second experiment. Similar to sugar content, rewatering decreased ionic leakage only in the Pono chemotype. No clear separation was found in the response of forest savory chemotypes to foliar selenium and silicon application. However, selenium-treated plants reduced proline accumulation under drought stress. Based on the obtained results, forest savory as a drought-resistance valuable medicinal plant can be introduced into the crop system, especially in regions with low precipitation and scarce water sources.

Automated summary

Little is known about the potential role of selenium and silicon post drought in plants, and the physiological mechanisms involved are yet to be explored. This study assessed the effects of two drought protectants, selenium and silicon, on the physiological traits and photosynthetic pigments of two forest Satureja chemotypes under drought stress and rewatering conditions. The results showed that drought stress increased proline and sugar content, and rewatering decreased sugar content. Drought stress also led to an increase in ionic leakage, which was reduced by rewatering. There were no clear differences in the response of the chemotypes to foliar selenium and silicon application.