Salicylic Acid and UV-B/C Radiation Effects on Growth and Physiological Traits of <i>Satureja hortensis</i> L.

Higher UV irradiation may affect the structure of ecosystems directly or indirectly. In the present work, Satureja hortensis L. defence mechanisms against UV stress was studied with or without salicylic acid (SA). For this aim, a factorial based experimental was conducted on completely randomized design with three UV treatments (control, UV-B and UV-C) as first factor and two SA levels (0 and 1 mM) as second factor. The results showed UV-B and C decreased shoot dry weight, plant height (PH), node number (NN), inter-node distance (IND), root length (RL), leaf area index (LAI) and chlorophyll content, but increased stem diameter (SD), leaf thickness (LTh), total flavonoid content (TFC), total phenolic content (TFC) and antioxidant activity. Plants treated with SA (1 mM) showed higher growth factors than non-treated one. It seems that SA can be used as an alternative substance against UV stress

Application of Nano-Silicon Dioxide Improves Salt Stress Tolerance in Strawberry Plants

Silicon application can improve productivity outcomes for salt stressed plants. Here, we describe how strawberry plants respond to treatments including various combinations of salt stress and nano-silicon dioxide, and assess whether nano-silicon dioxide improves strawberry plant tolerance to salt stress. Strawberry plants were treated with salt (0, 25 or 50 mM NaCl), and the nano-silicon dioxide treatments were applied to the strawberry plants before (0, 50 and 100 mg L−1) or after (0 and 50 mg L−1) flowering. The salt stress treatments reduced plant biomass, chlorophyll content, and leaf relative water content (RWC) as expected. Relative to control (no NaCl) plants the salt treated plants had 10% lower membrane stability index (MSI), 81% greater proline content, and 54% greater cuticular transpiration; as well as increased canopy temperature and changes in the structure of the epicuticular wax layer. The plants treated with nano-silicon dioxide were better able to maintain epicuticular wax structure, chlorophyll content, and carotenoid content and accumulated less proline relative to plants treated only with salt and no nano-silicon dioxide. Analysis of scanning electron microscopic (SEM) images revealed that the salt treatments resulted in changes in epicuticular wax type and thickness, and that the application of nano-silicon dioxide suppressed the adverse effects of salinity on the epicuticular wax layer. Nano-silicon dioxide treated salt stressed plants had increased irregular (smoother) crystal wax deposits in their epicuticular layer. Together these observations indicate that application of nano-silicon dioxide can limit the adverse anatomical and biochemical changes related to salt stress impacts on strawberry plants and that this is, in part, associated with epicuticular wax deposition