Effects of salinity and UV-B on seed germination behaviour of the halophyte Zygophyllum album L.: Enforced dormancy and trade-off strategy

Abstract

Understanding the behavior of halophyte seed germination under multiple abiotic stressors is crucial for restoring salt-affected lands. Zygophyllum album L. (syn. Tetraena alba (L.f.) Beier & Thulin) is a perennial halophytic species that spreads in the coastal ecosystems of Mediterranean areas. Halophytes' seed germination indices concerning the influence of UV-B remain unexplored in scientific investigations. We provide here data on the effects of salinity (0, 100, 200, and 400 mM NaCl) and light (total darkness, 12 h dark/12 h light, and 12 h dark + 9 h light + 3 h UV-B) on seed germination, seedling growth parameters, antioxidant enzymes, histochemical localization of O2−, and anatomical parameters of Z. album. The germination percentage was not significantly decreased under low and medium salinities (100 and 200 mM NaCl), but germination was entirely inhibited at 400 mM NaCl. Also, seed germination was reduced significantly under the combined treatment of 200 mM NaCl and UV-B light. The germination rate was significantly decreased at low salinity in darkness and under moderate salinity with all light treatments. However, the highest germination recovery was recorded under combined salinity and UV-B treatments. At the seedling stage, salinity reduced biomass and seedling length under all light treatments. Additionally, combined UV-B with salinity treatments had a negative synergistic influence on all growth parameters. On the other hand, the increase of catalase and peroxidase activities, as well as the accumulation of druses and idioblasts under combined treatment, suggest a trade-off between the growth of this species and its defense mechanisms. These results indicate that Z. album has a moderate tolerance to both salinity and UV-B stresses during germination, highlighting its significance as a potential source for reclaiming salt-affected lands and cultivating crops under future climate changes.