Effects of Temperature, pH, and Salinity on Seed Germination of Acinos alpinus subsp. Meridionalis and FTIR Analysis of Molecular Composition Changes

Abstract

This study aimed to determine the impact of three abiotic factors (Temperature, pH, and salinity) on the metabolic activities (macromolecules) and germination rate of Acinos alpinus subsp. Meridionalis (Satureja) seeds. In vitro, seed germination tests were performed in an aqueous medium. They were monitored as a function of time at different levels of temperature, NaCl concentration, and pH. The best germination rate (85.3%) was achieved at 15°C and pH = 7. However, the germination was nil at a higher temperature (more than 25°C), acidic pH (pH < 3.5), and higher NaCl concentration (more than >7.5 g L−1). Fourier transform infrared spectroscopy (FTIR) analysis showed an important variability of the chemical composition of germinated seeds. Indeed, the comparison of the absorbance peaks of chemical compounds in the treatments versus the control revealed significant differences in their concentrations and structures, which may justify why seeds fail to germinate under some extreme abiotic conditions. The results of this study are expected to serve as a guide for the protocols to be adopted in the ex situ conservation of this species.