Salinity tolerance in Atriplex halimus L.: Differential effects of soluble salts on seed germination and recovery - Acta Universitatis Sapientiae

Acta Universitatis Sapientiae, Agriculture and Environment, 16 (2024) 48–63

DOI: 10.47745/ausae-2024-0005

Abstract. The soils of arid rangelands contain a variety of salts that have differential effects on seed germination. In these regions, Atriplex halimus (L.) (Amaranthaceae) is one of the most commonly used medicinal and fodder plants. Little is known about its germination under saline stress operated by various soluble salts. The present work was designed to determine the effect of four soluble salts (NaCl, Na2SO4, CaCl2, and CaCO3) on the germination of A. halimus seeds. We tested the effect of salinity on final germination percentage (FGP%) and germination tolerance index (GTI%) using five concentrations (0, 200, 300, 400, and 600 mM) of each salt (NaCl, Na2SO4, CaCl2, and CaCO3). In addition, experiments were also conducted to assess the effects of salinity on germination recovery (GRP%) from high saline conditions (600 mM). Salinity level and salt composition significantly influenced germination characteristics. A. halimus seeds were non-dormant, exhibited approximately 90% germination in distilled water. Both FGP and GTI gradually decreased with increasing salinity. This study showed that the seeds of A. halimus can germinate under 400 mM in all tested salts. The salts causing germination inhibition exhibited specificity, with an increasing trend observed in the following sequence: Na2SO4 > NaCl > CaCl2 > CaCO3. When ungerminated seeds are transferred from 600 mM to distilled water, their germination ability is recovered according to the type of salt used. A. halimus is a highly salt-tolerant species that can tolerate a variety of salts and can be, therefore, a promising species for improving ecological balance in saline soils.

Keywords: arid rangelands, Atriplex halimus, germination, tolerance, soluble salts, recovery