Effects of soil salinity on growth and physiological responses of Sempervivum tectorum and Petrosedum rupestre

Abstract

The widespread application of sodium chloride (NaCl) for winter road maintenance contributes to the accumulation of soluble salts in soils, resulting in osmotic stress and physiological drought in plants. Succulents possess specialized water-storage tissues and physiological adaptations that may enhance their tolerance to saline conditions. The aim of this study was to evaluate the tolerance of two succulent species, Petrosedum rupestre and Sem-pervivum tectorum , to soil salinity induced by road de-icing salt. Young plants were cultivated in soil subjected to three salinity levels: control (0.172 mS·cm⁻¹), moderate salinity (6 mS·cm⁻¹), and high salinity (12 mS·cm⁻¹). The experiment lasted eight months and was conducted under controlled conditions. Plant growth, biomass increment, morphological changes, and chlorophyll content were assessed at the end of the growing period. The results demonstrated that both species survived exposure to elevated salinity levels throughout the experiment. However, increasing salinity significantly reduced biomass production and limited root and shoot development. Petrosedum rupestre exhibited substantially greater growth under saline conditions than Sempervivum tectorum . Under high salinity, biomass accumulation was markedly reduced in both species, although all individuals remained viable. Chlorophyll analyses did not reveal a clear decrease in pigment concentration in response to salinity stress. The findings indicate that succulent species of the Crassulaceae family may be suitable for use in urban areas periodically exposed to road salt contamination. Among the tested species, Petrosedum rupestre showed the highest tolerance to soil salinity and appears to be a promising candidate for plantings established in salt-affected environments.