Environ Exp Biol (2020) 18: 95–105

Coastal plant species as electrolytophytes: effect of NaCl and light intensity on accumulation characteristics of Atriplex glabriuscula from coastal drift lines

Abstract

The aim of the present study was to analyze growth response and ion accumulation characteristics in Atriplex glabriuscula, a species from coastal drift lines, as affected by increased concentration of NaCl in substrate and light intensity in controlled conditions. In the first experiment, different regimes and concentration of NaCl were used for treatment of A. glabriuscula plants, resulting in a Na+ concentration gradient in substrate (0.88 to 11.9 g kg^–1). In the second experiment, plants were subjected to different light intensity (25, 50, 75 and 100%), and half of the plants in each light treatment were constantly irrigated with 200 mM NaCl. Na⁺-treated A. glabriuscula plants showed a concentration-independent significant increase in shoot fresh and dry mass, but root mass was not significantly affected. The characteristic increase of Na⁺ concentration in shoots due to increasing substrate Na⁺ corresponded to a relationship typical for Na⁺-accumulating species. In the second experiment, dry mass of leaves and stems of control plants linearly increased with increasing light intensity, root mass increased relatively less, but a more pronounced increase was evident for flowers. Increasing light intensity stimulated NaCl-dependent Na⁺ accumulation in leaves, but decreased accumulation in stems and flowers. Absolute values of electrical conductivity in shoots were extremely high, with the maximum level of 520 mS cm^–1 in stems of plants at 25% light intensity. In A. glabriuscula plants, tissue electrical conductivity is tightly regulated by accumulation/exclusion of both Na⁺ and K⁺, confirming a special status of the species as an extreme coastal electrolytophyte.