Growth, ion content and photosynthetic responses of two <i>Elytrigia</i> Desv. species seedlings to salinity stress

Abstract

Salinity is among the major abiotic stresses limiting crop production in the world. Elytrigia species, the wild relatives of wheat, are extensively used as genetic resources in wheat breeding to improve its salt tolerance. The objective of this study was to examine the responses to different NaCl treatments (0, 65, 100, 135 and 170 mM) of two Elytrigia species (Elytrigia intermedia (Host.) Nevski. and Elytrigia trichophora (Link.) Nevski.) in terms of their growth, ion content and photosynthetic productivity during the seedling stages. For E. intermedia, salt treatment led to decreases in root and shoot biomass, chlorophyll content, photosynthetic rate (A) and stomatal conductance (g_s), and a concurrent increase in intercellular CO₂ concentration (C_i). Larger reductions in the parameters occurred in E. trichophora. Our results indicated that the two species differ in their sensitivity to salinity, with E. intermedia being classified as the more salt tolerant, and E. trichophora as sensitive. The two species also differed noticeably in leaf tissue concentrations of Na⁺ and K⁺ at various NaCl treatments, although, they both showed a trend for Na⁺ content to increase and K⁺ accumulation to significantly decrease in the higher salinity treatments.

Key words: Elytrigia, ion contents, photosynthesis, salinity.