Photosynthetic activity of some domestic and foreign cultivars of Lolium perenne L. under conditions of sodium chloride salinity

Abstract

In pot experiments carried out in 2005 and 2006, tolerance to sodium chloride salinity of 4 cultivars of perennial ryegrass (Lolium perenne) ('Nira', 'Stadion', 'Ronija', 'Darius') was studied. Three concentrations of NaCl in medium (earth + sand): 0.0 mM (control); 50 mM; 100 mM, were used in the investigations. In three successive crops of grass, fresh weight yield of leaves, stomatal conductance, photosynthesis intensity, content of chlorophyll and PS II maximum quantum yield (F_v/F_m) were determined. The obtained results showed that perennial ryegrass is a species tolerant to NaCl salinity. Among the studied cultivars, cv. 'Ronija' showed the highest tolerance, whereas cv. 'Nira' showed the lowest. The growth of perennial ryegrass plants under salinity conditions was limited by low stomatal conductance of leaves and photosynthesis, but not by the photosynthetic activity of chlorophyll and its contents.