Effects of salinity stress on water uptake, germination and early seedling growth of perennial ryegrass

Abstract

This research was conducted for the determination of effects of salinity stress on water uptake of seed, germination and early seedling development of perennial ryegrass (Lolium perenne L. cv. Ovation) in the seed laboratory of Field Crops, Department of Agricultural Faculty of Namik Kemal University, Tekirdag, Turkey, 2009. In this study, eight different sodium chloride (NaCl) levels, including electrical conductivities of 0, 2, 4, 8, 12, 16, 20 and 24 dS m^-1 were used as salinity treatments. Seeds were germinated at 25 ± 1°C for 14 days in a growth chamber. Water uptake of seeds during germination period were measured at 3, 6, 12, 24, 36, 48 and 72 h. Germination rate and some morphological and physiological characters were determinated on the 14th day after germination. Dry weights were measured after samples had been dried at 70°C for 48 h in an oven. The results showed that water uptake of seed, germination rate, and mean germination time of perennial ryegrass were affected by different salinity levels during germination period. Likewise, root and shoot length, coleoptiles length, leaf number, fresh and dry weights of root and shoot of perennial ryegrass seedling were also affected from different salinity application, but root number did not change statictically in different NaCl concentrations. While mean germination time increased with increasing salinity, germination rate decreased. Increasing NaCl concentration caused a significant reduction in root length, coleoptiles length, shoot length, and leaf number. Fresh and dry weight of root and shoot decreased significantly over 8 dS m^-1 NaCl concentrations during the germination period. In conclusion, it can be said that perennial ryegrass has tolerance up to 8 dS m^-1 salinity level at the germination and seedling growth stages.

Key words: Ryegrass, Lolium perenne L., salinity stress, water uptake, seedling growth.