The effect of NaCl salinity and temperature on the germination of three thyme populations

Abstract

A factorial experiment was performed in completely randomized design (CRD) with three replications to evaluate the effect of different densities of sodium chloride on germination traits of thyme plant seeds collected from three different habitats. The first factor was three different habitats, the second factor was different salinity levels (0, 50, 100, 150, 200 and 250 mM) and the third factor was different temperatures (15, 25, and 35°C). Analysis of variance showed that the effect of habitat was not significant on seeds germination characteristics. But temperature had a significant effect (P≤0.05) on germination percentage, germination speed, seed vigor, plumule length, radicle dry weight and plumule dry weight. Moreover, salinity had significant effects (P≤0.01) on germination percentage, germination speed, plumule length, seed vigor and ratio of plumule length / radicle length, plumule weight, and radicle dry weight. The maximum germination speed (1.02), germination percentage (45.4%), sees vigor (1.69), radicle length (3.99 mm), plumule length (2.66 mm), radicle dry weight (0.131 mg) and plumule dry weight (0.197 mg) was obtained in 15°C. Also, the maximum percentage of germination (69.5%), germination speed (1.34) and the radicle length (5.5 mm) was obtained from control treatment (without salinity stress).