Effects of the environmental characters on germination properties of seeds of Thymus daenensis and T.vulgaris

Abstract

This research was conducted to investigate the effects of salinity, temperature, pH and sowing depth on germination characters of two species of thyme in 2017. Two separate experiments with four replications using a randomized complete design were conducted in laboratory conditions. Treatments contained: a) fluctuating temperatures in a germinator 5/15, 10/20, 15/25, 15/30 and 20/3500C (day/night), b) concentrations of salinity by using solutions of 0, 10, 20, 40, 80, 160 and 320 mM NaCl, c) sowing depths of 0, 1.5, 3 and 6 cm, pH values of 5, 6, 7, 8 and 9. Results showed that the effects of different treatments were significant on germination percentage, germination rate and seed vigour. In most cases, upper concentrations of treatments had negative effects on germination indices. The emergence decreased with an increased concentration of salinity, planting depth and pH. In both species, the highest germination percentage (94%) was obtained in the combination treatment of 15/25C (day/night), 0 mM of NaCl, 1 cm of planting depth and pH=7. Germination was stopped in the combination of treatments of 35/20 (day/night), 320mM of NaCl, 6 cm of planting depth and pH=9. The combination of treatments in the upper level had a more inhibitory and destructive effect than single treatments.