Document Type : Original Article
Authors
1
Former M.Sc. Student, Faculty of Plant Production, Department of Agronomy, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
2
Associate Proffessor, Faculty of Plant Production, Department of Agronomy, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
Abstract
Nowadays medicinal plants are considered as economically important plants throughout the world, while basic information on these plants is scarce. This study was aimed to quantify germination rate response of annual savory (Satureja hortensis L.) to temperature and salinity stress. For this purpose, seeds were exposed to different temperature (12, 15, 20, 25, 30, and 35 ͦ C) and salinity levels (0, 25, 50, 75, 100, 125 and 150 mM NaCl) treatments at Seed Research Lab., Gorgan University of Agricultural Sciences and Natural Resources in 2013. Results indicated that temperature and salinity stress and their interactions had significant effects on maximum germination percentage (MGR), germination rate (R50), and time elapsed to reach 10, 50 and 90% of maximum germination. Along with salinity levels increment, both germination percentage and rate decreased. With temperature increasing to optimum temperature, both germination percentage and rate increased, while they decreased from optimum temperature onwards. Assessment of three nonlinear regression models including segmented, dent-like and beta models revealed that the last one was the superior model. Based on the superior model (Beta), base, the optimum and ceiling temperatures were estimated as 8, 24.77 and 41 ͦ C, respectively. Biological hours for control treatment (zero salinity level) were calculated as 83.68 hours. Optimum and ceiling temperatures were not affected by salinity stress, but the base temperature and biological hours for germination was delayed as 1.35 ͦC decrement and 1.65 hours increment per each 25 mM salinity levels.
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