The evaluation of germination parameters of Tanacetum polycephalum under simulated drought and salinity stress at different temperatures

In order to study germination characteristics of Tanacetum polycephalumin water and salinity stress conditions in different temperatures seven laboratories experimental were conducted. Temperatures regimes included 5, 10, 15, 20, 25, 30 and 45 °C. For each temperature, salinity and water stress was used in seven osmotic potential (0, -2, -4, -6, -8, -10 and -12 bar) of NaCl and PEG, respectively. Results of each experimental showed that increasing water and salinity stress decreased germination rate, germination percentage, plumule and radicle length, significantly. In salinity stress, germination percentage in most temperatures except 20 and 25°C in -12 bar of NaCl reached to 0, but in drought stress in most temperatures except 20 and 25°C -10  of PEG reached to 0. The maximum of germination percentage and germination rate was abserved in 0 bar in 25°C. Also maximum toleraance to salinity and drought stress was -12 and 10 bar of NaCl and PEG in 25°C, respectively. Results showed that 25°C is optimum temperature for this plant and it tolerates salinity stress up to -12 bar and water stress up to -10 bar at this temperature