Effect of salinity and temperature on seed germination indices of Zinnia elegans L.

Abstract: Laboratory studies were conduced to determine the effect of salinity and temperature on seed germination of zinnia plant with two temperature regimes (25 and 30 ^oC) and 5 levels of salinity (distilled water as control and 3, 6, 9 and 12 dSm^-1) in a factorial completely randomized design. Analysis of variance showed significant difference (P<0.05) between different levels of salinity, and salinity and temperature interactions on germination percentage, germination rate and length of rootlet. But temperature treatment only influenced rootlet length (P<0.05). Mean comparison of seed germination percentage showed that increasing salinity decreased the seed germination. The highest rootlet length was recorded in the control (8.273 cm) and the lowest (1.92 cm) was at 12 dSm^-1 of salinity. The effect of temperature on the germination percentage, germination rate and length of rootlet determined that the highest germination percentage and length of rootlet was at 25 ^oC temperature. The study on the interaction of temperature and salinity exhibited that highest percentage of germination, germination rate and length of rootlet were in control at 25?C, whereas it was lowest at 30?C and 12 dSm^-1 salinity.