Study on seed germination behavior of Kochia scoparia L. Schard in response to temperature and water potential

Kochia (Kochia scoparia) is an annual halophyte and drought resistant plant that can be irrigated with saline water and has the capability of being used as a valuable source of forage in ecosystems under drought and salinity stress. In order to evaluate germination characteristic of Kochia scoparia under different temperatures and water potentials, an experiment was conducted in 2009 at Physiology Lab of Ferdowsi University of Mashhad. Experiment was conducted in a completely randomized design with 4 replications. Treatments included 9 levels of water potential (-0.25,-0.5, -0.75.-1, -1.25,-1.5,-1.75 and -2 MP) and also the treatment not exposed to drought (control) and 8 temperature levels (5, 10, 15, 20, 25, 30, 35 and 40 0C). The results of variance analysis showed that different levels of temperature and water potential had a significant effect (P<0.01) on germination percentage, germination rate, mean germination time and germination index. Interaction effect between temperature and water potential on the mentioned parameters was also significant. The highest percentage of germination occurred at 20-250C and 4 primary levels of water potential with no significant differences between each other. Also, the highest germination rate occurred at 250C and in control treatment. With decrease of water potential, germination rate also decreased in all temperature treatments. In addition, decrease in water potential caused an increase in mean germination time. The lowest mean germination time was observed at 250C equivalent to 1.07 day. The highest germination index occurred at 250C and in control treatment. However, seeds of Kochia are able to germinate in a wide range of temperature and water potential.