Germination behavior of two populations of Cynanchum acutum L. in different temperature and lighting condition

In present study germination behavior of two populations of Cynanchum acutum L. investigated in different constant temperature, temperature fluctuations, periods of darkness / lighting and high temperature. The maximum seed germination in constant temperature was observed at 25 C in Karaj population (85.5%) and at 30 C in Kerman population (92%). while in temperature fluctuations Maximum seed germination was observed at 20/30 C in Karaj population (88%) and at 25/35 C in Kerman population (90%). Seeds of two populations were able to germinate at a wide range of temperatures. Different periods of dark / light showed no significant effect on seed germination of two populations. High temperatures a above 100 ° C caused a significant reduction in germination but Kerman population resistance was more than Karaj population in high temperatures.