seed viability of spotted spurge (euphorbia maculata) in various environmental conditions

to investigate the spreading possibility of spotted spurge (euphorbia maculata) as a new-introduced and troublesome weed species of soybean field in golestan province, viability of this weed seed in soil, water and elevated temperature conditions were examined. experiments were conducted as completely randomized design with eight replications. treatment levels of seed viability in soil and water included 1-11 months of seed burial at 10-15 cm depth, and 1-9 weeks of seed soaked in water, respectively. evaluation of high temperature effect were carried out as three-factor factorial experiment that consisted of 5 temperature levels (ambient temperature (25 ˚c as control), 80, 100, 120 and 140 ˚c), two exposure times (1 and 5 min), and seed moisture status in two levels (dry and wet). the results indicated that buried seed in soil after 11 months showed germination above 95%. seeds were not able to germinate under submergence. removed seed of water after 2 weeks germinated above 90%, but it reduced with increasing immersion time, as after 9 weeks lost their viability. elevated temperature had significant effect on germination. germination was significantly reduced by increasing temperature, as the maximum and minimum of germination was observed at control and 140 ˚c, respectively. elevated temperature, exposure times and seed moisture content had interaction effect. germination of wet seeds completely inhibited at 140 ˚c for 5 min. based on these results, spotted spurge seeds had high persistence in the soil. seed viability in water for a few weeks will provide the chance of dispersal by water irrigation.