Seed germination ecophysiology of hoary alyssum (Berteroa incana L.) in different temperature, dry heat and anaerobiosis conditions

Hoary alyssum (Berteroa incana L.) is a rangeland weed of British Colombia, Canada and a prolific seed producer. Knowledge of spatial and temporal dynamics of seed banks and factors affecting them is essential to understand the persistence strategy of this weed. Little information on distribution of B. incana seeds dormancy and modification of germination behavior by climatic factors is available. The hoary alyssum seed dormancy and temperature influence on seed germination were investigated. Effects of temperature on seed germination and dry heat on seed viability were studied in Petri dish assays. B. incana seeds showed that 25-30°C were the optimal temperatures for germination; germination did not occur at 40°C and above, exposure to dry heat (80 or 90°C) for 8 hr significantly reduced seed germination at 25°C. While 1 to 3 d of anaerobiosis delayed seed germination (by ~1 d) upon their subsequent incubation in Petri dishes at 25°C, it did not induce dormancy. A 5-d anaerobiosis reduced seed germination by 24-47 %.