Apr 20th, 1:00 PM - 4:00 PM
Primary and Secondary Dormancy in Lomatium Dissectum Seeds
Dr. Marcelo Serpe
Lomatium Dissectum (Apiaceae) is a perennial, herbaceous plant of wide distribution in Western North America. At the time of dispersal, L. dissectum seeds are dormant and have underdeveloped embryos. We investigated the environmental requirements for dormancy break and embryo growth. The embryos elongated between five and seven fold inside the seeds over several weeks of cold stratification. Embryo growth prior to and during germination occurred at temperatures between 3 and 6°C and was negligible at stratification temperatures of 0.5 and 9.1°C. Comparison of the cold stratification requirements of different seed populations indicates that seeds collected from moist habitats have longer cold stratification requirements than those from semiarid environments. Interruption of the cold stratification period by eight weeks of dehydration decreased seed viability by about 30% and induced secondary dormancy in the remaining seeds. The requirements for dormancy break and germination reflect an adaptation to trigger germination in late winter.