Germination variability and the effect of various pre-treatment on germination in the perennial spurge Euphorbia nicaeensis All.

Patterns of seed germination of the perennial spurge Euphorbia nicaeensis were studied in three populations in south-western Spain. We investigated the variation in seed viability and germination among individuals, and among populations over 2 consecutive years. We also studied if diverse factors such as temperature, acid scarification, darkness or caruncle loss affect the germination of the seeds.

Interindividual and interpopulation variability in seed viability was found. E. nicaeensis seeds are nondormant, so differences in interpopulation viability translate into differences in final germination rates. The germination percentage of the seeds from each population was similar in the 2 years studied. The effects of diverse factors were homogeneous in the two populations studied. Darkness has no effect on seed germination, and ecarunculate seeds germinated in the same proportions as carunculate seeds; this could allow the seeds to germinate in the chambers of deserted anthills. Acid scarification significantly reduced the germination percentage in only one of the populations, but over 50% of the seeds germinated, which could allow herbivores to act as occasional dispersing agents. The seeds that were preheated at 100 °C for 1 and 5 min germinated in the same proportions as the control group. The seeds that were preheated at 120 °C for 5 min displayed a significant decrease in germination, but the percentage was over 40% for both populations, indicating that the seeds could still germinate after the passage of a fire.