Influence of some physical and biological factors on seed germination of Scorpiurus subvillosus L.

Prickly scorpion's tail (Scorpiurus subvillosus L.) is a forage plant, with a high quality for animal husbandry, spontaneous in grass pastures of Mediterranean basin. It exhibits seed coat dormancy, that delays and reduces germination. With the aim of studying the influence of physical and biological factors upon germination of its seeds, the effects of two seed treatments (control and scarification), eight germination temperatures (from 5 to 40 degrees C, with steps of 5 degrees C) and three storage periods (35, 137, 200 days after seed harvest) were evaluated in the laboratory. Seed germination increased gradually as temperature was raised. It peaked at 20 degrees C (50% for control and 100% for scarified seeds), then declined with further increases of temperatures over 25 degrees C. Seed scarification enhanced germination percentage with values up to 100% within a wider temperature range (10-30 degrees C) than untreated seed. Storage time affected seed germination in both untreated and scarified seeds.