Exotic plant species can drastically affect ecosystem functions and cause major environmental damages and losses. Field sandbur (Cenchrus pauciflorus) was first recorded in 1983 and has become one of the worst invasive species in the Horqin Sandy Land (Inner Mongolia, China). Sandbur is well adapted for colonizing dunes, because of a well-developed root system and a high drought resistance. As an annual plant, sandbur reproduces through numerous seeds, and its seeds germination properties play a pivotal role in its spread, persistence and population dynamics. To understand the response of seed germination characteristic of sandbur to various environmental conditions, we collected fresh seeds and used laboratory experiments to determine its germination characteristic in relation to: storage time (1 Mon, 6 Mon, 12 Mon, 24 Mon), storage conditions (dry at room temperature, dry 4℃, dry at -20℃, 4℃ under wet sand layer), sand burial depth (fluctuating scale from 0 to 12 cm at 2 cm intervals), and light treatments (light or dark) in germination chambers.
We found that the germination rates of sandbur peaked at 12 Mon storage. Compared with the other conditions (dry at room temperature, dry 4℃, dry at -20℃), the mean germiation was significantly higher at the 4℃ under wet sand layer (P＜0.05). Increasing sand burial depth can prohibit sandbur seeds germination, and the light treatment promoted seed dormacy. However, sandbur maintains high germination rates even under adverse conditions (i.e. 24 Mon/dry at -20℃, 12cm burial depth). We concluded that environment influences sandbur germination rates, however, it has a very plastic range of condition under which it can germinate.