Seed Germination Ecology of and in Queensland Australia.

and are among the most problematic broadleaf weeds in eastern cropping systems of Australia. This study investigated the seed germination ecology of and . The study hypothesized that may have greater ecological advantages under adverse environmental conditions compared to . Results showed that consistently outperformed across different light regimes and stress conditions. At a lower temperature regime of 15/5 °C, seed germination of decreased by 19% compared to . Germination of significantly declined under dark conditions, while over 90% of seeds germinated under both light/dark and dark conditions. Under water stress (osmotic potential of -0.4 MPa), germination dropped by 74% compared to , indicating 's superior drought tolerance. Both species exhibited moderate salinity tolerance (40 mM NaCl) to germinate, highlighting their potential to invade saline cropping environments. The burial study revealed that had higher germination at the soil surface, but no germination occurred from 4 cm, while 23% of seeds still emerged from that depth. The burial depth required to inhibit 50% emergence of and was 3.3 cm and 0.3 cm, respectively. These findings highlight 's greater adaptability to low temperatures, burial depth, and stress conditions than . The insights from this study can inform agronomic strategies, including tillage depth and mulching, to mitigate the impact of these invasive species on Australian cropping systems.