Environmental factors on seed germination and seedling emergence of Phleum paniculatum   Huds.

Phleum paniculatum Huds., commonly known as British timothy, is an increasingly serious weed in wheat field of China. However, the biology of its seed germination and seedling emergence remain unclear. In the present study, the effects of environmental factors on seed germination and seedling emergence of P. paniculatum were explored. Phleum paniculatum seeds had a shallow dormancy (20-30 d) when stored at room temperature (25 ± 5 °C). Seeds could germinate at constant temperatures between 10 and 25 °C, except for 5 or 30 °C. Light was not essential for seed germination, and pH values from 4 to 10 did not inhibit germination. Seeds were moderately adaptable to water potential and NaCl concentration, and germination rates would be decreased 50% when water potential was -0.4 MPa or NaCl concentration was 130 mM. Increased soil burial depth decreased the seedling emergence, and no seeds emerged when the burial depth was more than 4 cm. Taken together, our results provide useful information of the germination and emergence of P. paniculatum seed, and strategies such as proper drainage systems managed and deep plowing are recommended to limit its detrimental effects on agricultural production.