Germination of Bahiagrass in Response to Temperature and Scarification

Abstract

Abstract The influence of temperature and various scarification treatments on the physical changes of the lemma and germination of bahiagrass (Paspalum notatum Flugge) were studied. Mechanically scarified seeds readily germinated on an agar medium. Acid-scarified seeds germinated better than untreated seeds, but not as readily as mechanically scarified seeds. All caryopses excised from nongerminated acid-scarified seeds readily germinated on an agar medium after 17 days. Excised caryopses were placed on a temperature gradient bar corresponding to positions at 15.5°, 21°, 26.5°, 32°, and 37.5°C. All caryopses germinated at 21° to 37.5°, but germination and seedling growth were best at 32° to 37.5°. Lipase and acid scarification improved germination when seeds were held at 24°, but did not enhance germination when seeds were held at 32°. Scanning electron microscopy revealed that acid scarification removed the cuticular substances of the lemma and the substances in the fissure of the germinating lid, probably facilitating entrance of the water and earlier emergence of the coleorhiza. The data suggest that the lemma and palea are physical barriers in bahiagrass.