Response of Eastern Gamagrass Seed to Gibberellic Acid Buffered below Its pKa

摘要: Eastern gamagrass [Tripsacum dactyloides (L.) L.] seed are usually dormant, often causing seedling establishment difficulties. This study was conducted to assess the effect of gibberellic acid (GA 3 ) buffered below its pKa (3.8) on germination eastern gamagrass. In one experiment, concentrations 0.001-, 0.005-, and 0.01 M GA solutions were applied with cupules removed from six commercial lots produced in three different years. After 28 d germination, GAS application increased total by 25 47 percentage points. The equally effective promoting all except one, where 0.001 more than . rate accelerated GA3 during process but did not result viable seeds. An average 10% caryopses remained dormant at end test. A second experiment evaluated intact after treatment for 24 or 48 h distilled water, solution, buffer solution. Buffered enhancing when left intact. These results suggest that there may be multiple dormancy mechanisms At least mechanism involves caryopsis is affected application. Furthermore, cupule-mediated mechanism(s) caryopsis-ulediated must addressed obtain complete seed.