SEED-GERMINATION ECOPHYSIOLOGY OF MEADOW SALSIFY (TRAGOPOGON-PRATENSIS) AND WESTERN SALSIFY (TYLENCHORHYNCUS-DUBIUS)

To understand persistence strategies of meadow and western salsify, ec ophysiological characteristics of their seed germination were studied. Anaerobiosis (immersion in deoxygenated water) induced secondary dorm ancy in seeds of both species. Dormancy could be induced in 86% of mea dow salsify seeds and in 65% of western salsify seeds by a 1-d anaerob iosis treatment. The induced dormancy was gradually released during st orage of air-dried secondary dormant meadow salsify seeds, and the rat e of this release was influenced by storage temperature; 30 C was more effective than 10 or 20 C in releasing secondary dormancy. These resu lts suggest that the two species may rely on induced dormancy as an op tion in their persistence strategy. The optimum temperature for germin ation of nondormant seeds of both species was 15 C. Maximum germinatio n percentages for both species were established within 4 to 6 d of inc ubation at 15 C and within 14 to 28 d of incubation at 25 C. Nondorman t seeds did not germinate below 10 or above 30 C. Stratification (at 5 C for 2 to 10 wk) stimulated germination of secondary dormant seeds o f meadow salsify. This stratification requirement can be important in preventing germination of dormant salsify seeds in the fall, thereby a voiding high seedling mortality in the winter. Light (red and far-red) had no effect on germination of seeds in secondary dormancy. In a sep arate study, seeds of both species were planted in pots at depths of 2 to 14 cm and seedling emergence was observed. Maximum emergence occur red when seeds were buried 2 cm deep. Seeds planted 8 cm or deeper ger minated but did not emerge.