| W. Eric Limbach and C.A. Call |
| Authors are with the Department of Biological Sciences, Idaho State University, Pocatello, ID. 83209; and the Department of Range Science, Utah State University, Logan, UT 84322. At the time of the research, Limbach was research assistant, Department of Range Science, Utah State University. |
Abstract |
| The effects of seed mass and fluctuating temperatures on the germination and heterotrophic seedling development of 3 seed sources of Russian wildrye, Psathyrostachys juncea (Fisch.) Nevski, were studied. Seeds that weighed 2.4, 3.0, 3.6, and 4.2 _ 0.1 mg of each seed source were germinated in an unlighted incubation chamber at 5-10o C, 5-15o C, 10-15o C, and 10-20o C. Germination and heterotrophic seedlings development were assessed using: 1) mean time to germinate (T1), 2) the mean proportion of seeds to germinate (G) and 3) mean maximum radicle and coleoptile extension. Data were analyzed using a 4X4X3 factorial analysis of variance (n=144) comprised of main effects, temperature (T), seed mass (M), and seed source (S). Time to germination was significantly affected by T (F=647.44, P < 0.0001), S (F=28.29, P < 0.0001) and the T X S (F=4.71, P < 0.0003) and S X M (F=2.21, P<0.0489) interactions. The mean maximum proportion of seeds to germinate was significantly affected by T (F=13.63, P < 0.0001), S (F=10.53, P < 0.0001), M (F=8.11, P<0.0001) and the T 5 M interaction (F=2.21, P < 0.0276). Radicle extension was significantly affected by T (F=21.94, P < 0.0001), S (F=14.29, P < 0.0001), M (F=12.70, P < 0.0001), and the T X S (F=13.69, P < 0.0001) interaction. Coleoptile extension was significantly affected by T (F= 810.24, P < 0.0001), S (F=68.83, P < 0.0001), M (F=56.00, P < 0.0001), and the T 5 M (F=3.84, P < 0.0003) interaction. Apparently, Syn-A seeds germinate more vigorously and have longer coleoptiles than Vinall but apparent differences remain confounded between seed sources since the effects of seed age and maternal environment cannot be eliminated from the study. |
| Key Words: coleoptile development, cumulative germination, Psathyrostachys juncea, radicle development, seed size. |