Temperature control of germination and its possible role in the survival of a non-dormant population of Avena fatua |
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Authors: | Ramma Sawhney rew I Hsiao William A Quick |
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Institution: | Agriculture Canada, Research Station, 107 Science Crescent, Saskatoon, Saskatchewan, Canada S7N OX2.;Agriculture Canada, Research Station, Box 440, Regina, Saskatchewan, Canada S4P 3A2.;Dept of Biology, Univ. of Regina, Saskatchewan, Canada S4S 0A2. |
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Abstract: | Germination of freshly harvested seeds of a non-dormant (ND) line (Stonehouse 319) of wild oats ( Avena fatua L.) was inhibited by incubation of the seeds at relatively high temperatures of 25 and 30°C. The germination inhibition in these seeds appeared to be a case of thermo-inhibition which was the direct effect of hightemperature treatment (HIT), since it did not persist after transferring the seeds to an optimum germination temperature of 20°C. Even a prolonged HTT of 30°C for over 5 weeks did not prevent germination of about 80% of the seeds transferred to 20°C. However, in a significant proportion of the seeds, thermo-dormancy was induced by 10 days of HTT at 30°C if the seeds were then incubated at sub-optimal temperatures of 5 to 15°C. This thermo-dormancy would appear to be 'restrictive' in form, since its expression was restricted to very specific conditions. Relatively low inclubation temperaturs of 5 and 10°C markedly slowed germination whether HTT was applied or not. The results suggest that thermo-inhibition and thermo-dormancy, induced during seasonal temperature fluctuations, may provide a survival mechanism for seeds of such ND lines as Stonehouse 319. |
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Keywords: | Seed dormancy seed gérminatio survival mechanism thermo-dormancy wild oats |
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