Seed Germination of Annual Vinca Responds to Irradiation and Temperature
| Autor: | Farrell C. Wise, Paul H. Henry, Frank A. Blazich |
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| Rok vydání: | 1995 |
| Předmět: | |
| Zdroj: | HortScience. 30:357-359 |
| ISSN: | 2327-9834 0018-5345 |
| DOI: | 10.21273/hortsci.30.2.357 |
| Popis: | Seeds of `Dawn Carpet' and `Little Bright Eye' annual vinca [Catharanthus roseus (L.) G. Don] were subjected to 32 treatments, arranged as a four × four × two factorial. For each cultivar, seeds were exposed to one of four temperatures (15, 20, 25, or 30C) during the 8-hour (day) and 16-hour (night) portions of the cycle. Within each temperature regime, half the seeds of each cultivar were irradiated for 1 hour daily, and the other half remained in constant darkness. Final germination percentages were suppressed at 15C day or night temperatures; at temperatures ≥20C, there were no significant differences between treatments. Heat input (daily degree hours) was a controlling factor in germination; different temperature cycles with equivalent numbers of daily degree hours had similar effects on germination response. There was a strong interaction between temperature and irradiation regime for both cultivars. Irradiating seeds for 1 hour/day reduced final germination percentages under cool (15C) conditions; response was not adversely affected when seeds at 15C were germinated in darkness. In a second experiment, seeds at 25C were exposed to daily photoperiods of 0, 1, 2, 4, 8, 12, or 24 hours. Germination percentages obtained in darkness and at photoperiods ≤12 hours were equivalent. Twenty-four-hour photoperiods suppressed germination compared to all other irradiation treatments. |
| Databáze: | OpenAIRE |
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