High R/FR HPS-pulses enhance earliness of flowering of exacum (Exacum affine Balf. F.) and geranium (Pelargonium × hortorum L. H. Bailey)
| Autor: | Michel Tardif, Blanche Dansereau |
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| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | Canadian Journal of Plant Science. 73:1163-1167 |
| ISSN: | 1918-1833 0008-4220 |
| DOI: | 10.4141/cjps93-155 |
| Popis: | Four consecutive crops (Fall 1988, Winter 1989, Summer 1989 and Fall 1989) of exacum (Exacum affine Balf. f. ’Elfin’) and geranium (Pelargonium × hortorum L. H. Bailey ’Hollywood Star’ and ’Hollywood Red’) were grown in a greenhouse under three lighting treatments: ambient: 16-h high pressure sodium (HPS) lighting of 100 μmol m−2 s−1 between 0600 and 2200 h; and 16 h HPS-pulse lighting (45 s shut off, 90 s recharge) once every hour between 0600 and 2200 h. The growth index [(height × width)/2] of exacum plants was similar, regardless of the light treatment used. However the growth index of both geranium cultivars receiving HPS-pulse lighting was significantly less than those receiving the two other treatments. Exacum top dry weight was 225% greater under pulse lighting than under ambient light. During fall 1988, HPS-pulse lighting increased flower dry weight of Hollywood Red by 400% and 87% compared to ambient and HPS lighting, respectively. Key words: Exacum affine, HPS-pulse, Pelargonium × hortorum, photomorphogenesis, photosynthesis, photosynthetic photon flux |
| Databáze: | OpenAIRE |
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