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Photoperiodic Responses of Brassica campestris cv. Ceres
Author(s) -
Friend D. J. C.
Publication year - 1968
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1968.tb07326.x
Subject(s) - brassica , biology , photoperiodism , germination , horticulture , period (music) , red light , light intensity , day length , botany , gibberellic acid , phytochrome , physics , acoustics , optics
The photoperiodic responses of Brassica campestris L. cv. Ceres were investigated to determine the suitability of this plant for further studies on the spectral require ments for floral initiation. This is a long‐day plant, sensitive to one inductive photocycle on the fourth day from germination. The flowering response increased with the length and intensity of a single period of supplementary light used to extend an 8‐hour daylength and was greatest at 25°C. Application of nitrates retarded floral initiation by about two days under short day conditions, but did not affect the re sponse to one long day. Gibberellic acid induced earlier floral initiation under short day conditions. The photoperiodic response was little affected by omitting the main light period immediately before or after the supplementary light, as long as the intensity of supplementary light was greater than 5000 lux. Short interruptions (5–10 minutes) of a single 16‐hour dark period with high energy red or far‐red radiation did not promote flowering. When given continuously during a single 16‐hour dark period, far‐red radiation was more effective in flower promotion than an equal energy of red.