Floral Initiation in Cestrum nocrurnum (the Nightblooming Jasmine)

Citation

Sachs, Roy Monroe (1955) Floral Initiation in Cestrum nocrurnum (the Nightblooming Jasmine). Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/13FE-YJ23. https://resolver.caltech.edu/CaltechETD:etd-12082003-113617

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. 1. The requirement for floral initiation in Cestrum nocturnum is satisfied if plants receive long days followed by short days. Continuous short or long days or short days preceding long days are ineffective. 2. A minimum of 5-7 long days followed by two short days is required for the production of flowers. 3. The sequence of reactions necessary for floral initiation in Cestrum is as follows: [...] a. "L" is a heat labile substance produced in leaves as a result of long-day induction and required for short-day induction. It is not translocated from the leaves. b. "S" is a heat labile substance, possibly identical with the floral stimulus, formed as a result of short-day induction. It is formed only in leaves which have previously received long-day induction and is translocated to the growing points. The production of "L" in other short day plants is controlled by day length independent reactions, and the production of "S" is controlled by daylength independent reactions in other long day plants. 4. For Cestrum the critical day and night lengths for long and short-day induction, respectively, overlap in the 11.5 to 12.5-hour photoperiod range; the low efficiency of the two processes in this range precludes the possibility of an intermediate daylength satisfying both requirements. Other plants, flowering only in intermediate daylengths, may be related to Cestrum in requiring long followed by short-day induction. However, the critical photo- and nyctoperiods, in these plants, overlap sufficiently to permit simultaneous satisfaction of both requirements in an intermediate daylength.

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