- Subject: Coincidence Or?
- From: Ed Olson Moore H20wrx@AOL.COM
- Date: Thu, 26 Sep 2002 20:11:34 EDT
Hi all -
Three things happened recently that may, or may not, be related:
1. In a posting on the Robin, Laurie reported that she had a Regal bloom
required 3 week period at temps below 55 degrees F.
2. Also on the Robin, Bill reported that one of his pelargonium species, from
section Otidia, was blooming for the second time and out of season.
3. I have a P. grandiflorum which bloomed this year. According to POSA1, this
species usually grows in mountanous habitat above 300 m. As such , and
because it is apparently one of the main parents of Regals, I would assume
that this species also requires an extended cold period in order to bloom. In
Central Florida that didn't happen this past winter. And my two P. cucullatum
plants, which I would also assume have the same requirements as Regals, did
not bloom at all.
Are all these coincidences, or the result of cultural conditions? There was
a recent "discussion" on a plant hormone group about Nitrate in fertilizers
stimulating "bud break". According to one study "Cytokinins ( a type of
plant hormone) are transported across the roots to shoots in response to
nitrogen availability". In a study quoted in The Flowering Newsletter,
cytokinin was found to stimulate flowering in orchids.
But cytokinins are not the only hormone that stimulates flower production.
Another plant hormone website states: "Treatments w/ gibberelins can often be
substituted for the photoperiodic (long or short day) or temperature
requirements" to induce flowers to bloom.
Sandy Connerly recently sent me information from an article published in the
Summer 1988 issue of GATW. The article is on growth regulators and geraniums,
and was written by E.J. Holcomb, then an associate professor in floriculture
at Penn State. According to this article, Gibberellic Acid (GA) does not
have a major beneficial effect on zonals, but GA application may substitute
"for the cold temperature that usually encourage flowering on Regal