From: "Juba" <[EMAIL PROTECTED]> Subject: [OGD] Re:CLabiataDaylength
Cattleya labiatas are native to Northeast Brazil, roughly from about 3 to 9
o South latitudes, and at 500 to 1000 m elevations. Such low latitudes means
that daylength varies little - from about 11.5 hours in the winter to 12.5
hours in the summer . Amazingly , most of the labiatas in nature , and even
in cultivation, will flower from the end of our summer to beggining of
autumn ( feb. and march), which means their daylength sensing for triggering
flowering with must be really acurate. As I understand, under greenhouse
conditions , without artificial light or shading, under US and European
latitudes, flowering times for labiatas occurs faithfully year after year
within a week or so, sometime around september. Rotor�s work enabled growers
to take advantage of this behaviour so that, by manipulating daylengh one
could flower C labiata ( and other Cattleyas) at any time throughout the
year, and even twice a year.
Here in northeast Brazil, other factors such as delay or advance in rainy
period may throw-off flowering time by as much as a month or so, but not
much more. My labiatas in cultivation , under frequent feeding and
irrigation , some will flower earlier ( end of December) but main flush is
still in february and ending in march. When I overfed them once ( 300 ppm
from 19-19-19) three times a week , I have had some plants flowering three
times in the same year. Much more work has to be done to understand fully
the flowering mechanism of C labiata.
Julio, from Recife ( northeast) Brazil
Thanks Julio, that answered a queston I've had for a while about where C labiata grows and its daylength.
It is also important to mention that Rotor's work linked daylength with temperature, too.
And thank you for pointing out that Rotor's wotk allowed nurseries to control the flowering time of cattleyas, work that has been extended to Phalaenopsis much to the benefit of some nurseries.
K Barrett N Calif, USA
_________________________________________________________________
Is your PC infected? Get a FREE online computer virus scan from McAfee� Security. http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
_______________________________________________ the OrchidGuide Digest (OGD) [EMAIL PROTECTED] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
