Posted by oldtimer1 on December 25, 1998 at 03:30:21 PT:
In Reply to: Didn't mean to 'steal' your handle brother!!!!! posted
by Old Timer (2) on December 23,
1998 at 16:51:47 PT:
Hi there Old Timer I have a couple of other thoughts on why the
quality of the vars has slipped in
Holland I think the main one is the way they grow or should I
say the type of lighting they use. Most
of the strains they have came from America and were either developed
under real sun or under big
halides and both these sources have a big uv content. The Dutch
are great gardeners and have had to
use supplementary lighting in their glass houses for years so
they can grow all the year round. The
lights they developed were a highbay type such as Poots and Phillips
fixed on grids 5 ft or so above the
finished plant canopy . And of course they chose the lamp that
gave the most photoactive lumens per
w, the sodium lamp which has virtually no uv output. Of course
when cannabis came to Holland the
farmers son who decided grow a bit of pot used the same system
as in dads 2.5 acre glass house.
There is no doubt that all the most potent varieties of cannabis
come from areas of the world where
the background uv is high to extreme and that the potency and
complexity of high relates the almost
directly these uv levels. Cannabis is a highly adaptable and
over a few generations change to new
conditions and this is what I think has been happening in Holland.
I could go into more detail but this is
not the board to do this on but it does relate to your comments.
It is interesting to notice that
Greenhouse seeds have mentioned uv for the first time I think
this must have come from Nevils input
and if they are now taking this into account maybe things are
turning to the better.
As far the var you were asking about I suspect D J Short would
be the man to ask, from I can glean
he is a very private person. You could try writing to him care
of Mark Emery sorry I cant help futher.
All the best have a great Crimbo all. Ot1.
O.K., but does U.V. content change genetics?
Posted by Uncle Ben Dejo on December 25, 1998 at 18:35:34 PT:
In Reply to: Re: Didn't mean to 'steal' your handle brother!!!!! posted
by oldtimer1 on December 25,
1998 at 03:30:21 PT:
Read in a Tom Flowers book on forced mj flowering, that MJ grown
on higher elevations, ie, 10,000
ft. tested for higher THC content. I assume this is the plant's
response to this particular environment.
I have always rotated my plants between sun vice HPS, security
and weather conditions permitting,
and can't complain re potency and growth habits.
So.....are you proposing that genetics have been altered on a
short term, or a long term basis, regarding
particular light setups by the Dutch?
Uncle Ben
Re:yes
Posted by oldtimer1 on December 26, 1998 at 04:57:24 PT:
In Reply to: O.K., but does U.V. content change genetics? posted by
Uncle Ben Dejo on December 25,
1998 at 18:35:34 PT:
I think it is a problem that has been developing through the generations.
Wernard of [Positronics] was
aware of it being a problem and now Greenhouse seem to be taking
it on board. I haven't read Tom
Flowers but high elevation plants that have been there for generations
are high in thc but more
importantly it is a lot more complex. On a short term basis a
clone from a known variety Indica type
will have a slightly more up high with the addition of uv during
flowering but Sativas seem to improve
a lot more with a much clearer up high. I would suggest that
if breeding for seed indoors the addition
of uv a/b tubes as supplementary lighting would help to improve
the stock a lot . Your plants getting
some real sun would probably allow them to express the potential
of that generation. You can easily
test this If you make a number of cuttings from a mum and grow
half with sodium only and
supplement the other half with sun when you can, I think you
will find quite a difference between the
two stones the more sat in the var the bigger the difference.
Ot1.
TOPIC - The net is too cool
DATE - Sat Jun 20 15:21:58 1998
FROM - Spliff
After a quick 'Altavista' search on UV and cannabis I came up with a few
items that pertain to this discussion. Here is the first:
Pate, D.W., 1994. Chemical ecology of Cannabis. Journal of the International
Hemp Association 2: 29, 32-37.
The production of cannabinoids and their associated terpenes in Cannabis
is
subject to environmental influences as well as
hereditary determinants. Their biosynthesis occurs in specialized glands
populating the surface of all aerial structures of the plant.
These compounds apparently serve as defensive agents in a variety of
antidessication, antimicrobial, antifeedant and UV-B
pigmentation roles. In addition, the more intense ambient UV-B of the tropics,
in combination with the UV-B lability of cannabidiol,
may have influenced the evolution of an alternative biogenetic route from
cannabigerol to tetrahydrocannabinol in some varieties.
TOPIC - Bingo
DATE - Sat Jun 20 15:27:39 1998
FROM - Spliff
How about this one:
Another stress to which plants are subject results from their daily exposure
to sunlight. While necessary to sustain photosynthesis,
natural light contains biologically destructive ultraviolet radiation.
This
selective pressure has apparently affected the evolution of
certain defenses, among them, a chemical screening functionally analogous
to the pigmentation of human skin. A preliminary
investigation (Pate 1983) indicated that, in areas of high ultraviolet
radiation
exposure, the UV-B (280-315 nm) absorption
properties of THC may have conferred an evolutionary advantage to
Cannabis capable of greater production of this compound
from biogenetic precursor CBD. The extent to which this production is also
influenced by environmental UV-B induced stress has
been experimentally determined by Lydon et al. (1987). Their experiments
demonstrate that under conditions of high UV-B
exposure, drug-type Cannabis produces significantly greater quantities
of
THC. They have also demonstrated the chemical lability
of CBD upon exposure to UV-B (Lydon and Teramura 1987), in contrast to
the stability of THC and CBC. However, studies by
Brenneisen (1984) have shown only a minor difference in UV-B absorption
between THC and CBD, and the absorptive
properties of CBC proved considerably greater than either. Perhaps the
relationship between the cannabinoids and UV-B is not so
direct as first supposed. Two other explanations must now be considered.
Even if CBD absorbs on par with THC, in areas of high
ambient UV-B, the former compound may be more rapidly degraded. This
could lower the availability of CBD present or render it
the less energetically efficient compound to produce by the plant.
Alternatively, the greater UV-B absorbency of CBC compared
to THC and the relative stability of CBC compared to CBD might nominate
this compound as the protective screening substance.
The presence of large amounts of THC would then have to be explained as
merely an accumulated storage compound at the end
of the enzyme-mediated cannabinoid pathway. However, further work is
required to resolve the fact that Lydon's (1985)
experiments did not show a commensurate increase in CBC production with
increased UV-B exposure.
TOPIC - Brief excerpt
DATE - Sat Jun 20 19:07:50 1998
FROM - Lady J
"The MV (mercury vapor) lamp produces more UV-A, violet and blue light
than any other type of lighting source commercially available. Cannabis
responds to the intense violets and blues of the murcury vapor lamp by
producing dark, almost bluish green leaves. Stalks grow strong but not
straight and sort of zigzag between short internodal lengths. Side-shoot
development is extensive, as is the formation ofresin glands on calyxes,
bracts and larger associated leaves. Poetency is very noticeably increased
when compared to clones grown under other hid lamps. Plants also
rejuvenate faster under mv lamps."
Just part of an excellent article by Owl(one of my fave growers).
Peace
TOPIC - uv=b
DATE - Sat Jun 20 19:27:55 1998
FROM - Lady J
here's a little info:
7. IMPACT OF UV-B ON PLANTS AND ANIMALS
UV-radiation has long been known to be damaging to life; indeed this quality
is being employed increasingly for the disinfection of water and for the
mutation of
microorganisms for laboratory experiments . UV-B affects plants and animals
by modifying both their biological and chemical environment. Damage may
occur in a
number of ways, including the direct destruction of the genetic material
DNA, deactivation of enzymes, disruption of membranes and other cell
structures and the
generation of highly reactive chemical agents known as "free radicals".
Although biological repair mechanisms exist, mutations may remain as errors
in
the repair processes. In addition, the repair mechanisms themselves may
be
deactivated by high UV doses. The interaction of all these processes can
lead to a
variety of adverse effects on plants and animals. Many effects are sub-lethal,
may
interact with other factors and may, therefore, be very difficult to attribute
to
UV-enhancement specifically.
Effects on plants in the sea, in freshwater and on land are of fundamental
importance because of their position at the base of all other food chains.
By
nature,
plants have evolved to maximize the surface area they expose to sunlight,
but
consequently their exposure to damaging UV-radiation is also increased.
Elevated
UV exposure can cause temporary or irreversible damage to photosynthetic
apparatus (including the bleaching of the pigments which trap the sun's
energy), to
processes of cell division and growth regulation, and to the composition
and
replication of genetic material. Consequences include a reduction in growth
yield,
changes in levels and effects of plant hormones and alteration of periods
of
dormancy, flowering, etc.
UV-B IMPACTS ON TERRESTRIAL ECOSYSTEMS
Increases in UV-B radiation:
Alter soil quality and the soil ecosystem;
Decompose soil litter;
Influence plant growth;
Influence plant life cycles including timing of flowering, leaf-drop,
dormancy and death;
Alter biogeochemical cycling of carbon, nitrogen, etc.;
Affect susceptibility of plants to disease, drought, temperature and
pollution;
Modify the distribution of species within an ecosystem;
Disrupt the terrestrial food chain;
Alter inter-species competition for food, light and space;
Damage eggs and larvae of terrestrial fauna.
TOPIC - ultraviolet
DATE - Sat Jun 20 20:06:13 1998
FROM - casamere
tom flowers has a bit to say re uv from his flower forcing book:
Marijuana is thought to be indigenous to foothill areas with elevations
of
1500-2500 feet [where there's high uv levels]. Many experienced growers
will
tell you pot grown at these elevations will be the most potent - up to
20%
more potent than the same variety grown at sea level.
Growers use two or more 20 minute UV light treatments during the day cycle.
Most [tanning] UV lights have timing units. [small face-tanning lights
for
400w, full body tanning systems for 1000w areas. used tanning lights
supposedly available cheap]
If you have to be in the growing area wear sunglasses that filter out UV
light
and a hat. The small amount of UV-b radiation these lights produce can
do
heady things to your marijuana. Don't get carried away though, the object
is
not to get the plants to glow in the dark.
Metal halide produce the best potent weed less lumens
for the money but better smoke. After years of testing
with some friends who did want to keep THEIR recipe
(more hps)
i foung there weed to be harsh, full of CBD, make
me eat and sleep, only good to sell to someone else taht you
dislike.
The blue spectrum will give you a final product
that have everything included :taste without curing, potency and
yield, To be effective a ratio of 2 MH for 1 hps
at the most.(hps)
Hps alone can produce a cash crop but not a connaisseur
crop.
Et Voila...