BC Growers Association

 
 

UV and It's Effects

 
Here are a few posts from friends on the net that I've collected.


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 - Differences
             DATE - Sat Jun 20 15:54:02 1998
             FROM - Spliff
 
             UV A : 320 - 380nm Used for UV Curing, Non Destructive Testing &
             Inspection.
             UV B : 280 - 320nm Used for Suntanning.
             UV C : 200 - 280nm Used in Dermatology.


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.
 



 
                            Posted by Frenchie on January 07, 1999 at 17:08:06
 
 
 
    All these new strains are made with kick ass lightning, there are no seeds breedders that are using fluo lightning so
    the plant after regenerating with so much light all his life tend to include this trend in his genetic pattern. They
    don't breed seeds for low light level YET>
    There are some older strain like NL that work well under low lightning.
    POTENCY> Metal halide coated cooler than sunmaster warm but the blue spectrum does some tricks with
    potency.
    let's say we talk about ordinary Northen light strain.
    I did always found a high level of CBD and CBN in NL when grown under to much red CRI. I think that since the
    resin is there to keep the flower from drying (natural no) it must make sens to keep the leaves alive and feeling
    well for a longer period so that the leaves can produce that thick enveloppe you need to keep those resin glands
    from oxidysing ( ouf) The blue spectrum will work on the resin glands to produce THC . Forrest of dreams.......
 

    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...
 
 

 

 
 
 

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