We got a very nice response. I have three separate attachments not included below
from Professor Davies whom we owe our gratitude for his compassionate response. I will read through them tonight when the straw hat goes on.
Professor Davies
Dear David,
You have some excellent ideas, though I am sorry to learn of your status.
So the question is would ABA simulate drought to increase the content of THC?
Somehow I think this unlikely because ABA is a reaction to water stress as is, per your note, THC. So the question is would ABA simulate drought to increase the content of THC? Somehow I think this unlikely because ABA is a reaction to water stress as is, per your note, THC.
From Wikie Integrin-like receptors play a role in protein-protein interaction and are found in the plasma membrane of plant cells in the leaf, root and vasculature of plants. Plants produce a physiological response that is dependent on information obtained from the environment. The majority of this information is received through mechanical signals which include touch, sound, and gravity. Therefore, the interaction between the extracellular matrix and the internal cell response is incredibly important for receiving and interpreting information. The specific functionality of ILRs in plants is not well characterized but in addition to mechanical signaling transduction, they are believed to have some role in plant immune response, osmotic stress sensitivity, and ion regulation within the cell.
So if the drought sensing in the cells it maybe that this sensing impacts THC production directly rather than via ABA, and if so ABA application would do nothing. In any case ABA is quite costly ($160 for 250mg) which is why it never caught on as a agricultural chemical, even if it did work to increase yield, which in general it does not. I guess you could try spraying ABA solution in a small experiment, but as I said above I do not expect it to work.
Now we need to ask why Cannabis produces THC – it is likely to ward off either pests or fungal diseases. There are two compounds produced by plants that trigger such defense: Jasmonic acid for insects and salicylic acid for fungi. These are cheap: salicylic acid can be purchased as wart remover at the pharmacy. Jasmonate is obtainable as a methyl ester on ebay, where incidentally is it claimed to increase trichome production Methyl jasmonate 1ml. methyl esters. Increase tricome production | eBay
Another possibility is ethylene which triggers fungal defense. A liquid formulation that releases ethylene is ethephon; here is a sample site Ethrel / Ethephon [Quart] | Hydro-Gardens
I attach a recent summary paper from a reliable journal on treatments increasing THC for your information, and a paper, and the figures separately, on the effects of ethephon. I can’t say that any of these would work but if you want to experiment the latter three would be much cheaper than ABA. The papers give appropriate concentrations for spraying because the concentrated solutions would kill the plant.. Note that Methyl Jasmonate is sparingly soluble in water (340 mg/L at 25 °C); dissolving it first in a little rubbing alcohol ( a mL or two) will help it get into solution in water. The other easy alternative is simply to grow your plants and then drought stress them just prior to harvest!
Your last question was ABA in seeds. In this role it is a germination preventer. Cuttings are fragile because they are deprived of water until they grow roots. It has nothing to do with ABA.
If you wish to improve the survival of cuttings make a clear plastic tent over the cuttings, have a plastic pipe run into the roof nd have mister nozzles inserted into the pipe, and an exterior solenoid valve driven by a timer so come on the 10 seconds every ten minutes. All these components are relatively cheap. If you need suggestions as to where to purchase let me know.
I hope that this helps.
With best wishes,
Peter