Common Auxins:
Dicamba An herbicide that I find particularly useful in the generation of callus in C.S.
2,4-D A weed killer. I’ve not used it
IAA It is likely that you all have used IAA as it is one of the more common hormones in rooting dip and powders – it works moderately well with C.S.
IBA is another very common rooting hormone used frequently. It is more stable than IAA being less sensitive to light and heat. This is the one I have selected to use, the Chinese study uses it and I have every confidence in it as it is used frequently in woody plants.
NAA is also used to produce roots and callus. I find NAA to be very useful as a balancing hormone in C.S.\
Comon Cytokinins:
BAP, one fo the most used growth hormone. It works with C.S.
PBA Used for auxiliary shoot production. It works with C.S.
2iP Another commonly used hormone that works with C.S.
Kinitin is a growth regulator that is isolated from DNA. IT works somewhat with C.S.
Zeatin is or was extracted from corn endosperm. Although it is a common Cyt, I found it worked poorly with C.S. in the proportions and amounts I tried.
Thidiazuron is a defoliant that has cyt properties I have found this to be a very good Cyt for C.S.
I can only speak to general actions of each of these classes of chemicals because they act differently on different plants and they act very differently in conjucunction with each other and with other growth inducing chemicals,
In general, tissue cultured with auxins CAN cause cells to grow large but not divide. When cultured with Cytonkinin alone there is little or no effect.
So we talk about apical dominance. This is a theory and I am sure many others could explain it far better than I. Auxins come from the apical bud and travel down shoots to inibit more bud growth so it promotes shoot but inhibits branching. Imagine a christamas tree where the top produces auxins to inhibit the plant from forming more shoot parallel to the main one. As the auxin is diminished futher down the plant, more auxiliary shoots form, so the plant gets wider the further it s from the top. Imagine the same effect on every lateral bud as well.
The point here I suppose is that one can not actually point to a single chemical and say "this chemical does this alone and this or that in combination with another chemical" It is a trial and error sort of thing and I am constantly juggling the ratios for a simple reason. I spoke earlier about a grid that one can use to settle on a particular ratio but in order to triangulate the amounts I have to go in steps. .01 .03 .05 and the like of each chemical. I don't think plants are aware of increments such as these and it could be that optimum performance could be gotten from something like .015 or .033. This would force me to experiment forever before I started actually seeing something green. In this case I have been bumping up the tdz a fraction each time for a portion of my plantlets. I will do the same with the balancing compound. This may not give me an optimum but it will get me closer.
I am very much looking forward to the rooting portion and and rather than make a final cutting,which is what I intend to do further on, I want to give them the best possible chance. I have another question though, and that is that there seems to be some distinction in sativa dominant and indica dominant types. They don't seem to grow the same. Sure, they both work quite well with the solutions I am using but I can't help but wonder if there are differences in their individual needs.
So now we wait for the brown truck.