I thought some of you might be interested in the comments I put up here:
http://www.shaman-australis.com.au/cgi- ... 2;t=001961 (http://www.shaman-australis.com.au/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=2;t=001961)
~Michael~
As always, well reasoned/well done... Thank you M.S.---- senorsal
I put a new post at the above link. Have a look.
~Michael~
Some cacti are consume for their fruit. Most likly, this is a positve reinforced strategy that scatters and firtilizes the seed,probably the points Tha MSSmith would be well aware of.
The chemicals in a plant though,I surprised that by now,somebody hasn`t answered the question this thread is asking,why,and in particular,why alkaloids in any particular cacti. Especially Lopho,I would of thought the attention would have been created there,for we seek to understand all things.., especially when it is pschoactive.
Is/was it a toxin. For an animal? How about another plant? Or does it aid in healing?. Is that even close to what mescaline ,and if considered,other alkaloids do for the cacti. Does prevalence of the chemical in a particular area of the cacti even have a reason?
One thing intersted me. I was examining myTrichs. a month or so ago. I discovered the spine(s) of one had penetrated,and caused rot,in the column of another.
So...
Let`s say I wanted to project on this,to assume a mechanism the plant had 'value' in;
A defense against a crowding neighbor... a defense against one of it`s ingrowing columns...best to spread out,to colonize.?
Even to the point of rotting off and pupping by the surviving horizontal cacti,. Or decay and provide firtilizer,food,for the rest of the 'colony'.
Or just something bad left over,and not usful to the plant ,though it still exists,perhaps because of other advantages?(Spines...covered)
I read of a plant latley that sends a chemical message, through it`s roots i think, to it`s nieghbors,and triggers them into some kind of runaway proccess and death. Parrellel, but not the same, as 2-4-d, ( or the ingredient within)if I understand right.
I hope to read the answers to this threads question`s someday,wouldn`t be suprised to see something in Nature,or Scientific American, or some publication for the layman,at least covering these subjects in general. They are good questions,and again,at least in the case of the famous Lopho. I`m suprised the chemical makeup hasn`t been covered.
Chemicals are made by plants due to random mutations which change their genetic makeup. Mutations can be caused by radiation, chemicals in the environment or other causes. Most mutations are negative and the plant dies or is weakened because of them. On rare occasions, the mutation may bring a positive change which is passed along to future generations. If it produces a poison that kills it's predators, that will be retained. If the mutation makes it taste yummy, the plant will be wiped out and the mutation most likely lost. This is how it works over millions of years.
Besides poisons, a chem that makes the plant taste bitter might give it a slight edge over other plants and help it survive. Mescaline is certainly bitter and is also disorienting to many animals. Other chems might make the plant resistant to freezing, retain moisture better, propagate seed better or something else. If the mutation gives no advantage it will be lost.
Quote from: "Stonehenge"Chemicals are made by plants due to random mutations which change their genetic makeup... .
Horizontal transmission is a possiblity that makes this seem problematic to me. However I do not not to play down your understanding of the evolutionary role in the emergence of new chemicals.
My own understanding is slightly different. There is a high degree of genetic mixing which occurs at several points in meiosis, this provides working varition (aside from exogenously influenced point mutations) for chemical variability. The result is that there is a natural tendancy for chemical diversity among the offspring without mutation.
Transposable elements also provide an interesting avenue of "mutation", however it might be noteworthy to consider that many mutations have no effect upon the organism at all. In plants somatic mutations occur frequently that since they are in cells that will never grow divide or produce offspring they never have an impact, negative or otherwise on a plants overall ability to pass its genes on.
It is also arguable that many mutations might not even have an impact upon transmission if they are in non-coding regions.
However this is all tangential, the point I wish to address is that Trichocereus entheogens are ancient cultigens that have been cultivated for from six to ten thousand years and possibly more. This means that natural selection has not been the major factor in the alkaloidal content of these cacti. Rather humanity has been the deciding factor by utilizing artifical selection for thousands of years resulting in a handfull of "species" with entheogenic properties. Species is dubious, for although the cacti are divergent enough that many hybrids show uniformity as opposed to a high degree of variation. It is easily evidenced that they are all the same species in the same way that all dogs are the same species.
The major alkloids prevelant across the trichocereus group include tyramine, hordenine and some colse chemical relatives. These compounds are toxic to insects via the nervous sytem. In active pervianus phenotypes such as the cuzcoensis have been found tomescaline in trace amounts and large quantities of tyramine and hordenine. These broad presense of the tyramine hordenine alkaloids seems to show genetic conservation of these alkaloidal pathways across the Cactaceae. The natural varition of enzymatic pathways allows these conserved pathways to serve as evolutionary stepping stones for the emergence of new alkaloids.
It is possible that the entheogenic properties of Trichocereus emerged after its medicinal and topical healing capacities had warranted its cultivation. What I mean to say is that it cannot be ruled out that it was artificial selection itself that caused the presense of mescaline in these cacti. In comparision to Lophophora which is a veritable alkaloidal pharmacy San Pedro and its allies have fairly simple profiles indicating further that the major factor for selection of all of the involved species was mescaline content, and the genetic capacity of the "species" to breed and bear fertile offspring indicates that the cultivars had a single common ancestor and are all in fact divergent cultivars of a single species. That the phenotype and chemotype of these species now show the divergences they do is a result of the longevity of the time they have been in cultivation.
I wish to propose that theories of natural selection do not apply so well to Trichocereus as an explantion for thier alkaloids. Furthermore with regard to the emergence of new alkaloids and ratios between them mutation is not required, for sexual variation and transposable elements can provide a pragmatic explaination for alkaloid variation. To be sure mutation can be a source of new alkaloids as well, however I would like to contast the theory of gradual evolution wiht puncutated equilibrium and say that major changes can occur in population over very few generations.
it should and could be remembered that in cacti there are pigment alkloids that utilize the same basic pathways that defensive as well as entheogenic alkaloids use. The presense of these alkaloidal pigments in families related to the cactus family shows that they were conserved from a common ancestor. This means that the potential for alkaloids could have a root in pigments.
In all cases of 'evolution" the selective pressure that results in the emergence of a trait is due to a secondary aspect of such a trait. This means that the properties of alkaloids in insects are accidental and that it proved to be a benefit once the insecitcidal secondary propeties of the alkaloids allowed some individuals to survive and breed when others died.
Thus it cannot be said that there is some inherant teleology in the presense of psychoactive alkaloids in plants, rather a degree of reciprocity between psychoactive plants and people only emerges after the fact of use and cultivation. Mescaline was not there in the cacti waiting for people to use them.
The cacti (knowing the meaning of life) merely experianced life such as cacti do and existed for the sake of their own existance.
For those of you who care I should like to add that I have ignored parsimony in regards to alkaloids in these plants merely because parsimony is inapplicable to artificial selection. Refferences if you want them.