Well…let me see. Ah! My comment on a discussion I’m having with Vic High, a canadian breeder.
*Me: **
** Well, after digesting the symposium several times with the aid of Mr. Webster, I’m still not convinced of the positive relationship between 1st, 2nd, 3rd generation, etc. clones and the claim that latent clone generations increase in regarding their degree of potency, in fact, this paper may suggest the opposite. As an aside, the one of the benefits senescence and latent aging has on a plant is the tendency of a plant to give up metabolites to its fruit and flowers. The positive effect of aging is only within the realm of physiological and chronological changes, which occurs relative to the amount of phytochrome increases that eventually trigger a flowering response. This being dependent on the genotype of the cannabis plant material and environmental conditions i.e. afghani/long nights.
This was a very interesting white paper, but in some parts confusing… such are postulations posed with different plant material (and one mesmerized reader ). This paper also did not represent current viewpoints…as if it matters, and no, I did not seek out recent data as I don’t have the time right now. Jury’s still out IMO.
What we have here is a paper that defines the meaning of ontogenetical, physiological, and chronological aging as defined by ‘early’ biological communities - how they may group and inter-relate, and how different types of plant material succombs to one or all processes eventually, unless rejuvenation takes place and that’s the kicker - rejuvenation. What this paper cannot address (of course) is the fact that no matter what effect these aging processes cause, cannabis potency is generally dependent on trichome density as well as the amount of cannabanoids and their makeup as found with those glands. You can have a heavy trichome field in which the stalked resin glands are filled with cannabanoid crap. Looks good, smokes bad. That is the key. If latent clone generations cause an increase in the amount of cannabanoids and the quality thereof… via a heavier density trichome field and improved resin gland composites, then we may have something here.
After wading thru a sea of definitions regarding what constitutes aging and senescence, the real meat is presented regarding our question - affects of rejuvenation (or aging) via pruning and the loss or enhancement of favorable characteristics… and I quote →
"Pruning also induces younger buds or tissue to form normal or adventitious shoots, these
being more juvenile than those removed. This can he seen as a kind of semi-ontogenetical
rejuvenation. Theoretically such a rejuvenation cannot be continued indefinitely, … This leads us to the old question of whether clones age or not (Rijhouwer, 1930), including the problem whether all plant cells remain totipotent… Based on extensive experiments with clones of Lemna minor L. (Vangerminn, 1965) the question regarding the ageing of clones can he answered negatively, provided the proper time and plant parts are chosen for propagation. Yet it cannot be denied that a continuous vegetative propagation sometimes leads to a loss of favourable characteristics (Hartmann and Kester, 1968)."
Take note - The “ageing of clones can he answered negatively, provided the proper time and plant parts are chosen for propagation”.
Another paragraph addresses the dynamics of clones as it relates to juvenile versus aging stages which again supports the theory that indeed cuttings (clones) may in fact be working AGAINST cannabis growers who hold dear to the hypothesis that clones are older and therefore “better”, and I quote →
"A true ontogenetical rejuvenation would mean that adult meristems could reproduce plants
***or parts being again completely juvenile." ***
How that is warranted or presented is not discussed, but I would presume that that would mean taking a cutting (which of course contains meristem tissue) and growing it out either in vitro or sticking the entire cutting in a rockwool cube or a pot and rooting it. In the case of Cattleyas (used as an example in my earlier post), that tissue is located at the foliar terminal tip.
" Some examples are represented by the production of new seedlings after amphimixis or even apomixis, and the spontaneous or artificial regeneration of juvenile plants, either in vitro or in vivo, from all kinds of adult plant parts, such as stems, leaves and flowers (Plerik, 1975). This ontogenetical rejuvenation is much more difficult to explain than the former physiological rejuvenation. It is supposed that an
isolation of a single or at least a limited number of totipotent cells from the surrounding tissue is a prerequisite for a totel rejuvenation (Steward, 1967). Comparable results were obtained by grafting juvenile seedlings onto the adult parts of the plant (ivy, sugarbeet, rubber), or by spraying them regularly with gibberellin (Stoutemyer et al., 1961). It should be noted that opposite effects were mentioned earlier, while discussing the probabilities of an accelerated ontogeny." ←
Alot of factors and considerations here. If I’m interpreting this right, the taking of meristem tissue (cuttings) actually causes a rejuvenation back to a juvenile state of the meristem portion. That doesn’t settle well with me per my earlier reflection of taking 8 year old budwood from a Pecan tree, grafting it to young rootstock, planting it, and watching as the new budwood grows and produces nuts very quickly compared to a seedling. The old budwood doesn’t know (chronologically) that it is now a one year old sapling, “thinks” it is an 8 year old tree, and bears as soon as it’s well established. Cuttings/budwood taken from the top part of a plant are considered botanically more juvenile than those taken at a lower point on the plant…per this paper, as an aside.
All in all, this was some great reading Vic, but ya done confused this cowboy once more - ma brain hurts! Time to smoke some Lone Star goodies!
Uncle Ben
From Vic:
Abstract:
An evaluation of literature leads to the conclusion that ageing and senescence can be
related to ontogenctical and physiological causes. Ontogenctical ageing is genetically
programmed, localized in the meristems, not related to exhaustion, and cannot easily be
reversed. This implies important consequences for vegetative multiplication and for the
characteristics of clones obtained. Physiological ageing is correlatively influenced, caused
by an increased disorganization and exhaustion, and is not localized in the meristems.
When not advanced, a reversal is possible. Senescence regards more often the
physiological ageing, but may he of ontogenctical nature.
*** Introduction:***
Terms related to ageing are used in confusion in every language because they are not
clearly defined. This regards, for example, ‘ageing’, and ‘senescing’, having a similar or
different meaning. It indicates the need for a better distinction and description of the
ageing processes, of its different phases, the process of ‘rise and shine’, covering the
juvenile and mature or adult phase, which received more attention than the ‘fall’,
representing the phase of full senescence. The latter negative aspect of ageing drew
interest more recently and became a new branch of science: phytogerontology.
This paper describes some of the present views with regard to ageing in the sense of
becoming more full grown, as opposed to ageing In the sense of getting more deteriorated.
It distinguishes an ontogenctical and a physiological type of ageing. This may have
implications and consequences for a discussion on ‘Juvenility in Plants’, the subject of this symposium.
General
Ageing in plants has three aspects, a chronological, an ontogenetical and a physiological one. In this order they are or, or less indicated by such opposing terms as: young and old, juvenile and adult, improving and deteriorating. There may be no contradiction if a plant is considered ‘young and adult’ or ‘juvenile and senescent’. Strictly taken all three aspects of ageing start from the formation of the zygote or, more in general, from germination or probably regeneration and terminate with the natural death…
