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Subject:  Its Back Sink Source Relationship

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Big Kahuna 21

Ontario, Canada.

The pruning of Dan MacCoy's mater plants is it really about removing apical dominance. This is basically removing the topmost shoot of a plant. Apical dominance is controlled by the production of plant growth hormones (auxins) that are developed in the plants leading shoot. These auxins inhibit and slow the growth of other branching and lateral shoots. Removal of this top most dominant shoot, results in a lowering of auxins throughout the rest of the plant. In turn this allows new lateral shoots to be produced that are more vigorous and robust. This Forces the lower branches and architecture of the plant to become stouter instead of being restricted by the apical dominance of the inhibitory auxins. Simply the other parts the plant become larger and more vigorous than they normally would develop.

The result is a plant that has more full-bodied and larger capacity of its vascular systems. Thus apical pruning alters the basic design of sink source relationship. The pathways Xylem & Phloem leading into the potential new fruit and of the other parts of the plant develop bigger than they normally would have become.

So is that the simple reason why the excessive pruning of the 8.41 tomato plants was very successful. Forcing the plants vascular systems and structures to grow bigger therefore signals vine plants to develop bigger and larger sinks.

11/26/2014 10:39:45 AM

26 West

Urban Prior

If you pruned a pumpkin plant down to 200/250 sq ft would you get a 3000 lb pumpkin.

11/26/2014 10:54:15 AM

Big Kahuna 21

Ontario, Canada.

Was this not thee premise in starting with the tree shape 20 or so years ago and limiting size to about 1,000. The sweet spot for agp seams to be already discovered in the 500 to 750 area.

The theory's suggested are in part based on research. Your suggestion to limit growth beyond 250 has never been demonstrated in a patch or documented in research. Apical dominance has however been studied extensively.

11/26/2014 12:05:37 PM



Big Kahuna, would you recommend to terminate the main vine of an AG plant as soon as one knows which fruit will become the keeper? If so, where would your prefer to terminate the main: A) right past the fruit and then growing the plant between stump and fruit in a pitchfork pattern, or B) a couple ft past the fruit and then growing the additional secondaries in the regular X-mas tree pattern, or C) ...your suggestion?

Thanks alot in advance.

11/26/2014 12:27:05 PM


Torrance, Ca.

See what you started Dan.

I love it!!!!

11/26/2014 12:37:41 PM

Master P

Ely Mn

sounds good to me Russ!
lol chris.

11/26/2014 1:29:49 PM

26 West

Urban Prior

Thank you. This is important for small growers like me. I grow " in town " on less than 1200 sq ft for all my gardening needs. I could now look at two ag plants being grown.

11/26/2014 1:30:44 PM

Big Kahuna 21

Ontario, Canada.

The need to research apicial dominance and how it affects plant architecture might help. The reference here is the overall efficiency of the plants vascular system. Plant size is another secondary co factor that is off in another direction.

Generally a plant with the largest functioning xylem at the peduncle would produce the greatest yield. What effects sink, fruit bud & xylem their structures development is much more pertinent.

A larger more robust and developed xylem allows for greater import into the fruit does it not. Just as a better structured phloem would for foster increased sink export into the fruit.

Viewed a different way > is It possible that bigger AGP come from the main vine because the architecture of the vine leading to the peduncle larger and more developed-therefore the channels are greater in size by channels I mean pathways.
If these pathways are in active development and they are competing saints what happens are they left starving? are they left searching for nutrients?😜are they left of meager size?

The answer is I believe I'm not in the plant size. It is found through the architecture of the structures that lead directly into the fruit and the sinks. For this and only this determines the strength of the sink source relationship.

11/26/2014 2:29:27 PM



In Tomato - Removal of Leaf Terminal Buds also lowers Auxin in a particular area and usually causes the bud directly beneath to grow ~rather than all of them and slot of pruning, it not only lowers Auxin...I believe it raises Cytokinin (increased Cell Division)

10/22/2019 8:36:00 PM

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