Basal shoots

[PlantAKiss]

I was just wondering...what makes a nep produce basal shoots? I would assume age doesn't necessarily have anything to do with it since I have young neps (mirabilis and truncata) producing shoots and an older one (ventricosa) that never has. Are some varieties more prone to do that than others? Can you do anything to force a plant produce a shoot (other than cutting the vine)? I'm just curious since some of mine are producing shoots and some aren't.

Suzanne

 

[Tony Paroubek]

Basal shoot production is related to a plant's apical dominance. The amount of apical dominance will vary from hybrid to hybrid, species to species and clone to clone. The stronger the apical dominance in a plant the less basal shoots it will produce and the longer the vine needs to be before the plant will start producing them.

Basically what happens is the plant produces auxin in the growing tip. This hormone travels down the stem to the root system where it promotes root growth while at the same time inhibiting shoot development. The roots produce cytokinins which travel up the plant and promote shoot growth. The concentration of auxin and cytokinin around the lateral buds AND the lateral buds sensitivity to it will determine lateral shoot growth. As the vine gets longer the auxin concentrations get weaker and weaker farther away from the top of the plant while cytokinin concentrations increase, until the point is reached where the lateral buds respond to the cytokinin and break dormancy.

All this boils down to:
Removing the auxin source from the plant.. ie cut the top off.

Reducing the auxin concentration at the base of the plant. Bending the top of the plant over so that it is below the lower portion of the vine. (yes gravity affects auxin flow) Turning the pot on it's side may also work if the vine isn't long enough.

Artificially increasing cytokinin concentration at the lateral buds, thereby overcoming the effect of the auxin and breaking dormancy. IE applying some BAP (cytokinin) to the base of the vine.

Tony

 

[Parasuco]

Orchid Keikie past works doest it?

 

[Tony Paroubek]

I have not personally tried inducing basal shoots by treating with cytokinin. Theoretically the keiki paste should work but how effective they are I couldn't say. I am sure that some species/hybrids would respond differently. Plus length of the vine and such would also affect the results.
Tony

 

[larry]

WOW, excellent and informative response Tony!
And, thanks for asking the question Plantakiss.

Looks like i may have to do some experimenting

 

[gr8oz]

I have a tube of some of the early 'shoot promoter' that was eventually marketed at Keiki paste. Its shelf life may have expired, if that's possible, because my results are mixed. While the paste does promote new shoots all along the stem of the plant, it tends to inhibit pitcher growth. I probably need to try this again with a fresh supply of Keiki, but the hormone definitely does induce lots of new growth. Oz

 

[PlantAKiss]

Wow...thanks guys! VERY interesting....

Tony....where in the world did you learn such techincal information? Just reading or researching on CPs/plants for years? I don't see that kind of specific information on the web at least regarding CPs.

Larry...SOMEBODY had to ask so it might as well have been me.

You got me curious about the shoot thing since some are producing and some aren't.

I have keikis on some of my dendrobiums...not really a good thing. One of them is actually in spike even though its still attached to the parent cane.

Thanks Tony and everyone.

Suzanne

 

[Tony Paroubek]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Tony....where in the world did you learn such techincal information?[/QUOTE]<span id='postcolor'>

Cornell Ag and Life Science, Plant Biology 242.
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