Hormonal induction of flowering

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naoki

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I came across this abstract:

http://www.actahort.org/books/766/766_36.htm

I didn't read the original, but it says that gibberellic acid (GA) can induce flowering in Paphiopedilum. Cytokinin (BA) seems to counteract the effect of GA. Auxins (NA) didn't have effects.

GA is a kind of hormones (gibberelins) frequently used for seed germination in plants, and similar flower induction effect is known in Brassicaceae (cabbage related family). GA did work for my poppies, too.

I don't know if this is used among professionals, but it could be useful for hybridizers to synchronize the flowering.
 
Yeah, I don't have the full article, neither. But I thought that the abstract have somewhat sufficient info. It seems to be pretty simple: 25ml @ 866ppm of GA sprayed to leaves and let it run into the pot. I'm not sure how many times (maybe once?). When my student tried GA on poppies, she sprayed and drenched a couple times. The response was pretty quick (within a couple weeks).
 
I had these hormones pulled up on ebay awhile ago and was ready to buy. I don't remember why I didn't! I'm going to re-visit that purchase again!
The cross,MACABRE × GLANDULIFERUM, they used in the experiment is very similar to plants I once own/shared with a friend. Callosum X glanduliferum was the same way, huge multi-growth plants and would never bloom. Impressive results from this experiment and worth a look into.
 
Natural gibberellins are quite unstable. Just about every seaweed contains them, but they degrade so rapidly that they are essentially "gone" by the time the products made from them are packaged.

A while back I purchased a bottle of ProGibb 4%, but upon reading the literature that came with it - and knowing that my motto in life is "Nothing Exceeds like Excess" - I decided to use it on my lawn, instead of my orchids.

There is nothing about orchids in that, but the commentary about other ornamental plants shows that timing and concentration can mean the difference between inducing blooming and inhibiting it, or enhancing flowers and creating grotesque gargoyles. Add to that the tendency of gibberellins to result in "leggy" growth, and I wasn't ready to experiment.
 
Rick, I'm guessing "glanduliferum" means praestans or something (they are pretty confusing). It is interesting that they pass on this reluctance to hybrids. Is the pure species also reluctant to flower? I've never grown these PNG species (I'm getting one next month, though).

Ray, in powdered form, the most common/available GA (GA3) seems to be pretty stable. But you are right some other GA could be less stable. I wonder if there are some enzyme involved in the breakdown of GA in seaweed.

Also it is a good point that plant hormones can have multiple effects depending on the context/timing. This applies to all hormones commonly used for orchids such as auxins, cytokinins, and salicylic acids. This feature is one of the differences between animal vs plant hormones.

Concentration is important, too. So it is good that this experiment gave us the rough guideline with regard to the concentration. Most hormones have bell shaped response, I believe. For example, cell elongation can increase with higher concentration of auxins, but above a certain point, the relationship reverses (more auxin actually reduces the rate of cell elongation). And the sensitivity differ among tissues (e.g. root vs shoot). A good example of this reaction from auxins is gravitropism.
 
SlipperKing said:
I had these hormones pulled up on ebay awhile ago and was ready to buy. I don't remember why I didn't! I'm going to re-visit that purchase again!
The cross,MACABRE × GLANDULIFERUM, they used in the experiment is very similar to plants I once own/shared with a friend. Callosum X glanduliferum was the same way, huge multi-growth plants and would never bloom. Impressive results from this experiment and worth a look into.
Click to expand...

Did you ever try this application or get to read the full paper?
 
I suppose my earlier comment about chemical instability was premature - if not flat wrong. A relatively recent analysis of 4-year old KelpMax showed the presence of high levels of GA, Abscisic acid, and a number of other stimulants, besides the auxins and cytokinins.
 
Ray said:
I suppose my earlier comment about chemical instability was premature - if not flat wrong. A relatively recent analysis of 4-year old KelpMax showed the presence of high levels of GA, Abscisic acid, and a number of other stimulants, besides the auxins and cytokinins.
Click to expand...

That's good to know, thanks for the new info.
Do you have any reference to the ppms of the PGRs listed on the analysis?
 
gonewild said:
Did you ever try this application or get to read the full paper?
Click to expand...

I did Lance but nothing yet. I sprayed at the recommended concentration 3 weeks in a row onto dele var. dunkel X roth. Multi- growth with bud brac last fall. No buds yet.:sob:
 

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