Does stress produce blooms?

[joan gero]

Can this be? My (current) most distressing plant is a large Cattlya Portage Glacier that has suffered cat chewing and broken leaves, poor care by house-sitters, and this summer several badly sunburned leaves. Now inside, it has a horrible case of aphids. I have set it apart in poor light because it seems almost hopeless (and window space is scarce), watered it even less than usual (forgotten in its solitude), and postponed the thankless job of eliminating the aphids. Today I decided to sponge it down and treat it... and discovered what seems to be a healthy ready-to-burst sheath!!! I couldn't be more surprised (if I'm correct).

Is there something to this? Do plants sometimes throw off blooms when they have given up hope for a normal life? This was true of the only Bulbophylum (graveolens 'Mount Millaiae') I ever got to bloom for me... after 5 years of no blooms but healthy growth, it stopped growing, the bulbs shrivelled... and it bloomed and died!

Is this common??? Thanks...

[kmarch]

Just a couple of thoughts on this:

1) Of course our orchids grow and bloom best under ideal conditions. In some cases "ideal conditions" means a seasonal drop in temperatures and/or very wet or dry seasons. Excellent growing conditions, even though they may seem harsh or stressful to us (the necessary wet/cold of some pleurothallids or the 8 months of bone dryness for Cymb. cannaliculatum for example) are not at all harsh to the plants. Rather quite the opposite, the orchids have evolved/adapted to such a degree that they expect/desire these conditions in order to thrive and bloom. Some people, when they refer to these seasonal extremes, talk about stressing the plants in org=der to get them to bloom but those ideal, seasonal conditions are only stressful to us, not to the plants who are expecting them.

It is true that conditions in cultivation often do do not exactly mimic nature. In cultivation plants usually do not have to compete for light or water or nutrients. This enables some orchid species to produce much better in cultivation than in the wild. Yet even though they exist in a non-competitive environment, they still need the sultural conditions they expect.

2) It does seem in my experience and in the experience of many of my orchid mates that from time to time we have an orchid that blooms profusely then immediately dies. I have heard a great deal of and even participated in discussion considering the possibility that an orchid blooms as a last ditch attempt to reproduce itself before it expires. I've never read a paper or seen any research on this though. It certainly seems possible and logical but I don't know if it has been specifically addressed in any research. So, using Mythbusters terminology (confirmed, plausible, busted), I'd have to say it's plausible.

I should like to hear from some of the more biologically inclined folks on this topic, especially if there has been any research.

[Andrew]

There's a considerable body of scientific literature based on non-orchidaceous plants suggesting that several of the genes expressed during times of stress are also involved in flowering.

[kmarch]

But they only deal with non-orchids? Does anyone know of any such research done on orchids?

[tom499]

Would it not kill the plant though? If its under stress and then produces flowers, surely It would drain the plant of all of its energy and kill it.

[pikevi]

joan gero: I think your observation is right on the mark. Plant hormones and pheromones are being studied extensively now in relation to stress, growth and yield. I believe it is still in its infancy.

Of the many hormones in the plants ( auxins, gibberellins,cytokinins etc.) one hormone,Brassinosteroid, is a stress hormone which also acts as a growth hormone. It is very similar to the human hormone(s) produced by the adrenal cortex in humans. In humans, however, its production is controlled indirectly by the thyroid glands (thryroxine) and directly by pituitary gland(Adrenocorticotropic hormone (ACTH)). Since plants don't have a circulatory system they produce their hormone in each cell.

Brassinosteroid is produced in high amounts under stress and that causes the plant to grow,including flowers.

I believe that the group of auxins and gibberellins have more than 100 individual compounds and they are all being currently studied.

The fact that stress causes premature blooms has been known /observed for at least a few centuries.

[joan gero]

Thanks Pikevi for that extensive answer. But the phenomenon I'm talking about occurs in fully mature plants that seem to bloom as a "last gasp". Would plant researchers still consider these "premature" blooms???

[janet_a]

sure; i've had a couple plants that were well on their way to shrivel-up-and-die and they put up spikes. (i cut them off of course.)

go ahead and get rid of the aphids and put the plant back in the light and see what it does.

[kmarch]

pikevi, joan,

If i read your reply correctly, pikevy, you were referring to joan's "last gasp" question, correct?

[Andrew]

Originally Posted by kmarch

But they only deal with non-orchids? Does anyone know of any such research done on orchids?

Such research is generally carried out in model organisms. Orchids are poor models for such research (slow growth and maturation/little commercial value) so you generally don't find such studies carried out on orchids. However, the absence of such direct studies is not crucial as a lot of basic molecular systems, particularly with respect to such broad questions as 'are stress systems and flowering systems related?', are applicable across genera. The same as how much of what we know about human molecular systems was determined using rodents, birds, frogs, fish, nematodes, yeast etc.

[sandra]

Early last Spring, I inherited an oncidium of some kind that was unsightly but I never had the nerve to get rid of it. As my collection grew and I ran out of room, I took it in the house and put it on the bar, forgetting about it. My thought was that the neglect would put it out of it's ugly misery and make it easier for me to get it one step closer to the garbage bin. All the neglect (lack of light, wasn't watered in over 2 weeks) encouraged 2 thick, huge spikes that seemed to appear from nowhere with the most outrageous, goregeous blooms. All the care I had given it previously, produced nothing.

I then put it back on the patio table where Lilly, the cat snacked on and shredded every single leaf.

P.S. I let Lilly live

[pikevi]

Well said, Andrew.

I would add fruitflies(life span of 30-40 days) and pigs (most compatible animal to humans).

joan gero: They would.

kmarch: Some findings obtained from research in ANY plant would be applicable right across the plant kingdom ( with a few exceptions, like fungi, I believe) . There could ,of course, be some slight variations in the type and amount of 'chemical compounds' that may be found in a particular research.

[joan gero]

Seems like forever that I've been trying to get up the courage to attack the uploading images problem... so here, finally, is my "last gasp" cattlya with a fat sheath ready to pop!!! You gotta search amid the sunburned and chewed and generally diseased leaves... but it's there!

Another question, of course, is why anyone would make their first posted flower such a pitiful one!!! Let's hope this works...

http://www.orchidgeeks.com/forum/att...1&d=1196645015
DSC00910.jpg

[pikevi]

Couldn't get the picture, joan gero.

Good luck in the next attempt.

[joan gero]

Hmmmph. This is another try to show my "Last Gasp" Cattlya Portage Glacier with its fat sheath amid pitiful foliage.

DSC00910.jpg

[pikevi]

Yep, I can see it.

I have seen Cattleyas in worse condition than yours but with beautiful flowers in garden centres. I am sure yours will come around.

Good luck.

[exasperatus2002]

Id say its plausable. I had a dendro that was half dead and dying from home depot that threw some keikis before it gave up the ghost.