I threw the salt study in there for giggles and sharts, but feel free to ignore the main thrust and latch on to a very small part of a large post.
I included the second study to show that different qualities of light produce different results. Many experienced growers (of which I am not) note the difference between pods pulled in mid summer with those from late fall. Surprise surprise, UV light levels also fluctuate with the time of the year...
Dave2000 said:
Heh, I think the word stress is being far too loosely applied, but it is quite a bit of work to very carefully monitor water rationing to the point that you stress a plant vs kill it (or are you suggesting we all stress them by merely waiting till they look like they need water to water them??), or trying to control temperature, soil salinity, etc. I suggest the opposite, that NOT waiting till they need water, instead giving them excess would be a stress.
What is your definition of work? Breathing on a couch? Sorry, couldn't resist. Even more of a prick these days than I usually am...
By water stressing my plants, I spend less time working each week. Instead of watering every 5-6 days, I water every 9-10. It takes me about 30 seconds to walk in to a room, scan the plants, determine who will get water in the morning, and leave. The time saved watering less frequently far outweighs half a minute a day in observation. Please explain how this is more work?
Dave2000 said:
Continually modifying any aspect of a grow instead of just letting nature do her thing is a HUGE amount of work compared to just sewing seeds, then fertilizing and watering every now and then. By huge I mean percentage increase, not how many hours in total.
If you could expand on that, it would be much appreciated. Besides your blanket statement that it takes more time, I am misunderstanding where this extra amount of work is coming from. Salt stressing your plants will require "more" work. Lets break it down in percentages.
I grow most plants organically, and do not mix nutrients. So:
Regular Watering
Mixing nutrients/dry salt - 0
Watering 5 plants - 20 minutes (this is a guesstimate based on my convoluted way of watering, 1/5 of total water, wait, 4/5 water)
Salt Stress Watering
Mixing nutrients/dry salt - 1 minute
Watering 5 plants - 20 minutes
A 5 percent increase in watering time is "huge"?
Dave2000 said:
Anyway it still comes back to the idea that blanket statements can't be made after reading specific studies where only one variable was altered but it's a shot in the dark how optimal the other variables were. Take the salt study for example, the claim that total plant biomass did not decrease with salinity increase, but that they had double fruit production opposed to vegetative growth? It's practically impossible unless there was some other severe problem. Plant biomass increases are directly tied to vegetative growth. All the salts and minerals in the word won't build anything without the solar energy to do it.
One variable is isolated and observed at a time, otherwise the results would reflect nothing other than the incompetance of the researchers. Welcome to the scientific method. There are many studies on water stress that have achieved similar result. There are no blanket statements here from one report, but the result of many studies altering current paradigm.
The study you are refering to ended after the first fruit flush, and vegetative growth clearly refers to leaf growth, not the entire biomass of the plant. The plants reacted to the stress of increased soil salinity by trying to expand their rhizosphere to more hospitable ground, and allocating the rest of their energy to reproduction (with the fringe benefit of increased capsaicin, perhaps result from greater placental tissue or simply more resources diverted toward pods).
The closing statement in the abstract:
Therefore, further investigations with higher levels of salt stress or longer growing periods may lead to statistically significant changes in morphometric data and capsaicin production.
Really brings it all together. I live in an environment where many plants will, with luck and less interference on my part, put out one good flush of peppers. If I can modify one aspect of my routine, barely increase my workload and achieve a noticeable difference, that is a bonus. Am I likely to follow through on this? Probably not, this is just one study, and I lack the resources to experiment properly, especially in regards to quantifiable testing.
Dave2000 said:
It could merely be something quite different involved, that salt is not a stress at all but rather the plants evolved in soil with such a salt content then NOT having it would be the stress.
Sources?
If it isn't obvious, you've kind of pissed me off with you hypocritical blabbering. But, as a result, much more information is readily available to the general community for their and our benefit.
Dave2000 said:
I'd recommend less speculation and more sources. While it may seem logical to assume capsaicin is a response to mammals not eating peppers on the surface, this really doesn't hold valid.
1) Other plants survive fine without this evolutionary change. Hot peppers are a minority plant, not a majority.
2) Many mammals will also pass seed through their digestive tract so it would increase chance of survival for peppers to not be offensive to mammals. It would be another method of spreading to new areas and actually mammals do eat hot peppers in a high stress environment where there is limited to no other food.
There are plenty of birds around here both large and small and they do not flock to my peppers, instead greatly preferring high sugar and water berries on other plants. They will fly miles to a berry bush but leave thousands of my pepper pods sitting there untouched as they hop around the plants looking for worms, berries, and other seeds.
3) You wrote "think". Plants don't think. They don't react, merely responding the best their genetics allow with the best adaptations having higher seed production - which has no direct relation to capsaicin. On the contrary as I speculated above it could be that peppers with lower capsaicin due to increased # of pods, have higher seed rate, are less offensive to mammals, and have the higher survival rate.
Another reason this would be fair to speculate is that in nature, the majority of plants on earth don't have much if any capsaicin level, including those in the areas hot peppers have greatest numbers in the wild.
4) The rest of the suggestions are not reasonable to consider without a lot of scientifically valid testing including a large sample size and years of research. In nature stress generally does not increase survival rate at all. It thins the herd. We could say the strongest survive but there is no evidence that strongest = highest capsaicin level per pod.
1) Other plants have their own evolutionary foibles. If you are doubting whether plants develope specific traits through evolution to attract specialized herbivores for seed dispersal, pollination or a variety of needs, look no further than the orchid. Apologies, I have provided no easy to read notes or links, but I'm about done with communicating with you.
2) Using your backyard as an example is dubious at best, and makes me suspect much of what you have to say. It is speculated (by highly educated, specialized scientists) that hot peppers originally "developed" capsaicin as an antifungal compound, but that it evolved into an a mechanism against toothed ground dwelling herbivores and their relatively short range of movement.
The Complicated Evolutionary History of Spicy Chili Peppers
How did birds adapt to eat hot peppers - I'm not sure there is general access to this, I can repost if needed
Directed deterrence by capsaicin in chillies - a more specific look at the Harvard link
3) You're arguing word choice. Looking at his statement in context, it's easy to infer his meaning. I can explain if you like?
4) We are looking at stress not as it pertains to evolution and scientific research, but as to how we can increase capsaicin content.
In the future, I would recommend citing sources before you make broad, undocumented claims.
Too bad there isn't an award for longest rambling post. I've wasted more time here than I do water stressing.
And how does watering your plants less equate to "crazy amounts of excessive work"? Another contradiction....
I can not help myself sometimes.