Do Jungle val shoots poison other plants?

[THE V]

****Note to self*****

Allelopathy is a surefire way to get Tom going :evil_lol:

*****End Note******

Alrighty - I'm on vacation all week and this looks like a great way to avoid the "honeydo list".

First off I agree that allelopathy via water only is ludicrous as the amount phytotoxic chemicals cannot accumulate to significant levels. However with aquarist using soil type substrates (eco-complete, etc...) the hobby enters the realm of saturated soil systems. My apologies, I thought that this was more transparent to the topic in the above references. My bias in knowledge towards terrestrial systems shows itself again.

It is documented that saturated soils/sediments can accumulate phytotoxic chemicals. However as this type of experimentation is expensive and complex there are very few studies done on true aquatic species. I did however find this excellent in situ experiment done on rice.

http://www.springerlink.com/content/r0486825723620r4/fulltext.pdf

Second off I disagree that using extracts immediately invalidates the experiment. Although not necessarily congruent with in situ experimentation it offers a valid starting point to discovery. The logic is simple, "If the extract has something in it that is phytotoxic, the plant may be excreting it into the environment." It is not conclusive by any means, simply a cheap a fast experiment to show that further work should be done. Sadly the authors of some of these papers (as usual) stretched their data a bit too far.

It's very difficult to demonstrate and provide controls for actual in situ ecological studies on allelopathy, and that..........is what is required for evidence.

Yes it is somewhat difficult to prove allelopathy. The complex nature of the inter/intraspecific competition/symbiosis creates a situation where unless it is extreme it is almost nearly impossible to detect by simple observation (Walstad). By isolating allelopathic chemicals from extract experimentation this becomes much easier. Subtle effects of the chemicals can be shown by some simple experimentation. A very small amount of change to growth rate, flowering, etc.. can have a dramatic effect on the ecological balance.

More recently some very good papers are coming out about this topic.

http://www.sciencedirect.com/scienc...94d2f32ae8016bc7d48dcaad6db9da21&searchtype=a

http://resources.metapress.com/pdf-preview.axd?code=g4577r1211824656&size=largest

http://www.springerlink.com/content/5w7856u2t417hx27/

There is also a large body of work coming out on how they inhibit cyano, and algae.

 

[plantbrain]

First off I agree that allelopathy via water only is ludicrous as the amount phytotoxic chemicals cannot accumulate to significant levels.

So why do so many run around claiming that is how plants retard algae?
Many do even when faced with some rather basic evidence for controls like water changes and activated carbon that would remove it.

However with aquarist using soil type substrates (eco-complete, etc...) the hobby enters the realm of saturated soil systems.

Afraid not, why do you assume that these are saturated or that any build up occurs? You still have relatively fast diffusion in/out of sediments in aquariums, about 0.2 to .6 liters per meter squared per day is a good range of exchange. If you had less, then you'd end up with H2S etc. And the bacteria, not the plants, would be killing the roots etc.

How would you measure this or differentiate btw bacteria chemicals and plant root exudates???

Ah.....not so easy.

In living systems, this can be a big problem.

My apologies, I thought that this was more transparent to the topic in the above references. My bias in knowledge towards terrestrial systems shows itself again.

Does not change the facts about ecological allelopathy studies. They have many of the same problems. You can have a lot of studies, but they often remain inconclusive regarding ecological allelopthy in real living systems.

It is documented that saturated soils/sediments can accumulate phytotoxic chemicals. However as this type of experimentation is expensive and complex there are very few studies done on true aquatic species. I did however find this excellent in situ experiment done on rice.

http://www.springerlink.com/content/r0486825723620r4/fulltext.pdf

You really wanna go here?
What is missing from the paper?
Not the amounts of chemicals, rather, the effects on the E grus-galli
How much growth reduction do these chemicals cause?
I do not see any, the paper reports that they produce chemicals etc.....in living systems.

Not much else. eg: No effects on relative growth rates.
Challenging one's own assumptions about what is really known/proven etc.......might be better/wiser?

Second off I disagree that using extracts immediately invalidates the experiment. Although not necessarily congruent with in situ experimentation it offers a valid starting point to discovery.

Starting point sure.........maybe we can extract a chemical that works on plants to kill weeds etc. But as far as a mechanism in live systems, that's not testing that. I can grind up rice and add it to rice and get some growth reduction. Suicide plants? It does not follow.

The logic is simple, "If the extract has something in it that is phytotoxic, the plant may be excreting it into the environment." It is not conclusive by any means, simply a cheap a fast experiment to show that further work should be done. Sadly the authors of some of these papers (as usual) stretched their data a bit too far.

Or some aquarist more likely.
I do not buy that logic personally.

Extracts are not the same, if you took chemical samples from the soil near a suspected region of allelopathy, perhaps(eg, like the Rice example).

Yes it is somewhat difficult to prove allelopathy. The complex nature of the inter/intraspecific competition/symbiosis creates a situation where unless it is extreme it is almost nearly impossible to detect by simple observation (Walstad).

Now wait a minute here.........you know what you/she just stated?
It's a minor effect.

If it's that minor, is it significant?
Probably not.

At least for aquatic systems.

By isolating allelopathic chemicals from extract experimentation this becomes much easier. Subtle effects of the chemicals can be shown by some simple experimentation. A very small amount of change to growth rate, flowering, etc.. can have a dramatic effect on the ecological balance.

We just have never seen this in aquariums, which is the topic here, true, a minor effect could be significant. I'm just questionign it in aquatic systems, no such research exists that I am aware of and that has faced some decent critique well.

More recently some very good papers are coming out about this topic.

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T4F-4R9GGY9-2&_user=10&_coverDate=05%2F31%2F2008&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_searchStrId=1554027815&_rerunOrigin=scholar.google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=94d2f32ae8016bc7d48dcaad6db9da21&searchtype=a

http://resources.metapress.com/pdf-preview.axd?code=g4577r1211824656&size=largest

http://www.springerlink.com/content/5w7856u2t417hx27/

There is also a large body of work coming out on how they inhibit cyano, and algae.

New stuff is fine and all. But without good methods and controls in place, they are mostly looking for a new herbicide.natural product, extract that can be used. Nothing wrong with that, but does not support natural ecological systems via competition using chemical warfare.

1st paper I do not have the access to see the methods, or results, which is key to evaluation. They also do not say allelopathy does, just that according to them, it may be the reason. You have to look at the controls and the other aspects. AB is a decent journal but they have had many allelopathy studies over the decades.

The last paper is about as close as you have gotten. It looks like a good paper. We do not grow invasive species of cattail in planted tanks.
But I might buy that study. Okay, 1 out 10, hehe.

It might be due to activated carbon's influence on bacteria or some other chemical uptake, so even the a control like AC has it's issues as well, but it's getting closer.

Extracts alone do not get you much closer.
Still, my point remains, there's no evidence, and it's baloney in planted tanks. You have a long way to go to demonstrate what I said is not true. It might not be........but I've seen no evidence of it in any planted tank for decades with many combinations, nor has Amano, nor have most experience aquarist.

In nature, we can see things we might suspect are allelopathy.
Does not mean they apply to us in our aquariums.

Regards,
Tom Barr

 

[platytudes]

Wow. Riveting discussion! And somehow still comprehensible by the science retarded, such as myself