Cryptocoryne Wendtii and Allelopathy

aquabillpers

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Tom Barr;26085 said:
The point I made was more about established vs new introduction.
Adding a plant to a dense bed of weeds vs adding it an open area..........where would you predict it might do better?[

Well, OK, at first thought I'd say that it would grow better in an open area.

But after thinking, I wondered why the "open area" is "open"? Why aren't plants growing there already?

If instead I planted the new plant in the middle of the established plants, ignoring any blocking from the sunlight, why do you think it wouldn't grow there? What defenses would the established plants use to keep it from growing?

To be fair, take one of each plant type and place them in an open area. Then see.

I have small numbers of the crypts in question in three other tanks and they are living in harmony with other plants. In the tank in question there are 40 to 50 crypts, confined to half of the tank. Maybe there is a tipping point somewhere?

Bill
 

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Tom Barr;26087 said:
Well, there was something missing then. Anyway, the article Ole wrote pretty much states it's never been demonstrated in any natural system.

Yes, but he does cite numerous examples of it in land-based systems.

And, aquariums are far from being natural systems. They are a lot smaller with less water turnover, among other things. Poisons can accumulate in them that would never happen in natural systems. That is particularly true in NPT's, where water changes are infrequent.

I linked it some time ago in the articles, it was his refute of Diana Walstad's speculation of allelopathy. I took a different approach in my refute.

Yes he did convincingly refute her claim that allelopathy might control the growth of algae, as far as I am concerned.

The test are rather easy once you have a suspect.
But choosing your plants is the hard part. All you need is to have the plants doing well together in another tank as an example to falsify the hypothesis that they have a chemical interaction. Then add activated carbon etc as a control as well.

I am reporting a special situation in which a tank contains 40 to 50 crypts that seem to be inhibiting the growth of new plants. If one such crypt produces x amount of an inhibitory chemical it probably would have no observable effect. If all 50 are doing that, it might. I don't know.

You have to be careful in your speculations since it might just be horticulture issues rather than biological relationships like allelopathy or algae prefer this or that.

Not to be picky, but speculation = hypothesis, the first step in the scientific method, right? I am just tossing out the hypothesis. I have seen plants die, fast. There seems to be no reason other than that the dominant crypts are doing something. But I am certainly open to other explanations.

If you have poor control as an aquarist, or you think you have control but really do not........then you are in trouble and cannot correct the issue easily. That will lead you to think everyone is crazy and you are right.

You have to trust folks that are growing the plants well together. They have no reason to lie. Then you go about figuring out why they have no issue but you do.

Uh, I am growing crypts and other plants together with a fair amount of success. It is only in this extreme case that it isn't working.

In my experience, most people are truthful and few are crazy, although there are always exceptions. But some people do get wed to a concept and are very reluctant to change it. There was an article in a recent issue of Scientific American or Discover about that tendency.

Bill
 

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aquabillpers;26091 said:
In the tank in question there are 40 to 50 crypts, confined to half of the tank. Maybe there is a tipping point somewhere?

Bill

I'd say so........There's just not much space for any roots in a crypt "ball".

Not much light, it's hard for other plants to compete at low light/non CO2 conditions against them. That is their niche in natural systems and why they are popular going way back before the time of CO2 gas and snotty scaping critiques. Swords are somewhat similar.



Regards,
Tom Barr
 

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aquabillpers;26093 said:
Yes, but he does cite numerous examples of it in land-based systems.

Oh I can can as well and locally at that as I wonder through the state.
Several Bromus species are able to do this.

And, aquariums are far from being natural systems. They are a lot smaller with less water turnover, among other things. Poisons can accumulate in them that would never happen in natural systems. That is particularly true in NPT's, where water changes are infrequent.

Back to the experiment ...............speculation is getting you nowhere and even more down the road of confusion.........

Adding Activated carbon is the standard control for allelopathy studies which I have done myself, thus adding that would remove the effect if it's what you, Diana or anyone wants to claim or stand by.........

Easy to add, easy to observe, easy to relate to an aquarium specific model......I hear this same argument, maybe 1001 times.....aquariums are unique, they are all different, poisons(such as? And do these poison's do anything or have any impact anyone can see?) etc........

Look, suspicions are nothing more than that unless you bother to test and see if you can show cause or rule out something/falsify them. A little experimental research goes a long long way.

I've added AC to tanks, I've never seen any effect on algae. If you remove more organics, the O2 demand goes down, thus more O2 is available and the plants pearl more. A DO probe can measure this, or you can use COD or BOD measurements.

Yes he did convincingly refute her claim that allelopathy might control the growth of algae, as far as I am concerned.

He took another path, I decided before I knew much about the research, to apply the AC to the system and experiment.

I am reporting a special situation in which a tank contains 40 to 50 crypts that seem to be inhibiting the growth of new plants. If one such crypt produces x amount of an inhibitory chemical it probably would have no observable effect. If all 50 are doing that, it might. I don't know.

You might be right, but it needs tested to see.
There are suspicions...but you need to test(which is not a hard one).
In most plant ecological situations, we see large groups of plants growing in monocultures.

Allelopathy is often suggested, but it's never been shown.......thus I have a difficult time accept any evolutionary reasoning for it such systems, in terrestrial systems, perhaps, no water to wash away all the allelopathic compounds........

Not to be picky, but speculation = hypothesis, the first step in the scientific method, right? I am just tossing out the hypothesis. I have seen plants die, fast. There seems to be no reason other than that the dominant crypts are doing something. But I am certainly open to other explanations.
In my experience, most people are truthful and few are crazy, although there are always exceptions. But some people do get wed to a concept and are very reluctant to change it. There was an article in a recent issue of Scientific American or Discover about that tendency.

Bill

True, read Karl Popper sometime. There are others.
You need to test the hypothesis now you have made it.

Regards,
Tom Barr
 

aquabillpers

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Tom Barr;26097 said:
I'd say so........There's just not much space for any roots in a crypt "ball".

Not much light, it's hard for other plants to compete at low light/non CO2 conditions against them. That is their niche in natural systems and why they are popular going way back before the time of CO2 gas and snotty scaping critiques. Swords are somewhat similar.

Sure, but note that in this case the crypts are confined to one half of the tank. The plants that died were either floating or planted under a two WPG CF fixture, so low light doesn't apply here. Maybe the crypt roots spread that far, but hygros are pretty flexible about where they get their nutrients.

Bill
 

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Tom,

I would be willing to try filtering the water through activated charcoal and then adding more plants, but I don't know what that would prove.

If the new plants prospered, I would assume that there had been some chemical in the water that was selectively killing newly added plants. Whether that chemical was allelopathic in nature or came from another source I wouldn't be able to say.

If the new plants died, that could mean several things: that the AC didn't filter out the chemical that was causing the problem; that more of that chemical was being produced in the tank; that there was a non-chemical cause for their demise; and on and on. I don't see how AC filtering would help to answer the question in this case.

Plants of 4 different species died almost immediately in a tank that was half full of healthy crypts. Light and water column nutrients were at least adequate. The water was from a well and a wilderness stream and was being used in other aquariums with success.

Since allelopathy in terrestrial plants has been well documented, it seemed at least possible that the mass of crypts was using allelopathic warfare to protect their turf, so to speak. :)

The only way to prove that theory would be to find the chemical that the crypts were using. According to the Tropica article, that has been done numerous times in cases of terrestrial allelopathy. Producing a result by changing a variable in an experiment is not proof. Coincidence is not causation, right? :) You need to find the agent that is producing the result in question.

Thanks for your stimulating responses!

Bill






You might be right, but it needs tested to see.
There are suspicions...but you need to test(which is not a hard one).
In most plant ecological situations, we see large groups of plants growing in monocultures.

Allelopathy is often suggested, but it's never been shown.......thus I have a difficult time accept any evolutionary reasoning for it such systems, in terrestrial systems, perhaps, no water to wash away all the allelopathic compounds........



True, read Karl Popper sometime. There are others.
You need to test the hypothesis now you have made it.

Regards,
Tom Barr[/QUOTE]
 

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aquabillpers;26113 said:
Tom,

I would be willing to try filtering the water through activated charcoal and then adding more plants, but I don't know what that would prove.

If the new plants prospered, I would assume that there had been some chemical in the water that was selectively killing newly added plants. Whether that chemical was allelopathic in nature or came from another source I wouldn't be able to say.

If the new plants died, that could mean several things: that the AC didn't filter out the chemical that was causing the problem; that more of that chemical was being produced in the tank; that there was a non-chemical cause for their demise; and on and on. I don't see how AC filtering would help to answer the question in this case.

Plants of 4 different species died almost immediately in a tank that was half full of healthy crypts. Light and water column nutrients were at least adequate. The water was from a well and a wilderness stream and was being used in other aquariums with success.

Since allelopathy in terrestrial plants has been well documented, it seemed at least possible that the mass of crypts was using allelopathic warfare to protect their turf, so to speak. :)

The only way to prove that theory would be to find the chemical that the crypts were using. According to the Tropica article, that has been done numerous times in cases of terrestrial allelopathy. Producing a result by changing a variable in an experiment is not proof. Coincidence is not causation, right? :) You need to find the agent that is producing the result in question.

Thanks for your stimulating responses!

Bill

AC would/does remove the offending chemical in question.
Then if you repeated the test and had the plant die without AC, then repeated the same test again with AC and it did not, then you'd have evidence that alleopathy is occurring and is significant.

I'd wait at least 2-4 weeks between treatments for the levels of allepoathic chemicals to build up.

If it takes longer than that, then the levels are no that significant in their impact and will be difficult to measure and see conclusively. Tanks also change over time, so repeated measurements using the same methods/protocols needs addressed.

But if after say 4-6 X cycles of this, where you see strong effects on plants with/without the AC, then you have good evidence that Allelopathy is occurring.

I am very curious why folks are so very willing to lend alleopathy such leeway and speculation, yet are so critical about other alternative reasons for poor plant growth which are more reasonable and have been shown in many studies on aquatic plant ecology.

Do not believe everything you think or want to believe.

the evidence against it occurring in aquatic systems is far far greater than for it, both in aquariums as well as in natural systems. There's no evolutionary pressure I can really think of either.
Our aquariums might be small finite boxes full of plants, but they are not natural nor anything like the large highly varied examples in the field. And that is where natural selection will take place, we put a lot of pressure on aquatic weeds/plants these days, but we really do no pick only the best plants for our tanks over time and thus it's more like agricultural ecology and crop evolution than anything inherently "natural"
without influence from man kind.........we obviously influence many things and plant growth with our aquariums. So pin pointing it is something that would need tested and tentatively accepted.......if we find evidence for it based on results, not hypothesis, speculation or the desire to believe some "nice" theory.

So we need to see that first, then argue more about why, it's potential etc.
It's like the folks that claimed excess PO4 = algae blooms, they never even bothered to test their hypothesis that they made, they told everyone about it and ran around promoting the theory.

And after I do bother to test it, I get questioned harshly often times.
Why aren't folks questioning allelopathy more harshly is my question?

I have offered up this simple test to test this hypothesis and it's been around for several years now, yet no one other than myself has appeared to have done it to date:(
However, there seems to be an infinite number that will fall into the "allelopathy trap" mind set.
Keep in mind that the easy road is not the best or the right road.

FYI.........I am speaking generally here, not at your line of questioning or personally etc.

Ask away there.

Regards,
Tom Barr
 

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aquabillpers;26113 said:
The only way to prove that theory would be to find the chemical that the crypts were using. According to the Tropica article, that has been done numerous times in cases of terrestrial allelopathy. Producing a result by changing a variable in an experiment is not proof. Coincidence is not causation, right? :) You need to find the agent that is producing the result in question.

Thanks for your stimulating responses!

Bill

Even if you isolated it, it does not mean that plants will exude it into the environment. Endogenous chemicals vs exogenous chemicals are two very radically different cases.

As far as the test I suggested, the goal is not proof.
I never said the test was "proof".

It is support however that it might be occurring.............
If we see significant growth reduction without AC and none with.........something is occurring that AC is removing that influences growth, that can be stated.

However, it does not offer "proof". That's not the goal of the test either.
It's just to rule out that alleopathy is occurring.
It does not tell you what is occurring, only what it is not.

To take this to the next step, you'd remove the AC in the test(if you saw an effect without AC and no effect with AC), then remove the chemical from the AC in a column. From there you could isolate it fairly easily.

Typically, you will find several organic compounds and you to see which is doing the effect/s and if they have any interactions(which often they do).

Rather than doing all that which is far beyond the typically aquarist.........I suggest falsifying it to see if the hypothesis holds any water............

Then you do not need to do all this work;)
Which is a lot wiser and more clever than them other folks.......at least for our purposes, but the next step is interesting to me and the researchers.........

Regards,
Tom Barr
 

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To test the hypothesis that the crypts are secreting a chemical that is killing the other plants, instead of filtering the tank water through AC, would removing most of the crypts, doing 2 50% water changes over 3 days, adding the 4 species of plants that died, and reporting the result, suffice?

That would seem to get rid of most of the allelopathic chemicals, if they exist. If the plants prosper I'd think that would be strong evidence that the crypts had killed the other plants at least the ones without roots.

Advantages to me of this approach are that I am probably going to take this tank down anyway, and this would be the first step. I am also deathly sick of those crypts. :)

I'll be kayaking in the weed-infested bays of Lake Ontario over the weekend. Kayaks are about the only boats that can make their way through the masses Myriophyllum spicatum and the curly-leaf pond weed, Potamogeton crispus, without frequent cleaning of the motor lower unit.

Bill
 

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aquabillpers;26133 said:
To test the hypothesis that the crypts are secreting a chemical that is killing the other plants, instead of filtering the tank water through AC, would removing most of the crypts, doing 2 50% water changes over 3 days, adding the 4 species of plants that died, and reporting the result, suffice?

That would seem to get rid of most of the allelopathic chemicals, if they exist. If the plants prosper I'd think that would be strong evidence that the crypts had killed the other plants at least the ones without roots.

Advantages to me of this approach are that I am probably going to take this tank down anyway, and this would be the first step. I am also deathly sick of those crypts. :)

I'll be kayaking in the weed-infested bays of Lake Ontario over the weekend. Kayaks are about the only boats that can make their way through the masses Myriophyllum spicatum and the curly-leaf pond weed, Potamogeton crispus, without frequent cleaning of the motor lower unit.

Bill

No, that would not address it, you have dramatically changed things and set up.
Adding Ac would.

I know you have ulterior motives, you want to redo the tank etc:D
How much interest do you have in redo vs the test?
That really is where it comes down too.

We have the same weeds you have there, we have in many waters here in CA.
the American river I do my runs along has these as well as some Elodea.
Hard to kill.

Regards,
Tom Barr
 

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I don't think that three days is all that fast for a deficiency to show up in fast growing plants. Adaptation plays a role and is working against the plant already too, with both the stress of adaptation and the lack of some nutrient, I can see hygro dying off that quickly without a problem. It seems to me that you have a tank that is probably extremely low on some key nutrient(s) (in the water column, at least), growing only slow growing root feeders that are already well adapted, and then you add fast growing leaf feeding plants to it. It only seems logical, at least from what I understand of this setup, that they could die. Crypts and other slow growers can do just fine in tanks where other faster growers would die off. Why not add another slow growing root feeding plant instead to see what happens?
 

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Depends on the nutrient.

3 days is plenty for N and CO2.
Not for PO4............or Fe etc.......

Regards,
Tom Barr
 

aquabillpers

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Carissa;26156 said:
I don't think that three days is all that fast for a deficiency to show up in fast growing plants. Adaptation plays a role and is working against the plant already too, with both the stress of adaptation and the lack of some nutrient, I can see hygro dying off that quickly without a problem. It seems to me that you have a tank that is probably extremely low on some key nutrient(s) (in the water column, at least), growing only slow growing root feeders that are already well adapted, and then you add fast growing leaf feeding plants to it. It only seems logical, at least from what I understand of this setup, that they could die. Crypts and other slow growers can do just fine in tanks where other faster growers would die off. Why not add another slow growing root feeding plant instead to see what happens?

Carissa,

Two of the four plants that died were vals and E. tennelus, which in normal conditions grow fairly fast after they are established. The former hung on for several weeks before I removed it because it was falling apart without producing any new leaves. The latter just got smaller and smaller and just about disappeared before I removed it.

I am pretty sure that the water column nutrients are OK.
If anything is lacking I'd think it would be in the 4 years old soil substrate, but the crypts are doing well, so . . .

Bill
 

Carissa

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I never had good success with vals, even with fertilizing everything. Not sure why, probably light in my case.

Why would you think that you have enough of all your nutrients in the water column, if you haven't been fertilizing? I don't know, it just seems logical to me that if stem plants and fast growing plants die but slow growing root feeders are living, that the water column must be somewhat deficient and maybe the substrate too for that matter, but maybe not so much. Maybe try a sword or some different crypts? You could at least rule out some causes, if you could get something else to live.
 

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Tom Barr;26116 said:
AC would/does remove the offending chemical in question.
Then if you repeated the test and had the plant die without AC, then repeated the same test again with AC and it did not, then you'd have evidence that alleopathy is occurring and is significant.

I'd wait at least 2-4 weeks between treatments for the levels of allepoathic chemicals to build up.

If it takes longer than that, then the levels are no that significant in their impact and will be difficult to measure and see conclusively. Tanks also change over time, so repeated measurements using the same methods/protocols needs addressed.

But if after say 4-6 X cycles of this, where you see strong effects on plants with/without the AC, then you have good evidence that Allelopathy is occurring.

An 8 to 24 week test would work in a lab but not in my living room. Would the results of one cycle be of any value?

I am very curious why folks are so very willing to lend alleopathy such leeway and speculation, yet are so critical about other alternative reasons for poor plant growth which are more reasonable and have been shown in many studies on aquatic plant ecology.

My only interest is to try to find out why the plants died. Allelopathy seems to be the only possibility left. Lighting and nutrients are OK. Carbon is low but the crypts are thriving. I can't think of any other cause, and no one else has suggested one.

It well might be that allelopathy manifests itself more in an enclosed environment like an aquarium more than in nature. My dog will affect my lawn; when we walk in the woods he doesn't affect anything noticeably.

Perhaps plants in aquariums act differently than they do in the wild?


Why aren't folks questioning allelopathy more harshly is my question?

Well, I don't know either. :) But one can infer an answer to a problem by eliminating all other possibilities, right?

The problem is, why are those plants dying? Allelopathy is one possible answer. Ruling out inadequate light and insufficient water column nutrients, in the environment that i have described, what else could it be?

Bill
 

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Your nitrate test kit is no longer accurate. And, you are very low on nitrates, because the crypts are now big enough to hog all that is there. Without nitrates and no established root systems, the newly planted plants die. That is my hypothesus.

Since excess nitrates do not harm either the fish or the plants, within the limits of the EI fertilizing routine, you could dose about 20 ppm of nitrates and see if the plants begin to do better. And, just to be sure you have sufficient carbon for the plants to be able to use the nitrates, you could dose a water change dose of Excel. Just to be sure your phosphate test kit is still valid, you could also dose about 4 ppm of phosphates to eliminate that as a problem. I'm betting the plants will do much better then. Don't ask the amount of my bet - I'm chicken!
 

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aquabillpers;26202 said:
An 8 to 24 week test would work in a lab but not in my living room. Would the results of one cycle be of any value?

Perhaps to falsify it, but I'd still want a few more examples before moving forward.
Still, it would not look good for the allelopathy folks if no response was seem either treatment:cool:

My only interest is to try to find out why the plants died.

Depends on how bad you want to answer that question or just move on and redo the tank..............always a trade off there...... and most chose to redo the tank.

Allelopathy seems to be the only possibility left. Lighting and nutrients are OK. Carbon is low but the crypts are thriving. I can't think of any other cause, and no one else has suggested one. It well might be that allelopathy manifests itself more in an enclosed environment like an aquarium more than in nature.

Then the activated carbon would show a much greater impact based on this line of thinking.......but near as I or anyone else can tell, it does not.

My dog will affect my lawn; when we walk in the woods he doesn't affect anything noticeably.

Manures will too, and concentrated salts from urine will as well, this is known in agriculture................and documented going back 1,000's years. you are adding a lot more to one single area. But how does a plant evolve such a compound give in nature, it offers no use? This shoots the allelopathy theory of evolution in aquatic plants in the foot. Given most aquatic systems where plants are found are seasonal, the water is always changing volume and the levels move all over the place..............and where it is not, the system is massive and or is unidirectional, river/stream etc.

Otherwise in moves all over.
Thus the location and volume of the system changes massively.

Perhaps plants in aquariums act differently than they do in the wild?

I'd agree with that, they are pretty fat and happy in most cases.


Well, I don't know either. :) But one can infer an answer to a problem by eliminating all other possibilities, right?

The problem is, why are those plants dying? Allelopathy is one possible answer. Ruling out inadequate light and insufficient water column nutrients, in the environment that i have described, what else could it be?

Bill

Well, the obvious one is that the system is CO2 limited. Plants have different abilities to acquire CO2..........they take time to adapt to each location and flow pattern.........

A simple difference between that, and also, how can you be so sure about all the other variables as far as nutrients?

I have a rough time ruling it out with the testing I've done.......I can with EI dosing for limitations.........but that's more for CO2 enriched systems, but I can modify and apply it to non CO2 systems at a reduce rate also and test from there.

Observational data alone is good and all, but will only get you so far and not help you get that much closer to cause.

You need to do a manipulative test to see.
and you have low replications as well, one:)

So.......I'd just redo the tank.

Regards,
Tom Barr