Allelochemicals?

There have been 97 species reported. She listed Cambomba, Vals, Hornwort being able to inhibit the grow of Duckweed. The chapter was more about how it works and how it can affect your aquarium. Most of the studies that she listed worked with inhibition of Duckweed and algae. There is a partial list in her book but I am sure there are ways to find out which species they are.

Of course some of this goes unknown to us since water changes drop the level of the chemicals and enable most of the plants to coexist in the aquarium.
 
Miguel said:
Diana Walstad's book: The Ecology of the Planted Aquarium has a chapter dedicated to this. It is true and some plants can inhibit some types of algae as well as other plants. I just finished the chapter last night.
Click to expand...

Yes, if you grind up any old plant and put these ground up extracts into a test well with algae, ..............

That's NOT the same as allelopathic control of algae in LIVE plants.

Such information can be misleading.

Ole Pedersen also made a refute to the chapter.

There's a simple test you can do as control if you believe this, simply add activated carbon, it's used a control for allelopathic test where folks actually can and have demonstrated the effects.

AC removes the Alleopathic chemicals very well, so if you think there's anything to it, then you should see negative responses using AC, but no one I've ever met, nor myself and own test has been able to show this.

Knock your self out. Speculation does not make it true.
A test to see if it is...........that is a lot more useful than simply speculating.


http://www.tropica.com/article.asp?type=aquaristic&id=531

I also made the point that strong plant growth, no matter which species of say 300+ species all seem to have the same impact on algae.

What are the odds that all 300 species all make the same chemical and have the same intensity? Not likely, as most plants are amphibious as it is and have little need for chemical warfare against algae.

I'll take the bet and roll the dice based on those odds.
That and I've actually set up such test and done chemical removal without any effects.

So there's several layers of doubt here.

Duckweed competes with algae in the simplest of terms: light blocking, most floating plants are excellent at that.



Regards,
Tom Barr
 
This question seems to come up here about once every 2-3 months, perhaps a sticky might be appropriate for repeat questions.

I've answered this same question about 20 x over the last decade +.
At least 5x here.


Regards,
Tom Barr
 
Thanks guys, I was thinking more about plants affecting other plants, but the comments concerning fish and algae were interesting.

I was asking because I had a great stand of Cabomba furcata in the below tank, beautiful with brilliant color. It was growing well for almost year then disintegrated within a month. There was no change in ferts. or water conditions that I know of. It started dying shortly after I introduced some Sunset hygrophillia. Perhaps it was a coincidence in timing, or some other factor, but it lead to my curiosity.


1a.JPG
 
Nice looking tank. Thanks for sharing
 
I think the issue is more competition, not allelopathy.

Eg, one plant is very aggressive for CO2 uptake, or NO3 etc...........another is not.

It's nothing to do with allelopathy, it's just regular old competition.
Simple solutions:

1 Add more ferts
2 Add more CO2
3. Trim the darn weeds!

If you again, fall for this allelopathy malarkey, add activated carbon, takes care of any organic chemicals.
Do large frequent water changes etc.

Very easy to rule it out as a cause in an aquarium.

Ruling out CO2/light/nutrients is always the issue.
Folks tend not to be good at that, think they have a good handle, then go looking for other things, rather than realizing they made an assumption/boo boo with those 3 things.

I've had massive stands of Cabomba, never seen any evidence, neither has Amano or others.

Regards,
Tom Barr
 
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