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Cryptocoryne Wendtii and Allelopathy

Discussion in 'General Plant Topics' started by aquabillpers, Jun 5, 2008.

  1. aquabillpers

    aquabillpers Lifetime Charter Member
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    My problem: I have a 29 gallon tank that has been set up for about 4 years. At the present time the left half contains about 40 C. wendtii plants, all healthy and sending out runners. They are descendants of a few that were planted when the tank was set up.

    I can't get anything to grow on the right half. Most recently I planted 8 healthy Vallisneria spiralis (?). They were raised in another tank, had strong white roots, and were sending out runners. After 6 weeks it became apparent that they were dying. They had produced no new leaves and the roots were dark and not growing.

    At the same time I also planted 6 healthy E. tenellus, also from another tank. These remained green but got smaller and smaller and have almost disappeared.

    Two anubuias, which had been in that tank for about 2 years, have remained healthy but show no growth.

    Three days ago I added several short stems of Hygrofila polysperma. They already show signs of decline.

    The aquarium is lit by a new Coralife 65 watt CF fixture. CO2 in not injected, but there is a soil substrate.

    That soil substrate is 4 years old and should have long been depleted of many of its nutrients. However, Walstad maintains that the droppings of the fish will make up for that loss. Since the crypts, heavy root feeders, are doing well, I assume that the substrate is not the problem.

    Nitrate (20 to 30 ppm) and phosphate (1.5 ppm) are within normal limits. GH is 22 degrees, some of which is from Equilibrium. Flourish is added monthly.

    I have several other soil-based tanks that are maintained in a similar (but not identical) manner. All have a profuse growth of a number of plant species. Some contain C. wenditii, but not in the density of the problem tank.

    The only thing that I can think of that would be preventing the new plants from growing is that the large number of crypts is somehow inhibiting the growth of newer plants.

    Can anyone suggest another possibility?

    Thanks,

    Bill

    (BTW, I Google'd 'cryptocoryne allelopathy' and found a few sites but nothing conclusive.)
     
  2. tedr108

    tedr108 Lifetime Charter Member
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    In my limited experience, it seems to me that crypts (at least the wendtii type) are very forgiving. The other plants you are trying are not as much so. You would know best what the difference is between this tank and the ones you are getting the other plants from.
     
  3. Gerryd

    Gerryd Plant Guru Team
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    Hi Bill,

    Have you had a chance to gravel vac that section? If compacted heavily, it can produce hydrogen sulfide which is toxic to all.......

    IME I had 1/2 of my 180 with wendti at one point and did not cause any issues. Was doing a bit of c02 at the time, regular floro tubes, but no other ferts using flourite. Was able to grow other things with no problems.

    Clean out that side of the tank and ensure all old roots, etc is gone.

    Then again try some of your new cuttings.

    I don't think the wendti is inhibiting it.

    I think the specific area is the problem.

    Let us know.
     
  4. Tom Barr

    Tom Barr Founder
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    What happens to a house plant when it becomes root bound?

    4 years is a long time, try pruning it.
    Add some "Mud cubes", that will address nutrients pretty well.

    In general, I've found when Diana and others make the claims about some plants waning and ebbing, it's always due to a lack of some nutrient.

    However, it also might be due to too much organic matter that's built up over time in the sediment.

    The sediment is so reductive, that the other plants cannot establish their roots whereas the Crypt has a massive O2 pipe/root system and are not as effected.

    I'd go in a cut some out.
    Add some new mud cubes.

    If you want to test allelopathy, add some activated carbon in the area and add a lot and mix well into the sediment.

    This will mop up any allelopathic compounds fast.
    Add AC to the filter if you think the allelopathics are in the water column.

    Fairly simple test.

    I think most of the speculation many claim with Allelopathy are merely differences in the nutrient tolerance between plant species, not allelopathy itself.

    In other words, I've never seen a case yet that was due to plant- plant allelopathy in aquariums.

    Also, at higher levels of nutrients, CO2, light, with the respective faster growth rates(10-20X), we should also see similar increases in allelopathic chemicals and even if not that much, at the bare minimum, at least the same as the non CO2 situation.

    I've not seen any evidence growing this plant in non CO2, CO2 or emergent situations yet.

    Regards,
    Tom Barr
     
  5. VaughnH

    VaughnH Lifetime Charter Member
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    Is it possible that the crypts are using up the nutrients in the water, but having a big root system, can continue to grow from root feeding? That would leave the newly planted vals and microswords short of nutrients, but without the roots needed to feed that way.

    Also, I have always had problems getting vals to start growing when first planted. They almost always shed all of their leaves, leaving only a rooted stub. Eventually that stub sends out new leaves and the vals become the nuisance they can become. Since I have never had E. tennellus grow for me I can't comment on that.
     
  6. aquabillpers

    aquabillpers Lifetime Charter Member
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    Thanks for your responses!

    I will assume that the substrate is the problem. I'll replace it in the half of the tank in which things won't grow and plant new plants.

    Should I expect the substrate that I remove to be crowded with crypt roots? If it isn't, what will that mean?

    There are plenty of nutrients in the water column, excepting carbon. If plants are able to make use of ferts in the water column, why won't the plants simply use the substrate to hold on to, and get their food from the water? The H. polysperma which I added a week ago should be able to do that if any plant can, yet they started dying on day 2 and are just about dead now.

    I'll post the results of this in a few days.

    Thanks again.

    Bill
     
  7. helenf

    helenf Junior Poster

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    My understanding is that higher tech tanks generally get more water changes than lower tech tanks. Which means that the level of allopathens, along with everything else, will be reduced.

    Could that not explain allelopathy not being seen in high tech tanks?

    Would a plant growing more slowly produce more or less allelopathen per unit of growth than a plant growing fast? Maybe there is a difference there, too.

    Would a plant growing faster be able to cope with more allelopathens in its environment than a plant growing more slowly?
     
  8. ceg4048

    ceg4048 Lifetime Charter Member
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    Bill,
    I don't really think this is a good assumption. Instead of looking at allelopathy, which as far as I can see is akin to witchcraft, it would be more productive to troubleshoot the macronutrient content of the tank.:cool:

    You mentioned that the 30 gallon tank is illuminated by 65 watts of Compact Fluorescent. If so this is just over 2WPG and really no longer qualifies as a low tech tank. Further, you noted that no CO2 is being injected. So a fast growing stem is placed in a high light environment without CO2 supplementation and it fails. I would conclude that the failure is at least in some part due to the inability of the stem to adapt to the low CO2 levels while being driven to high CO2 uptake via light energy input.

    I think that every hobbyist has a tank wherein some plants do well and other plants struggle or fail completely. Some plants are more adaptable by having more efficient nutrient uptake and processing mechanisms. This adaptability enables them to succeed in a wider variety of environmental conditions, including more stressful environments than those with less efficient systems.

    The crypts may have adapted to the tank conditions and have had 4 years to do so whereas a new plant may have difficulty under these conditions.

    If you wanted to test the possibility of CO2 starvation you could add CO2 either by gas injection or by the addition of copious amounts of Excel. If you wanted to test the possibility of light driven starvation then you could insert say, a 30 watt bulb or otherwise screen the 65 watt bulb to reduce the amount of light entering the tank. A combination of these actions would probably work.

    Additionally, it's unclear how you are determining the nitrate and phosphate levels. Are you measuring with test kits, or is that from your water report, or are you adding this amount weekly?

    There is enough ambiguity to question the dynamics of nutrient/CO2 uptake within this tank configuration. Only when these conditions are verified, and when you are satisfied that the conditions for proper growth exist within the tank can we then move on to other possibilities regarding unknown assailants/agents.

    What we do know for certain though is that rapid degeneration of plant tissue is a classic symptom of CO2 starvation often exacerbated by poor nutrition.

    Hope this helps.

    Cheers,
     
  9. Tom Barr

    Tom Barr Founder
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    No, the observations:

    We can also not do water changes in high tech high growth tanks.
    The production of secondary compounds generally matches the rates of growth as well(not all, but in general). again, we do not see presumed or suspected allelopathic effects.

    As mentioned, the control is adding activated carbon(AC) in the filter for the water column effects and AC in the sediment for root based effects. So adding AC should remove those effects.

    Likewise, the same can be done in a non CO2 system.
    Standard protocol is using something that will rapidly absorb the chemical and AC is an excellent choice.

    BTW, there's have never been a single study(See Ole's refute in Articles here or on Tropica's web site) showing a significant effect in any natural system. I'm not saying there is not any, it's just never been seen or found to be significant and it's not from a lack of trying to find it.

    I've refuted it with some rather simple test that any aquarist can do and see for themselves if they can see any differences over time. No one has yet. Self competition for resources is also a possible factor not considered by many folks as well. And then just basic good horticulture, eg trimming the and thinning plants, making sure there are enough nutrients/CO2, decent lighting.
    Those are by and far the largest issues and where folks see the most impact.

    Also, how does the plant know how big the water it lives in is?
    What about rivers and streams that are unidirectional? What good would that be for the water column? Swords, Crypts etc are all very much stream and river plants.

    They need large roots for mechanical reasons as well as when the water recedes and they no longer can get water for the leaves any longer.

    If you want to read more, it's a long review:

    SpringerLink - Journal Article


    Regards,
    Tom Barr
     
  10. Tom Barr

    Tom Barr Founder
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    Some plants grow very well only when there's plenty of nutrients and CO2 etc and then they grow like mad, others will trade off high rates of growth for slow and steady growth over a wider range of environmental parameters. So which plant would you predict would do best under lower levels of CO2 or nutrients?
    I think given some time, the stem plant will adapt, but placing it in a very competitive area with another plant that's well established is not a good test.
    You do not really see that in natural systems except with nasty competitive weeds like Hydrilla etc. That plant does not produce allelopathic chemicals, it beats on other plants by physiological means(excellent nutrient uptake, CO2 uptake and C4 like MET, Root and water column uptake, very low light compensation points) and ecological(very long lived Tubers + turion formation, fragmentation, very dense light blocking canopy, extremely dense biomass, rapid rates of growth).

    These traits are worth more in terms of competitiveness than allelopathy and far more effective in any aquatic system. Light is the main competition in aquatic systems for both plants and algae.


    Regards,
    Tom Barr
     
  11. Carissa

    Carissa Guru Class Expert

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    You could float the hygro. It should still grow fine since it's a leaf feeder. If it still dies, that rules out substrate poisoning (unless it's something getting into the water itself from the substrate). Hygro shows co2 deficiencies with holes/leaf loss. But usually you will still see new growth happening. It's not a hard plant to keep, but sucks up nutrients fast. I transplant cuttings from my co2 to my non-co2 tanks with just a slack in growth for a few days to a week until they get adapted again, at which point they continue to grow, albeit slower than in the co2 tank. If hygro dies on you, there's got to be some nutrient lacking there that the slow growing crypts don't have as much demand for and/or are getting it from the substrate, not the water column.
     
  12. aquabillpers

    aquabillpers Lifetime Charter Member
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    Thanks, Ceg,

    I have monitored the nitrate and phosphate levels in this tank since it was set up. There have been ups and downs, but for at least the last 2 years they have been within a normal range. I dose Flourish monthly, and I added some Equilibrium a month ago just in case.


    I understand that. But high light and inadequate carbon usually result in stringy growth in stem plants until they die off. The hygros just withered in a few days (if plants can wither underwater) :). Note that the root plants also died in a few days.

    All of the plants came from non-Co2 injected environments.

    I measure macros and hardness with test kits. I validated the phosphate kit; I've used the nitrate kit for years with satisfactory results in all environments.

    I know that there are many variables. I am just reporting what I observe. I think normally, given the symptom of rapid death of new plants in just a few days, some would suggest a poisoning of some kind.

    BTW, 2.5 days ago I added a tbsp. of duckweed to that tank. It covered about 1/5 of the surface, loosely spaced. Duckweed grow great for me in other tanks. This morning it was all gone, except for about 10 pieces. None of those plantlets had any roots!!!

    Thanks again.

    Bill
     
  13. aquabillpers

    aquabillpers Lifetime Charter Member
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    Tom posted, in part
    I don't know to what extent you were commenting in the hygro - crypt situation, but isn't it likely that a plant that gets it's nutrients from the water column, like hygro, would have no trouble competing with a substrate-feeder, like crypt, no matter how long it had been established? (Unless the crypt was putting out allelopathic poisons, of course.):)

    Bill
     
  14. aquabillpers

    aquabillpers Lifetime Charter Member
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    I posted earlier (after your post) that I added about a tbsp. of duckweed to the tank in question and it died in less than 3 days, except for about 10 plantlets who are hanging on without roots. I'm sure they will be gone tomorrow.

    Instead of looking at this from a not-enough-nutrients angle, why not consider a poison-in-the-water possibility?

    Bill
     
  15. VaughnH

    VaughnH Lifetime Charter Member
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    Just a minor quibble: plants with extensive root systems are not necessarily "root feeders", just as plants with few roots are necessarily "water feeders". Roots serve the purpose of anchoring plants in moving water, as well as feeding then, so those plants with roots may or may not depend on their roots for food.

    Now, my two cents worth:
    It seems obvious that something changed in your tank, and changed for the worse. Even a shortage of nitrates shouldn't cause the rapid decline you reported. In fact I doubt that any shortage would cause that.

    I also doubt that allelopathy is the problem. So, I'm left wondering if something like chlorine, or chloramines could be involved. Or copper, except that would kill off the fish before bothering the plants. Perhaps a detergent residue? If you had the capability of doing a thorough water quality analysis of your tap water that would be my first suggestion. If not, then RO/DI water, reconstituted properly, would be my next suggestion.

    On second thought, take my advice free! Keep the two cents.
     
  16. Carissa

    Carissa Guru Class Expert

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    You could try planting another crypt in there. The way you are describing it, it does sound like something major is amiss, not just a simple deficiency. If I had to guess right now, I would say that either there is something in the water, or too much of something in the water, that the crypts have adapted to, but other plants are having trouble adapting to. If it's allelopathic compounds from the crypts, another crypt should live fine, or at least as well as a crypt will do when transplanted, which might be hard to qualify.
     
  17. Carissa

    Carissa Guru Class Expert

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    Fast growers like hygrophila polysperma (you can't get much faster than that) will show deficiencies much sooner than slow growers like crypts. Their faster rate of growth means that they have a very high demand on nutrients, which shows itself very quickly if any nutrients are at semi-low levels; whereas a crypt can live under very low levels of nutrients, sometimes indefinitely, without any visible problems, especially if nutrients are available in the substrate and it has an established root system to get them already. I think that's the big difference between your crypts and the plants you are adding, besides some being fast growers, they are relying on the water column heavily for their nutrients, plus the stress of changing conditions etc. is not in their favor; whereas the crypts do not need to rely on the water column at this point, and probably have very extensive roots. The anubias are also extremely slow growers. In my co2 injected tank, I'm lucky if I see a leaf a month or every two months.
     
  18. aquabillpers

    aquabillpers Lifetime Charter Member
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    Hoppy, most of the water in the troubled aquarium has come from my 150 foot deep well, which I have been drinking and using in aquariums for decades. It has been augmented with water from a brook that flows from a swamp, cool, acid water that supports a good population of native brook trout. I've been using that for a long time, too.

    I do have some copper pipe in my house, but the fish and plants in other tanks are thriving, and those tanks use the same water.

    Looking back at my aquarium log, the only things that have been added to the aquarium in the last 18 months has been KNO3 (a little every other month), Fleet Enema (rarely), Equilibrium (once), Flourish (3 or 4 times), and Excel (3 or 4 times.) The last Excel dose was 5 weeks before the vals were planted.

    Carissa, your idea of adding a crypt from another tank is a good one, but the crypts in the tank in question continue to produce new plants, and I'd think that they would not inherit any "immunity" to water conditions that the parent had. I'm not sure, though.

    The poor hygros did not live long enough to show any signs of nutrient defficiency.

    Here's a link to an article by Ole Pederson of Tropica on allelopathy in aquatic plants. He cites a number of examples, none, unfortunately, involving crypts. Tropica

    Bill
     
  19. Tom Barr

    Tom Barr Founder
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    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?

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

    Regards,
    Tom Barr
     
  20. Tom Barr

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

    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.

    Still, neither he or I, nor any researcher I know would suggest that it plays a strong role in any system studied to date.

    I've grown Crypts for decades and some of the flowers are on the Crypt's pages.
    I've done hormone treatments like Dr Kane on them. Most of the results/data suggest what the research suggest.

    Perhaps one day they will find it in a natural system or perhaps an aquarium, I was asked that some years ago at the AGA, I could not do anything other than speculate and guess and the guess was wrong and there was not any interaction after I did the test later.

    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.

    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.

    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.

    Fairly straight forward process.
    But sometimes the folks doing well do not know what they are doing, or assume their parameters are one when they are something quite different(CO2 most commonly- go figure.........)

    Regards,
    Tom Barr
     
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