Merit of adding Mycorrhizae to potting medium

[naoki]

With effective microbes (EM-1, Inocucor), similar to Ray, I haven't seen much difference in media degradation, neither. I deflasked Vanda barnesii last year, and divided them into two groups: EM-1 (for every watering/fertigation) and control. For each treatment, I had about 5 small pots (replicates), each with 3-4 seedlings. They were randomized (in position). I continued the experiment about 6-8 months (and saw significant growth meanwhile). I didn't see much death in either group, and I didn't see any difference in the above ground size. I was going to weigh each plant, but it was pretty clear that there wasn't enough difference to be picked with the lower statistical power, so I didn't weigh them. I wouldn't make a conclusion from this negative results (other than we don't know the effects of effective microbes on orchids). Maybe it was too short (e.g., difficult to see the difference when seedlings are growing with some residual "power" from high nutrient flask). Sample size is too small. If there isn't pathogen threat, you can't see the effect etc. But I also didn't see difference in the media degradation (maybe it is too short compared to what Keith observed), neither. If there were, it wasn't visually obvious.

 

[gonewild]

I think you meant cytokinins, not auxins.

I dont know if I did or not :wink: I guess I should just have written "Hormones" so it would be all inclusive. Auxins, cytokinins, ect all are included in the scope of this.

 

[keithrs]

With effective microbes (EM-1, Inocucor), similar to Ray, I haven't seen much difference in media degradation, neither. I deflasked Vanda barnesii last year, and divided them into two groups: EM-1 (for every watering/fertigation) and control. For each treatment, I had about 5 small pots (replicates), each with 3-4 seedlings. They were randomized (in position). I continued the experiment about 6-8 months (and saw significant growth meanwhile). I didn't see much death in either group, and I didn't see any difference in the above ground size. I was going to weigh each plant, but it was pretty clear that there wasn't enough difference to be picked with the lower statistical power, so I didn't weigh them. I wouldn't make a conclusion from this negative results (other than we don't know the effects of effective microbes on orchids). Maybe it was too short (e.g., difficult to see the difference when seedlings are growing with some residual "power" from high nutrient flask). Sample size is too small. If there isn't pathogen threat, you can't see the effect etc. But I also didn't see difference in the media degradation (maybe it is too short compared to what Keith observed), neither. If there were, it wasn't visually obvious.

Is this product mycorrhiza based or bacteria based product?

 

[naoki]

Is this product mycorrhiza based or bacteria based product?

EM-1 (and Inocucor) contain both bacteria and fungi (yeast), but not the mycorrhizal fungi. I re-read your post, and you were probably talking about the products with mycorrhizal fungi since you were talking about mushrooms. Is it right? Then it makes sense. I assumed that you meant EM-1/inocucor from Ray's reply. Sorry for misquoting.

 

[keithrs]

EM-1 (and Inocucor) contain both bacteria and fungi (yeast), but not the mycorrhizal fungi. I re-read your post, and you were probably talking about the products with mycorrhizal fungi since you were talking about mushrooms. Is it right? Then it makes sense. I assumed that you meant EM-1/inocucor from Ray's reply. Sorry for misquoting.

This is correct.... Mycorrhizal fungi is what "eats" the potting media. Bacteria does as well just at a much slower rate. I used a product a while back named Hygrozyme. I do believe this is a EM-1 product as well(I'm not to familiar with EM-1 products). It's marketed as a soil conditioner/cleaner. It's a enzyme product. I used it for 6-8 months. I found it to be garbage for orchids. This is almost the same product marketed as 'Orchid Champion'. Enzyme products differ from both bacteria and mycorrhizae products. Enzymes strains are chosen depending on what material you want them to catalyze on. They will only eat that one type of material. This may be why your not seeing media degration.

 

[myxodex]

I guess you are talking about this paper:
Sudheep, N. M. and K. R. Sridhar 2012. Non-mycorrhizal fungal endophytes in two orchids of Kaiga forest (Western Ghats), India. Journal of Forestry Research 23(3): 453−460
In case of A. niger, it seems that it uses sugar (glucose sucrose) and produce citric acid.

There is no doubt that there are lots of endophytes associated with orchids in addition to mycorrhizal fungi, but I don't think that people has convincingly demonstrated the benefit of endophytes on orchids. They may be just there without positive or negative effects. Or they may have minor negative effects. Here is an easy review, which I got this info from:
Bayman, P. and J. T. Otero 2006. Microbial endophytes of orchid roots. In B. Schultz, C. Boyle, T. Sieber (ends) Soil Biology Volume 9: Microbial Root Endophytes, Springer-Verlang, Berlin (I think the pdf is accessible to anyone). It mentions that when they killed all fungi (endophytes and mycorrhizal fungi), the plant suffered (e.g. higher death rate), but a targeted fungicide, which doesn't kill orchid mycorrhizal fungi, didn't have much effect (p.172). The authors of reviewers think that more data is need about the nature of relationship between endophytes and orchids before any conclusion can be drawn.

More specifically with regard to A. niger, it is an interesting point, but where is A. niger getting C from to make the citric acid? They can use sugar (glucose, sucrose etc) to produce citric acid, but plants can probably more efficiently produce citric acid (almost all organisms can synthesize citric acid by them selves) than passing sucrose to the the fungi, and getting citric acid back. If they are obtaining C source from the soil (or some other place), then it is a possibility to "help" plant. But plants are good at getting C without citric acid, right? Under cultivation, they can utilize additional organic acids if there are no other limiting factors. But in nature, plants generally offer C (mycorrhizae, N-fixing rhizobia, nectar for pollinator) in exchange of other limiting factors.

Just to make sure, I'm not disagreeing with usefulness of organic acid as supplements for plant cultivation. I looked into this a little bit, and I agree that there are fair amount of evidences indicating the benefit.

I've noticed with both vandas and phals, it is not uncommon to see exuded nectar. Not sure of what induces this to happen, just that it seems not to be routine and possibly a stress response. Maybe to attract ants ? It seems that orchids get a number of favours from other organisms by trading sugar; pollination by insects, protection by ants, nutrient exchange from mycorrhiza or perhaps a bit of chemical protection from fungi which produce mycotoxins.

At the other extreme are those few orchids that are totally parasitic and don't even bother making chlorophyll anymore, and even intermediate relationships ... http://botanyboy.org/two-helleborine-orchids-from-japan-genus-cephalanthera/ ... which allow these to grow in poor light habitats. I often wonder with observations like these whether there could be an unseen continuum here, from those that play fast and loose with their sugar to those that are living on the edge in carbon terms. Those section barbata species like hookerae that seem to do well growing in low light conditions, ... are they pulling a bit of extra carbon from somewhere ?

As for fungi sold as beneficials, ... they aren't always as beneficial as claimed on the product label. I tried a Trichoderma product raved about on a hydroponics forum. The 3 plants I have treated with this are all struggling 4 years after application ... it seems impossible to get rid of, ... every time I repot these plants, the sparse mycelium spreads through the medium within weeks. I've tried soaking the plant in physan before repotting ... but no go. It seems that it has penetrated the root somehow and so is protected from treatment. It doesn't kill the plants, but seems to be inhibitory in some way, possibly parasitic and the plants are getting smaller by the year; shrinking back to seedling size. I do not recommend Trichoderma at least for paphs anyway.

Finally something I meant to post earlier, but didn't and forgot. About uptake of N from arbuscular mycorrhiza.
There is a review on arbuscular mycorrhiza and nitrogen uptake, it is open access, but I had some problems cutting and pasting the link. The paper is:
Role of Arbuscular Mychorrhizal Fungi in the Nitrogen Uptake of Plants: Current Knowledge and Research Gaps. Bucking, H., and Kafle, A., (2015) Agronomy 5: 587-612

The model that they illustrate with diagram to summarize what is known, is in line with what Naoki got from wiki.

Another study on AMF suggests that the fungus made a difference in what amino acids were taken up. They used nanolabels ... I'm not sure how to interpret their results and what effect the labelling method might have. Their results are interesting however, may indicate uptake of amino acids ?
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0047643

 

[Ray]

1) Keith - all of these microorganisms consume a carbon source, and their metabolites are known to break down cellulose, but it is apparently a matter of degree.

2) Naoki - the reason you saw no difference between the treated and untreated plants was because you didn't use Inocucor! <insert grin here>

 

[cnycharles]

A mode of action for some orchids is to 'allow' the fungus to infect the root, then special structures eat the fungus. Some may connect to the mychorrizae and who knows what after that. You can read my native orchid educational display text here http://www.cnyos.org/natives/educexhibita.pdf

 

[naoki]

I often wonder with observations like these whether there could be an unseen continuum here, from those that play fast and loose with their sugar to those that are living on the edge in carbon terms. Those section barbata species like hookerae that seem to do well growing in low light conditions, ... are they pulling a bit of extra carbon from somewhere ?

I think this is a good point, and I agree that there is a continuum in terms of reliance on fungi; from mycotrophy (orchid eating fungi) to mutualism to parasitism (fungi exploiting orchids) for some species. I'm not sure if there is a data showing that normal green orchids are receiving carbon from fungi. It seems that with stable isotope analysis and fungicide, this can be easily demonstrated. Mycotrophic orchids do have quite different fungi (I only listed mycorrhizal fungi associated with green orchids in the previous post), but they do have mechanism to pass carbon.

The 3 plants I have treated with this are all struggling 4 years after application ... it seems impossible to get rid of, ... every time I repot these plants, the sparse mycelium spreads through the medium within weeks. I've tried soaking the plant in physan before repotting ... but no go. It seems that it has penetrated the root somehow and so is protected from treatment.

Interesting. Do you happen to know which Trichoderma product you used? From what I read, there is a big variation among strains (and species), and some are effective to specific pathogen. So, it is possible that some strains are more parasitic than mutualistic. I have used RootShield a couple times.

Another study on AMF suggests that the fungus made a difference in what amino acids were taken up. They used nanolabels ... I'm not sure how to interpret their results and what effect the labelling method might have. Their results are interesting however, may indicate uptake of amino acids ?
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0047643

This one looks interesting. They seem to preferentially uptake rare amino acids. Thank you for the refs.

2) Naoki - the reason you saw no difference between the treated and untreated plants was because you didn't use Inocucor! <insert grin here>

That's a possibility! What I did isn't completely controlled, and I didn't quantify, so I would just say that it was inconclusive (and Inocucor is probably different). But when you look at the components of bacteria, I wonder what the secret is. In theory, the community can end up in a different equilibrium composition even if the environment is exactly same, depending on where you start from. So the initial ratio of components could influence it. When you look at the effective microbe literature, the benefit isn't really clear cut (compared to what the marketing dept. illustrates). I'm more toward believing that there is some benefits, but it depends on the other factors.

A mode of action for some orchids is to 'allow' the fungus to infect the root, then special structures eat the fungus. Some may connect to the mychorrizae and who knows what after that. You can read my native orchid educational display text here http://www.cnyos.org/natives/educexhibita.pdf

Very nice write-up, Charles!

 

[Kawarthapine]

I concur, very well written indeed.

Your explanation of the relationship between fungi and orchids was succinct and informative.

Kudos!

 

[cnycharles]

Ty! It was written probably over 10 years ago and I don't know if there is any new info about this


Elmer Nj