Wild Orchids - Roots and Nutrition
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Here are a couple plants growing in one specific tree species. The trees are not tall and have a sparse canopy that allows a lot of direct sun on the orchids. There are a lot of orchids on this tree species but none growing on other tree species in the same plot.
The bark of this tree is very smooth and offern little chance for leaves of other organic matter to accumulate from above. The limb structure does not allow for rain water to trun down a trunk to the orchid plants. All water must come from direct rainfall and dew.
Every where an orchid grows so does moss and lichens.
it is obvious that this plant is in a perfect environment nutrient wise or it would not be growing and flowering and producing seed. Also note it is not dark green.
Another orchid species in the same tree. Note here the roots are the host for a type of moss, at least I think it is a moss.
Close up of above roots
The bark of this tree is very smooth and offern little chance for leaves of other organic matter to accumulate from above. The limb structure does not allow for rain water to trun down a trunk to the orchid plants. All water must come from direct rainfall and dew.
Every where an orchid grows so does moss and lichens.
it is obvious that this plant is in a perfect environment nutrient wise or it would not be growing and flowering and producing seed. Also note it is not dark green.
Another orchid species in the same tree. Note here the roots are the host for a type of moss, at least I think it is a moss.
Close up of above roots
Look closely at the surface of the rock..... it looks to be covered in lichens.
Trithor
Chico (..... the clown)
As I said earlier, I noticed that orchids and lichens kind of go together. The question is, is it as a result of a similar requirement for microclimate, or is there some kind of symbiotic benefit. Old peppercorn trees in Madagascar are covered in lichen and a variety of orchids as well. This was my original logic behind using it as a host tree in my garden in South Africa (Sorry Jean, I have no chance of taking any photographs of the tree, as I cut it down some years back due to the mess it made and the invasive root structure)
In Magoebaskloof, (a wonderful low mountain area in the Eastern part of Northern South Africa) the easiest way to find orchids in the forested areas is to look for lichen covered branches. Plenty lichen = plenty orchids
In Magoebaskloof, (a wonderful low mountain area in the Eastern part of Northern South Africa) the easiest way to find orchids in the forested areas is to look for lichen covered branches. Plenty lichen = plenty orchids
Don't know if you are kidding??
Obviously the dust comes from very far away. Just google scientific papers and find the two mayor known sources today: Taklamakan desert and the former Lake Chad. You will also find that most red floods caused in the Caribean are due to iron content of saharian dust. This ones - the saharian dust - we know only too well at Canary Islands; we suffer them a few times a year 'undiluted'. And believe me: it's not what you would call 'household dust'.
I lived a 'very hot' time of my life in Piauí, Brazil. (Just another example of a dust source 'nearer' to you, gonewild.) There also is plenty of dust generated every year (as generally is in desert and semidesert areas). Add to this the incredible amount of burnings, that every year comes to a point of closing airports, and you have the sources - both natural and manmade - for regular rainfall in the tropics (cristalization agents) and regular 'week daily' feeding that compenses and exceeds the proposed washing-out effects of haivy rainfalls.
The only thing I didn't find written down up to now is the synergistic effect I assume must be there where epiphytes appear: first lichens, second mosses, third ferns. I do believe that there must be these effects, because a completely clean branch of a tree (sometimes complete trees, depending on species/smoothness of bark) can be seen beside branches covered with luxuriant life. If this first epiphytes appear, there is nothing stopping it.
\Trithor,
I believe the epiphytes create a microclimate and share it, similar to the benefits of the canopy of a forest: the ecosystem creates the microclimate it needs. There is a quite consistent theory that the southern border of the Amazon forests are artificial, evolving from little isolated 'islands' of cultivated parcels (a system we would now call a kind of shifting permaculture) that would be left to their own evolution after a few years growing over the years to form forest like structures until merging into the nearby pre-existing forests. The forest not only creates internally the microclimate it needs but also helps to the local climate (that is. rainfall) as well. I think there is an analogy: The epiphyte community cannot create rain but is responsible for an increased 'horizontal rainfall' everytime clouds and fogs and dews reach the branches. That works mostly in montane forests, but not only. In semidesert forests and bushes the dews are more intense where lichens and mosses cover the bark of treebranches. The lichens and mosses kind of capture the moisture that otherwise would 'only' be a thin film of moisture. This 'horizontal rainfall' as it is called over here sometime more than doubles the 'official' rainfall meassured at weather-stations.
Looking into what nutrients lichens might provide for orchids I found this paper..
http://www.hindawi.com/journals/chem/2011/420673/abs/
It seems at least one species of lichen is nutrient rich based on the analysis in the report. About everything an orchid needs except Nitrogen.
This table is copied from the paper..
Table 2. Mineral composition of E. cirrhatum
Element Quantity, ppm
Phosphorus (P) 24.67±0.57
Potassium (K) 1542±1.52
Magnesium (Mg) 1506±1.15
Calcium (Ca) 5191±1.00
Iron (Fe) 893.7±1.10
Zinc (Zn) 66.3±0.60
Manganese (Mn) 53.13±0.32
Copper (Cu) 5.83±0.35
http://www.hindawi.com/journals/chem/2011/420673/abs/
It seems at least one species of lichen is nutrient rich based on the analysis in the report. About everything an orchid needs except Nitrogen.
This table is copied from the paper..
Table 2. Mineral composition of E. cirrhatum
Element Quantity, ppm
Phosphorus (P) 24.67±0.57
Potassium (K) 1542±1.52
Magnesium (Mg) 1506±1.15
Calcium (Ca) 5191±1.00
Iron (Fe) 893.7±1.10
Zinc (Zn) 66.3±0.60
Manganese (Mn) 53.13±0.32
Copper (Cu) 5.83±0.35
Don't know if you are kidding??
Obviously the dust comes from very far away. Just google scientific papers and find the two mayor known sources today: Taklamakan desert and the former Lake Chad. You will also find that most red floods caused in the Caribean are due to iron content of saharian dust. This ones - the saharian dust - we know only too well at Canary Islands; we suffer them a few times a year 'undiluted'. And believe me: it's not what you would call 'household dust'.
I'm not kidding.
I'm also not discounting that dust does carry nutrients. But I do not believe dust is the primary source for nutrients in tropical forests.
Orchid roots systems are not evolved to be dust filters.
I will suggest that orchid roots may be extracting nutrients from the bark of the trees they grow on.
This would explain why some tree species contain orchids and other don't. I like this idea better than the usual idea that the trees that don't grow epyphytes have toxins in their bark. The trees that have orchids have the proper nutrients in their bark.
When tree bark gets wet minerals dissolve out of it. If the water is from rain the minerals in the water flow down to the ground. possibly this flow through runs over orchid roots to provide nutrients. But I don't think this is how orchids get most of their nutrients.
I think the moisture to dissolve the nutrients comes at night as dew. Every night here in the Andean rainforest the humidity approaches 100%. All foliage and limbs and tree trunks are wet from condensation. This happens every night even during the dry season.
Orchid roots spread out on the tree limbs and are most often tightly attached in contact with the tree bark. The nightly dew wets the bark and the roots, the water on the bark surface dissolves nutrients from the bark and the orchid roots absorb the nutrient enriched moisture (dew).
Orchid roots may get the same benefit from contact with lichens on rocks or from lichen growing directly on the orchid roots.
I don't think orchids rely solely on decaying vegetation for a nutrient supply, too many grow extensive root systems that don't trap detritus.
These are just my thoughts of the day.
This would explain why some tree species contain orchids and other don't. I like this idea better than the usual idea that the trees that don't grow epyphytes have toxins in their bark. The trees that have orchids have the proper nutrients in their bark.
When tree bark gets wet minerals dissolve out of it. If the water is from rain the minerals in the water flow down to the ground. possibly this flow through runs over orchid roots to provide nutrients. But I don't think this is how orchids get most of their nutrients.
I think the moisture to dissolve the nutrients comes at night as dew. Every night here in the Andean rainforest the humidity approaches 100%. All foliage and limbs and tree trunks are wet from condensation. This happens every night even during the dry season.
Orchid roots spread out on the tree limbs and are most often tightly attached in contact with the tree bark. The nightly dew wets the bark and the roots, the water on the bark surface dissolves nutrients from the bark and the orchid roots absorb the nutrient enriched moisture (dew).
Orchid roots may get the same benefit from contact with lichens on rocks or from lichen growing directly on the orchid roots.
I don't think orchids rely solely on decaying vegetation for a nutrient supply, too many grow extensive root systems that don't trap detritus.
These are just my thoughts of the day.
Stone
Well-Known Member
Dust must be one source, Many tons of it from Africa ends up in the Amazon each year. Remember also that rain droplets form around dust particles. But I think a major source of nutrients for epiphyes comes from exudations or leaching from the leaves of trees. Mosses and lichens also disolve rock and bark with acids which release nutrients. Another main source must surely be bacteria and fungi which release nutrients as they die. Add to this mychorriza which can effectivly increase the mass of a root system many times and you have enough nutrients for the orchid.
E
Eric Muehlbauer
Guest
Could there also be N-fixing cyanophytes in the moss and lichens?
Yes, I forgot about the micorrhiza. This fungal relation to (as far as we know now) almost all plants makes the 'sponge' really work. There is nearly no mineralisation occuring outside cells, all that arrives is captured and re-introduced to the living system. This system has NOTHING to do with the feeding we try in a pot based culture...
I'm not really concerned about where the nutrients originate from but rather what nutrients are available and in what ratios.
Dust, rain and dead leaves are obvious sources but certainly do not supply the majority of the nutrients.
Leaf litter contains nutrient ratios that have been measured at least in some research papers. Rick used those ratios to formulate the low potassium theory. But leaf litter alone is not necessarily an accurate measure of nutrient ratios orchids growing above the ground have access to. I'm looking for a different source of nutrients since orchid roots are not well designed to forage nutrients from dead leaves. If the major source of nutrients was trapped leaves, dust or other flowing material the orchid roots would have evolved to trap such materials or be more branched and net like. But orchids grow out long thin separated roots. So I want to see what they are getting nutrients from.
Reading the table of nutrient content of lichens how does that compare to the nutrient content of K-lite??? it seems pretty close to me.
Except for Nitrogen which the lichen uses itself, but the nitrogen source for the lichens come from algae and bacteria. Orchids could also access this nitrogen. I don't know much about lichens but reading a little it seems they get all of their nutrients from the atmosphere and convert them to solids within the lichen. If orchid roots are always found in association with lichens then that may be where to look for the exact nutrient ratio to use for fertilizer.
Lichens seem to have very high ppm content of nutrients but how does an orchid root get these nutrients?
Now I need to try to find orchid plants that don't have any lichens near their roots, so far they all do.
Please post any info that might pertain to this subject, my internet connection does not make googleing easy.
Dust, rain and dead leaves are obvious sources but certainly do not supply the majority of the nutrients.
Leaf litter contains nutrient ratios that have been measured at least in some research papers. Rick used those ratios to formulate the low potassium theory. But leaf litter alone is not necessarily an accurate measure of nutrient ratios orchids growing above the ground have access to. I'm looking for a different source of nutrients since orchid roots are not well designed to forage nutrients from dead leaves. If the major source of nutrients was trapped leaves, dust or other flowing material the orchid roots would have evolved to trap such materials or be more branched and net like. But orchids grow out long thin separated roots. So I want to see what they are getting nutrients from.
Reading the table of nutrient content of lichens how does that compare to the nutrient content of K-lite??? it seems pretty close to me.
Except for Nitrogen which the lichen uses itself, but the nitrogen source for the lichens come from algae and bacteria. Orchids could also access this nitrogen. I don't know much about lichens but reading a little it seems they get all of their nutrients from the atmosphere and convert them to solids within the lichen. If orchid roots are always found in association with lichens then that may be where to look for the exact nutrient ratio to use for fertilizer.
Lichens seem to have very high ppm content of nutrients but how does an orchid root get these nutrients?
Now I need to try to find orchid plants that don't have any lichens near their roots, so far they all do.
Please post any info that might pertain to this subject, my internet connection does not make googleing easy.
C
Cheyenne
Guest
I took a class on mycorrizal fungi and plant relationships. As everyone knows there are many different kinds and they all can perform different functions. Some can be an extention of the root system and increase the root system surface area by a great deal. Some can just adhere to the roots and actually pull elements directly from the atmosphere like nitrogen. I was reading how catasetum in cultivation are heavy feeders but in nature it would seem that they do not have much acces to nutrients. It is because they have a relationship with a special kind of wood eating fungi that breaks down the molecules of wood "eating it" and supplies the plant with what it needs.
A while ago I was going to start a thread on this but never got around to it. I saw a expeiment done in a forest on mycorrizal fungi. The experiment was to show how vast of an area the fungi covered and that it connected all the plants in the forest so that the small plants and seedlings were able to access the nutrients of the larger plants. Also that plants in the trees were connected to plants on the ground accessing the nutrients of the forest floor. The way they did this experiment was to completely seal a plant on a tree or a single branch with a plastic bag, then in the bag they injected radioactive carbon gas. A day later they took the meter to measure radioactivity around the forest. They found it in small seedlings on the forest floor and in branches of other species and other trees very far away. They hypothesized that the forest was so connected by the fungi that it was almost living as one and plants that do not have access to enough light or nutrients in there area simply share them with the plants that do as a community.
A while ago I was going to start a thread on this but never got around to it. I saw a expeiment done in a forest on mycorrizal fungi. The experiment was to show how vast of an area the fungi covered and that it connected all the plants in the forest so that the small plants and seedlings were able to access the nutrients of the larger plants. Also that plants in the trees were connected to plants on the ground accessing the nutrients of the forest floor. The way they did this experiment was to completely seal a plant on a tree or a single branch with a plastic bag, then in the bag they injected radioactive carbon gas. A day later they took the meter to measure radioactivity around the forest. They found it in small seedlings on the forest floor and in branches of other species and other trees very far away. They hypothesized that the forest was so connected by the fungi that it was almost living as one and plants that do not have access to enough light or nutrients in there area simply share them with the plants that do as a community.
I remember reading somewhere that moss roots secrete very small amounts of amine compounds. Back when we had a number of Phrag vittatum seedlings, we grew them with the com-pots sitting in R/O water. After a few months, a lush carpet of moss grew on the pot surface, and the plant roots were most vigorous directly under the moss. Since the vittatum seedlings were only fed w an extremely dilute (TDS around 15 ppm) urea based fertilizer on a monthly basis, I assume the mosses were also contributing some N through the breakdown of the amine compounds.
Trithor
Chico (..... the clown)
Now this is getting interesting! The concept of plant inter-connectivity is not revolutionary, it is simply 'right'. Wow, I love it and embrace the concept!
Stone
Well-Known Member
I just read a paper on epiphyte nutrition and apart from the mycorrhiza, there is aparently a huge population of bacteria living IN the spongy velamen of orchids roots and quite a lot of (very fine) organic material on the roots as well which the bacteria live on and no doubt mineralize and make it available to the orchid.
Also, the acumulated humus which some (many) orchids grow in, such as in tree crotches and between rocks etc. where many of our favorite orchids live, has been found to be richer in nutrients than many top soils in temerate regions! So maybe they are not on the starvation diet that we believe. When you think about it, humus is very fine (colloid sizes) and has a very hich Cation Exchange Capacity ( not like chunks of bark ) so it will be capable of capturing and holding good ammounts of ammonium, calcium, magnesium, potassium, sodium etc. and holding all the anions as well.
Its pretty obvious to me that to grow orchids well ( like the wild ones in prime positions ) you need to feed them well! I believe that we cant just go by analysis of nutrient through fall etc to determine orchid nutrition. Feeding that way in a modern mix is not enough IMHO.
Also, the acumulated humus which some (many) orchids grow in, such as in tree crotches and between rocks etc. where many of our favorite orchids live, has been found to be richer in nutrients than many top soils in temerate regions! So maybe they are not on the starvation diet that we believe. When you think about it, humus is very fine (colloid sizes) and has a very hich Cation Exchange Capacity ( not like chunks of bark ) so it will be capable of capturing and holding good ammounts of ammonium, calcium, magnesium, potassium, sodium etc. and holding all the anions as well.
Its pretty obvious to me that to grow orchids well ( like the wild ones in prime positions ) you need to feed them well! I believe that we cant just go by analysis of nutrient through fall etc to determine orchid nutrition. Feeding that way in a modern mix is not enough IMHO.
Stone
Well-Known Member
naoki
Well-Known Member
Mike, Would you mind of sharing the citation? I have access to most journals, sojournal names, volume, and page is all I want to know. Thanks.
Stone
Well-Known Member
Click on the ''click here''
http://www.oecologiaaustralis.org/ojs/index.php/oa/article/viewPDFInterstitial/281/352
