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Lollons

jimscott

Tropical Fish Enthusiast
Not sure if this is the right forum for this topic, but occasionally the term lollon has been used, but I do not not know hat part of the plant it is or its function. I have seen thin, stringy, non-flowering, non-leaf plant parts projecting from my utrics. Are they lollons or potential flower stalks?
 
Strictly speaking, Utricularia don't have true leaves or roots, these should all be referred to as stolons. The term 'lolon' was coined by Tamlin to refer to those stolons which have a photosynthetic (they are green), leaf function and occur above the soil (L for leaf and olon from stolon). The name seems to have stuck amongst growers here at Terra Forums.

Taylor, in his book 'The Genus Utricularia - a taxonomic monograph' (the utric bible), uses the term leaf for these structures, whilst acknowledgeing that they are not true leaves.

Vic
 
Interesting. How are they different than the "green structures" that are wider and shorter, that I would refer to as being leaves? Does that make sense?
 
I believe what you are thinking of are the lolons (photosynthetic stolons). There are also "rolons", the parts of the plants under the substrate, doing the root-like buisness. Does that make sense?

Cole
 
Stolons and lolons and rolons, oh my! Under the substrate? These are above the substrate. Are they like probing above ground?
 
Jim,

What you call a "leaf" is what the group her commonly refers to a "lolons" for the reason Vic cited. And then there are the "rolons" that Cole talked about. Anything that is transitional (i.e. it is growing half ont the surface and half under the surface) I generally refer to as just a stolon. And then there are the aerial stolons that you get with some species like nelumbifolia that are a means of 'jumping ship' to a new location.
 
Please could someone let me know the reason why the leaf-like organs of Utricularia should be called stolons. As I understand it, a stolon is a horizontal stem bearing leaves and roots at the nodes - this description more-or-less fits for what Taylor terms the stolons of Utricularia, but not the 'leaves'.

It may well be true that Utricularia lacks 'true' leaves & roots, but that does make the whole plant composed of modified stems. To the best of my knowledge, neither Taylor nor Lloyd use the term 'photosynthetic stolon' (In The Genus Utricularia and The Carnivorous Plants respectively.
If you can gain access to it, this article contains a useful discussion of Utricularia morphology:

Rolf Rutishauser and Brigitte Isler
Developmental Genetics and Morphological Evolution of Flowering Plants, Especially Bladderworts (Utricularia): Fuzzy Arberian Morphology Complements Classical Morphology
Ann Bot 2001 88: 1173-1202, 10.1006/anbo.2001.1498

Their mainthesis is that, rather than compartmentalising morphology into rigid boxes of leaves, shoots, roots etc., we should remember that plants result from complex developmental processes and need not conform to conventional ideas of morphology. It may not be that Utricularia have lost their roots without trace, but that genes usually responsible for root development are involved in the development of various organs such as the stolons and rhizoids. My own view is that, in the absence of clear evidence in favour of calling them something different, there is nothing wrong with calling the leaf-like organs leaves.

Giles
 
hear hear!!
leaves is the most appropriate term!!
biggrin.gif
 
Mention leaves or roots in association with Utricularia and someone will jump out of the bushes to correct you, wait and see!  This is a very highly evolved genus, and they in fact do not have leaves or roots. I can accept someone referring to leaves for simpliciy's sake, but there is really no distinction in this structure from any other part of the stolon, it is interchangable with any other part of the plant, depending on its substrate orientation, if I have it right.  A stolon can morph into a leaf and vs vs.  To me this is a very distinct botanical quality, and one lacking in plants of other genera where a leaf is a leaf, and a root is a root.   So, I doff my cap to this genus and will not demote it's uniqueness.  I stand by rolons, stolons and lolons and think that special structures deserve special names that more accurately reflect their function while granting their morphological similarities.

What I am interested in is the process governing the actual production of the traps.   I have noted trap formation on the lolons of several species. I have also noted stolon production from the lolons. Stolons placed on the surface of the substrate easily morph into lolons.   I wonder if an actual bladder could likewise morph into a lolon given the right environmental cue, or produce a stolon, but I would wager it could.  What a fascinating study this would make if we could examine the gene transcription governing this differentiation into more specialized structures.  What produces an apical tendency in a stolon at some particular point on its length to generate a lolon?

I also am curious of why traps are produced.  The traps are very specialized, and have true digestive capabilities.  Their structure is vastly different from all other parts of the plant.  It's not just a matter of the bladders having microbes inside them which make the nutrients available to the plant, since axenic cultures still demonstrate digestive capability.  But, they can form anywhere on the plant!  I am curious as to why.

Giles, does the paper you list get into this? I sure would love to read that one if it does.
 
  • #10
Tamlin,
I very strongly recommend that you get hold of a copy of the paper. It is really a review and discussion of the concept of fuzzy morphology, in which the boundaries between organs are blurred (as opposed to classical morphology, with discrete categories of roots, leaves, stems etc.), but it takes Utricularia as a case study in a lot of depth, with many illustrations of meristems etc.

To say that Utricularia lacks roots & leaves, and is therefore composed of modified stems/stolons is an oversimplification. They point out the similarity between Pinguicula roots (atypically lacking root caps) and stolons of eg. U. longifolia, which have a similar arrangement of vascular tissue. I don't know much about Genlisea, not growing it myself, but it could well be that the trap 'leaves' really have at least a partial origin in roots, and likewise for Utricularia 'stolons'. I accept that Utricularia does not have 'classical' roots & leaves, but it doesn't have 'classical' stolons either. My main point is that Utricularia have not 'lost' leaves & roots, they have rather merged their vegetative organs together to produce a morphology that doesn't fit into classical morphological boxes. This is found in many other species as well,to some extent, as in compound leaves which may have stem characteristics. Another example is the climbing fern Lygodium, where the 'leaves' have indeterminate growth like a stem, so it is impossible to distinguish separate leaves & stems.

Giles
 
  • #11
I dont think people should be making up stupid names like 'lolons', this is just going to cause confusion:p
 
  • #12
Giles,

Thanks for the information. The paper sounds very interesting indeed and I will see if I can secure a copy of this.
I see the sense of what you are saying, and am interested in learning more.

gardenofeden:

As to new words (whether stupid or no) words are coined to fit concepts, which is how language evolves. Language is not determined by a dictionary, but rather by common usage. Let posterity judge the stupidity of my new words, but for the purposes of speaking in the here and now with my friends and associates, I will continue with their use, with apology to those not so inclined. If you want to call them leaves, roots and stems that's fine by me, and I can respect your opinion (and not think you stupid).

Well, time to galumph off as I chortle merrily away!
 
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