Moss Protonema

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mrsonchus
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Moss Protonema

#1 Post by mrsonchus » Sun Nov 25, 2018 12:00 pm

Hi all, following on from my other thread re moss here are a few images of what I think is moss protonema, discovered yesterday during a wander around the garden with the dog. I pullled up a piece of moss from the lawn and had a quick look at it in my tiny lab, as is my habit and indeed passion....

The protonema is the filament that develops from a germinating moss spore, the very beginning of the leafy gametphyte stage of a moss's life.
Well, I can't be certain of the following information in terms of it's technical accuracy as I'm pretty much a beginner with mosses and definitely protonemata, but here we are...
(the only image I forgot to take was of course an image of the moss gametophyte adult, so I can't even begin to guess what species this is from - oops! :oops: )

The big black blob is the piece of what looked like decaying Sunflower stem to which the protonemata were attached and then teased-away for the rest of these images,
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Protonema differentiates into two types of filament, the green chloronema that will go on to form buds (may be many per chloronema) that develop into the familiar leafy gametophyte of the moss, the caulonema which is brown-ish, that serves more as an anchorage part.. Another distinguishing feature besides the colour is the angle of the transverse cell walls relative to the lengthwise walls. The caulonema has oblique or 'slanting' cell walls whilst the chloronema has perpendicular (non-slanting) cells walls. This is slightly evident in some of these images I think.
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The caulonema seems to have what I think may be a 'bulbil' or vegetative propagule, whilst the chloronema has an outgrowth that may be a branching of the filament or even the beginning of a new leafy gametophyte shoot - I don't know much about moss so all of this is almost guesswork I'm afraid....
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Finally here are some images of those first leaves of a shiny-new gametophyte developing from the chloronema. Even at this early stage the leaf-lamina's cells are seen to be different between the lamina and it's border. The cells of the lamina (the leaf's flat blade if you like) are more rounded whilst the border's cells are elongated - taxonomic characters for sure, but that's all I know!
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Hope you find this interesting, a little low on content I know, but I thought some may find these really early stages interesting - I know I do!

John B.
John B

Hobbyst46
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Re: Moss Protonema

#2 Post by Hobbyst46 » Sun Nov 25, 2018 12:13 pm

mrsonchus wrote:Hope you find this interesting, a little low on content I know, but I thought some may find these really early stages interesting - I know I do!John B.
Me too. Cell differentiation is amazing! Thanks for the post!
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

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SutherlandDesmids
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Re: Moss Protonema

#3 Post by SutherlandDesmids » Sun Nov 25, 2018 12:40 pm

Yes, it's fascinating, isn't it? I will never tire of lower plant forms of all types. Unfortunately the mosses have never been my special field, but it is absolutely protonema. A nineteenth-century textbook of mine indicates a good place for protonema-hunting ''the green stuff so often seen in flower-pots that have been allowed to get too damp''.

I will not make a fool of myself by attempting to identify the doubtful points. The protrusion of the protonematal cell reminds me of the initial hypha put out by the moss-spore that segments to form the protonema, but whether that means it is an incipient branch of the protonema or an incipient bud that will give rise to a gametangiophore I simply do not know.

Thank you very much indeed.
“If you march your Winter Journeys you will have your reward, so long as all you want is a penguin's egg.”

-- Apsley Cherry-Garrard, 'The Worst Journey in the World' vol. ii p. 578

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mrsonchus
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Re: Moss Protonema

#4 Post by mrsonchus » Sun Nov 25, 2018 1:38 pm

John B

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SutherlandDesmids
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Re: Moss Protonema

#5 Post by SutherlandDesmids » Sun Nov 25, 2018 1:59 pm

I've glanced through the paper, it seems most interesting. I will get it printed out at the town library and study it properly when I've more time to devote to it. My sincere thanks.
“If you march your Winter Journeys you will have your reward, so long as all you want is a penguin's egg.”

-- Apsley Cherry-Garrard, 'The Worst Journey in the World' vol. ii p. 578

charlie g
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Re: Moss Protonema

#6 Post by charlie g » Thu Nov 29, 2018 3:59 am

Thank you, thank you, Mr.Sonchas/ John B. for this depth of study of our neighbor mosses. Often times I wonder when a filamentous organism is an algae thalus...vrs. a moss protonema...your kind link gives me useful content for my observations of freshwater communities.

I find your choice of microscopy objective optics excellent for my appreciation of your gardens moss neighbors...bravo, yes, yes! Thanks for this series of shared postings on your home region mosses, Mr.Sonchas Charlie g, fingerlakes/US

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SutherlandDesmids
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Re: Moss Protonema

#7 Post by SutherlandDesmids » Sat Dec 01, 2018 12:08 am

Often times I wonder when a filamentous organism is an algae thalus...vrs. a moss protonema...your kind link gives me useful content for my observations of freshwater communities.
Chloroplast morphology should be a great help in a doubtful case -- none of the septate Chlorophyte algae possess numerous discoid chromatophores as a higher plant does and the only traditional ''green algal'' group that does, the Siphonales (actually chromists) are not septate and so have an immediate distinguishing feature even apart from their very distinctive morphology. Vaucheria is the only possible slip for the beginner and it's so common a ''type'' I'd be prepared to lay a small wager you've seen it on a prepared slide, and you will notice the lack of septa at a low power on any microscope.

Taking a few common branched forms, the Cladophorales have a single, elaborate reticulate chloroplast in each cell. The Chaetophorales have a dissected-edged parietal band-shaped chloroplast across the middle of the cell. False branching occurs in Tolypothrix, a ''blue green alga'', but as you know they are actually cyanobacteria, there is no chloroplast and the colouring matter seems diffuse through the cell.
“If you march your Winter Journeys you will have your reward, so long as all you want is a penguin's egg.”

-- Apsley Cherry-Garrard, 'The Worst Journey in the World' vol. ii p. 578

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