Moss Protonema
Posted: 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! )
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, 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. 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.... 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! 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.
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! )
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, 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. 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.... 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! 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.