Full Version: Potentially relevant moss info
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"The light requirement for moss spore germination is species-specific (Meyer, 1948). While certain species can germinate without any light if water and nutrients are available, P. patens does require light to germinate (Ashton and Cove, 1977). Moreover, P. patens protoplasts require light to divide"

"However, tip growth can occur in P. patens in the absence of light, providing a carbon source is provided (Cove et al., 1978), indicating that light itself is not required for all tip growth."

-- Annual Plant Reviews, The Moss Physcomitrella patens (2009)
(my emphasis)

This is potentially critical. If we need spores that are only germinated when the moss is in space, we might need to use a different species of moss...
We would appear to need data on the lifespan of a spore (for any moss looked at) before it must be germinated and the lifespan of an already germinated plant in a dormant state. Consider that it may have to sit for (best guess) 3-4 months in storage at NASA or somewhere. I suppose we'd also have to set up some environmental requirements for handling that match the internal requirement for the plants while in storage/prep for launch.
Yeah, I'm sifting through a lot of stuff to find relevant information like environmental conditions needed.

But I thought this needed a post of its own so it wouldn't get lost in the rest of the data, since it's potentially so critical.
Important background for much of the rest of this info: a 'protonema' is the first thing that comes out of a germinating moss spore, a thin filament. Basically the moss equivalent of a seedling/sprout in seed plants.

We will see that term a lot Wink

EDIT: The protonema starts out as a single thread (“chloronema”). The “caulonema” develops later and then gives rise to buds.

also, "bryophytes" is the group including mosses as well as liverworts.
Sorry this took so long...

Growing conditions

[From the old thread]
"Even tropical bryophytes seem to do poorly above 25°C (Frahm 1990)"
"Indeed, for most bryophytes, the optimum is near 20° C and for many it is much lower."
"Physcomitrella patens developed capsules best at 15-19ºC, "
"Hohe et al. (2002) found that the highest number of sporophytes in Physcomitrella patens were produced at 15ºC, with numbers dropping greatly at 25ºC. Vegetative growth, on the other hand, was best at 25ºC. "
Glime, Janice M., 2007 Bryophyte Ecology .

"the lethal cold temperature for 50% mortality (LT50) for P. patens protonemal tissue is around -2 C"
Annual Plant Reviews, The Moss Physcomitrella patens

pH and calcium are important to the growth of moss:
“In Funaria hygrometrica, acidification of the medium to pH 5.5 increases the extension of the tip cells, whereas buffering to a pH of 6.8 prevents it. Calcium seems necessary for the acquisition of new materials to the wall and the ability to extend the wall.”
“Forman (1964) found that spore germination in Tetraphis pellucida requires a pH of 3.0-7.3 whereas growth of the leafy shoot occurs in the much narrower pH range of 5.1 to 5.8.”

“Temperature requirements, on the other hand, are broader for the leafy shoot, but as the humidity drops, the viable temperature range narrows.”
Growing the moss in liquid media can inhibit the formation of caulonema.

Chloronema grow toward light, whereas caulonema grow away from light.

“The chloronema, at least in culture, is able to grow vertically as well as horizontally, but the caulonema grows only horizontally (Bhatla 1994).”

“Furthermore, the change from chloronema to caulonema can be delayed by inappropriate environmental conditions. Bopp (1961) found that the caulonema stage, and thus the bud stage, can be delayed by low temperature, submersion, or low light.”

"In the ephemeral Physcomitrella patens (Figure 6), high light intensities promote branching of the caulonema, thus proliferating the potential bud sites (Cove et al. 1978, 1979)"

"Both cell types of the moss protonema, chloronema and caulonema, grow via tip growth, like pollen tubes of seed plants. While chloronema does not grow in the dark, caulonema grows negatively gravitropic [away from gravity] in the absence of light (Cove, 1992)."
A little more growth info:

"The chloronema, at least in culture, is able to grow vertically as well as horizontally, but the caulonema grows only horizontally (Bhatla 1994)."

"Unlike fungal hyphae, pollen tubes, and root hairs, the growth of the moss protonema is slow (Bhatla 1994) and is not confined to the apex."

"left in the dark after protoplasting, protoplasts produce cell walls but do not initiate cell elongation or division (Jenkins and Cove, 1983a)"

Light intensity and quality affect both orientation of tip growth and branching.
-- Annual Plant Reviews, The Moss Physcomitrella patens (2009)
OK, so that was the first "batch" of information I found.

Next I will be looking into
-more details on growing conditions and procedures
-potential moss species to use if we can't use Physcomitrella patens
Just to let you know I am keeping up with your posts here. I just hadn't replied. Don't think they're falling on deaf ears.

The major plant nutrients are C, H, O, P, K, N, S, Mg, Ca, Fe.

Mosses need these same nutrients, but generally in lower concentrations than vascular plants. “Needs of young shoots are greater than those of older shoots and nutrients may be moved from old to young tissues.”

Moss "can suffer osmotic shock when transferred to substrates with high nutrients.” (This effectively drains water out of the cells through osmosis and can cause cells to collapse.) “If a plant has grown from spores at a certain nutrient/ion level, then its osmotic potential is more
likely to be adjusted to that of its environment. The same is likely to be true for plants grown from fragments and other propagules. Moving a plant to another location can strongly affect that balance.”

The list of plant nutrients I posted above comes from the "Bryophyte Ecology" textbook I linked.

Sources written from an agriculture/gardening perspective tend to focus on N, P, and K.

C, H, and O are provided by photosynthesis (from CO2/H2O) so sometimes aren't considered. But if we are growing in darkness then we need to provide a carbon source.
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