Fern prothallus as aquatic plants

[Badis]

I've been curious for a few days about how a prothallus of a terrestrial fern species, such as Lomariopsis lineata, can grow continuously under water without any problem. Yes, I am talking about Süßwassertang. I only know of one other similar case, that of the Microsorum (Leptochilus) pteropus prothallus, but as this is an aquatic species it does not seem so surprising. Anyway, in both cases, I am curious why the gametophyte does not give rise to the sporophyte. Although I'm biologist, botany is not my field, but as far as I know, an aqueous medium is required for gametes produced by gametophytes to fuse and give rise to sporophytes.

Why doesn't this happen in these cases?

Could the prothalli/gametophytes of other fern species be used as aquatic plants?

 

[dw1305]

Hi all,
Welcome to UKAPS,

I've been curious for a few days about how a prothallus of a terrestrial fern species, such as Lomariopsis lineata, can grow continuously under water without any problem. Yes, I am talking about Süßwassertang.

That is a interesting question. As far as I know it's the only one.

I only know of one other similar case, that of the Microsorum (Leptochilus) pteropus prothallus, but as this is an aquatic species it does not seem so surprising.

It isn't really exactly aquatic, it is a terrestrial fern that grows in zones which are often inundated.

Anyway, in both cases, I am curious why the gametophyte does not give rise to the sporophyte.

In the UK we have a filmy fern (Killarney Fern - (Trichomanes speciosum)) that usually occurs only as a gametophyte.

Although I'm biologist, botany is not my field, but as far as I know, an aqueous medium is required for gametes produced by gametophytes to fuse and give rise to sporophytes.

It is, the the male haploid cell migrates in a film of water from the antheridia to the archegonia, same in all Pteridophyta, even those that grow in deserts.

Could the prothalli/gametophytes of other fern species be used as aquatic plants?

Almost certainly they could, it would just be a case of finding them and recognising they weren't thalloid Liverworts.

Cheers Darrel