pollination in aquatic plants

[eub]

So many aquatics seem to prefer to reproduce asexually. Is waterborne pollination that much chancier than airborne? Or, hm, my impression is that even aquatics with aerial flowers have an asexual tilt, so maybe it's not about the pollination?

I should find this paper Evolution of Aquatic Angiosperm Reproductive Systems:

Why do most aquatic plants reproduce asexually? [...] Why and how did hydrophily (water pollination) evolve, and why are only 5% of aquatic plants hydrophilous? The authors discuss hydrophily at length.

Also, do any plants use aquatic creatures as pollinators? Why the heck not? It would please me.

Comments

[marzipan-pig.livejournal.com]

It would please me.

:) And that is, afterall, what it's all about.

[eub.livejournal.com]

Just picture the wee rotifers buzzing around with pollen grains sticking to their membranes.

whole cloth

[jinian.livejournal.com]

Is waterborne pollination that much chancier than airborne?

Not an ideal question, since I think water plants are all angiosperms and would tend not to use wind pollination anyway. (Yes, some do. It's not usual.) I would say yes, anyway, since water-living algae &c. have swimming gametes which probably exhibit tropisms rather than passively carried pollen grains. In fact, pollen is pretty counterproductive in a water environment; lots more mass to probably just fall to the bottom, no real need for watertight protection of gametes. ("Hydrophily" fails to appear in either bio book or specifically plant bio book. Bedtime precludes trawling in Zomlefer.)

So aquatic angiosperms are at a disadvantage for sexual reproduction, and successful clones are those that multiply vegetatively. Makes sense.

Why the heck not?
For one thing, the pollen would wash off. Water is way more viscous than air, so unless honeybees went diving there wouldn't be any anatomy present that would work to carry the pollen around. Food rewards might work (lipids or pollen itself), but you'd still need orchid-style pollen in a prebuilt, sticky backpack to get it anywhere. Bees use sight to locate similar flowers, which would work much less well in water, but assuming there was another tropism that worked your aquatic orchid might do okay if it lucked into a pollinator. Let me know if you manage to breed one.

Re: whole cloth

[eub.livejournal.com]

The free-swimming gametes are an interesting strategy. Popular among marine animals, IIRC. So now I wonder if that would work for plants. But I suppose that technology's not in their lineage, is it.

Huh, ginkgos have flagellated sperm cells? Cool.

I might see about engineering my plants to use eelgrass-style mucus-pollen composite to try to stick to bearers.

[aquaeri.livejournal.com]

I think jinian has a lot of it. Plants (in this sense) evolved on land, and pollen takes advantage of characteristics of air that don't transfer well to water. It's analogous (I think) to the way that whales and seals can't go back to breathing water.

Sex is somewhat of a tenuous notion; last time I was reading in the literature, the maths still added up to an advantage for asexual reproduction. And certainly, most plants reproduce asexually quite well, and have no particular germline distinction like animals do.