This is... either improbable or much more
difficult than isolating genes for ocean-based
plant life (surviving in the sea) and modifying
the watermeal genome with it, so it can thrive
on the oceans,
but.... just an idea:
if. to isolate the genome that allows watermeal
its growth on freshwater.
and combining this with every other land-based
plantation out there.
It would need much, much more water, but
the growth of it would be... immense.
but... possibly improbable/incompatible unless to
change much of the target vegetation's characteristics.
while still retaining that value on growth over land.
can it still benefit from the water,
and rapid growth/division of cells?
it will also change the biochemical composition
of the vegetation. so what is a potato, no longer
tastes like a potato. what is tomato, no longer
tastes like a tomato. what is grass, is no longer
grass.
however. if to benefit from the 'growth' of it all.
and still is edible for animals.....