You know, it's funny, I was just sitting here thinking about the plant thing. They are really so slow, at least assuming you're not doing a planted tank with pressurized and all that, which I assume you're not. Roots on submerged plants are such a different thing, somewhat left over or having a lot to do with the period of the year when the plants are emergent (which the vast majority of the selections the hobby has ended up with are (well it would be hard to put a percentage on it, but a lot I'd say.) With non-aquatic terrestrials I think stimulation/need for a big strong root system is driven by the powerful need for water. But once plants evolved back into water environments water became readily available and could be absorbed all over the plant, so you see slower and less root development. Of course it varies widely by species.
WD, I always enjoy reading your posts and right at this moment, I still have water dripping off of my hands as I am half way through replanting my main display tank after an upgrade.. and I'm thinking "I think someone forgot to tell my plants that they're always underwater"! Even my
Hygrophila have extensive root systems which keep them anchored in place, and don't get me started on the Crypts et al. I do think that for the most part, the roots' main function is anchorage.. but at the same time, a lot of rosette plants appear to benefit from root fertilisation, so they must retain at least some feeding function.
[I wrote that about 6 hours ago, just never got round to posting, planting is now complete and I'm going to have fun watching the plants survive at 0.6 wpg after they had been used to 1.2 wpg, at least until I can get some new lights. Thank god that the spare tubes which came with the tank were daylight instead of actinic and rosy.]
