In message , Alan Gould
writes
In article , Corncrake
writes
On Wed, 11 Aug 2004 05:50:02 +0100, Alan Gouldwrote:
Franz Heymann writes
I'm lost here. I thought that Oxygen was a plant waste product. What
does the plant do with the Oxygen you say it needs at the root system?

It is a waste product of photosynthesis. But all living cells have to
respire to produce metabolic energy plant cells do this the same way as
all other living things* and need oxygen to do it.

(*) Excluding for the moment the tiny number of extremophiles that live
in exotic environments and derive power from other chemical reactions..

It is one of the minerals taken up by the plant.
--
Alan & Joan Gould - North Lincs.

An essential element perhaps, not a mineral, though.
It is a factor in anaerobic/aerobic conditions mediating bacterial
and fungal activity in the root systems and enabling (or otherwise)
the plants ability to take up nutrients.

I'm sorry, I don't fully understand that. Could you put it another way?

Bacteria, fungi and for that matter the cells in the roots that govern
the active uptake of mineral salts require oxygen to power their cells
metabolism. An additional problem is that in anaerobic conditions the
soil chemistry can become very hostile to most plant roots. There are
specialist bacteria that thrive in anaerobic soils and lakes some of
them are very nasty - the organism causing botulism for one example.

A handful of plants have roots that are extremely sensitive to oxygen
starvation and will lose them at the drop of a hat. They are mostly
epiphytes adapted to living in tropical forest tree canopy leaf litter.
Very open coarse composts have to be used and even then they are not
foolproof.

Regards,
--
Martin Brown