Symplast
- a) Symplast is the network of highly ordered, connected living axial and
radial parenchyma cells in sapwood and inner bark. The symplast stores energy
reserves. b) The symplast is the highly ordered, three-dimensional, connected webwork of living protoplasm in trees. It's like a webwork of jelly. The
living protoplasm is contained in thin-walled cells called the parenchyma,
which have small cell wall openings that act as tunnels where the protoplasm of
one cell connects with the protoplasm of adjoining cells. The symplast stores
energy reserves. The apoplast (dead fibers and tissues) stores bound water.
Trees store their money (glucose), in the form of starch, in the symplast. As the symplast decreases, so does
storage space. As storage of energy reserves decrease, so does the defense
potential. Pathogens seem to know this very well. In other words,
when the tree becomes symplastless, the tree or
tree parts, has moved onto another ecological stage. (See
TREE ANATOMY, SHIGO,
1994)
Apoplast, Symplast - Apoplast dead, symplast living – think
think think. Apoplast is the dead portions of the tree, the cell walls,
the vessels in time, the tracheids in time. I say in time because they are all
born alive, but in short time they all die. Just like the fibers are born
alive and the outer bark is born alive and then they die and become a part of
the apoplast.
The symplast –think living – everything is born alive. Then
as it stays alive and works many, many, bodies inside the cells keep jiggling
if you wish, moving if you wish –that’s what metabolism is all about –highly
ordered movement inside the cell in order to utilize energy that is supplied to
it.
Think symplast the living webwork. And wood is living and
dead, so what shall we call it? It is a duality of living and dead parts and
dying. The living network is primarily the inner contents of the parenchyma
cells, the thin walled cells that are still living and contain a nucleus and
DNA and other substances. So as we put dyes and materials into trees and
inject trees some of the materials move in the apoplast and some move in the
symplast. This is the reason why any physiologist never should except a paper
where someone injects a dye and then says this is the way the system goes.
Because the dye can spread in the apoplast and the symplast. Symplast - living
network and Apoplast - dead network.