Quiz: Describe the difference in wood structure
between diffuse porous and ring porous trees.
Meristem- key to
tree growth,
Undifferentiated cells, located on surface area of tree, apical and lateral
Growth of individual tree parts
1. Branches (aka Shoots) and Leaves:
Growth:
primordia located in buds, leaves grow out first and
then shoot elongation. Elongation stimulated by auxins.
Indeterminate
vs. determinate (free vs. fixed)
Determinate-
only one set of leaves and shoots per season- oaks and pines
Early
Leaves vs. Late leaves
2. Roots:
Growth similar to shoot
growth (cells)- at apical meristem.
Correlation
of elongation to root diameter. Elong.
Also affected by temperature, excess water (because of oxygen losses),
compaction
3.
Bole
Growth:
Meristem divides into fusiform cells and ray cells ( both
are in xylem),
Ring
width and area:
Wood
is produced along perimeter,
From
base of crown downwards
Types of Wood:
Coniferous wood- tracheids,
no differentiation in function (support or transport) of tracheids
Diffuse porous- small vessels spread throughout wood used for
water transport
Ring porous- large vessels in early wood and smaller vessels in
late wood
Early
vs. late wood
Reaction
Wood
Compression
– conifers, forms on underside
Tension-
hardwoods, forms on the upperside