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
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
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
Compression – conifers, forms on underside
Tension- hardwoods, forms on the upperside
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