Wood
If you buy a piece of wood you are mostly buying which kind of tree stem tissue?
Modified plasmodesmata in xylem and phloem conductive cells where the secondary cell wall is missing and the primary cell wall is very thin... these allow water to pass from one cell to the next. These regions are called:
pits or pit pairs
Phloem cells are are living but lack vacuoles and nuclei. True or false?
True
A highly ordered arrangement of living, dying, and dead cells that have cell walls made of cellulose, lignin, and hemicelluloses
Wood
bark
Age-altered wood that is i) interior to the vascular cambium, and ii) no longer conductive
heartwood
Conductive cells that comprise xylem in gymnosperms and ferns are:
tracheids
Phloem loading and unloading (moving chemicals like sugars and wastes into and out of phloem cells) is done by companion cells in angiosperms and _______________ in gymnosperms.
albuminous cells
Phloem always flows down from the canopy towards the roots.
False
Phloem moves from source to sink because of:
Osmosis
Wood that is i) conducting water and ii) nourished by living parenchyma cells
Sapwood
"Retired" xylem (heartwood) is usually decay resistant because of its low water content (life requires water), low N content (N is moved outward to sapwood as parenchyma cells in wood die), and a high content of:
Terpenoids and other secondary metabolites
Angiosperms have tubular, continuous phloem vessels made of sieve tube elements joined end to end at sieve plates. Gymnosperms have sieve cells, tapered at the ends and not joined longitudinally. In these, fluid flows between ___________.
pits or pit pairs
Starches and oils are some of the secondary compounds stored in phloem parenchyma (e.g., albuminous cells and ray parenchyma cells. This implies that some energy is stored in, and used by, the stem of the plant. True or false?
True
What tissues nourish stem and root tissues via radial/horizontal flow? (Hint: Xylem and phloem both have these tissues, in which water and nutrients flow symplastically via the plasmodesmata.)
Rays
The phellogen, also known as the cork cambium, produces what tissue?
Bark
Intercellular spaces bordered by thin-walled, resin-secreting parenchyma (living) cells.
Resin canals or rays