Lecture 22: Secondary Growth Flashcards
what are the two kinds of lateral meristems?
cork cambium
vascular cambium
what is the function of vascular cambium?
adds layers of secondary xylem/phloem
what is secodnary xylem?
wood
the vascular cambium is typically bifacial, what does this mean?
secondary xylem grows inward, secondary phloem grows out… vascular cambium is producing tissue from both directions!
what is the main function of the cork cambium?
replaces epidermis with periderm
“periderm” refers to all layers of outer bark… what are these components?
cork, cork cambium, phelloderm
secondary growth occurs ____ elongation in mature stems
after
primary and secondary growth occur ____
simultaneously
secondary growth does not happen in ___
monocots
grasses/cereals/palm trees are examples of…
monocots
which structure provides lateral transport in secondary vasculature?
rays
in what order do the cork cambium and vascular cambium develop? and why?
cork cambium develops after the vascular cambium because it is limited in its growth
lateral meristems shut down in ____ but come back in the _____… why?
winter
spring, because its growing season
one growth ring = ….
one growing season
what kind of cells make up the vascular cambium?
undifferentiated parenchyma cells
the ____ is wholly responsible for the production of secondary vascular tissue
vascular cambium
in what order do these structures fall… vascular cambium, pith, cortex, primary xylem, primary phloem
pith, primary xylem, vascular cambium, primary phloem, cortex
more secondary _____ is produced than secondary ____
xylem
phloem
____ has thin cell walls, bigger cells, and occurs in the spring
early wood
___ have thick cell walls and small cells, in the late summer
late wood
____ has uniform texture
soft wood
___ have variable texture and colour variations in dicots
hard wood
___ is “living”, lighter in colour
sap wood
___ is non-living, darker in colour
heart wood
conifers (gymnosperms) have which kind of wood?
soft wood
what are some of the traits of softwood?
small amount of parenchyma, dominated by tracheids, have resin canals for sap
angiosperms have what kind of wood?
hard wood
what are some traits of hardwood?
vessels/tracheids/parenchyma are equal in amount, more variation in wood structure, have fiber tracheids
do monocots make wood?
no
