Stems Flashcards
what are bud scale scars?
scales protect the meristematic tissue over the winter and then fall of in the spring leaving behind scars
leaf primordia turns into…
leaves
as the cells elongate, what happens to the stem?
it grows upwards
the stem elongates until?
it reaches the final length and stops
once the stem reaches the final length and stops, what keeps growing?
the tip of the apical meristem
the vascular cambium turns into…
secondary xylem and phloem
cork cambium turns into…
cork and periderm
how does the vascular cambium create the secondary xylem and phloem?
by forming a ring of cells and encircling the entire stem
what cells are added to the outside?
phloem
what cells are added to the inside?
xylem
secondary xylem =
wood
what way do cells typically divide in vascular cambium?
down the middle
what does the vascular cambium alternate making?
xylem and phloem
why are monocots not woody?
because they dont have secondary growth
what are the three types of tissue patterns?
protostele, siphonostele, and eustele
what is the pattern for protostele?
xylem in the middle surrounded by phloem, then cortex, then the epidermis
what is the pattern for siphonostele?
multiple regions of xylem surrounded by phloem
what is the pattern for eustele?
pholem near the top and xylem near the bottom
what are vascular bundles?
patches of xylem and phloem
herbaceous eudicots have very distinct what?
vascular bundles
what is the vascular cambium?
dividing line between xylem and phloem
what is the bundle cap?
fibers that next to phloem to hold it together
why does phloem need bundle caps?
because it lacks lignin so it needs support
why doesn’t xylem need bundle caps?
because it is able to keep itself together due to lignin
xylem is produced when?
in the spring
spring means what size diameter?
large
fall means what size diameter?
small
what happens during secondary growth of a woody eudicot?
the epidermis is ripped apart
what happens to the cells outside of the cortex?
they become meristematic and produces cells
cells produced outside becomes?
cork
cells produced inside become?
periderm
the oldest xylem is towards the…?
middle
the oldest phloem is towards the…?
outside
an annual ring is what?
secondary growth in a year
what is heartwood
part at the center that no longer transports xylem
what is sapwood?
part outside, xylem that is transporting
what is softwood?
only tracheids
what is hardwood?
vessels and tracheids
what is the bark made up of?
periderm, cortex, primary phloem, and secondary phloem
what are bundle sheath cells?
fibers that surround vascular bundles
what doesn’t the monocot tissue have?
cortex and pith
how are the vascular bundles arranged in a monocot?
scattered
horizontal stems that grow beneath the ground
rhizome
what are the leaves like on rhizomes
scale like leaves with axillary bud and they are attached at the node
what kind of roots do rhizomes have?
adventitious
horizontal stems above ground
runners
runners that are below ground and grow in all directions except horizontal
stolons
where do runners arise from?
axillary buds (not the main stem)
runners are relatively ____ in diameter and produce ____
thin, plantlets
what are tubers
enlargements of the stolon
what is an example of a tunicate bulb
onion
what is an example of a non tunicate bulb
garlic
bulbils
baby bulbs
in tunicate bulbs, the layers are made up of…
modified leaves and basal
in tunicate bulbs, they will ____ with food
swell
non tunicate bulbs are made up of ____ bulbs
multiple
what are corms
non fleshy bulbs that are mostly stem
what kind of leaves do corms have?
few, papery leaves
what allows leaf stem to grow in a corm?
food stored
what are flat stems that look like leaves?
cladophyll
what are thorns?
stems of branches, modified to be woody, pointy, and hard
thorns are ____ structures and _____ grow into thorns
protective, axillary buds
modified stems that grow vertically and are supportive
tendrils
