Chapter 25 and 26 Stems Flashcards
What has the largest stem in the world?
Adonsonia Boabab
What has the tallest stem in the world?
Douglas Fir
What has the stem with the most volume?
giant sequoia
What are the six functions of stems?
support of above-ground parts of plants (leaves and flowers) transport (by conduction) storage (tubers and bulbs) protection photosynthesis reproduction
What is a node and why are they important?
a node is a spot where leaf connects to stem. It adds plumbing needed and the presence of nodes make stems more plex than roots.
What is an internode?
stem section between two nodes
Describe the dicot stem pattern as described in lecture.
- the primary vascular tissue with separate vascular bundles organized in a ring.
- the primary Phloem is outside while the primary xylem is inside.
- has a pith.
vascular bundles are open (they are forming the vascular cambium. - if you see sclerenchyma bundles or sheath it’s now closed.
Describe the second dicot pattern of stems discussed in lecture.
wider vascular bundles that touch
xylem in, phloem out
primary vascular tissue appears as cylinder
common in stems that undergo a lot of secondary growth.
Describe the monocot stem structure discussed in lecture.
vascular bundles are scattered throughout ground tissue (but not random)
ground tissue is not separated into a pith and cortex.
vascular bundles form screaming monkey face.
what is the stolon?
a horizontally oriented stem above ground (we know its a stem because of nodes)
How do tendrils grow?
up and around support structure.
What are thorns?
pointy objects that are for defense.
What does a succulent stem store?
it stores water.
What is a cladophyll?
(branch leaf) flattened stem that is photosynthetic.
Leaves always grow…
below the bud.
What is a Rhizome?
a horizontally oriented stem below ground.
What is a bulb?
a small stem surrounded by thick fleshy leaves.
What is a corm?
a fleshy stem surrounded by thin, papery leaves.
What are tubers?
fat, underground storage stem (like potatoes).
The eyes of a potato are also…
stem nodes.
When viewed under a microscope, the eyes of a potato closely resemble what?
an apical meristem
What three stems also serve as storage structures that we discussed in lecture?
bulbs, corms, and tubers.
What are the two secondary meristems that produce secondary growth?
vascular cambium, and the cork cambium.
Most secondary growth comes from which secondary meristem?
the vascular cambium.
How thick is the vascular cambium?
one cell thick.
What does the vascular cambium produce?
the secondary xylem and phloem.
When is the epidermis lost?
during secondary growth.
How do you tell the difference between a stem and a root?
a stem will have a pith and a root with have the primary xylem.
What is the cork cambium responsible for producing?
the periderm.
What are the names of the three cuts we can make in woody stems?
cross-section, radial, and tangential.
Which cut goes through the middle of the stem?
radial.
Pine, spruce, juniper, and redwood are all examples of…
conifers which produce soft wood.
Oak, maple, walnut, and birch are all…
angiosperms and make hard wood.
Why are conifers considered homogenous?
they have few cell types, they have tracheids but no vessels, rays are 1 cell wide, and resin ducts can be present.
What purpose do resin ducts serve?
defensive strategy against insects.
Why are angiosperms (hard wood) considered heterogenous?
they have many cell types, tracheids and vessel elements, fibers, both heavy density and finer grain, parenchyma, rays are more than 1 cell wide, and lack resin ducts.
The vascular cambium goes through two growth periods throughout the year. Name them.
Spring wood: (cell w thin walls and wide lumens.)
Summer wood/late wood: cells with thick cells walls and narrow lumen.
True or False. heartwood is neccessary for the life of the tree.
False.
What is heartwood?
older, central wood that is not conducting, sometimes dark in color.
What is sap wood?
conducting wood that is younger than heartwood, farther out and lighter in color.
What are the functions of the secondary phloem?
transports sugars, the innermost layer is functional for transport, the rest is crushed, and the youngest part is the ring just outside the vascular cambium.
The periderm is a collection of what three tissues?
cork, cork cambium, an phelloderm.
How can you tell you are looking at the periderm?
the cells like up well.
What type of wax do cork cells have that make them impermeable to water and gas exchange?
suberin.
Where is the tree alive?
between the vascular cambium and the cork cambium.
What are lenticels?
holes through the periderm that allow for gas exchange.
Bark is considered to be what?
everything past the cork cambium.
Outer bark is…
tissue outside the innermost cork cambium.
Inner bark is…
tissue between the vascular cambium and the cork cambium.
Which of these is non-living? Phloem, cortex, cork, or phelloderm.
cork is non-living.
