Stems Flashcards
What is a stem?
a plant organ consisting of nodes and internodes
What is a node?
the point leaves are attached on a stem
What is an internode?
the stem segments between nodes
What is the 3 main purposes of a stem?
Structure, protection, and transport of nutrients
How does the stem provide structure?
the stem holds up the plant allowing it to grow towards the light
How does the stem provide protection?
thorns, bark
How does the stem transport nutrients through the plant?
Vascular tissue transport water and other nutrients through the plant
What is an apical bud?
The growing shoot tip that grows long
What is an axillary bud?
lateral growth, branch, thorn or flower
What are the two types of stems
herbaceous and woody
What is wood?
a natural composite of cellulose fibers embedded in a matrix of lignin
what are meristems?
a region of undifferentiated cells that produce new tissues through cell division
What does it mean when meristems are dormant?
they are regions the have the potential to develop new stems, leaves and roots but are in “arrested development”
what does it mean when meristems are active
the meristems are growing into new stems, leaves, and roots
What is primary growth?
growth in length
What is secondary growth?
growth in thickness
what plants have secondary growth?
secondary growth occurs in gymnosperms and many true dicots, but is rare in monocots
What parts of the plant experience secondary growth?
stems and roots rarely the leaves
What does secondary growth consist of?
tissues in the vascular cambium and cork cambium
do primary growth and secondary growth occur at different times?
no they are simultaneous
What is the anatomy of a tree trunk?
Bark, vascular cambium, and secondary xylem
What does the bark consist of?
layers of periderm, and Secondary phloem
What is the use of the layers of periderm?
Protection from disease and pests, insulation from fire
What is the use of the phloem?
they are living cells that conduct nutrients down the tree
What is the use of the Vascular Cambium?
makes new Xylem and phloem cells
what does the secondary Xylem consist of?
Sapwood and heart wood
What does heart wood do?
nothing it is dead cells
What does sapwood do?
Living cells that conduct water up the tree
What are the parts of a tree
Crown, trunk (bole), roots
What does the crown of a tree do?
where the leaves are for photosynthesis
what does the trunk (bole) of a tree do?
holds leaves up to light, supports crown, transports nutrients and water
What are different types of bark?
Smooth, furrowed, fissured, peeling/exfoliating, fibrous, plated
What are the parts of a twig stem?
terminal bud, axillary bud, node, internode, lenticel, terminal bud scar scales, bundle scar, leaf scar
what is a leaf scar?
scar left on twig after dropping of a leaf
What is a bundle scar?
smaller scars left inside the leaf scar left by leaf veins
What is Glaucous?
Blue/white waxy covering
What does pubescent mean?
having hair
What does glabrous mean?
no hair
What are the two types of buds with scales?
Imbricate and valvate
What do you call a bud with no scales?
naked bud
what are bud scales?
reduced or modified leaves that cover the bud
What do valvate scales look like?
a pair of scales meeting at an edge
What do imbricate scales look like?
Overlapping scales
What is a twig?
a young shoot, generally applied to the growth from a previous year
What is a bud?
underdeveloped shoot (will produce next years leaves and twigs)
What is a terminal bud?
bud terminating growth at the end of the branch
what is a pseudo-terminal bud?
lateral bud that assumes the role of a terminal bud, adjacent leaf scar
what are lenticels?
corky spots on surface of twig that are torn epidermis cells that aid in the gas diffusion in stem (CO2 and water vapor)
what is a stipule?
a leaf like appendage that occurs at the base of a leaf patiole
What is a stipule scar?
scar left behind on a twig after stipule is shed.
What are some modified stems?
Rhizome, Tuber, Thorn, Stolon
What is an example of a tuber?
a potato
