L4: Plant Body and Meristems Flashcards
Angiosperms are found as both _____ and _________
monocots, dicots
Gymnosperms
long distance pollination
angiosperms
flowering plants
Monocot characteristics
1 cotyledon
parallel leaf venation
flower parts in multiples of 3
scattered vascular bundles
fibrous root system
rare to have secondary growth with vascular cambium
Eudicot characteristics
2 cotyledon
reticulate leaf venation
flower parts in multiples of 4 or 5
vascular bundles in a ring with cortex/pith
tap root system
common to have secondary growth with vascular cambium
Shoot apical meristem
small mass (dome) of undifferentiated cells, capable of rapid cell division to produce new cells for the primary growth of the stem
location of shoot apical meristem
tip of each shoot
root apical meristem
small mass (upside down dome) of undifferentiated cells, capable of rapid cell division to produce new cells for the primary growth of the root
location of the root apical meristem
tip of each root, just above protective root cap
plant growth is dependent on the presence of _______________
embryonic meristematic tissue
initials
actively dividing cells that maintain the meristem as a continuing source of new cells
derivatives
undifferentiated cells of meristem that arise from division of initials
main difference between initials and derivatives
initials stay meristematic, while derivatives leave, entering differentiation
In what way does the apical meristem cause the plant to grow
grow in length
In what way does the secondary (lateral) meristem cause the plant to grow
grow in width/girth
What kind of organization is the shoot apical meristem described to have?
“tunica-corpus” organization
tunica
outermost layer(s) of the shoot apical meristem; undergoes surface growth by anticlinal cell divisions
corpus
interior layers of the shoot apical meristem, beneath tunica; undergoes volume growth by cell division in all planes
central zone
contains pluripotent, undifferentiated cells that divide infrequently
peripheral zone
surrounds the central zone; mitotically active (lots of cell division)
primordia
buds/outgrowths from the shoot apical meristem that form new organs
differentiation proceeds _______
outwards
root cap
protects root apical meristem, sheds and secretes mucilage to lubricate root movement, and even senses gravity
Quiescent centre
rarely dividing pool of stem cells within the root apical meristem. Maintains surroundings more frequently dividing initials
primary meristems
partly differentiated tissues that remain meristematic for a limited time, before differentiating into primary tissues
types of primary meristems
protoderm, ground meristem, procambium
types of primary tissue systems
dermal, ground, vascular
residual procambium
the leftover region of the procambium that did not differentiate into xylem or phloem
What happens when the plant has secondary plant growth?
the residual procambium begins dividing and becomes the vascular cambium
Parts of the vascular cambium
secondary xylem and phloem
periderm
secondary growth version of epiderm
cork cambium
tissue in the stem of a plant that gives rise to cork on its outer surface and a layer of cells containing chlorophyll on its inner surface.
Location of the intercalary meristem
base of internodes
intercalary meristem
enables rapid growth in height of bamboo (internode elongation)
unique to monocots and enables re-growth of grass removed by grazing or mowing
