42 terms

Ch 23 Roots, Stems and Leaves

Pretice Hall
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epidermal cell
cell that makes up the dermal tissue, which is the outer covering of a plant
vessel elements
A specialized short, wide cell in angiosperms; arranged end to end, they form continuous tubes for water transport.
sieve tube element
phloem cell that is joined end-to-end to similar cells to form a continuous sieve tube
companion cell
A type of plant cell that is connected to a sieve-tube member by many plasmodesmata and whose nucleus and ribosomes may serve one or more adjacent sieve-tube members.
parenchyma
the primary tissue of higher plants composed of thin-walled cells that remain capable of cell division even when mature
collenchyma
type of ground tissue cell with a strong, flexible cell wall; helps support larger plants
sclerenchyma
type of ground-tissue cell with an extremely thick, rigid cell wall that makes ground tissue tough and strong
meristem
undifferentiated tissue from which new cells are formed, as at the tip of a stem or root
meristemic tissue
types of tissue including the apical meristem and lateral meristem
apical meristem
Embryonic plant tissue in the tips of roots and in the buds of shoots that supplies cells for the plant to grow in length.
differentiation
(biology) the structural adaptation of some body part for a particular function
taproot
main root of a plant growing straight downward from the stem
fibrous roots
part of a root system in which roots branch to such an extent that no single root grows larger than the rest
root hair
tiny projection from the outer surface, or epidermis, of a root
cortex
Ground tissue that is between the vascular tissue and dermal tissue in a root or dicot stem.
endodermis
The innermost layer of the cortex in plant roots; a cylinder one cell thick that forms the boundary between the cortex and the vascular cylinder.
vascular cylinder
central region of a root that includes the vascular tissue-xylem and phloem
root cap
thimble-shaped mass of cells covering and protecting the growing tip of a root
Casparian strip
A water-impermeable ring of wax in the endodermal cells of plants that blocks the passive flow of water and solutes into the stele by way of cell walls.
node
point on a stem where a leaf is attached
internode
a segment of a stem between two nodes
bud
a swelling on a plant stem consisting of overlapping immature leaves or petals
vascular bundle
a unit strand of the vascular system in stems and leaves of higher plants consisting essentially of xylem and phloem
pith
soft spongelike central cylinder of the stems of most flowering plants
primary growth
type of plant growth that occurs at the tips of roots and shoots
secondary growth
pattern of plant growth in which stems increase in width
vascular cambium
lateral meristematic tissue that produces vascular tissues and increases the thickness of the stem over time
cork cambium
A cylinder of meristematic tissue in plants that produces cork cells to replace the epidermis during secondary growth
heartwood
older xylem near the center of a woody stem that no longer conducts water
sapwood
newly formed outer wood lying between the cambium and the heartwood of a tree or woody plant
bark
tree structure that includes all tissues outside the vascular cambium, including phloem, the cork cambium, and cork
blade
especially a leaf of grass or the broad portion of a leaf as distinct from the petiole
petiole
the slender stem that supports the blade of a leaf
mesophyll
The ground tissue of a leaf, sandwiched between the upper and lower epidermis and specialized for photosynthesis.
palisade cells
cells that are underneath the upper epidermis, Site of most photosynthesis (layer in cell)
spongy cells
located beneath the palisade cells also contain chloroplasts but more importantly they are the site of gas exchange
stoma
opening in the underside of a leaf that allows carbon dioxide and oxygen to diffuse into and out of the leaf
guard cell
Pairs of cells that surround stomata and control their opening and closing.
transpiration
the emission of water vapor from the leaves of plants
adhesion
the property of sticking together
capillary action
a phenomenon associated with surface tension and resulting in the elevation or depression of liquids in capillaries
pressure flow hypothesis
hypothesis that considers plants in terms of where they produce and use materials from photosynthesis