Chapter 34: The Plant Body
adventitious roots
"arriving from outside"; the roots of a typical monocot; form a fibrous root system composed of numerous thin roots; have large surface areas for the absorption of water and minerals
node, internode, axillary buds
Each phytomer in the shoot consists of a _____ carrying one or more leaves; an ______, which is teh interval of stem between two nodes; and one or more _____ ____, each of which forms the angle where a leaf meets the stem.
threes, fours, fives
Monocot flowers have parts that occur in _____; eudicots have floral parts that occur in ______ or ______.
radicle
embryonic root from which angiosperm root systems develop
stomatal guard cells
epidermal cell that form stomata for gas exchange in leaves
trichomes
epidermal cell; leaf hairs that provide protection against insects and damaging solar radiation
root hairs
epidermal cells that greatly increase root surface area
secondary cell wall
forms in some plant cells when cell expansion stops; internal to primary cell wall
collenchyma
ground tissue system cells resemble parenchyme cells that have been modified to provide flexible support
sclerenchyma
ground tissue system cells that have thickened secondary walls that enable the cells to perform their major function: support
middle lamella
ground tissue system layer of pectin that cements adjacent plant cells together
parenchyma
ground tissue system most common cell type in plants; have large vacuoles and thin walls consisting of a primary wall and the shared middle lamella
primary growth
growth characterized by cell division followed by cell enlargement results in proliferation and lengthening of shoots and roots
determinate
growth that ceases when the adult state is reached; occurs in animals
secondary growth
growth that increases plant sickness; usually in woody plants
growth
increase in body size
vessel elements
individual cells that are a water-conducting system made up of vessels in flowering plants
cotyledon
leaf in the embryo; monocots only have one, whereas eudicots have two
lignin
major component of wood; complex, carbon-containing polymer that forms a hydrophobic matrix; strong, waterproof, and resistant to digestion by animals; second most abundant polymer on earth
apical meristems
meristems found at the tips of shoots and roots and allow plants to continue growing throughout their lives
floral meristems
meristems that develop into flowers
primary meristems
meristems that give rise to the three major tissue systems; meristems that produce the tissues of the primary plant body
vegetative meristems
meristems that give rise to vegetative tissue; also known as shoot apical meristems
inflorescence meristems
meristems that help the transformation of shoot apical meristems
lateral meristems
meristems that orchestrate secondary growth
inderterminate
open-ended growth; lifelong process growth of shoots and roots in plants
epidermis
outer covering of a plant
stems
part of shoot system that hold and display the leaves to the sun and provide connections for the transport of materials between roots and leaves
shoot system
plant organ system consists of the stems, leaves, and flowers
root system
plant organ system that anchors the plant in place, absorbs water and dissolved minerals, and stores the products of photosynthesis from the shoot system
stomata
pores in leaves
taproot
primary root that extends downward by tip growth and outward by initiating lateral roots; form taproot system
cuticle
protective extracellular layer secreted by epidermal cells; made up of cutin, a complex mixture of waxes, and cell wall polysaccharides
root cap
protects the delicate delicate growing region of the root as it pushes through the soil
meristems
regions of undifferentiated cells where cell division occurs; like stem cells in animals to replace tissues lost through damage or apoptosis
phytomers
repeating modules that make up shoots and roots
prop roots
roots that support aboveground growth
sources
sites of production of carbohydrates
sinks
sites of utilization or storage of carbs formed by sources
companion cells
specialized parenchyma cells that retain all their organelles and function as "life support systems" for the sieve tube elements
tracheids
spindle-shaped; major cell type in the wood of gymnosperms
determination
the commitment of cells to their ultimate fates
terminal bud
the end of a stem or branch that is distinguished from the axillary buds
cortex
the ground meristem gives rise to the region of ground tissue that is many cells thick and internal to the epidermis
endodermis
the innermost layer of the cortex; control the movement of water and dissolved mineral ions into and out of the vascular tissue system
morphogenesis
the organization of cells into tissues and organs
mesophyll
the photosynthetic parenchyma tissue in leaves; can form an upper layer (palisade) and lower layer (spongy)
tonoplast
the vacuolar membrane
primary cell wall
the wall of a growing plant cell
dermal, ground, and vascular
three tissue systems of plants
dermal tissue system
tissue system that forms the epidermis of a plant and usually consists of a single cell layer
vascular tissue system
tissue system that provides the pant's plumbing, or transport system; composed of xylem and phloem
root system and shoot system
two systems of plant organs
fibers
type of sclerenchyma cells that are often organized into bundles and provide relatively rigid support to wood, bark, and other parts of the plant
sclereids
type of sclerenchyma cells that pack together densely, as in a nut's shell or some seed coats
stele
vascular cylinder within the endodermis
xylem
vascular tissue system; distributes water and mineral ions taken up by the roots to all the cells of the stems and leaves
phloem
vascular tissue system; performs a variety of functions, including transport, support, and storage; transports carbs away from sources
pericycle
within the endodermis; consists of one or more layers of relatively undifferentiated cells; has the tissue within which lateral roots arise, contributes to secondary growth, and contain membrane transport proteins that export nutrient ions into the cells of the xylem
central vacuole
account for up to 90% of a cell's volume; single watery sac in mature plant cells containing a high concentration of solutes, including enzymes, amino acids, and sugars produced by photosynthesis
bark
all the tissues external to the vascular cambium
ground tissue system
all tissue lying between the dermal tissue and the vascular tissue in both shoots and roots; makes up most of the plant body
bud
an undeveloped shoot that can develop further to produce another leaf, a phytomer, a flower, or a flowering stem
root apical meristem
at the other end of the axis; contains undifferentiated cells that will continue to divide to give rise to the organs that will develop during the life of the plant
shoot apical meristem
between the cotyledons in shoots; contains undifferentiated cells that will continue to divide to give rise to the organs that will develop during the life of the plant
leaf primordia
bulges that develop on the sides of the shoot apical meristem at regular intervals
cork cambium
cambium that produces mainly waxy-walled protective cells; supplies some of the cells taht become barkwood
differentiation
cell specialization
initials
cells that perpetuate the meristems
sieve tube elements
characteristic cells of the phloem in flowering plants
leaves
chief organs of photosynthesis; part of shoot system
wood
complete cylinder of secondary xylem
tracheary elements
conducting cells in xylem tissue that have secondary cell walls and undergo apoptosis before assuming their function of transporting water and dissolved materials; contains tracheids and vessel elements
vascular bundles
contains both xylem and phloem; scattered in monocots, forms a cylinder in eudicots
vascular cambium
cylindrical layer of tissue consisting predominantly of elongated cells that divide frequenctly
periderm
dermal tissue developed by the stems and roots of woody plants