Biology Ch. 33: Vegetative Organs of the Vascular Plant Body Flashcards
primary growth
growth that occurs due to apical meristems
apical meristem
clumps of self-perpetuating tissue at the tips of their buds, stems, and roots
zone of cell division
root apical meristem and the actively dividing cells behind it
merges into the zone of elongation
cells of apica meristem segregate into three primary meristems
-procambium
-ground meristem
-protoderm
zone of elongation
most of the increase in a root’s length comes about here as cells become longer as their vacuoles fill with water
-“hydraulic” elongation
zone of maturation
cells do not increase in length but they may differentiate further and take on specialized roles
taproot system
single main root adapted for storage
roots branch off the tap root
diameter increases as main root grows downward
fibrous root system
adapted to absorb water and nutrients from the upper layers of soil
spread out laterally from the base of the stem
hold topsoil in place and prevent erosion
casparian strip
found in root endodermal cells
impreganted with suberin
positioned like a band of packing material around the contents of a package
endodermis
thin, selectively permeable barrier that helps control the movement of water and dissolved minerals in the stele
has a casparian strip in its radial and transverse walls
pericycle
between the stele and endodermis
one or more layers of parenchyma cells that can still function as meristems
give rise to lateral roots
root primordium
rudimentary roots
arise at specific sites in the pericycle
give rise to lateral roots
vascular cylinder
also called the stele
runs vertically
pith inside, cortex outside
root cap
surrounds and protects the meristem as the root elongates through the soil
cap cells secrete a polysaccharide-rich substance that lubricates the tip and eases the root’s passage through the soil
root hair
trichomes
found in zone of maturation
found in epidermis
greatly increase the plant’s absorptive surface
slender tube with thin walls made sticky by a coating of pectin
prop roots
found in mangrove trees and corn
adventitious roots that develop from the shoot node nearest the soil surface
secondary tissue
tissues we know as wood and bark
secondary growth
woody layers of xylem and phloem
begin to grow once initial, primary plant body forms
add girth to roots and stems over two or more growing seasons
lateral meristem
produce secondary growth
vascular cambium
undifferentiated cells between the primary xylem and phloem that give rise to a cylinder of vascular cambium that encircles the xylem and pith of the stem
2 types of initials (dividing cells in a meristem)
-one produces secondary xylem and phloem
-the other produces rays
cork cambium
type of lateral meristem
produces cork, a secondary epidermis that is a major ingredient in bark
periderm
consists of cork, cork cambium, and secondary cortex
contain lenticels
-permit exchanges of oxygen and CO2 between the living tissues and outside air
bark
tissues sandwiched between the vascular cambium and the stem surface
-includes the secondary phloem and periderm
add girth to roots and stems over two or more growing seasons
“normal” functions of a root
anchoring into the substrate
absorbs water and dissolved minerals from soil
stores carbohydrates
provides structural support for a plant’s upright parts
how are storage roots modified?
larger, thicker
-single main root in a taproot system
how is a velamen root modified?
spongy, multiple epidermis that covers some roots, such as that of the orchid
helps absorb nutrients
protects roots
how are prop roots modified?
adventitious roots
help brace the plant
supply water and minerals when the radicle (embryonic root) dies
how is a pneumatophore modified?
specialized aerial roots that enable plants to breathe air in habitats that have waterlogged soil
be able to sketch a c.s. of a dicot root and a l.s. of a root tip
SKETCH
where do branch roots arise?
from the pericycle, which is between the stele and endodermis
shoot
the main stem or leaves
includes flowers in angiosperms
apical dominance
terminal buds release a hormone that inhibits the growth of nearby lateral buds
bud primordia
NO IDEA
leaf primordia
group of cells that will form into new flowers
bud, bud scale
bud scale
- modified. nonphotosynthetic leaves that form around the apical meristem and insulate it from the elements
- most cell metabolic activity shuts down and the leaf bud becomes dormant when this happens
- covers the terminal bud and embryonic leaves of a plant during winter
terminal bud
occurs at the apex of each stem
release a hormone that inhibits the growth of nearby lateral buds (apical dominance)
node
where one or more leaves attach to a stem (axillary bud attachment)
between stem and offshoot
-meristematic tissue is located there
internode
area between two nodes
internode cells below the apical meristem divide and elongate to grow
axil
upper angle between the stem and an attached leaf
pith
ground tissue (parenchyma) that is inside the stele
cortex
ground tissue that is outside the stele
vascular bundle
multistranded cords of primary xylem and phloem
wrapped or capped by sclerenchyma
thread lengthwise through the parenchyma, forming a stele
herbaceous
plants that show little or no significant woody tissue
term given to angiosperms
mature and reproduce quickly, with a relatively small investment of energy and other resources
lenticel
tubular openings that develop in periderm function lke snorkels, permitting exchanges of oxygen and CO2 between the living tissues and the outside air
leaf scar
found in ginkgophyta
called a spur shoot
left when an axillary bud begins to grow and produces leaves that don’t get very big and die in the winter
what are the “normal” functions of a stem?
make leaves
orient leaves
support leaves
transport
provide mechanical support for body parts involved in growth, photosynthesis, and reproduction
house the vascular tissues
often are modified to store water and food
have specific stem regions that contain meristematic tissue, which gives rise to new cells of the shoot
what are the “normal” function of a leaf?
photosynyhesis get C get energy hegulate water loss transport
tendril modification
leaf modification
help to support the climbing plant’s stem
tuber modification
stem modification
enlarged by the presence of starch-storing parenchyma cells
cladophyll
petioles become flattened and widened and the true leaves become reduced or vanish altogether
can be thick, allowing the plant to survive harsh conditions
rhizome
long underground stem that extend into the soil and rapidly produce new shoots when existing ones are pulled out
runner (stolon)
stem modification
slender stems which grow along soil surface
used for reproduction
strawberries
corm
stem modification
starch-storage adaptation
thorn
leaf adaptation
used for protection
bulb
stem modification
modified shoot that consists of a bud with fleshy leaves
starch storage
blade (lamina)
provides a large surface area for absorbing sunlight and carbon dioxide
petiole
where the blade narrows
attaches the leaf to a stem
stipules
outgrowths borne on either side of the base of a petiole
part of the anatomy of a typical flowering plant
-can be inconspicuous or entirely absent
simple leaf
one leaf per axillary bud
compound
more than one leaf per axillary bud
pinnate
leaves arranged along the main or mid-vein
palmate
leaves radiating from the end of the petiole
sessile
unable to move from one place to another
sheath
layer of cells that protects a meristem (radicle) as it grows
leaflet
in compuond leaves
name for the division of the blade
mesophyll
below epidermis in leaves
ground tissue composed of loosely packed parenchyma cells that contain chloroplasts
also contains collenchyma and sclerenchyma to support the leaf blade
palisade mesophyll
contain more chloroplasts and are arranged in compact columns with smaller air spaces between them
typically toward the upper leaf surface
spongy mesophyll
toward underside of leaf
irregularly arranged cells with a conspicuous network of air spaces that gives it a spongy appearance
veins
carry the xylem and phloem in leaves
bundle sheath
layer of cells that surrounds a vascular bundle
abscission zone
in deciduous trees
separation zone
formed at the base of the petiole
allows the leaf to be shed
succulent
plants having parts that are more than normally thickened or fleshy
usually to retain water
leaf modification water storage
succulent
-thick, fleshy leaf
leaf modificationfood storage
bulb is made of leaves
spine
defense against grazing by herbivores
cactus leaves
insect traps
found in areas where there is a shortage of nitrogen
hydrophyte vs. xerophyte vs. mesophyte
hydrophyte
-aquatic plants that have adapted to living in aquatic habitats
xerophyte
-plant that has adapted to live in an environment with little water
mesophyte
-terrestrial plants that are adapted to neither a wet or dry habitat
leaf scar vs. bud scale scar
leaf scar
-mark left by a leaf after it falls off
bud scale
-produced when the modified leaves (scales) that protect the bud fall off
alternate leaves vs. opposite leaves vs. whorled leaves
alternate -a single leaf attached at a node opposite -two leaves attached at a node -whorled -3 or more attached at a node
shoot primordia
created by apical meristem
bulges that are the first developmental stages of leaves, additional shoots, and reproductive structures such as flowers
what do tubers, rhizomes, and corms have in common?
meristematic tissue at nodes from which new plants can be propagated - vegetative (asexual) reproduction mode
