PLANT STEM Flashcards
groups within magnoliophyta
basal angiosperms
eudicots
monocots
2 types of plant body
woody and herbaceous
cells with thin primary walls, active metabolically, most remain alive after they mature.
Parenchyma
specialized parenchyma (4) and definition
chlorenchyma - photosynthesis
glandular cells - secrete nectar fragrances mucilage resins oils
transfer cells - mediate short distance transpo of material
phloem - conducts nutrients over long distances
thin primary wall that becomes thickened in some areas
allows plasticity
collenchyma cells
collenchyma location
beneath epidermis supporting vascular bundles
has thick primary wall and a thick secondary wall that is lignified
elastic
dead at maturity
sclerenchyma
2 types of sclerenchyma
mechanical and conducting
sclerenchyma - fibers are long and flexible, sclerids are short, isodiametric, inflexible and brittle
mechanical
sclerenchyma - tracheary elements of xylem
conducting
stem area above the point where a leaf attaches
leaf axil
found in extreme tip of stem
terminal bud
arrangement of leaves on the stem so they do not shade each other
phyllotaxy
stem modification:
have especially long and thin internodes allowing dispersal of daughter plants.
stolon
stem modification:
short shoots that have thick, fleshy leaves.
bulbs
stem modification: vertical, thick stems that have thin, papery leaves.
corms
stem modification:
fleshy horizontal stems that allow a plant to spread underground.
rhizomes
stem modification:
horizontal like rhizomes, but they grow for only a short period and are mainly a means of storing nutrients.
tubers
function of axillary buds?
some develop into branches, etc
some stay dormant
If the apical meristem is killed axillary buds become active and replace it.
primary tissues:
outermost surface of a herbaceous stem
A single layer of parenchyma cells.
epidermis
where interchange of material between a plant and its environment occurs
epidermis
coating of outer walls of epidermis
cutin / cuticle
stomata
prevents dessication and prevents gas exchange
how do guard cells swell
absorb water
time of opening / closing of stomata
Remain closed after sunset or during periods of water stress.
Some epidermal cells elongate outward and become
trichomes
trichomes function
Deter herbivory.
Minimize water loss.
Protect for over exposure to sunlight.
primary tissue: Often homogenous, composed of photosynthetic parenchyma and sometimes collenchyma.
cortex
loosely packed cortex with large intercellular spaces
aerenchyma
primary tissue:responsible for the conduction of materials throughout the plant.
vascular tissues
vascular tissues (2) and definition
− Xylem conducts water and minerals.
− Phloem distributes sugars and minerals.
vascular tissue dead and hollow at maturity
xylem
vascular tissue alive at maturity
phloem
consists of tracheids and vessel elements collectively referred to as tracheary elements
xylem
water moves between tracheids through
pit membranes
form between vertically stacked vessel elements
perforations
only angiosperms have tracheids t/f?
t
conifers have only tracheids t/f
t
has two types of conducting cells: sieve cells and sieve tube members, collectively called sieve element
phloem
sieve cell shape?
elongated and tapered
sieve tube member morphology
sieve plates on each end-wall, they align vertically to form a sieve tube
only angiosperms have sieve tubes t/f
true
sieve tube members are controlled by ____ which are involved in loading sugars. they have prominent nucleus and dense cytoplasm filled with ribosomes.
companion cells
vascular bundle arrangement in monocot
distributed as a complex network
vascular bundle arrangement in eudicot
arranged in a ring surrounding the pith
a central region of parenchyma similar to the cortex
pith
difference of apical and subapical meristem
apical meristem - found at tips, where cells retain their ability to divide, expanding daughter cells push the apical meristem up, subapical meristem contain cells dividing and growing producing cells from the region below.
epidermal cells that are in the early stages of differentiation
protoderm
Young xylem and phloem cells
provascular tissues
The equivalent stages of pith and cortex
ground meristem
the growth and tissue formation that results from apical meristem activity.
primary growth
