External and Internal Structure of Stem Flashcards
GENERAL FUNCTION OF
STEM
Provide pathways for the:
§ Movement of water and
dissolved minerals from the
roots into the leaves
§ Food synthesized in leaves
to move into roots
PRIMARY FUNCTION OF
STEM
§ Support and orient the leaves
§ Conduct water and minerals
§ Bear flowers and fruits
SECONDARY FUNCTION
OF STEM
§ Storage
§ Perennation
§ Vegetative propagation
§ Photosynthesis
§ Protection
§ Climbing
EXTERNAL STEM
MORPHOLOGY
area of a stem where a leaf
or leaves are attached
Node
EXTERNAL STEM
MORPHOLOGY
the stem region
between nodes
Internodes
EXTERNAL STEM
MORPHOLOGY
a structure that has
the potential to form a lateral shoot
or branch
Axillary bud
EXTERNAL STEM
MORPHOLOGY
aka: terminal bud, is
located near the shoot tip and
causes elongation of a young shoot
Apical bud
EXTERNAL STEM
MORPHOLOGY
helps to maintain
dormancy in most non-apical buds
Apical Dominance
EXTERNAL STEM
MORPHOLOGY
structure that
permits the passage of
gas inward and outward
Lenticels
EXTERNAL STEM
MORPHOLOGY
characteristic
scar on stem axis made
by leaf abscission
Leaf scar
EXTERNAL STEM
MORPHOLOGY
small
modified leaves for
protection from
desiccation
Bud scales
EXTERNAL STEM
MORPHOLOGY
a stem’s primary
growing point. It can
either be leaf buds or
flower buds.
Bud
EXTERNAL STEM
MORPHOLOGY
scars left
from the removal of bud
bud scar
EXTERNAL STEM
MORPHOLOGY
an
immature lead of the
shoot
Leaf primordium
EXTERNAL STEM
MORPHOLOGY
portion of the
internodes above the node and it is
made up of actively dividing cells
responsible for the elongation of the
monocot stem
Intercalary meristem
SHOOT APEX AND ITS
ORGANIZATION
The outer group consisting of one or
more peripheral cell layer is known as
the ______. These cells divide
perpendicular to the surface of the
shoot apex.
tunica
SHOOT APEX AND ITS
ORGANIZATION
The ______ lies below the tunica and
initially has a single layer of cells. Its cells divide perpendicular to the
surface of the shoot apex and parallel
to the surface of the shoot apex.
corpus
SHOOT APEX AND ITS
ORGANIZATION
A shoot apical meristem is a _____-____ mass of dividing cells at the
shoot tip
dome-shaped
SHOOT APEX AND ITS
ORGANIZATION
Leaves develop from leaf primordia
along the sides of the?
apical meristem
SHOOT APEX AND ITS
ORGANIZATION
This develop from
meristematic cells left at the bases of
leaf primordia
Axillary buds
SHOOT APEX AND ITS
ORGANIZATION
Primary Meristems:
: the outermost
layer of cells. It develops into
epidermis (a primary tissue
that covers and protects all
underlying tissues, prevents
excessive water loss and
allows exchange of gases
necessary
§ Protoderm
SHOOT APEX AND ITS
ORGANIZATION
Primary Meristems:
: comprises
the greater portion of
meristematic tissue of the
shoot tip.
§ Ground Meristem
SHOOT APEX AND ITS
ORGANIZATION
Primary Meristems:
§ Primary tissues forming the
ground meristem are:
: in the very center of
stem
§ Pith
SHOOT APEX AND ITS
ORGANIZATION
§ Primary tissues forming the
ground meristem are:
: in a cylinder just
beneath the epidermis and
surrounding the vascular
tissues. Sometimes pith
and cortex are connected
by pith rays
§ Cortex
SHOOT APEX AND ITS
ORGANIZATION
Primary Meristems:
give rise
to primary vascular tissues
namely: primary phloem and
primary xylem
Procambium cells
STEM ANATOMY
are perpetually
embryonic tissue and allow for
indeterminate growth
MERISTEMS
STEM ANATOMY
are
located at the tips of roots and
shoots and at the axillary buds of
shoots. Apical meristems
elongate shoots and roots, a
process called primary growth
APICAL MERISTEMS
STEM ANATOMY
§ Stems usually undergo primary
growth which results in the
formation of primary tissues.
These include the:
§ Epidermis
§ Ground tissue
§ Primary vascular tissues
(primary xylem and primary
phloem)
This term is
applied to the part of
the stem that includes
the primary vascular
tissues, pith and pith
rays. The primary
plant body is
composed of the
above primary
tissues.
stele
outermost single
layered, covered
with cuticle, bears
multicellular hairs,
and offers protective
function
epidermis
vascular tissues? (6 items)
§ Phloem
§ Vascular cambium
§ Xylem
§ Cortex
§ Pith
§ Pith rays
: conducts food
phloem
produces secondary phloem and secondary
xylem
vasculart cambium
conducts water and mineral salts, and gives strength to
stem
xylem
stores food and in young stems, manufactures food,
strengthen and protects
cortex
Stores food
pith
store food, conduct water, mineral salts and food
radically
pith rays
Secondary growth occurs in stems
and roots of woody plants but
rarely in?
leaves
The Secondary plant body consists
of the tissues produced by the
vascular cambium and cork
cambium. Secondary growth is
characteristic of __________ and
many edicts, nut not monocots.
gymnosperms
These tissue layers for the
PERIDERM
phellem
phellogen
pheloderm
The outermost layer of periderm, consisting of cork
cells.
phellem
immediately into the inner of perriderm, also known as the cork
cambium, consisting of
flattened dividing cells
phellogen
The third layer of periderm, few cell layers
in thickness
pheloderm
a cylinder of
meristematic cells one cell layer thick.
It develops from undifferentiated
parenchyma cells
vascular cambium
In _____ _______, the vascular
cambium appears as a ring of initials.
The initials increase the vascular
cambium’s circumference and add
secondary xylem to the inside and
secondary phloem to the outside.
cross section
this accumulates as
wood and consists of tracheid, vessel
elements (only in angiosperms) and
fibers
secondary xylem
formed in the spring, has
thin cell walls to maximize water
delivery
early wood
formed in late summer,
has thick-walled cells and contributes
more to stem support
late wood
In _________ ______, the vascular
cambium of perennials is dormant
through winter.
temperate regions
these are visible where late
and early wood meet, and can be
used to estimate a tree’s age
tree rings
the analysis
of tree ring growth patterns and can
be used to study past climate
change
Dendrochronology
As a tree or woody shrub ages, the
older layers of secondary xylem, the
_________, no longer transport water
and minerals.
heartwood
The outer layers, known as _______,
still transport materials through the
xylem
sapwood
Older secondary phloem _______ ___
and does not accumulate
sloughs off
gives rise to the
secondary plant body’s protective
covering, or periderm
cork cambium
consists of the cork
cambium plus the layers of cork cells it
produces
periderm
consists of all the
tissues external to the
vascular cambium, including
secondary phloem and
periderm
bark
in the periderm
allow for gas exchange
between living stem or root
cells and the outside air.
lenticels
A plant can grow throughout
its life; this is called
INTERMEDIATE GROWTH
Some plant organs cease to
grow at a certain size; this is
called
DETERMINATE
GROWTH
- complete their life
cycle in a year or
less
Ex: Cereals and Legumes
annuals
- require two
growing seasons
Ex: Onion and Carrots
biennials
live
for many years
Ex: Shrubs and Trees
perennials
SPECIALIZED STEMS
RHIZOME
RUNNERS AND STOLONS
TUBERS
BULBS
CORMS
CLADOPHYLLS/PHYLLOCLADE
TENDRILS
§ horizontal stems that grow below
ground with short internodes and
bears scale-like leaves.
§ Ex: ginger, cogon grass
rhizome
horizontal stems that grow
above ground, generally along the
surface.
Ex: strawberry
runners
like runners but are
produced beneath the surface of the
ground and tend to grow in different
directions but usually not horizontally.
Ex: potato
stolons
a thick under ground storage stem,
usually not upright bearing outer buds
but lack protective scales.
tubers
§ consist of small amount of vertical
stem and a massive quantity of thick,
fleshy storage leaves.
§ Most of them consist of concentric
rings of scales attached to a basal
plate
bulbs
§ resemble bulbs but differ from them in
being composed almost entirely of
stem tissue, except for a few papery,
scalelike leaves sparsely covering the
outside.
§ Consist of one or more internodes with
at least one growing point.
§ Formed from a swollen bases of
stems
corms
The entire shoot is flattened and leaf
like
CLADOPHYLLS/PHYLLOCLADE
These are specialized stems in grapes
but are modified leaves or leaf parts in
plants like peas and cucumbers
tendrils
a
stress-related disease that
affects sweet gum, oak, elm and
willow trees. The disease is
caused by a microorganism that
ferments the sap that seeps or
bleeds from cracks and wounds
in the bark. The result is a white,
frothy ooze that has a fermenting
odor similar to beer.
White Flux or Alcoholic flux
Filled with nutrients and
minerals, ___ is the blood of
a tree. It carries energy out into
the branches when new buds are
forming in spring-time.
sap
Because sap is like the engine that keeps nourishing
ingredients running throughout the tree, small amounts
of sap may ooze all year from pines. Usually that happens after
they’re ____, when they begin budding or as the seasons
change. Typically, you’ll see the most sap flow in spring and
early summer.
pruned
The pine produces excessive amounts of sap to protect itself against
the?
bark beetle