1. Introduction and Plant Anatomy Review Flashcards
main parts of plant anatomy
plant structure (primary and secondary growth) –> leaf structure –> stem structure –> root structure (monocots vs dicots)
physiology of plants are
angiosperms which can be either dicots vs monocots
Tomato (Solanum lycopersicum) is an example of a
dicot
Rhoeo (tradescantia spathacea) is an example of a
monocot
the morphology of a plant structure is its
external shape
diagram of a external shape of a plant shoot and root
page 2
what is the shoot of the plant and where is it found
the shoot of the plant is the leaf and stem and it is found above ground
what is the root of the plant and where is it found
the root of the plant is found below ground in the rhizosphere
leaf in plants can be either
simple leaf or compound leaf
parts of a simple leaf
node and internode
what is a node
those points on the stem at which leaves or buds arises
what is a internodes
the regions of the stem between the nodes
the upper surface of the leaf can be either the
adaxial surface or dorsal surface
parts of the upper surface of the leaf
midrib
leaf veins
lamina (blade)
leaf petiole
diagram of the upper surface of the leaf
page 3
what is a meristem
a collection of undifferentiated cells that can divide and become other specialized types of cells in the plant.
Meristem tissue is important because it allows for plants to grow and repair damaged tissue.
For example, the buds on the ends of leaves are the product of the meristem.
Leaf meristem is the
Leaf primordium / Growing point
Shoot apical meristem:
Shoot apex
Growing point
Axillary meristem:
Bud
Growing point
shoot apex is the
shoot apical meristem
dicots new leaves and roots
shoot apex - shoot apical meristem
and root apical meristem
monocots new leaves and roots
new leaves emerge from stem
shoot basal meristem (Intercalary meris
internal meristems:
Vascular cambium Pericycle
Pericycle cells function to support, protect, and functionally assist xylem and phloem cells
where is the bud or growing point on a plant
at the axillary meristem
where is the shoot apex or growing point on a plant
at the shoot apical meristem
where is the leaf primordium or growing point on the leaf
at the leaf meristem
root apical meristems are seen in
dicots
shoot basal meristem (intercalary meristem) is seen in
monocots
in monocots new leaves emerge from
the stem
cotyledon
first leaf or first pair of leaves produced by the embryo of a seed plant
the 3 levels of tissues in the leaf
leaf epidermis
stem epidermis
root epidermis
diagram of leaf structure anatomy
page 7 #1
leaf cross section diagram
page 7 #2
epidermis is
what covers the entire plant
protects the plant from infection and water loss
regulates gas exchange in plant cells
stomata
tiny openings on the epidermis of leaves
gaseous exchange and photosynthesis
controls transpiration rate by opening and closing
Despite their great diversity in form and size, all plants
carry out
physiological processes
As primary producers, plants convert
solar energy to chemical energy.
Being nonmotile, plants must
grow toward light, and they must have efficient vascular systems for movement of water, mineral nutrients, and photosynthetic products throughout the plant body.
Green land plants must also have mechanisms for avoiding desiccation
The major vegetative organ systems of seed plants are
the shoot and the root.
The shoot consists of two types of
organs:
stems and leaves.
Unlike animal development, plant growth is indeterminate because of the presence of
permanent meristem tissue at the shoot and root apices,
which gives rise to new tissues and organs during the
entire vegetative phase of the life cycle.
Lateral meristems (the vascular cambium and the cork cambium) produce growth in girth, or secondary growth
Lateral meristems (the vascular cambium and the cork cambium) produce
growth in girth, or secondary growth
Three major tissue systems are recognized:
dermal tissue
ground tissue and
vascular tissue.
Each of these tissues contains a variety of cell types specialized for different functions.
Plants are eukaryotes and have the typical eukaryotic
cell organization, consisting of
nucleus and cytoplasm.
The nuclear genome directs the growth and development of
the organism.
The cytoplasm is enclosed by a plasma membrane and contains numerous membrane-enclosed organelles, including plastids, mitochondria, microbodies, oleosomes, and a large central vacuole.
Chloroplasts and mitochondria are semiautonomous organelles that contain their own DNA.
Nevertheless, most of their proteins are encoded by nuclear DNA and are imported from the cytosol
The nuclear genome of plans directs
the growth and development of the organism.
The cytoplasm in plants is enclosed by
a plasma membrane and contains numerous membrane-enclosed organelles, including plastids, mitochondria, microbodies, oleosomes, and a large central vacuole.
which are semiautonomous organelles that contain their own DNA.
Chloroplasts and mitochondria
most of plant proteins are encoded by
nuclear DNA and are imported from the cytosol
The cytoskeletal components—microtubules, microfilaments, and intermediate filaments—participate in a variety of processes involving
intracellular movements, such as
mitosis
cytoplasmic streamin
secretory vesicle transport
cell plate formation
cellulose microfibril deposition.
The cytoskeletal components are
microtubules, microfilaments, and intermediate filaments
The process by which cells reproduce is called
the cell cycle.
The cell cycle consists of
the G1, S, G2, and M phases.
The transition from one phase to another in the cells cycle is regulated by
cyclin-dependent protein kinases.
CDKs
The activity of the CDKs in the cell cycle is regulated by
cyclins and by protein phosphorylation.
During cytokinesis, the phragmoplast gives rise to
the cell plate in a multistep process that involves vesicle fusion.
After cytokinesis,
primary cell walls are deposited.
The cytosol of adjacent cells is continuous through the cell walls because of
the presence of membrane-lined channels called plasmodesmata, which play a role in cell–cell communication
cells are the basic building blocks that define
plant structure.
As Earth’s primary producers, green plants are the ultimate solar collectors. They harvest the energy of sunlight by
converting light energy to chemical energy, which they store in bonds formed when they synthesize carbohydrates from carbon dioxide and water
Terrestrial plants are structurally reinforced to support their mass as they
grow toward sunlight against the pull of gravity
Terrestrial plants lose water continuously by evaporation and have evolved mechanisms for avoiding
desiccation
The primary function of a leaf is
photosynthesis,
the plant stem is support, and that the root is
anchorage and absorption of water and minerals.
There are two categories of seed plants:
gymnosperms - less advanced, 700 species known
The largest group of gymnosperms is the
conifers (“cone-bearers”), which include such commercially
important forest trees as pine, fir, spruce, and redwood.
Angiosperms, the more advanced type of seed plant,
first became abundant during the Cretaceous period, about
100 million years ago.
Today, they dominate the landscape,
easily out competing the gymnosperms.
About 250,000 species are knownThe major innovation of the angiosperms is the
flower; hence they are referred to as flowering plants
The major innovation of the angiosperms is the
flower; hence they are referred to as flowering plants
A fundamental difference between plants and animals is
that each plant cell is
is surrounded by a rigid cell wall.
In animals, embryonic cells can migrate from one location to
another, resulting in the development of tissues and organs
containing cells that originated in different parts of the
organism.
In plants, such cell migrations are prevented because
each walled cell and its neighbor are cemented together by
a middle lamella. As a consequence, plant development unlike animal development, depends solely on patterns of
cell division and cell enlargement.
Plant cells have two types of walls:
primary and secondary
Primary cell walls are typically thin (less than 1 µm) and are characteristic of young, growing cells.
Secondary cell walls are thicker and stronger than primary walls and are deposited when most cell enlargement has ended.
Secondary cell walls owe their strength
and toughness to
lignin, a brittle, gluelike material
The evolution of lignified secondary cell walls provided
plants with the structural reinforcement necessary to grow
vertically above the soil and to colonize the land.
Bryophytes, which lack lignified cell walls, are unable to
grow more than a few centimeters above the ground
The evolution of lignified secondary cell walls provided
plants with
the structural reinforcement necessary to grow
vertically above the soil and to colonize the land.
Bryophytes, which lack lignified cell walls, are unable to
grow more than a few centimeters above the ground
Plant growth is concentrated in localized regions of cell
division called
meristems.
Nearly all nuclear divisions (mitosis) and cell divisions (cytokinesis) in plants occur in
meristematic regions.
In a young plant, the most active meristems are called
apical meristems; they are located at the tips of the stem and the root
apical meristems are located at
the tips of the stem and the root
At the nodes, axillary buds contain
the apical meristems for branch shoots.
Lateral roots arise from the
pericycle, an internal meristematic tissue
Proximal to (i.e., next to) and overlapping the meristematic regions are
zones of cell elongation in which cells increase dramatically
in length and width.
Cells usually differentiate into specialized types after they
elongate.
upper epidermis
found directly below the cuticle.
helps protect the leaf by aiding in preventing water loss and providing an extra layer between the outside and inside of the leaf
palisade mesophyll layer is
where most of the photosynthesis occurs in the leaf.
The palisade cells contain a lot of chloroplasts to help them perform this photosynthesis.
The palisade cells are closely packed together to maximize light absorption.
The spongy mesophyll’s function is to
allow for the interchange of gases (CO^2) that are needed for photosynthesis.
The spongy mesophyll cells are less likely to go through photosynthesis than those in the palisade mesophyll.
xylem function
Xylem moves water from the roots upward to the leaves or shoots to be used in photosynthesis
also delivers dissolved minerals and growth factors to cells through passive transport.
Support - Xylem provides structure and support in stems and branches and is the main component of wood.
Phloem is the vascular plant tissue responsible for
the transport and distribution of sugars produced by the photosynthesis
The lower epidermis of a leaf contains
stomata and guard cells that allow carbon dioxide to enter the leaf, and oxygen and excess water to exit the leaf.
stomata
Stomata allow for gas exchange to occur, mainly carbon dioxide to enter the plant to make food molecules such as glucose and for oxygen to be released by the plant.
It also allows water vapor to escape the plant via transpiration which is a necessary evil.
Plants need to open and close the stomata
guard cell function
Guard cells are cells surrounding each stoma.
They help to regulate the rate of transpiration by opening and closing the stomata.
Light is the main trigger for the opening or closing.
Each guard cell has a relatively thick and thinner cuticle on the pore-side and a thin one opposite it
diagram of the stomata
page 8
The phase of plant development that gives rise to new
organs and to the basic plant form is called
primary growth.
primary growth is the
phase of plant development that gives rise to new
organs and to the basic plant form
where new tissue is created through cell division and expansion
Primary growth results from the activity of apical
meristems, in which cell division is followed by progressive cell enlargement, typically elongation. After elongation in a given region is complete,
secondary growth may occur.
secondary growth uses
cell division and expansion to thicken tissue that is already present
Secondary growth involves two lateral meristems:
the vascular cambium (plural cambia) and the cork cambium.
The vascular cambium gives rise to secondary xylem
(wood) and secondary phloem.
The cork cambium produces the periderm, consisting mainly of cork cells
vascular cambium is the meristem to allow
lateral expansion
cork cambium is the meristem found in some plants that form a
protective peridem (bark)
diagram of a stem
page 9 #1
diagram of a stem cross section primary growth
page 9 #2
diagram of a stem cross section secondary growth
page 10
diagram stem longitudinal section
page 11 #1
diagram xylem tracheids
page 11 #2
simple pits are
porous regions including pit pairs and pit membranes
diagram xylem vessel elements
page 12 #1
diagram phloem sieve tube elements
page 12 #2
diagram of a root
page 13 #1
diagram of a root cross section
page 13 #2
