LESSON 10: Plant Anatomy Flashcards
How do plants talk to each other?
- Through the air
-through the soil
Airbone chemicals
Plants rely on airborne chemicals to get messages from one part of a plant to another
Messages through soil
Plants can rely on sending messages through soil
-Plants have a symbiotic relationship with fungi
-fungi have networks to seperate plants whcih act like highways for chemcial messages
Plant cells
-are basic building blocks
Can specialize in form and function
-By working together, forming tissues, they can support each other and survive
Level of orginzation
-Atoms > Molecules > Cells > Tissues > Organs > Plant > Population
Plant vs, Animal cells
Plant + Animal:
- Cytoplasma
-Nucules
-Cell membrane
-mitochondria
Differences:
Plant:
-chlroplast
-Cell wall
-vacoule
Plant Cells and Tissues: Meristematic
-These cell are all developed from unspecialized cells called meristematic cells
-These are similar to stem cells in animals
-Active through the life of the plant
Where are Meristematic cells found?
-The growing tips of their roots and leaves
- A special layer of their stem called the cambium
Plant Cells and Tissues: Epidermal Tissues
These cells and tissues can be found on the exterior of the plant
–Clear and very thin layer of cells
Function of Epidermal tissue
These cells form a protective outer covering
-Allows for exchange of materials and gasses in and out of the cell
Example of epidermal tissue
Specialized guard cells form a pore
-The pore is called the stomata
Allows for exchange of CO2, H20 vapour, and O2
Plant Cells and Tissues: Ground Tissue
This tissue makes up the majority of the plant
The function will be different depending on where it is in the plant
Examples of ground tissue
-Ex: in the roots ground tissue is involved in food and water storage
-EX: in the leaves it is involved in photosynthesis and gas exchange
Called the mesophyll
-EX: in the stem it provides strength and support
Plant Cells and Tissues: Vascular Tissue
Transports water and nutrients throughout the plant
What are the two types of vascular tissue?
Xylem and Phloem
Xylem
-Xylem: responsible for the movement of water and minerals from the roots up to the stem and to the leaves (one way flow only of water and minerals)
Phloem
-Phloem: transports sugar produced in photosynthesis from leaves to other parts of the plant (two way flow of food and water)
Plant Cells and Tissues: Xylem vs. Phloem
Xylem cells are DEAD!
-They are hollow cells and consist only of cell wall
-These cells transports water and dissolved minerals
Phloem cells are ALIVE!
-However, they lack nucleus and organelles
-These are the cells that transport organic materials (sugars)
Plant Organs: Roots
Roots are made up of epidermal, ground and vascular tissue
Functions of roots?
-Anchorage
-Absorption of water & dissolved minerals
-Storage (surplus sugars, starch)
-Conduction water/nutrients
Plant Organs: Stems
This organ is above-ground usually
This organ is also made of a combination of epidermal, ground, and vascular tissue
function of stems?
It serves many functions including:
-Support of leaves and fruits
-Transportation of water and sugars throughout plant (xylem and phloem)
Dicot and Monocot
There are more than one type of stem:
Monocot stems are circular shaped with lateral branches, they are bounded with a layer of dermis
-Dicot stems have a well defined epidermis with cuticle (layer of dermis with multicellular stem hair)
Woody stem and green stems
-Woody plants produce a hard woody stem above the ground
-Herbaceous plants produce soft flexible green stems above the ground
Plant Organs: Leaves
The leaf is the ‘Photosynthetic factories’ of the plant
The leaf is also made of epidermal, ground and vascular tissue
-This means its major function is to perform photosynthesis which produces food for the whole plant
Photosynthesis can be represented by the word equation below:
Carbon dioxide + water 🡪 sugars (i.e. glucose) + oxygen (and sunlight energy)
6CO2 + 6H2O 🡪 C6H12O6 + 6O2
Uses of vascular, epidermal and ground tissue in leaves?
The epidermal tissue of the leaf is a transparent protective layer
-May include a waxy cuticle and stomata with guard cells for gas exchange
The ground tissue, called mesophyll, performs photosynthesis and is spongy to allow for gas exchange
The vascular tissue is made of both xylem and phloem are for transportation of materials
Uses of vascular, epidermal and ground tissue in Stems
The epidermal tissue of the stem provides protection
-This may include the production of a waxy cuticle to prevent water loss or trichome hairs for protection
The ground tissue is there for support, storage of materials and photosynthesis if green
The vascular tissue is made of both xylem and phloem are for transportation of materials
Uses of vascular, epidermal and ground tissue in Roots
Dermal tissue covers and protects the plant
-Ground tissue serves as a site for photosynthesis, provides support for vascular tissue, and helps to store water & sugars
-Vascular tissue transports water, minerals, and sugars to other parts of the plant
The root epidermal tissue is there for protection and absorption of water
-It also has root hairs that increase the surface area
The root ground tissue is there to provide support and store sugars, starches and other substances
The vascular tissue is made of both xylem and phloem are for transportation of materials
chloroplast
an organelle found in large
numbers in many plant cells; the site of
photosynthesis within a plant cell
photopigment
a pigment that undergoes
a physical or chemical change in the
presence of light
blade
the fl at part of a leaf
petiole
the stalk that attaches the leaf
blade to the plant stem
venation
the arrangement of veins within
a leaf
mesophyll
the photosynthetic middle layer
of cells in the leaf of a terrestrial plant
palisade mesophyll
the layer of
elongated photosynthetic cells arranged in
columns under the upper surface of a leaf
on a terrestrial plant; part of the mesophyll
spongy mesophyll
the layer of loosely
packed photosynthetic cells with large air
spaces between them under the lower
surface of a leaf on a terrestrial plant; part
of the mesophyll
stoma
a small opening in the epidermis
of a plant that allows gas exchange
guard cell
one of two kidney-shaped
cells that control the opening and closing
of a stoma
aerenchyma
tissue composed of loosely packed parenchyma cells with large pores;
found in aquatic plants
meristematic tissue (meristem)
tissue consisting of dividing undifferentiated cells
(meristematic cells) found in areas of the
plant where growth can take place
vascular bundle
the arrangement of
vascular tissue that consists of xylem and
phloem
Function of stems:
raises and supports leaves and reproductive
-connects vascular tissue in the vascular levaes to the vascular tissue in the roots
-Raises up for sunlight exposure
-Rasing flower and cone for a good place for pollination and production of seeds
TRUE OR FLASE: Woody stems do not carry out photosynthesis
TRUE
vascular cambium
the meristematic cell
layer in vascular tissue
bark
the protective outermost layer of the
stems and roots of woody plants; consists
of phloem, cork cambium, and cork
cork cambium
the meristematic layer in
a woody plant that produces cork
Sapwood
the younger xylem through which water and minerals are transported to the leaves.
two types of xylem cells
Trachied and vessell elements
tracheid
an elongated, tapered xylem
cell with thick cell walls containing small
pits; tracheids overlap one another at the
ends to form continuous tubes from root
to shoot
vessel element
a shorter, blunt-ended
xylem cell with thick cell walls containing
small pits; vessel elements are stacked
end to end to form vessel tubes that run
from root to shoot
perforation plate
the perforated end wall
of a vessel element
sieve cell
a phloem cell with pores in
its cell walls; contains all necessary cell
organelles
sieve tube element
a phloem cell with
pores in its side cell walls and a sieve
plate at the end walls; sieve tube elements
lack organelles and depend on associated
companion cells
sieve plate
the perforated end wall of a
sieve tube element
companion cell
a small, nucleated
phloem cell that is always associated with
a sieve tube element
Three types of phloem cells found in vascular plants
Sieve cells,sieve tub elemetn and sieve plate
in gymnosperms usually xylem tissue
tracheids is found
in gymnosperms usually pholem tissue
sieve cells
in angiosperms usually pholem tissue
sieve tube elements
companion cells
in angiosperms usually xylem tissue
tracheids
vessel elements
Humans use stems for..
-food
-medication
-fuel
two basic systems for roots
Taproot system
Fibourous root system
taproot system
a root system composed
of a large, thick root; can have smaller
lateral roots
lateral root
a smaller root that branches
from a larger root
root hair
a microscopic extension of the
epidermal cells of the root
fi brous root system
a root system made
up of many small, branching roots
root cap
the mass of cells that form a
protective covering for the meristem at the
root tip
root cortex
a region of parenchyma cells
under the epidermis of a root
endodermis
the innermost layer of cells
in the cortex of a root
Casparian strip
the wax-like strip
that runs through the cell wall of an
endodermal cell
vascular cylinder
the central portion of
a root that contains the xylem and the
phloem
Transport of water and nutrients into the root happens by two diff erent processes:
water enters the root cells by osmosis,
nutrients enter by active transport
Transport in roots
-Water molecules therefore enter cells in the plant root by osmosis.
-The water molecules move toward the vascular cylinder
-use active transport to move nutrients from the soil water into the root cells.
-they are moved through the cells of the cortex toward
the endodermis
-they encounter the
Casparian strip and have to pass through endoermal cells
-. Once
inside the vascular cylinder, nutrients are actively pumped across cell membranes into
the xylem.
root pressure
the osmotic force pushing
xylem sap upward in root vascular tissue
capillary action
the tendency of a liquid
to rise or fall because of attractive forces
between the liquid molecules
Transportation into stems:
-Once water molecules and dissolved nutrients have crossed the Casparian strip, the
liquid they form is called xylem sap
-root pressure and capiliary action help rise xylen sap upwards
-xylem sap moves through xylem tubes
Transport to leaves
- leaves bring xylem sap to the top of a tree
-plant releases water vapour through their stomata during transeriation, this makes water coloum move
transpiration
evaporation of water
through the stomata of plant leaves
source
a plant cell with a high
concentration of sugars and other solutes,
such as a leaf cell
sink
a plant cell with a low concentration
of sugars; sugars may be converted to
starch for storage or used rapidly for
energy or as building blocks of other
carbohydrates
Sugars are actively transported from..
Sugars are actively transported from source to sink in the phloem.
Phloem sap moves along…
the phloem tubes as a result of a pressure
difference between source cells and sink cells.
Movement of fluid in the xylem is always
upward
Movement
in the phloem can be
upward or downward
