Astolot Educational Centre – Alisa Miller – SNC2D
4.1 Systems in Plants (focus on flowering plants)
Pg. 125 – 128
•
•
•
Plants have two obvious distinguishing features:
o They are typically green in colour – caused by chlorophyll (used to
photosynthesize)
o They cannot move from place to place – they have structures
(usually roots) to anchor in place
Plants perform photosynthesis to make their own food
o They do not need to move around to search for food
o They do not need the complex organ systems that animals have
Plants do have to perform many of the same functions as animals:
o Exchange gas with their surroundings
o They require an internal transport system to move water and
nutrients around their bodies
o Reproduce
Hierarchy of Organization in the Plant Body
• The flowering plant body has two main body systems:
o The root system
! Made up of one or more separate roots
o The shoot system
! Consists of the stem, leaves, and flowers
! These are sometimes called the plant’s organs
• Plant parts are made up of a wide variety of specialized cells
o Like in animals, groups of specialized cells are called tissues
• Three main types of tissue systems:
o Dermal tissue system – the tissues covering the outer surface of the
plant
o Vascular tissue system – the tissues responsible for conducting
materials within a plant
o Ground tissue system – all plant tissues other than those that make
up the dermal and vascular tissue systems
The Root System
• Root system – the system in a flowering plant, fern, or conifer that anchors
the plant, absorbs water and minerals, and stores food
• Usually grows below ground, but can appear above ground or above
water
• The root system can spread underground to cover a large area
• Some roots are specialized for nutrient storage
o E.g. radishes and carrots
• Roots are a useful source of foods (sweet potatoes, carrots, sugar beet),
flavourings (liquorice, ginger), and natural remedies
Astolot Educational Centre – Alisa Miller – SNC2D
The Shoot System
• Shoot system – the system in a flowering plant that is specialized to
conduct photosynthesis and reproduce sexually
o It consists of the leaf, the flower, the stem
The Leaf
• The main photosynthetic structure of the plant
• In photosynthesis, tissues in the leaf use carbon dioxide (CO2), water, and
light energy to produce glucose (a sugar) and oxygen
o Glucose is used for plant growth, cellular respiration, and energy
storage)
o Light energy + carbon dioxide + water " glucose +oxygen
• The cell structure that actually performs photosynthesis is an organelle
called a chloroplast
o Contain flat, disc-like structures called thylakoids
o Thylakoids are arranged into stacks called grana
o These stacks collect sunlight
• Some leaves are adapted for support, protection (e.g. thorns),
reproduction, and attraction
• Many leaves are edible (e.g. lettuce, spinach, onion, tea, and herbs), or
sources of waxes and medicines
The Flower
• Specialized structures developed for sexual reproduction
o Contain male or female reproductive structures, sometimes both
• Male reproductive structures produce pollen grains, and female
reproductive structures produce eggs
o Eggs are fertilized by pollen
o After pollination, the female flower parts form seeds
o In most flowering plants, the seeds are contained within a
specialized structure called a fruit
• Pollination occurs with the help of wind or animals
o Flowering plants like grasses and many tree species are wind
pollinated
! The flowers are small and not colourful, but produce a lot of
pollen
o Others are pollinated by animals like insects, bats, and birds
! They have large colourful and fragrant flowers to attract
pollinators
! Most also produce nectar
Astolot Educational Centre – Alisa Miller – SNC2D
The Stem
• The stem (or trunk, for trees) supports the branches leaves, and flowers,
and provides a way to transport materials
• Contains a lot of vascular tissue for carrying substances to and from roots,
leaves, flowers, and fruits
• Some are specialized for food storage, protection, photosynthesis, and
reproduction
• Provide us with sugar cane, potatoes, wood and paper products, cork,
linen, and some medicines
4.2 Plant Tissue Systems
Pg. 129 – 133
Cellular Differentiation and Specialization in Plants
• When a seed starts to grow, the cells divide very quickly
o As the seed develops into an embryo, many cells differentiate into
specific tissues
o The region of growth are at the tips of plant roots and shoots
o Plants with woody stems, such as trees, also have a region of growth
just below the surface of their stems
Meristematic Cells
• Just like animals have unspecialized cells called stem cells, plants have
unspecialized cells called meristematic cells
o Can differentiate into specialized tissue types
• As cells in the meristem regions continue to divide, some of the new cells
always remain in the undifferentiated state
Tissue Systems in Plants
3 major tissue systems:
o Dermal tissues cover the entire outer surface of the plant but do not
occur within the plant
o Vascular tissues are found within every root, shoot, and leaf of the
plant
o Ground tissues account for all other internal tissues in the root, stem,
and leaves
Dermal Tissue System
• Forms the outer layers of a plant
o Includes both epidermal and periderm tissues
• Epidermal tissue (epidermis) – a thin layer of cells covering all non-woody
surfaces of the plant
• Periderm tissue – tissue on the surface of a plant that produces bark on
stems and roots
•
Astolot Educational Centre – Alisa Miller – SNC2D
Vascular Tissue System
• A plant must obtain water and minerals from the soil
o Absorbed by the plant’s roots
• The vascular tissue system is the transportation system that moves water,
minerals, and other chemicals around the plant
• 2 types:
• Xylem – vascular tissue in plants that transports water and dissolved
minerals from the roots to the leaves and stems of the plant
o Made up of elongated cells
o Hollow tubes with rigid walls – they have no cytoplasm, nucleus or
other organelles, which allows water to move easily through the
tubes
o Mature xylem cells are not living tissue
• Phloem – vascular tissue in plants that transports dissolved food materials
and hormones throughout the plant
o Made up of elongated cells
o Mature cells are alive
Ground Tissue System
• Most of the cells of young plants are ground tissue cells
• They are the filler between the dermal and vascular tissues
• Perform a variety of functions:
o In the green parts of the plant, they manufacture nutrients by the
process of photosynthesis
o In the roots, they store carbohydrates
o In the stems, they provide storage and support
Homework
-Read 4.1 Systems in Plants, Pg. 125 – 128
-Complete Plant Body System Tree Diagram
-Pg. 128 #3, 4, 5
-Read 4.2 Plant Tissue Systems, Pg. 129 – 133
-Pg. 133 #2, 3