PLANTS – DAY 4
REPRODUCTIVE MECHANISMS
Transportation Worksheet Answers
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Which picture is showing net venation, and which is
showing parallel venation?
A.____NET__________ B. ____PARALLEL______
What is the major difference between a single leaf and a
compound leaf? Draw and label this difference.
Single leaf- have a single, undivided leaf blade
Compound leaf - have a blade divided into two or
more leaflets
Transportation Worksheet Answers
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Explain why most plants have stomata mainly on the
lower surface of their leaves.
Stomata are openings in the leaf that allow
oxygen to leave the plant and carbon dioxide to
go into the plant. They also allow water vapour
to escape from the plant when they are open.
When the sun is shining, plants want to keep as
much water as possible. If stomata are on the
underside of the leaf, less water vapour will
escape from the plant. These stomata are out of
direct sunlight.
Transportation Worksheet Answers
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Why are guard cells important to stomata?
They regulate the opening and closing of the stomata.
Without them, stomata would always be open and
carbon dioxide would continuously come in and water
vapour would continuously leave the plant –
photosynthesis would not occur regularly due to too
much/too little of needed reactants.
Predict the environment in which you would expect to find plants with several layers
of palisade mesophyll cells densely packed with chloroplasts. Explain why.
Lots of chloroplasts – must be a lot of sunlight because
chloroplasts are the site of photosynthesis. Perhaps an
open field, an environment in the tropics.
Transportation Worksheet Answers
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What is the difference between a taproot and a fibrous root?
Taproot – root systems where the primary root remains
predominant, though very small secondary roots are
present
fibrous root= root systems whose primary roots have
disintegrated and were replaced by other smaller roots.
Why are pneumatophores so important to certain plants?
Pneumatophores are roots that evolved to let plants survive
in waterlogged, oxygen-poor soils (swamp) environments.
These are special extensions which grow up and out of the
water and function to supply oxygen to the root tissues
below. Oxygen then diffuses into the plant parts that need
Transportation Worksheet Answers
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How does root pressure form within the root?
Root pressure is the culmination of water and
minerals, together called xylem sap, in the root.
Minerals get into the root by a process called
active transport, water follows by a process
called osmosis. This pressure pushed xylem sap
up the xylem tubes. However, this pressure can
only push the sap up the plant so far.
Transportation Worksheet Answers
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What does water transport in the xylem depend on within
the plant? Briefly describe each of these factors. Does
water transport within the plant require energy of any
kind?
-root pressure pushed water (xylem sap – mix of water
and minerals) into xylem
-water adheres to inner walls of xylem, creating a
pulling force on the column of water molecules
-water is cohesive and sticks together continously from
ground to top of the highest leaves
-transpiration pull pulls water up the stem to the leaves
Transportation Worksheet Answers
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Speculate why sugar maple trees demonstrate the
importance of plants to the growth of Canadian society.
Why is this xylem sap, better known as maple syrup, so
important to our society?
-economically: brings money into our society, means of
money for maple syrup producers, shop owners;
Canadian maple syrup renowned throughout the world
-socially: pancake dinners, shrove Tuesday, brunches,
used to have ‘syrup’ parties
NATURAL REPRODUCTION – SEED
PLANTS
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Seed plants are called spermatophytes, a
subdivision of vascular plants
Seed plants have roots, stems, and leaves exhibiting
a huge variety of textures, sizes, shapes odours and
colours; the most recently evolved plant group
Have reproductive structures that are NOT
dependent on water; all seeds ensure survival of
embryos by reducing excessive water loss
SEED PLANTS
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Seed plants have separate
male and female
gametophyte tissue
2 types of spermatophytes –
gymnosperms produce
unprotected “naked” seeds in
conelike structures (conifers)
and angiosperms produce
seeds that are enclosed and
protected inside a fruit,
formed by various flower
parts
We’ll look at angiosperms
ANGIOSPERM
ANATOMY
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Carpel: female part of flower
Stamen: male part of flower
Pollination occurs when pollen (contains sperm
cells)from anther goes to the stigma (wind/insects)
Self pollination - transfer of pollen from anther to
stigma on same flower
Cross pollination – transfer of pollen from anther
to stigma on different flowers
ANGIOSPERM REPRODUCTION
•Pollen grains travel down pollen
tube into an ovule in an ovary
•Fertilization occurs when pollen
grains (n) fuse with an egg (n) in the
ovule to form a diploid zygote
•Zygote grows by mitosis to form an
embryo, and the embryo remains
inside the ovule
•The ovule is called a SEED now
that there is an embryo inside the
ovule
SEED DEVELOPMENT
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While changes occur in the
seed, the ovary are
developing into a fruit,
which provides protection
for seeds and often helps
secure dispersal of the
seeds
As time goes by, mature
fruit falls; under suitable
conditions, fruit
decomposes, seed coat
splits, and germination
occurs – embryo grows
quickly and is called a
seedling
EMBRYO
SEED
GERMINATION OF SEEDS
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A seed consists of an
embryo, tissue to provide
nutrients for the embryo,
and a protective seed coat
A growing embryo slowly
forms a root and shoot
structure
Cotyledons often contain all
nutrients needed for embryo
OR there may be additional
nutrient-rich material called
endosperm
GERMINATION OF SEEDS
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When temperature and moisture
conditions are optimum, seeds
start to germinate
Seed and seed coat absorb
water, embryo grows rapidly
Seed coat ruptures and roots and
shoots emerge
Root absorbs water and nutrients
and grows downward, shoot
grows upward
Nutrients stored in endosperm
and/or cotyledons support
development until new plant has
enough root surface area
ARTIFICIAL PROPAGATION
A: CUTTINGS
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Artificial Propagation: is a method of asexual
propagation in which new plants are produced and
multiplied by the use of parts and buds of the selected
mother plants and employing several methods as
cuttings, layering, grafting and budding
Parts of plants are cut from a parent plant and
inserted into water, sand, soil-less mixes, or many
possible combinations thereof, where they form roots
and become new plants
Cuttings are classified either according to the plant
parts used - as roots, stems, or leaves
CUTTINGS
LEAF
CUTTING
ROOT CUTTING
STEM CUTTING
ARTIFICIAL PROPAGATION
B: GRAFTNG
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Grafting encompasses any process whereby a part
(called the scion) taken from one plant, is made to unite
with and grow upon another plant or part of a plant
(called the rootstock).
The scion may be a single bud, a piece of stem (as of a
cactus), or a fragment of root of a desirable variety.
The scion and stock are tied into place
Sealed with grafting wax, tape, or paraffin, to prevent
the evaporation of available moisture.
As the two parts of a graft grow together they are said
to form a "union".
To graft 2 organisms (plant), they must be of the same
genus
GRAFTING
SCION
ROOTSTOCK
DID YOU KNOW?
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John Macintosh discovered an apple tree in 1811in
Dundas County, Ontario- Macintosh apples!!
Mac seeds were saved and planted, but offspring
always were a disappointment – inferior apples
Scions from Mac tree attached to other root stocks from
different apple trees in 1835
All tissues, including the fruit, above the graft are
genetically identical to Mac tree, resulting trees
produced desired apples!
ALL Macintosh apples sold today come from grafts of
the original tree found