Download 1.1 We study a flower Task Additional Information

Science - Biology - General Biology - 1 We study plants and
animals (P8010000)
1.1 We study a flower
Experiment by: Phywe
Printed: Oct 8, 2013 10:23:42 AM
interTESS (Version 13.06 B200, Export 2000)
Task
Task
How is a flower structured?
Study the parts composing a flower and how those parts are arranged.
Additional Information
Most plants we know in nature or as pot plants, form flowers. They are therefore
called flowering plants. The time at which a plant flowers differs very much between
individual plant species. Anemones, primroses, cherry trees and apple tree flower in
spring; larkspurs, roses and carnations in summer; dahlias and chrysanthemums in
autumn and the Christmas rose in winter.
The students shall recognize in this experiment that a flower is made up of various
parts. Some of these parts are similar, but we also find parts of different shapes and
colours in the same flower.
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Hints on Setup and Action
• It is recommended to examine cherry flowers. Are no cherry flowers available,
you can also use other flowers. When you make your choice, keep in mind that
the flower should be a hermaphrodite anyway, further the flower should be of
appropriate size and form, so that an easy is dissection possible. Because of the
great similarity with the cherry flower, apple flowers and pear flowers are also
very suitable.
Use the space below for your own notes.
Logged in as a teacher you will find a button below for additional information.
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Material
Material
Material from "TESS advanced Biology basic set General Biology, BIO" (Order
No. 15296-88)
Position No.
Material
Order No. Quantity
1
Tweezers, straight, pointed, 120 mm
64607-00
1
2
Dissecting needle, pointed
64620-00
1
3
Magnifier, plastic, 5x, d = 30 mm
88002-01
1
Additional Material
Cherry flowers
Material required for the experiment
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Setup and Action
Setup and Action
Hold a cherry flower by the stem and carefully detach all the individual parts with tweezers.
Begin with the outer parts of the flower and work inwards. Finally, cut off the part of the stem
in the middle of the flower.
In doing this, take care that all the parts of the flower are detached at exactly the place where
they are attached, so that they are kept complete and their shape can be correctly recognised.
Fig. 1
Place similar parts in groups. Arrange the groups on the table in the order in which the parts
are detached from the flower.
Have a look at the different parts of the flower. Read the information given on the Results page
and insert your observations on the composition of the cherry flower at the correspondent
positions.
Use a magnifier in order to see the individual components better.
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Results
Results
How many groups of flower parts can be distinguished?
There are four groups of flower parts.
The group detached first are the sepals. They form the calyx which protects the bud before
blossoming.
Of what colour and shape are the sepals? How many are there in the cherry flower?
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The cherry flower has five leaf green sepals, which have an almost triangular shape.
The leaf edge of the sepals is in contrary to the other leaves of the cherry tree without
toothing.
The second group contains the petals. They form the corolla, protecting the inner parts of the
flower and attract insects.
How many parts are there in the corolla of a cherry flower? What shape and colour are they?
The corolla of the cherry flower consists of five nearly circular petals. According to
the cherry species, the colour of the petals varies between white and rosy.
Sepals and petals form the perianth together. The sepals and petals of some species
of flowers fade into each other, for example the Christmas rose, other species, for
example tulips show no division in the leaves of the perianth.
In the third group are the stames of the cherry flower.
What shape are they? How are they coloured? How many stamens are there?
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The cherry flower has up to stamens. Using a magnifying glass, a thin stalk, the
filament, can be seen on each stamen, on top of which sits the anther. The anther
contains the pollen.
We are now left with the last part cut away from the stem. It is called pistil. The pistil consists
of three sections. The convex lower section, adjoining the stem, is the ovary, which merges
into the style at the upper end. The tip of the style is called stigma.
The stames are the male parts of the flower. The pistil is the female part. Both parts are
combined in one flower on the cherry tree. The cherry flower is, therefore, a hermaphrodite.
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Evaluation
Evaluation
Question 1
Summarize all the results. What are the four main parts of a flower? In what order are they
arranged going from the outside to the inside of the flower?
The cherry blossom is composed of different parts. Outside there are the sepals,
which enclose the inner parts of the flower protective. Particularly well the sepals are
visible when the flower bud is still unopened.
Following are five white, sometimes slightly pink petals. They are especially striking
and attract insects such as bees and bumblebees.
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Inside the flower you can find up to 30 stamens. These consist of the long, thin
filament and the anther, which sits at the end of the filament. The anther contains
yellowish pollen.
In the middle of the flower sits the stamp. At its upper end you can see the sticky
stigma, below there are the style and the thickened ovary.
Question 2
The scheme below shows a flower. Fill in the missing names of the flower parts in the fields
next to the appropriate letters.
Fig. 2
a:
nnnnnnnnnnnnnnnnnnnn
b:
nnnnnnnnnnnnnnnnnnnn
c:
nnnnnnnnnnnnnnnnnnnn
d:
nnnnnnnnnnnnnnnnnnnn
e:
nnnnnnnnnnnnnnnnnnnn
f:
nnnnnnnnnnnnnnnnnnnn
g:
nnnnnnnnnnnnnnnnnnnn
h:
nnnnnnnnnnnnnnnnnnnn
i:
nnnnnnnnnnnnnnnnnnnn
j:
nnnnnnnnnnnnnnnnnnnn
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a:
pistil
b:
stigma
c:
style
d:
ovary
e:
petal
f:
anther
g:
filament
h:
stamen
i:
sepal
j:
pedicel
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