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Mariam Kamel
Professor Bill
Biology 1500 Lab
10 October 2014
Seed Germination
Introduction:
Seeds shield the plant embryo until they encounter a condition that is appropriate for
growth as an independent plant, and they extend their shoots upwards for light to absorb energy
for growth. When a seed encounters this suitable condition, it will germinate. Germination is the
growth of an embryonic plant that is contained within a seed. The seed of a vascular plant is a
small bundle produced in a fruit (angiosperm) or cone (gymnosperm) after they unite the male
and female sex cells. A fully developed seed contains an embryo and in most plant species they
contain a seed coat. Most seeds go through dormancy where there is no active growth. Only
under favorable conditions, the seed will begin to germinate and resume growth. Seed
germination depends on factors such as, temperature, oxygen, light, and water.
Temperature is required for germination because some seeds have a range of
temperatures that they must meet for them to germination. The average temperature to cause a
seed to germinate is usually between 60-70 degrees Fahrenheit, if temperatures are too low it will
cause chilling and the seed will not grow. Oxygen is used in aerobic respiration, and the main
source of the seedling’s energy until it grows leaves. Light is important because for
photosynthesis to occur light must be present and the plant will not grow in darkness unless a
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specific plant exhibits etiolation. Lastly, water is one of the most important environmental
factors to effect germination because mature seeds are often extremely dry and need absorb
significant amounts of water for growth to continue.
Although factors such as temperature, oxygen, and light are important factors, what the
seed absorbs effects germination greatly. This experiment exhibited what different solution will
have an effect on different seed germination. This is important because some solutions such as
water, bleach, or hydrogen peroxide can cause a greater increase in germination than some other
products. One or all of these solutions can increase seed germination more than the other. The
investigation of germination of the three types of solutions will be tested between either pinto
beans, radish seeds, or grass seeds in either water, bleach, or hydrogen peroxide solution. If grass
beans are placed in either solution of water, bleach, and hydrogen peroxide then it will grow
regardless of the solution it is in.
Materials and Methods:
Obtain 20 seeds (grass, pinto, or radish) that you are assigned to, soak them in hydrogen
peroxide for an hour, wet paper towel with solution (water, hydrogen peroxide, or bleach), fold
seeds within the towel, store in plastic bag with some air, check every two days for germination.
Results:
The results of grass beans placed in various treatments for seven days are shown below.
Grass beans were soaked in either water, hydrogen peroxide, or bleach. Graph 1 displays the
number of seeds that germinated with in the seven days, and table 1 shows a more detailed chart
of the growth measurements of the root and shoot.
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Graph 1:
Days (n) and number of seed germination in root and shoots (mm)
20
16
16
Number of
seeds
germination
15
10
Seeds
6
5
0
Day 3
Water
Day 3
Bleach
Day 3
H2O2
Day 5
Water
Day 5
Bleach
Day 5
H2O2
Day 7
Water
Day 7
Bleach
Day 7
H2O2
Days
Table 1:
Number (n) and % seed germination, root and shoot growth (mm)
Treatment
Grass soakperoxide;
wetting waterwater
Grass soakperoxide;
wetting bleach
(day 3)
n
6
(day 3)
%
30%
(day 5)
n
16
(day 5)
%
80%
(day 7)
n
16
(day 7)
%
80%
Average Average
Root
Shoot
32
41.5
0
0
0
0
0
0
0
0
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Grass soakperoxide;
wetting
hydrogen
peroxide
0
0
0
0
0
0
0
0
Refer to graph 1 and table 1 the data shows that the solution water had the greatest effect
on germination. On the third day the root and shoot germinated 30%, on the fifth day the root
and shoot germinated 80% and on the seventh day they stayed at 80%. This resulted in the
average of 32 mm root growth and 41.5 shoot growth for the grass seed in water solution.
In both the grass seeds soaked in bleach and hydrogen peroxide no seed germination was
shown throughout the week as table 1 and graph 1 displayed.
Discussion:
This experiment showed the effects on germination of different seeds in different
solutions. Recall that germination is the growth of a plant within a seed. Overall, the hypothesis
was incorrect. The hypothesis stated that the grass seeds will germinate regardless of the solution
that it is in. The grass seed only germinated in the water solution and refused to germinate in
hydrogen peroxide and bleach.
The grass seeds in water experienced a great amount of germination. They germinated
30% on the third day and 80% on the fifth and seventh day. They had an average shoot growth of
41.5 mm and average root growth of 32 mm. Water is an important seed component in seed
germination, hence why is did very well in this lab.
Hydrogen peroxide was supposed to dissolve the outer coat of a seed and allow water to
travel from the seed to the embryo therefore increasing germination, but hydrogen peroxide did
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not do that. The average measurements throughout the class for the root and shoot of the grass
seed was 0 mm throughout the seven days.
It is understandable why bleach had no effect on the increase in germination because
bleach destroys the cell membrane by its toxic chemicals, and this it will get to the cell wall
destroying the process of allowing the seed to germinate. Therefore, having the results show zero
germination is logical.
Many factors could have played a role onto why none of the seeds germinated in the
other solutions. For future experiments on germination the seeds should be kept in the same
room under the same amount of light, and have the same amount of oxygen in the bag. These
factors along with the solution effect germination greatly. If someone had their seeds in a bag
with hydrogen peroxide and was set under sunlight they could have exhibited growth while
someone with the same solution showed no light to their seeds did not have any growth. Also,
having some part of your bag open so the seed can have air is an important factor for growth.
Oxygen is one of the main environmental factors to effect germination along with water. Having
the same controls throughout the class might change up the results for this experiment.
Experimental errors could have also occurred in this lab. Not soaking the seeds for the
full hour, or soaking them for longer than an hour could have disrupt the data. Personally, some
errors that happened to me was I left my seeds in my bag for the whole seven days with my
heavy books and they could have been crushed. Also, my seeds were very small so if there was
any growth it might not have been visible to my eyes.
Although the hypothesis was incorrect, massive amount of new materials was learned
throughout this experiment. Data taking skills were tested in this experiment as well being able
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to conduct an experiment and keep up with it at home. Seed germination was the main subject
for this experiment and taught how many factors could contribute to seed growth, and that water
is quite essential for seed germination.
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Work Cited
"Germination." - Definition from Biology-Online.org. N.p., n.d. Web. 12 Oct. 2014.
Koornneef, Maarten, Leónie Bentsink, and Henk Hilhorst. "Seed dormancy and germination."
Current opinion in plant biology 5.1 (2002): 33-36.