Steven Pham
Seed Lab Report
2nd Blue
Environmental Conditions Affecting Seed Germination
Water Amount and its Impact on Radish Seed Germination
Background Information:
Seeds are living organisms that will react once introduced to certain factors, such as
moisture, air, temperature, and light. In our experiment we will be focusing on the amount of
water. My parents grow a garden every spring, so during the winter time we have to get our
seeds to germinate. Watering a seed is one of the first things you have to do to get it to
germinate, so we decided to focus on “how much water is too much?”. What we’re trying to
find is the “just right” amount that could provide the best rate of germination.
A dormant seed only contains 10-15% water and is dehydrated until water is absorbed,
making it active. Water is absorbed by the seed coat and enzymes inside the seed start
functioning. Eventually the embryo within begins to swell as it metabolizes stored food
reserves. Since there are no leaves yet, the focus is plainly on moisture because photosynthesis
has not yet begun.
The medium used to hold the seeds must be able to retain water and also effects the
amount of water must be used. Different varieties of soil can impact water retention; some
require less water and some require more. One common method to germinate seeds is to wrap
them in paper towels and place them into bags. This eliminates the need to water, and the high
water retention inside the sealed bags aids in the germination process by maintaining seed
moisture.
Research Question: What is the effect of various amounts of water on the rate of germination
in Radish seeds?
Hypothesis: There is an optimum amount of H2O that will slightly increase the germination
rates for the radish seeds. The rate of germination relative to water will slowly increase until it
reaches its optimum point and then will dramatically decrease. Seeds require moisture in order
to crack open the seed coat, and too much water will rot and “drown” the seed, failing to
germinate because too much water destroyed the enzymes inside.
Independent Variable: Amount of water in the seed bag
10ml, 15ml, 20ml, 25ml, and 30ml
Dependent variable: Number of plants that germinate
Obtained by counting the amount of seeds every morning for three days.
Control: Temperature of environment, light, seed medium, and control of evaporation
Steven Pham
2nd Blue
Seed Lab Report
Constant Variables:
 Temperature of Environment- 68-72 (Room Temperature): All seed bags were kept in
the same room so they all experienced the same temperature fluctuations, changing the
temperature would skew the results.
 Light- None: Seeds don’t need sunlight as there are no leaves for photosynthesis, adding
light might have an impact on different seeds, but radish seeds are fine in the dark.
 Seed Medium- Paper Towel (Unknown Brand)- The medium used to retain water must
remain the same, and changing the mediums would skew the data.
 Control of Evaporation- Zip Lock Bag: The rate of evaporation must stay the same, or the
growth might be impacted and skewing our data.
 Seed Amount- 30: Changing the amount of seeds in each bag would severely hinder our
ability to collect data on seed germination
Materials: Zip lock bags, tap water, flask with volume markings (mL), dark cabinet or
container, radish seeds, marker, and paper towels
Procedure:
1. Start by counting out five groups of thirty seeds for each bag. Separate them and
wrap them in the paper towel. Place the seeds wrapped in the paper towel
inside the bags.
2. Mark the bags with the marker with the following measurements: 10ml, 15ml,
20ml, 25ml, and 30ml.
3. Water the bags with the correct amount of water as indicated on the bags using
the marked flasks. Repeat this procedure on the next day
4. Count the amount of seeds that have germinated out of the thirty in each group
and write down the amount for all five groups. Repeat for a total of three days.
Data Collection
Raw Data: Impact of Water Amount on Seed Germination
H20 Amount (ml)
Day 1
Day 2
5
20
29
10
22
24
15
6
23
20
11
24
25
12
22
Day 3
29
30
27
24
24
Steven Pham
Seed Lab Report
2nd Blue
This line graph visually represents the slopes for each germination relative to the
amount of water it received each day. The different amounts of water are represented by
different visual colors on each line (green 5ml, purple 10ml). The number of germinated seeds
are visually marked by indicators (going up by 10, each line is 5 seeds), and the amount of days.
The slopes represent the increase of seeds per day, with different variations in growth in each
group. Higher amounts of water on the graph seem to start out lower on the graph and
germinate slower.
Conclusion:
The purpose of this experiment was to explore a factor that impacted seed germination,
which was the amount of water. An independent variable of H20 amount was applied to a
dependent variable of seeds and the amount that would germinate over 3 days. Specifically, the
question asked the effect of different milliliters of water on radish seeds.
The hypothesis inferred that with an increase in amount of water, the amount that
would germinate would increase, but there would be an optimum “perfect amount” that would
provide the best germination out of all of them, thought to be somewhere in the middle. It was
also predicted that the higher amounts of water would greatly slow the germination rates.
From the data, the hypothesis is not supported. The interval created by the germination of the
seeds decreased as the amounts of water increased, leaving almost no room for an “optimum”
Steven Pham
Seed Lab Report
2nd Blue
amount of water, as indicated by the almost linear impact on seeds. From the background
information, the hypothesis asserted that the relationship was caused by the ability of the seed
medium to retain the perfect amount of water to inhibit seed casing penetration and
metabolism. It is known that too much moisture would damage seed enzymes inside the seed
and this is reflected by the lower slope on the graph for the 25 ml and 30 ml groups. This
explanation explains the lower amounts of seed germination, but evidence of an “optimal”
amount of water was not provided in the data.
Because the impact of water can vary so much between the almost endless amount of
seeds in the world, this lab can only provide results for radish seeds alone. There are many
weaknesses and limitations to this lab. The most significant error was the failure to provide a
control group and zero repeat trials. Without these, we can not fully be confident that water
amount alone is responsible for altering germination behavior. There are also many other
variables that could have impacted germination such as the paper towel medium, as even those
could have altered germination behaviors.
Sources:
http://seedbiology.osu.edu/HCS631_files/5B%20Seed%20germination,%20mark%20bennett.pd
f
http://www.bio.miami.edu/dana/161/evolution/161S11_germination.pdf