The Effect of Seed Size on Germination Rate

Researched by Kelli M.
1999-2000 



PURPOSE

This experimentís purpose is to determine whether the sizes of kidney bean seeds affect the speed and percentage of germination.

I selected this idea because I have had a strong interest in plants for several years. Since I am a rather impatient person, I hoped this experiment would show a fast way to germinate seeds, so if I ever become a gardener I will know what size germinates fastest.

The information gained from this experiment may help farmers select seeds that germinate faster. This would be useful to places like Alaska, which have a very short growing season.



 
 

HYPOTHESIS

My hypothesis is that the bigger seeds will have a higher percentage rate.

I base my hypothesis on my observations that a bigger organism is usually healthier. So bigger seeds will probably germinate faster.



 
 

EXPERIMENT DESIGN

The constants in this study were:
Amount of water for each group. (250ml)
Amount of seeds in each size. (100)
Amount of trials for each seed size. (5)
The length of each trial. (5 days)

The manipulated variable was the size of the kidney beans: small, medium and large.

The responding variable was the percentage of germinating seeds of the three sizes of beans.

To measure the responding variable I will count the number of germinated seeds each day for each size.



 
 

MATERIALS



QUANTITY
ITEM DESCRIPTION
15 plastic cups
30 paper towels
300  kidney beans
 30 (250oz) tap water
15 pieces of Saran Wrap
1 triple beam balance 
  accurate to 0.1grams



 
 

PROCEDURES

1. Gather one pound of kidney beans.
2. Separate beans into small, medium, and large by weighing on a triple beam balance, in small is defined as 0.4g, medium is defined as 0.5g, and large is defined as 0.6g.
3. Then place twenty small beans on a damp paper towel in a row.
4. Cover damp paper towel with Saran wrap.
5. Then roll it up along the beans.
6. Wrap a paper towel around that.
7. Wrap another layer of Saran wrap around it.
8. Tape the Saran wrap.
9. Stick the roll in a plastic cup with 250ml of water, with all the seeds at the top that is not wet.
10. Repeat steps three through nine with medium and large beans.
11. Label each trial "small", "medium", or "large."
12. Open small, medium and large each day and keep a chart of each size showing how many seeds germinated. Do this for  5 days.
13. Each day add one fourth of water to cups and change the outside paper towel of each roll.
14. Find the percentage of seeds that germinated of each size for that period of time.
15. Repeat steps three through fourteen four more times for better reliability.



 
 

RESULTS

The original purpose of this experiment was to determine whether the sizes of kidney bean seeds affect the speed of germination.

The results of the experiment were bigger bean seeds germinate faster than smaller bean seeds and medium bean seeds. The bigger seeds germinated 2 more than medium and four more than small beans. The percentage of the beans that germinated in the "large" trial is 90, "medium" is 88 "small" is 86.
 
 



 
 

CONCLUSION

My hypothesis is that the bigger seeds will have a higher percentage rate. 

The results indicate that this hypothesis should be accepted because in most of the trials the largest bean seeds germinated more in one week.

Because of the results of this experiment, I wonder if the size that germinates faster varies in different plant types. If the results change for a coconut, or wheat seeds like the smaller the seed the higher percentage.

If I were to conduct this project again I would use different types of plants like other bean seeds and different sizes like 0.4g, 0.6g and 0.8g.



 

RESEARCH REPORT

Introduction 

Seed germination is important to the world because all the people get most of their food from plants. Even people who eat meat are dependent on plants for the animals to eat. 

Germination

Germination, is the sprouting of a seed. When germination begins the seed needs a lot of water. The water makes a chemical change that enables the embryo to store food and energy for growth. The water also causes the embryo to enlarge and split the seed coat. Germinating seeds require a large amount of oxygen because of their high rate of respiration. Respiration is taking in oxygen and giving off carbon dioxide. The radical then emerges and grows forming its first root.

Needs

All seeds need moisture, oxygen and warmth to germinate. If they donít have warmth the seeds will go through dormancy. That prevents seeds from germinating. Most seeds remain dormant in the winter because of weather conditions. Some seeds germinate in the summer because they need higher temperatures than others do that germinate in the spring. Most seeds require a cold period before starting germination.

Part of a Seed

All seeds have three main parts: the seed coat, the embryo and the food storage tissue. The seed coat protects the embryo and the food storage tissue from loss of water, insects and injury. The seed coat can be thin and delicate, as in wheat and beans, or thick and tough, as in a coconut. The embryo contains the part of the seed that develops into the first root, then the stem and the first leaves. The cotyledons in the seed absorb and digest the food from the food storage tissue. The cotyledons in some of the dicotyledon seeds absorb the food in the endosperm. The cotyledons then store the food in the embryo.

Importance of Agriculture

Agriculture is important to the world because it provides food for people and animals, oxygen from the plants. It is important because agriculture provides almost everything that people and animals need to survive. Farming gives people food from crops and animals. 

Plants

The two main groups of plants are angiosperm and gymnosperm. Flowering plants are called Angiosperms. Angiosperms make up more than 90 percent of the 260,000 kinds of plants. Angiosperms are protected by a seed case, in fact "angiosperm" means "enclosed seed." They are any plants that produce fruits and flowers. Angiosperm can be broken up into two smaller groups called monocotyledons and dicotyledons. Monocotyledons grow from seeds that contain a single seed leaf called a cotyledon. In dicotyledons there are two cotyledons or leaves in the seed. 
 Gymnosperms produce seeds that are uncovered like most trees and shrubs but do not produce any flowers. "Gymnosperm" means "naked" and "seed" in Greek. Gymnosperm has about 800 species of seeds.  Gymnosperms can be cone bearing such as pinecones.
 
 

Summary

Agriculture is important to all humans, so understanding germination is a benefit to everyone. Germination has to occur for the dormant embryo to grow into a plant. 


BIBLOGRAPHY

Hershey, David R. Plant Biology Science Projects. New York: John Wiley &Sons, Inc. 1995 pp 21-22

"Plant" World Book Encyclopedia. 1995. Vol. 17 pp 519

"Seed" World Book Encylopedia. 1995. Vol. 17 81-283

"Seed" World Book Multimedia Encylopedia. 1999ed. CD-ROM, Chicago IL.

"Seed" Microsoft Encarta Encylopedia. 1999. Microsoft corporation, 1993-1998

Silverstien, Dr. Alvin, Virginia and Robert. Plants Brookfield, Connecticut Twenty-first Century Books, 1996 pp 20-24
 


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