ABSTRACT

The purpose of this experiment is to determine how radishes grow in different hydroponic environments.  The environments were simulated microgravity, sand, potting soil, and water.

The first step was to grow the plants in a paper towel with water only.  Then assemble the different variations of the hydroponic environments.  The plants grew in the different environments for two weeks.  I measured the mass of the plants before and after the experiment.  I then measured the mass through biomass.

The plants grew the best in the potting soil environment and worst in the simulated microgravity environment.  The mass of plants in the sand and water environments were in the middle when compared to the other environments.

My results indicate that my hypothesis should be accepted.  I had hypothesized that the plants growing in the potting soil would have the most alive plant mass and the plants growing in simulated microgravity would have the least.

PURPOSE

The purpose of this experiment is to determine how radishes grow in different hydroponic environments.  The environments were simulated microgravity, sand, potting soil, and water.

I became interested in this project when my teacher was telling me about a similar experiment that had been done.  I did a previous project with hydroponics before and thought that this idea seemed interesting.

Astronauts could find this information useful because one of the environments is simulated microgravity.  Gardeners will also find the results interesting to know how to produce the best vegetables.

HYPOTHESIS

My hypothesis is that the group growing in simulated microgravity will have the least amount of growth and living plants.  I also think that the group growing in potting soil will have the most growth and living plants.  I base my hypothesis on the fact that gardeners often use potting soil to enhance their soil and get high-quality results.

EXPERIMENT DESIGN

The manipulated variable was the growing environment for the plants. The growing environments were simulated microgravity, potting soil, sand, and water. The responding variable is the amount of plant growth.  The responding variable was measured after three weeks by using biomass and comparing it to the original mass of the plants.

The constants in this experiment were:

• The type of hardware cloth used to grow the plants in while in the variations of the hydroponic environment
• The frequency of watering before germination
• The environment and method used to germinate the seeds
• Growing time
• Type of seed
• The room in which the experiment was conducted
• The temperature of the growing room
• The number of plants from each growing container

MATERIALS

QUANTITY   ITEM DESCRIPTION
1                     Bag, Children’s play sand
1                     Bag, potting soil
2                     Clear containers that are at least 3 cm deep
10                   Connectors 30 cm each
1                     Measuring cup in mL
1                     Meter, yarn
1                     Oven
3                     Packet, of seed (Champion seed was used)
1                     Pair of wire cutters
3                     Plastic containers for the sand, potting soil, and water environments
1                     Roll, hardware cloth ¼” (6 mm)
1                     Roll, paper towels
1                     Rotational Christmas tree base/stand
                       Shredded paper (enough to fill the inside of the microgravity environment)
1                     Spray bottle
1                     Triple-beam balance
1                     Watering container
1                     Wooden dowel 63 cm long with a tapered edge and 2.5 cm thick
 

PROCEDURES (a)

1.     Place a paper towel in an area where they can grow for a few weeks without disturbance.
2.     Empty the three packets of seeds onto a paper towel, spreading them out evenly.
3.     Place another paper towel on top of the seeds.
4.     Spray the seeds thoroughly with a spray bottle.
5.     Now use a three cm deep pan to cover the seeds while germinating.
6.     Water the seeds every couple of hours using the spray bottle.
7.     After four days of growing as explained above, transfer half of the plants to another environment similar to the one above and continue to let them grow.
8.     Cover both environments with a clear lid/pan to allow sunlight to reach the plants.
9.     After one week of continuously watering the plants, start the experiment.

PROCEDURES (b)

1.     With the wire cutters, cut two pieces of hardware cloth to be 30 cm x 21.5 cm.
2.     Cut one piece of hardware cloth to be 44 cm x 21.5 cm this is to be used in the water environment.
3.     Cut one piece of hardware cloth to be 53 cm x 60 cm this is to be used for the simulated microgravity environment.
4.     Cut the 10 connectors out of twine wire.
5.     Drill 10 holes through the wooden dowel.
6.     Maneuver the wire through the holes and have half of each connecter on each side.
7.     Connect the hardware cloth in a circle around the wooden dowel by fastening the connecters to it.
8.     Sew the hardware cloth together at the ends.
9.     In all three containers fill to 7 cm deep of a substance (water, potting soil, or sand).
10.   Count out 20 plants from each container to form the testing environments.
11.   Using the triple-beam balance determine the starting mass of each group of plants.
12.   Now carefully thread the plants through the hardware cloth in the potting soil, sand, and water environments so that the roots are going into the substance.
13.   In the simulated microgravity environment thread the plants through the hardware cloth so that the roots are growing on the inside.
14.   Using shredded paper, stuff the inside of the microgravity environment to withhold moisture to the plants.
15.   In the potting soil and sand environments add 2000 mL of water evenly distributed to the plants.
16.   Water the microgravity environment two times a day with the watering can and add water to the other environments every three days.

PROCEDURES (c)

1.     After two weeks remove the plants from the different environments keeping them separated.
2.     Find the mass of each group individually.
3.     Heat a oven to 250º F (121º C)
4.     Cook the plants for 10 minutes.
5.     Find the mass of each group individually after they have been cooked.
 
 

RESEARCH REPORT INTRODUCTION Some people may think that there is no other way to grow plants other than in soil; there is however, another way.  This way is called hydroponics.  Some plants grow really well in a hydroponic environment, but others do not.  Currently astronauts are working on a solution to grow plants in outer space.    Plants have a basic structure for the way they live. PLANTS Plants have a basic structure to them that is how all plants are connected.  Life first starts for a plant after the parent plant has bloomed.  A tough coat called a testa protects the seed.  In the testa there is a small hole called the micropyle.  The plant already has leaf-like structures called cotyledons.  They have a radicle with tiny shoots that are called the plumule to collect nutrients that seeds need.  This is how plants start their lives out- in a small but complex seed that grows fast. A seed grows rapidly and changes into a young plant.  The radicle grows and forces it way through the testa and outside of the plant into the soil.  The plumule then grows upward and eventually breaks through the ground as the shoot of the plant.  As soon as the shoot reaches the light the plant turns green and starts the process of photosynthesis.  Photosynthesis is when the plant makes food through the energy (light) that it gets.  The seed has now turned into a small shoot that is poking through the ground. The shoot now has a different structure once it has grown out of the seed stage.  There is a main root on every plant that has many lateral roots growing from it.  The lateral roots all have tiny root hairs that collect water and vital minerals from the soil which it is growing in.  The water and minerals that are absorbed are then passed to the cortex and from there enter the xylem tissue.  The xylem connects to all of the parts of the plant and provides nutrients to help them grow.  Food is made in the leaves then passed to the phloem tissue to help the root grow.  The root tip has a protective cap on it that shields it from damage done by the soil.  The stem forms the shoot and supports the leaves and buds of the plant so that this life system can continue.  In a stem there is a straight system known as the internode that join together at swollen areas on the plant called a node.  Leaves and buds start at the node.  Leaves main purpose is to catch as much light as possible and photosynthesis takes place inside of the leaf. Plants serve as a vital part of our environment.  Plants breath and produce oxygen into the environment.  Stomata pores can let oxygen out and carbon dioxide in.  Plants are the contributors of oxygen in the earth atmosphere.  Without plants oxygen would never have been put into the atmosphere.  They have served to be a necessity to life on earth and would be vital for any human colonies. HYDROPONICS Hydroponics is the growth of plants in a substance other than soil with water.  Although many people have never heard of hydroponics it has been around since the 1600’s.  There are many variations to a hydroponic environment some of which are peat, sand, gravel, or glass wool.  The purpose of these substances is to support the plants so they aren’t drowning in the water.  Plants need minerals in order to survive.  These minerals are found in soil; since hydroponics is growing plants in water then the minerals must be added to the water to have healthy plants.  These nutrients usually come in a liquid form that is easily added to the water to make it more nutritious for the plants.  Through this method experimenters get plants that have a higher quality, less maintenance, larger crop yielded, costs less, and less health risks. Hydroponics has been around for a long time yet many people still are uninformed about the process. The nutrient requirements change depending on the plant.  Certain plants are harder to grow in a hydroponic environment.  However other plants can grow better in a hydroponic environment instead of a regular soil environment.  All types of plants can grow in a hydroponic environment.  Some of these plants include fruits, vegetables, flowers, trees, etc.  As the research in the field of hydroponics continues scientists will be able to determine exactly which plants can grow in a hydroponic environment and which cannot. MICROGRAVITY Microgravity is an environment with very weak gravity.  Scientists often use it to answer questions, which cannot be answered on earth because of the constant force of gravity.  Because of the International Space Station experiments in microgravity are becoming more and more popular.  Aboard the Space Station there will be experiments that are tested in the microgravity conditions.  One of these experiments is growing plants hydroponically in the Space Station.  Microgravity is used to study many different types of experiments. Scientists are currently testing to see if plants will be able to grow in space.  The importance of this information is that the plants would provide food, water and vital oxygen.  They are developing a plan to test their theorem in space with an entire environment for the humans and plants to live together.  Since plants need carbon dioxide to live and humans need oxygen; the plants will get their carbon dioxide from that which is exhaled from humans and the plants will produce oxygen for the humans to breathe. Now that humans have started to explore space, microgravity will become more important and useful.  Scientists are exploring the possibility of establishing an environment that is beneficial to the International Space Station or long-term flights.  Experiments are being conducted to discover if plants can grow in the condition known as microgravity. SUMMARY Plants can be grown in many different ways one of which is hydroponically or without the use of soil.  Microgravity is the condition of very little amounts of gravity.  Plants may be small but still have a very complex anatomy. Experiments are currently being executed testing to see if plants are capable of growing in a microgravitational environment thus resulting to see if they are capable of growing in space.

RESULTS

The purpose of this experiment was to determine in which hydroponic condition plants grow best.  The results from my experiment show that the potting soil was the best substance to grow the plants in with the water group next.  The sand group was the third best to grow the plants in and the simulated microgravity environment was the worst variation to grow the plants with.

PLANT GROWTH WHILE IN VARIATIONS OF A HYDROPONIC ENVIRONMENT

GROUP	STARTING MASS	ENDING MASS	DIFFERENCE	BIOMASS
water	6.49	3.73	2.76	0.76
potting soil	7.25	4.06	3.19	1.36
sand	7.63	2.21	5.42	0.54
simulated microgravity1	7.74	0.27	7.47	0.27
simlulated microgravity2	8.31	0.36	7.59	0.36

CONCLUSIONS

The results from this experiment show that potting soil is the best substance to grow plants in hydroponically while simulated microgravity is the least supportive to growth.  Sand and water are also substances in which plants can be grown hydroponically but are not the most supportive.  My hypothesis was that potting soil would have the most living matter and the simulated hydroponic environment would have the least.  Due to my results I now accept my hypothesis.  Because of the experiment I wonder how the astronauts have grown plants in space.  I am also wondering if radishes are a plant that cannot be grown hydroponically.  Another question I have is if I had added minerals to the water that the plants were growing in would it have caused the results to change.  Some possible sources for error are that no matter how much I watered the simulated microgravity environment it never retained water.  To improve this experiment I would test several types of plants instead of just one.

BIBLIOGRAPHY

ADVANCED ASTROCULTURE. NASA. 07 Jan. 2002 <http://www.spaceref.com/iss/payloads/advasc.html>.

Bates, Dr., Jeffery . SEEDS TO PLANTS. New York, NY: Gloucester P, 1991.

HOW PLANTS DETECT GRAVITY. Science Daily Magazine. 07 Jan. 2002 <http://www.sciencedaily.com/release/1999/07/990727073836.htm>

HYDROPONICS. Crop King. 03 Jan. 2002 <http://www.cropking.com>.

 PLANT NUTRIENTS. General Hydroponics. 10 Dec. 2001
<http://www.generalhydroponics.com/nutrients.html>.

RADISHES. The Gardeners Companion. 03 Jan. 2002 <http://www.almanac.com/garden/radishes.html>.

SPACE STATION SCIENCE. NASA. 03 Jan. 2002 <http://microgravity.grc.nasa.gov>.

WISCONSIN CENTER FOR SPACE AUTOMATION AND ROBOTICS . 20 Feb. 1996. Dr. Raymond J. Bula. 02 Jan. 2002 <http://liftoff.msfc.nasa.gov/shuttle/USML2/science/asc.html>.