Gravitropism of Radish Seeds in Microgravity

Concord, North Carolina

Principal Investigators: Sreenidhi Elayaperumal, ZaynebShaikh, Paige Starnes

Teacher Facilitators: Megan Mcnutt and Paul Fields

Introduction

• In the 2016-2017 school year, our school participated in the Student Spaceflight Experiments Program (SSEP).

• Our proposal, Gravitropism in Microgravity, was the selected to be sent aboard the International Space Station with many other experiments.

• The experiment was sent in August and came back in late September.

Our Experiment

• The purpose of our experiment: To find the differences between germinated radish seeds in gravity and microgravity

• The Question: How does gravitropism vary in these different environments?

The Purpose

•To find out if plants can develop properly outside of Earth's gravity

• Germination is the first stage of a plant's growth, so it is important it happens properly.

• Agriculture in space could benefit astronauts in many ways.

Gravitropism

• Gravitropism is a plant's response to the stimuli of gravity.

• It occurs when starch granules in amyloplasts settle to the bottom of the organelle due to gravity.

• This causes a set of reactions to occur, which leads to the release of IAA.

Gravitropism (Continued)

• Gravitropism allows the shoot of the plant to grow upwards, against gravity.

• IAA slows growth in the roots, while stimulating it in the shoot.

Our Hypothesis

• Our hypothesis: In space, the germinated seeds will have longer shoots and shorter roots.

• We also believe the shoots and roots will grow in random directions.

• These will be the results of a lack of gravitropism.

Our Experiment Aboard the ISS

• The FME Mini-Lab contains three compartments.

• The first contains 3.4 ml of water, the second having 2.5 ml of soil with three Raphanus sativusseeds, and the third containing 2.5 ml of Formalin.

Requested Interactions

Time Requested Interaction Occurring Action

A = 0 Remove Clamp A, shake vigorously Water is released into the soil, activating germination

U - 14 Remove Clamp B, shake vigorously for 20 seconds

Formalin is released, ending the experiment and preserving the specimens

Results

• After our harvest and analysis on September 26, 2017, we observed that the lengths and visible characteristics of all germinated seeds were very similar.

Conclusion

• We have concluded that germination is not hindered by microgravity or varied gravitropism, and that our hypothesis was incorrect.

• Germination is too early in a plant’s development to be greatly affected by gravitropism’s importance.

Partners

Thank you to these partner institutions for making our flight possible:

• J. N. Fries Magnet Middle School

• Cabarrus County STEM

• Burroughs Welcome Fund

• North Carolina Space Grant Consortium

• Center for the Advancement of Science in Space (CASIS): SSEP National Partner

• Subaru of America, Inc.: SSEP National Partner

References• "SSEP | Student Spaceflight Experiments Program." SSEP Student Spaceflight Experiments Program. N.p., n.d.

Web.

• "Plant Responses to Gravity - Boundless Open Textbook." Boundless. N.p., n.d. Web.

• "JAXA Japan Aerospace Exploration Agency." JAXA. N.p., n.d. Web.

• Chen, Rujin, and Elizabeth Rosen And. "Rujin Chen." Gravitropism in Higher Plants. N.p., 01 June 1999. Web.

• "The Influence of Microgravity on Plants." The Influence of Microgravity on Plants NASA ISS Research Academy and Pre-Application Meeting South Shore Harbour Resort & Conference Center League City, TX August 3-5, 2010 Howard G. Levine, Ph.D., n.d. Web.

• "Encyclopedia Britannica." Encyclopedia Britannica Online. Encyclopedia Britannica, n.d. Web.

• "From Seed to Seed." Garden Online. N.p., n.d. Web.

• "Can Plants Grow Without Soil?" Wonderopolis. N.p., n.d. Web.

• "Tips on Preserving Tissue (Roots Lab)." Roots Lab (Penn State University). N.p., n.d. Web.

• "What Is Gravity?" Live Science. N.p., n.d. Web.

• "Plants For Kids." Gravitropism Lesson. N.p., n.d. Web.

• "Tropisms." BBC. N.p., n.d. Web.

• "How Long Does It Take for Radishes to Germinate?" Home Guides. N.p., n.d. Web.