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Meet a Scientist Monday: Barbara McClintock

After a few posts about science in the garden, have you wondered whether any scientists have made discoveries using gardens or garden plants? The answer is that a whole “field’ of science (sorry ☺) was discovered in a garden and it is still progressing due to work on garden plants.

You’ve probably heard that the science of genetics was born in a monastery garden in the 1860’s. Gregor Mendel was a monk who carefully worked out genetic inheritance by growing garden pea plants. He work was ignored for about 30 years, until a few other scientists came up with the same ideas and rediscovered the importance of Mendel’s experiments.

In an interesting parallel, a woman named Barbara McClintock was born about the same time as Mendel’s work was being rediscovered, in 1902. As a child, Barbara liked playing sports and spent a lot of time outdoors. By the time she was a teenager she discovered she liked learning new things and decided to go to college. At the time women were not always encouraged to go to college, but she was determined to go. She went to Cornell University without even having enrolled, and they let her in.

Barbara liked Cornell and studying science so much she stayed on as a graduate student, getting her PhD in botany. She studied the genetics of corn plants. She studied what the clumps of DNA called chromosomes looked like in corn plant cells, years before scientists discovered what DNA was and how it worked. She also went out to the field and planted the corn, so she knew each plant and where it came from. When she worked in the corn field she wore “knickers” she had specially made, at a time when most women only wore dresses.

Barbara_McClintock_(1902-1992)(Acc. 90-105 – Science Service, Records, 1920s-1970s, Smithsonian Institution Archives Persistent URL:Link to data base record Repository:Smithsonian Institution Archives View more collections from the Smithsonian Institution.)

After graduating, eventually she got a job as an assistant professor at the University of Missouri. Her job only lasted a few years because she didn’t always follow the rules and did unusual things. Once when she realized she had forgotten her keys and found her work building was locked, she climbed up the front and crawled through a window. Assistant professors were not supposed to climb buildings.

Finally Barbara found a position at a research laboratory, Cold Spring Harbor Laboratory. There she spent many years growing corn and studying corn genetics. Soon she realized that the corn seeds were not coming out in the colors expected based on simple genetics. Interested in finding out why, Barbara worked hard and came up with an answer. The only problem was that the answer was that the genes were jumping from place to place. Because her answer was so different from what anyone expected, many other scientists didn’t understand or didn’t believe her. Her work was kind of like Mendel’s, ignored and forgotten by and large.

The good news is that Barbara persisted and finally people did begin to understand what she had discovered. In fact, scientists were so impressed with her work that in 1983 she was given the Noble Prize in Physiology and Medicine.

So you see, studying plants in a garden can lead to great things.

For more information:
The National Library of Medicine has files of Barbara McClintock’s actual papers/correspondence and photos under The Barbara McClintock Papers.

Books: (Covers and titles are affiliate links to Amazon)

Barbara McClintock: Genius of Genetics (Great Minds of Science) by Naomi E. Pasachoff

Barbara McClintock: Pioneering Geneticist (Makers of Modern Science) by Ray Spangenburg and Diane Kit Moser

Barbara McClintock: Pioneering Geneticist (Unlocking the Secrets of Science) by Kathleen Tracy


Books for adults:
A Feeling for the Organism, 10th Aniversary Edition: The Life and Work of Barbara McClintock by Evelyn Fox Keller

I read this book as a graduate student and remember it had a large impact on me. Now I recently re-read it and see that it has some flaws, but is still interesting reading.


For another viewpoint, try: The Tangled Field: Barbara McClintock’s Search for the Patterns of Genetic Control by Nathaniel C. Comfort


Weekend Science Fun: Germination Science Experiments

Did you try the germination tests from last week? Did you get anything that looks like this?

bean radicle

If you enjoyed sprouting seeds, then here are a few more ideas for seed germination science experiments.

Before starting, however, let’s take a minute and think about how information from experiments on seeds and germination might be important. Last week we discussed how you could use a germination test to see if old seed you have lying around is still viable (able to make new plants). Plant scientists interested in maintaining rare plants, entrusted with ensuring maximum yields from crop plants and/or concerned with storing seeds in seed banks for the future study the changes in seeds over time and how to slow or prevent loss of viability. These scientists subject seeds to different conditions and examine the physical and chemical changes that occur as time passes. Their findings indicate that factors such as temperature, moisture, diseases, and chemical pollutants can all change seed viability.

Experiment 1. Effect of temperature on seeds and seed germination

Think of ways to test whether temperature effects seed sprouting or percent germination.

Example A:
Choose seeds of one kind of plant to test. (Note: Be sure to check the seed package carefully. Some seeds are treated with pesticides). Randomly assign the seeds to three categories. With the help of an adult, place 1/3 of the seeds on a paper towel or on a microwave safe plate and heat in a microwave on high for thirty seconds. Allow seeds, especially oily ones, to cool before touching them.  Add 1/3 of the seeds in a freezer overnight in a freezer. Leave the remaining seeds at room temperature. Then perform a germination test as described last week. Count the number of seeds that germinated for each treatment and divide by the total of seeds (for that treatment) to obtain the percent germinated. If there are no differences, how can you modify this test?

Example B:
Choose seeds of one kind of plant and divide into three groups. Prepare each group for germination as discussed last week. Place one group in the fridge, one at room temperature and one in a sunny window or other place warmer than room temperature. Make sure they all stay moist but not too wet. Record the number of days until germination and also the percent germination (see Example B.)

Experiment 2. Rate of germination of seeds from different plants
Collect seeds from different plants (two examples of plants with vastly different germination times are radishes and carrots.) Perform the germination test as described last week.

Note:  because radishes and carrots have different germination times, it is possible to plant them together in a garden. The radishes will come up and mature first. The slower carrots will benefit from the extra room left behind as the radishes are pulled out and used.

Experiment 3. Effect of chemicals or pollutants on seed germination

Use your imagination to come up with treatments that may increase or decrease germination. Think about things like salts (may be present in the water or soil), nutrients, and/or antimicrobial treatments that might change how many seeds of a given batch germinate.

As always, we would love to hear your ideas and/or results.

tomato seed sprouting

For further study:
Seeds and Plants (Science Workbook) by Diane O’Hanesian, John Jones (Illustrator)
Grades 2-3

This book does a good job with terminology and also showing concrete, real world examples. Better done than many science books for the younger set.


The Magic School Bus Plants Seeds: A Book About How Living Things Grow by Joanna Cole (Author), John Speirs (Illustrator), Bruce Degan (Illustrator)


For many more suggestions, visit our list of children’s books about seeds at Science Books for Kids.

childrens-books-about-seeds

And a treat for adults interested in science and plants:
Seed to Seed: The Secret Life of Plants by Nicholas Harberd


Disclosures: I am an affiliate for Amazon. If you click through the linked titles or ads and make a purchase, I will receive a small commission at no extra charge to you. Proceeds will be used to maintain this self-hosted blog.

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