Research Page for The Bush School, Team 9

4/22/05 10:11AM - T9: First upload of our journal is complete.
4/24/05 5:05PM - Dr. Susan R. Singer: Hello! I'm looking forward to following you project. I'm a plant biologist at Carleton College in Minnesota and am particularly interested in plant development. Good luck with your research.
4/24/05 5:05PM - Dr. Susan R. Singer: Hello again. I enjoyed reading about your initial observations on alfalfa. I work on pea which is a cousin of alfalfa (both are legumes) and am particularly excited to see what you will find out.
One of your observations was that your seeds got twice as big when you put them in water. Plants and wood from plants can absorb tremendous amounts of water. When the Egyptians were building the pyramids, they took advantage of your observation that plant material can absorb much water to cut stone for the pyramids. They would chisel holes in a few places along the line where they wanted the stones to separate. Then, they hammered pieces of wood into the holes and allowed the wood to soak up water. The wood expanded just like your seeds and created enough force to break the stone. This same force will allow break the seed coat of your alfalfa seed so the root can emerge.
Best wishes, Susan
4/24/05 5:32PM - Dr. Beverly Brown: Your sprouts seem to be going great all out. I'm wondering why your sprouts are quick to germinate and Team 8's are much slower. Have you compared notes with them? What do you think could account for the differences?
4/25/05 4:06PM - T9: Over the weekend, our plants grew a lot. They are a least three times as big as on Friday. After the first couple of days, they grew to such a size that they shed their outer covering. After this initial growing period, we plan on growing more alfalfa and growing them in different types of light. Potential types of light could be red light, black light, normal light, fluorescent light, blue light, green light, heat lamp, and no light. Do you have any other suggestions for lights or for an interesting experiment?
4/26/05 10:30AM - PEER COMMENT fromg Emporia T1: Hi Team 9! My name is Jennifer Beecher, from Emporia State University Team 1. Our experiment also involves light, and sounds similar to yours. Your light source list looks great- you should get interesting results. What you are going to measure for your data? Are you measuring only the sprout growth (what we are doing), planting the sprout and measuring the plant’s growth above the soil or something else all together?
4/27/05 2:56PM - Dr. Beverly Brown: Finding quality light sources for specific wavelengths has proven a challenge for us. We finally bought colored filters from Kodak. These are a bit pricey. Others have suggested using gels from stage lights. Is it possible you could borrow some gels from someone?
4/29/05 1:53PM - Dr. Susan R. Singer: I'm enjoying following your journal. You asked about why alfalfa sprouts so quickly and why some parts of the germinating seedling are white. Here are a few ideas.
1) Alfalfa has a lot of endosperm (stored nutrients) that it can use once it absorbs water and begins germinating.
2) Seedlings turn green after they have been exposed to light. Chlorophyll, which is necessary for photosynthesis, takes a lot of energy to make. Until a seedling is exposed to sun it would be wasteful to produce chlorophyll. Most of the available stored energy goes into shoot growth so the seedling can reach the surface and begin producing it's own food.
3) The root (radicle) emerges first because water uptake is essential for cracking the seed coat and also for allowing all the biochemical processes to get started inside the seed. Roots generally do not make chlorophyll because it there is no sunlight underground. Have a wonderful weekend.
5/4/05 4:26PM - PEER COMMENT fromg Bush T10: That is a novel idea team 9. We are wondering what colors you used to grow you’re plants. Did you have more success with green, blue, red light. Sincerely Cameron
5/8/05 3:38PM - Dr. Susan Singer : Greetings Bush Team 9, It's great that you're exploring light effects on your alfalfa seeds and seedlings. You found that blue light affects plant growth. While you might not expect blue light to have an effect, both blue and red light have been shown to affect the development of plants. Red light is needed for photosynthesis and also can regulate when a plant flowers. Blue light is known to affect aspects of plant development as well. I'm not sure how much you have learned about cell biology and how information is relayed in organisms. I thought I'd try to write a little bit about how a plant can respond to blue light. Let me know if you have questions about my explanation. There are molecules called blue light receptors in cells. When blue light (not red or orange or green) reaches a blue light receptor molecule, it changes shape. This receptor now changes the shape of other molecules (it's a bit like playing tag). Eventually one of these molecules is able to enter the nucleus of a cell and turn on genes needed for changes in the development of the plant. This process is called signaling - blue light is the signal that triggers a signaling pathway to eventually turn on genes. As your seedlings grow, different colors of light may have different effects on your plant. All the best, Susan