The%20War%20of%20the%20Roses

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The War of the Roses

• Case Study 1, Part 2

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• When Jason went back to school he took a sample
  of leaves from his mothers rose bush with him.
  Ill show these to Professor Jackson and
  Professor Perkins and see if theyll tell me
  whats up with the roses. Im sure theyll know,
  and they can tell me what Mom should do about
  it.

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• Professor Jackson was out, but Professor
  Perkins was in her lab, where she was busy
  studying diseases that affect apple orchards.
  Sure, Ill look at it, she said. Apples are in
  the rose family, and there are some shared
  diseases.
• When Professor Perkins looked at the rose
  leaves, she smiles. Jason, she said, you
  should recognize this from your textbook. Its a
  common problem of roses.

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• Um, really? Jason asked. What is it?
• Oh, no, Professor Perkins replied. Im not
  letting you off that easy. I want you to tell me
  what it is. First, is it a disease, an insect
  problem, or something your mother is doing
  wrong?
• Jason looked puzzled. Well since shes
  treating all her roses pretty much the same, I
  dont think its something shes doing. But then
  again, if its a disease or an insect, wouldnt
  all of the roses be affected the same way?

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• Not necessarily, Professor Perkins replied.
  As with most plants, some varieties are more
  disease-resistant. So how can we find out what is
  causing these spots?
• Look at them under the microscope? Jason
  guessed.
• That would be a good start. It might tell us
  whether were dealing with a disease, or very
  tiny insects. Professor Perkins helped Jason
  take a small sample from the leaf surface and put
  it under a microscope.

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Under the microscope
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• So what do you see? Professor Perkins asked.
• Jason pondered for a moment. The cells of
  whatever is on the roses look long and stringy.
  Fungus cells look like that. Those smaller cells
  look like spores. Is it a fungus?
• Thats a good hypothesis, Professor Perkins
  said. How can you find out if youre right or
  not?

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Question Set 2

1. Is the problem with the roses a disease, an
   insect problem, or something to with the way the
   roses were cultivated? How do you know? List at
   least three sources of information that support
   your answer.
2. Why is the problem affecting some of Mrs. Cooks
   rose bushes, but not others?
3. Why is it more difficult to diagnose a plant
   disease than a human disease?

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Write a summary

• Explain how the disease affects plant tissues,
  growth, and the transport of water and nutrients.
• If you were Jason, what steps would you recommend
  your mother take to solve the problem with her
  roses? List several measures that can be taken,
  and the advantages and disadvantages of each.

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To turn in

• Question sets 1, and 2
• Plant disease sheet
• Summary
• Turn in by Wednesday, April 30