Science Buddies: "Ask an Expert"

No. The increase in plant mass was probably caused by the extra light of other wavelengths. If you had used the Philips narrow-spectrum UVB lamp, then you could say it was caused by UVB.

Anthocyanins in the leaves could have made them appear darker, which is what your image density data shows. As far as I could tell from a quick reading of the paper, ONLY UVB causes increased anthocyanin--not light of other wavelengths. Growth is due to increased photosynthesis, which results from increased light of longer wavelengths.

Since your Zilla lamp emitted both UVB and longer wavelength light, you had two things going on at the same time--increased growth from photosynthesis and increased leaf pigmentation through biosynthesis of anthocyanins.

You did not say what time today you were turning in the report or whether you still wanted my comments, but here they are:

• “All plants need ultraviolet radiation to grow”—No. All plants need VISIBLE LIGHT in the part of the spectrum from about 430 to 650 nm to do photosynthesis. UV is invisible and below this.

• “How does the amount of time organisms are exposed to UV radiation affect them?”

• The numbers corresponding to the references should be inserted in the text at the point where data or results from that reference is discussed—like this [1].

• “This photoreceptor is known as UVR8. UVR8 (UV Resistance Locus8) has just recently been discovered…” [REFERENCE?]

• “The genes for flavonoid biosynthesis are expressed or turned on when exposed to certain amounts of UV-B radiation.” – You should mention anthocyanins here because they may be more important to your results than flavonoids.

• “groups were weighed and the density (chlorophyll content) of the leaves of each plant were found.”—No. I told you. UVB does NOT stimulate chlorophyll production. The darker pigmentation of the leaves is most likely a result of anthocyanins.

• “A full spectrum UV fluorescent lamp” You should give the manufacturer and the name and type of the lamp.

• “Scale that goes down to grams” I hope the sensitivity was 0.1 g.

• “The ImageJ Program (can be downloaded for free)” Give the URL for the program.

• “UV Fastcheck strips” Give the manufacturer of the strips.

• “Expose the strips to the same amounts of UV-B the plants are receiving (2 hours and 12 hours of the light from the lamp and 9 hours of sunlight).” You need to say WHERE you put the strips in the terrarium. The UV intensity decreases as you get further from the lamp, so the strips should have been put at a distance that is about where most of the plants’ leaves were.

• Table 1 should have a title. The radiation that the test strips measure is UV and you should say this in the label to column two—not just sunlight. The same goes for column three where you should say Extra UV Radiation. In the 4th column, you should say Percentage Increase in UV because that is what you measured. The word RADIATION can mean anything. In science you have to be specific and clear.

• Figure 1 should be labeled as such with the title. The x-axis label should be UV Dose in Millijoules/sq cm

• Table 2 - Needs title. The 2nd column label should be Average weight +/-SEM

• Figure 2. The bars should have the SEMs as you did on the graph of leaf pigment density.

• “Summary” should be renamed RESULTS AND DISCUSSION

• “A t-test was also conducted, comparing the control to the two and twelve hour exposed leaf density values,” You should give the p-values that you got from the test. The judges will ask you this and it should be in your report as it is critical to your conclusions.

• “responses such as the biosynthesis of flavonoids” and anthocyanins

• “By finding the density (chlorophyll content)” Change this to “pigment content” nor just say “By finding the pigment density…” I told you to omit the mention of chlorophyll.

• Thanks for acknowledging Scibuddies! Who is Mrs Mondal, your science teacher? You should say who she is.

Thank you very much for the help. I sent this report to you before knowing about anthocyanin but went ahead and changed it all Ready.

OK. You should have sent me the current version as soon as you finished it. Do you want me to check it or are you out of time? Do you have to give a poster or powerpoint presentation of your work?

Thank you very much. Don't worry about it, I finished everything today, but because of your help, I scored a 100/100. Thank you

EXCELLENT!! Good job. We're proud of you. I think we might have hit close to a record number of posts for one project!

Now you can start thinking about next year's project. We'll be waiting to hear your ideas.

All the best,

Sybee