Develop your hypotheses:
Read through this handout so you know what you’re going to do. You may work in groups, but every student is responsible for their own report. (Note: there are basic protocols at the end of this document to help you understand what types of measurements are possible.)
Develop your hypotheses: Your multiple hypotheses must relate to plant adaptations to water stress. Here are a few questions under which your hypotheses might be developed: (1) To what extent is there phenotypic plasticity (i.e., acclimation) in leaf characteristics within a species depending on water availability?; (2) What trends are there in the types of leaf characteristics exhibited by different species that grow in habitats with different water availability (or wind exposure, temperature, or humidity)? You are welcome to develop a different question as well, but it must be more interesting than what plant adaptations you observe. Your hypotheses should be specific, describing what you expect to see and a rationale for why. It is ok to have different hypotheses for different species or for different water availabilities. It is ok to have alternative hypotheses that are directly contradictory as long as you have a rationale. But, you must be specific and have a logical rationale.
Develop your methods: You must measure several leaf characteristics. Your methods must directly relate to your hypotheses. Your methods should describe your sampling design, the types of leaf characteristics you will measure, and how you will analyze your data (basic statistics like mean and standard deviation, t-Tests, ANOVA, etc.). The sampling design should include replication so you can estimate variability. I will provide protocols for making imprints of leaf stomata and other types of measurements.
Conduct your study: Collect your data as outlined in your methods – if you change anything, make sure to make note of it. Mark your locations on the map (last page). Take general field notes (like you did for the CUI tour) describing your locations, making sure to take note of the four aspects of the abiotic environment described above as being important for plant water relations. Your general description should talk about the setting of your site (where it is, what surrounds it, if there are streams or other topographic features, flat or slope or ridge, etc.), the weather during your observation (including temperatures, clouds, wind), and the plant community (e.g., riparian, grassland, dead forbs, etc.). Take imprints of leaf stomata. Collect leaves for analysis using the shears.
Analyze your data: Input your data into Excel or similar. Do your statistical analysis. Make tables or figures that provide support for or falsify your hypotheses.
Interpret your data: Interpret your data in light of your hypotheses – is there support or do the results falsify each hypothesis? Do some research (textbook, internet, peer-reviewed publications, etc.) to see if you can find out why and to see how your hypotheses and results compare to those of other researchers. Describe why there are similarities or differences (methods?; location?; species?). Your research must include at least ONE peer-reviewed publication (journal article, conference proceedings, or government report) and at least ONE other source (anything reputable looking, including Wikipedia). You must CITE your research sources in your assignment.
You will turn in an abbreviated lab report with the following sections:
The lab report should be short (500-800 words), double-spaced, and turned in on Blackboard before class on Friday, February 9 (week 5).*I will change the semester calendar to reflect this.
Map of field sites (mark and label the approximate location of your field sites)
Abiotic factors: Measure your abiotic factors, such as temperature, soil water, or wind, using one of the available pieces of equipment. If not possible, then make sure you qualitatively assess the abiotic factors (e.g. obvious soil moisture differences, North facing hill versus E, W, or S-facing hills, obvious wind exposure/protection)
Leaf size (cm2) – outline and count squares on grid paper or ImageJ image processing (more accurate)
Leaf density – calculate g/cm2
Leaf shape and margin – qualitative; compare to guide
Leaf spectral absorbance/reflectance – spectrophotometer
1) Prepare your samples
a. Wear goggles and gloves!
b. Tear leaf into small pieces, discarding large veins
c. Weigh out 0.3 g of leaf tissue
d. Place leaf tissue into small beaker with 30 mL ethanol
e. Grind tissue in ethanol until pulverized
f. Filter liquid through a coffee filter into a clean beaker
i. Throw away your used coffee filter!
g. Fill a clean glass cuvette to 2/3 full with your leaf liquid
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