Materials:
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Freshly gathered clover plants with roots (choose those with obvious pink root nodules)
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Scalpel or razor blade
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Microscope
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Microscope slides
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Cover slips
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Observation notebooks
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Gloves
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General Stain
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Procedure
Shake off excess soil from clover roots and rinse with deionized water and alcohol. Using a scalpel or a razor blade, break open a root nodule. (The tissues inside the nodule should appear pink indicating the presence of the plant protein, leghaemoglobin, that is necessary to fix nitrogen). Smash nodule or chop into very small pieces, place a small amount on a slide and mix with a drop of water to create a wet mount. Place cover slide over specimen and examine wet mount under a microscope. To make cells more visible, a general stain can also be used. For staining, first heat fix the specimen to the glass slide by allowing the sample mixed with the water drop to dry onto the slide by passing the slide back and forth over a flame (specimen side up and not in contact with the flame). Next, flood heat-fixed specimen with a general stain (e.g. Gram's crystal violet, methylene blue) and allow it to sit for one minute. Then gently rinse the slide with tapwater to remove excess stain (until water runs clear). Add a water drop and cover slide for observation under the microscope. Rod shaped bacteria should be visible under the microscope. Record observations in Interactive Notebook.