Introduction

Lauren Beach

In Lab Stream 1, we explored the differences in the carbohydrate composition, photosynthetic pigments, and enzyme composition of Bartlett pears, Pyrus communis , and

Macintosh apples, or Malus pumila in our independent lab research . We chose to research the differences between these two fruits after learning that the exact genetic

relationship between apples and pears remains undetermined, though scientists have conducted research that suggests that apple SSR's (small subunit RNA's) can be used to

determine good sequences for pear SSR analyzation –results that show a significant genetic link (Yatamoto, 2001). Perhaps unsurprisingly then, both P. communis and M.

pumila belong to the same family, Rosaceae, and the same sub-family, Pomoideae (Yatamoto, 2001). Despite these similar taxonomies, however, researchers find that

significant differences between apples and pears exist in sugar levels, with pears containing approximately 15% sugar while apples contain about 40% (Calderone, 2003).

We compared the carbohydrate composition of Bartlett Pears and Macintosh apples, therefore, by analyzing the types and levels of carbohydrates present in both fruits.

We hypothesized that the two fruits will both contain the same types of sugars that we test for, including (monosaccharide) reducing sugars, glucose, and starch, and that

the sugar levels in the two fruits will not be equal.

We also analyzed the pigments present in the leaves of each of both fruits, as well as to determine both of their action and absorption spectra. This gave us the ability to

analyze how the two plants photosynthesize light, allowing us to observe the level of similarity between the two fruits. We hypothesized that the types of pigments present

in pear and apple leaves should not differ, since research has shown them to be fairly closely related and photosynthesis is a highly conserved plant biological process

(Yatamoto, 2001). Furthermore, we expected the absorption and action spectra to show similar patterns in their results.

Lastly, we tested for the presence of PPO, observed the effect that heat and inhibitors enacted, tested the pH, and performed Bradford assays on both fruits. As with the

last two experiment clusters, we hypothesized that the two fruits should show similar results in all three tests due to their relatedness. Overall we hypothesized that no

significant differences in the lab results of apples and pears would exist.

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