Avocado Leaf Plasticity Essay
DIFFERENCES IN SUN AND SHADE LEAVES OF AVOCADO TREES BY PHENOTYPIC
PLASTICITY
INTRODUCTION: Phenotypic plasticity, or differing phenotypes from one genotype in different
environmental conditions, is a way for sessile organisms to adapt to changing environmental
conditions (Valladares et al., 2007). Plasticity was expected to be abundant, however, it did not
occur as often in nature due to resource limitations and environmental stress (Valladares et al.,
2007). An experiment by Matos tested the phenotypic plasticity to light availability in shade and sun
leaves of coffee trees (Matos et al., 2009). Their research indicated that compared [to] sun leaves,
shade leaves had a lower stomatal density, a thinner palisade mesophyll, a ... Show more content on
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This process was done twice on each tree in the understory for shade leaves, and in the canopy for
sun leaves. Each leaf was measured for its surface area, length to width ratio, mass, specific leaf
mass, and color. Surface area was measured by a leaf area meter in squared centimeters. Length
to width ratio was measured by measuring the length (vertically along the bridge of the leaf) and
the width (horizontally on the widest part of the leaf) with a ruler in centimeters, and dividing
the length by the width. Mass was calculated by a balance in grams. Specific leaf mass
(thickness) was measured by dividing the mass by its surface area in grams per squared
centimeter. Color was measured by having three reference leaves provided by the instructor,
indicating light (L), medium (M), and dark (D) leaves and compared our collected leaves. After
recording all of the data, these data were then input into a statistical program called StatCat to
determine normality through a normality test. The data for surface area, length to width ratio,
mass, and specific leaf mass for sun and shade leaves were both normal, therefore, we chose a
paired sample t test for all of them. A normality test was not needed for color for sun and shade
leaves due to it being a nominal scale data. The number of light, medium, and dark shade leaves
were tallied up according to color, and the same was done for the sun leaves. A contingency table
was made in
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