Developmental Plasticity in Oak Leaves: A Comparison of Sun Leaves vs Shade Leaves - Lab Report Example

There exists a notable variation in leaf shape within a tree canopy for plants such as oak and maples. This phenomenon is such that leaves fully exposed to the sun will have very deep sinuses to facilitate maximum penetration of sunlight to the other leaves underneath them (Chabot, et al, 1979). However, the leaves in the shade have shallow sinuses to enable them to intercept the maximum sunlight available to them. Further, sun leaves have additional layers of photosynthetic cells which makes them thicker than shade leaves (Jurik, 1986).

This lab exercise report attempts to establish the differences in the shape and sizes of the sun and shade leaves. Introduction Leaves in plants are the photosynthetic sites. They absorb the requirements for photosynthesis in the sunlight. Since light is a key requirement for photosynthesis, plant leaves will tend to trap more or the maximum sunlight they can access (Collinveaux, 1986). As such, most plants develop leaf modification depending on their habitat and ecological niche hence broad, narrow and spiky leaves appear in various plants in various habitats.

The oak leaves are not any different and so will portray different surface areas and sinuses for those in shade and sun. Materials and MethodsIn this experiment, graph paper, a Glant press, and a weighing machine with an accuracy of 0.1g were used. Leaf samples were obtained from the Oak plant with emphasis laid on the relative position of each leaf. Thus 45 leaves were picked from the shade while another 45 were from the light. Using the graph, the leaf surface areas were obtained and with the Glant press, a polygon was traced on each leaf to determine the sinusoidal surface of each leaf.

The procedure was repeated for each leaf and enough data was obtained for analysis using computer software for the t-test. From the experimental results, it is established that sun leaves are narrow while shade leaves are wide. However, the sun leaves are thicker than the shade leaves based on the average sinuosity. This points to the general requirement of light by the two types of leaves.