Chlorophyll is a substance found in chloroplasts, found in the cells
of leaves. They are used to produce glucose which is used as plant
food and growing materials (e.g. cellulose).A leaf which is exposed to
plenty of light will have sufficient amounts of food and will not need
an excessive amount of chlorophyll. This enables the leaf to have a
small surface area. It is also necessary for leaves in areas of high
light intensity, and thus high temperature, to have small leaves to
reduce the amount of transpiration. The heat will cause water to
evaporate a lot faster.
Leaves in shaded areas will need a large surface area full of
chlorophyll to collect as much sun light as possible; essential for
survival. These leaves will also have no threat of excessive
transpiration because the temperature in the shaded area will be lower
and the humidity probably higher.
Transpiration is the removal (evaporation) of water from a plant
through the stomata in the leaves; this water is removed in a cycle
due to the active uptake from the roots. Transpiration involves
osmosis; which is the diffusion of water from a high concentration to
a lower concentration through a partially permeable membrane, until
both the concentrations are equally saturated.
All these factors i.e. transpiration and photosynthesis, come together
to confirm my hypothesis.
To support my hypothesis further, I did a pilot study in a meadow in
which I studied the population of certain plant species in areas of
different light intensities. I learned that different plants need
different environmental factors to grow well. The leaves in the shade
were larger than those in the open field.