Light Intensity Experiment

Introduction

Photosynthesis is one of the most important sections of biology and has always interested me. This process is affected by many aspects which drove me to question if one can identify the effect of high and low light intensity specifically from leaves on any plant. The structure, dimensions and pigments of a leaf should (theoretically) all be indicators of the type of light intensity environment the plant is situated in.

Light intensity is one of the factors affecting the rate of photosynthesis. Other factors are concentration of carbon dioxide, temperature and to a lesser degree, water. Light is a limiting factor when the light intensity is too low to allow the light-dependent reaction to proceed at its maximum rate. Light is not

As light intensity is increased further, however, the rate of photosynthesis is eventually limited by some other factor. (Benckiser, 2013) So the rate reaches a maximum. At very high light intensity, chlorophyll may be damaged and the rate drops steeply. This source is reliable as it is a document that focuses on the limiting factors that affect photosynthesis and pertains to this experiment because according to the graph provided, a plant photosynthesises at different rates at different times of the day. According to a school-curriculum based website which supports this source (IGCSE, 2014), a plant is unable to harvest light at high intensities and the chlorophyll system can be damaged by very intense light levels.

The difference between shaded and non-shaded plants and their rate of photosynthesis can be seen in an example of a rubber leaves experiment where the photosynthetic rate of rubber leaves developed in 25% full sunlight was less than one-third that of plants growing in full sunlight. (RODRIGO, 2003) This result can be deemed reliable and valid as it was conducted by three biologists at the University of Wales. This experiment indicates that plants have adapted to survive in shaded conditions and thus should be depicted in its structure and chlorophyll

Step 2: Measure the length and width of each leaf for both the non-shaded and shaded plants and record the measurements in a data table. The length must be measured according to maximum vertical vein structure and the widest width of the leaf.

Step 3: Place safety gloves over your hands and secure the face mask on your head.

Step 4: Place 50 ml of isopropyl alcohol into the bottom of a clean empty glass jar using a syringe.

Step 5: Take 10 leaves of the non-shaded plant and use the scissors and the pestle and mortar to crush the leaves as much as possible. It is essential to use the leaves when they are as fresh as possible, do not leave them unattended after the measurements are taken.

Step 6: Place the crushed leaves into the bottom of the glass jar of isopropyl alcohol so that they cover the bottom.

Step 7: Place the lid on the glass jar tightly.

Step 8: Pour hot water into a large bowl and place the glass jar in it.

Step 9: Leave the glass jar in the hot water for an hour and shake the jar gently sideways from time to time to stir the leaves.

Step 10: Prepare chromatography strips by measuring and cutting 13mm x 130mm rectangular