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Different wavelengths of light affect on photosynthesis rates in tomato plants

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Background Information:
The leaves of a plant are the main photosynthetic organs and are involved in gas exchange and water transportation throughout a plant (Evans et al, 17). A leaf typically consists of an upper and lower epidermis, the mesophyll cells, veins, guard cells and stomata. The mesophyll cells contains spongey cells which have large gaps between each cell to allow oxygen and carbon dioxide circulation. The mesophyll cells contain palisade cells, which are located beneath the upper epidermis. The palisade cells contain many chloroplasts, which are green organelles. Located in the internal layers of chloroplasts is the pigment chlorophyll which is involved in trapping the light energy in photosynthesis (Evans et al, 17). …show more content…

 Short wavelengths = high frequency = more energy
 Long wavelength = low frequency = less energy

Plants can absorb a number of different length light waves, although not all of them are equal in power or energy which influences a plants growth. Approximately 80% of light that reaches a leaf is absorbed and depending on its wavelength, may excite chlorophyll pigments (reference text book). Plants absorb both red and purple light waves, however because purple wavelengths are shorter, they contain more energy. The green pigment involved in photosynthesis is chlorophyll. Chlorophyll is green in appearance because it absorbs red and blue light, making these colours unable to be seen. It is the reflection of the green light that reaches out eyes, giving chlorophyll a green colour. This green light that can be seen cannot be used by the plant for photosynthesis. Therefore, theoretically growth should be inhibited in the plants only exposed to green light.

There are two main types of chlorophyll, chlorophyll a which absorbs wavelengths of 430nm (blue) and 662 (red) and is the main photosynthetic pigment, and chlorophyll b, which doesn’t directly participate in the photosynthetic process, but is capable of donating its energy to chlorophyll a

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