The Success of Photosynthesis in Geranium Leaves Using Visible Light Wavelengths Obstructed by Black Paper, and Red, Blue, and Green Translucent Filters.
Title: The success of photosynthesis in geranium leaves using visible light wavelengths obstructed by black paper, and red, blue, and green translucent filters. I. Abstract Photosynthesis is a process in which plants use light, water, and carbon dioxide to produce sugars, water and oxygen. Chlorophyll a and chlorophyll b, in the chloroplasts of a leaf, are responsible for absorbing wavelengths of light for use in photosynthesis with red and blue wavelengths being optimal. Testing for the most productive wavelength of light was done using four separate geranium leaves that were covered by red, green, and blue translucent filters, and black paper. The experimental areas of the leaves were compared to a control area that was left uncovered and a subjective rating from 0 to 5 was given to each area depending on the color seen after adding I2KI solution to the leaf. I2KI solution was used because this solution turns purple in the presence of starch. The red filter showed more starch content overall followed by blue, green, and black paper. The red filter was more successful because it transmitted red wavelengths that were better absorbed for photosynthesis, although the blue filter was also successful. The reasoning for the blue filter not being as successful as the red is not clear. The green filter was less successful because it transmitted light that chlorophyll usually reflects. The black filter was the least successful because it absorbed nearly all of the wavelengths and few were able to transmit into the leaf. II. Introduction Photosynthesis is the process that plants use to make food. Green plants use pigments called chlorophyll, located in chloroplasts, to absorb the incoming light and use it in the photosynthetic process (Massa, Carabella, & Fornasari, 1997). According to Lawlor (1987), there are two different types of chlorophyll: chlorophyll a and chlorophyll b, that collectively capture almost all of
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