Week 1: The Set up
November 7, 2011
Purpose
The purpose of this experiment was to obtain and set up the four differnt types of Wisconsin Fast Plants for observation, determine how the effect of the blue light source would be investigated, determine what phenotypic characteristics would be analyzed for the plants and by what measurements they would be recorded. Additionally, the purpose was to plant the Wisconsin fast plants so that the determined phenotypic characteristics could be observed over the following week.
Background
In this part of the experiment, two types of each of the four plants were randomly set up in a plant flat under a blue light source so that phenotypic characteristcs could be obseved. Plants normally absorb light in the red and blue regions and reflect green light. The principal photoreceptors are the red and far red light-sensing phytochromes, as well as the blue-light sensing cryptochromes and phototropins (Azari, 2009). Cryptochromes are nuclear proteins that mediate light control which ultimately mediates stem elongation, leaf expansion and the circadian clock. These photoreceptors may interact with proteins such as the phytochromes. Recent studies suggest that cryptochromes undergo a blue-light dependent phosphorylation that influences conformation, intermolecular reactions and protein abundance within the plant, as well as the physiological activities of the plant itself. Additionally, phototropins are blue light and UV light receptors that mediate light driven movement that causes photomorphogenetic responses including inhibition of stem elongation, stimulation of leaf expansion and opening of the stomata (Lin, 2003). Additionally, plants have anthocyanin pigments which are often red, purple or blue. These pigments have been found to help protect a plant against light stress, specifically blue and UV lights. Based on this information the hypothesis for this part of the experiment was that the non-purple plants would have a higher average percent growth and a lower average leaf area than the other plants because they lack the anthocyanin pigment and will therefore, absorb more blue light.
Methods
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Two plants of each of the four Wisconsin Fast Plant species (standard, variegated, purple, and non-purple) were obtained after having been germinated a week before and grown under 24 light.
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A plant flat with 8 pots was obtained and each of the 8 plants was placed randomly in a pot of the flat
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A box was obtained and the lid of this box was cut to insert the light source apparatus which was donated by Dr. Kevin Folta of the University of Florida.
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The light source in this specific experiment set the blue light to an intensity of 9 and the far-red, red and green lights were set to an intensity of 1.
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The plants were each watered and then the flat was placed inside of the cardboard box.
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Over the next week, the stem height (mm), leaf area(squared millimeters) and the direction of growth were measured and recorded for each plant daily between 12:00pm-2:00pm.
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Plants were watered as necessary.
Results
No interpretive results were obtained during this first week, however, the resulting plant set up was recorded.
Conclusions
No formal results were obtained in this experiment, only the set up of the plants and the decision to have blue light at an intensity of 9 and red, far-red and green lights at an intensity of 1 were made. Phenotypic results were compiled in Week 2. Therefore, there were no conclusions drawn from this first week.