The Action Spectrum for Photosynthesis
C) Engelmann's experiment revealed that very little oxygen was released by the region of algae that was exposed to what color(s) of light?
Photo provided by Pexels
Because the weight of carbon absorbed was less than the total weight increase of the plant, de Saussure reasoned that water is absorbed, and in so doing correctly outlined the major chemical transformations in photosynthesis.
Timeline is organized by the year when they were born, except for the first two
Theodor Wilhelm Engelmann was a German botanist, physiologist, microbiologist, university professor, and musician whose 1882 experiment measured the effects of different colors of light on photosynthetic activity and showed that the conversion of light energy to chemical energy took place in the chloroplast.
In 1883, Engelmann devised an experiment to learn which wavelengths (colors) of light were the most effective in carrying out photosynthesis in the green alga Spirogyra
He did this by illuminating the alga with light shone through a prism.
PPT - Photosynthesis: Harvesting Light Energy …
Photo provided by Flickr
Our experiment tested which color (red, blue, green) would influence the plant to produce the most amount of photosynthesis. There are four main photosynthetic pigments found in the chloroplast of the plant called chlorophyll a, chlorophyll b, xanthophylls, and carotenes. All these pigments absorb light and possibly utilize the light energy in photosynthesis. Light energy is essential for photosynthesis. An initial experiment showed that all the pigments at peak absorbance showed violet/blue light at the highest level, orange/red light as the second highest, and yellow/green having the lowest level of absorption. We hypothesized that photosynthesis was affected by the light absorption rate.
photosynthesis occurs in chloroplasts, mainly in leaf cells
Our results are contradictory with our hypothesis, based on our statistical results. There were several problems with our experiment that could have been taken into consideration. First, when taking respiration rates the foil wasnt covering the chamber all the way letting some external light in. Second, the colored cellophane only allows approximately 70% of light through; this might have prevented the plant from absorbing the amount of light energy needed to have a significant photosynthetic rate. Third, the fast paced moving between trials lost time and efficiency. By having short trials (2.5 min.) we might not have allowed the plant enough time to adjust its photosynthetic rate to the different wavelengths of light energy. Plus by moving the plant, and switching from cellophane to foil (or vise versa), might have screwed up the photosynthetic cycle by exposing it to white light.
Answer activity light energy and pigments click ..
Other students who did the same experiment had results that also supported that blue light was not responsible for the rate of photosynthesis. Experiments Warsh et al. 2001, Bahramzadeh et al. 2001, and Whorley and Weaver. 2002 all showed that red had much higher rates of photosynthesis than blue, but these experiments had fewer trials or shorter trials. Lots of other students also used white light as a controlled variable; this would have been a good thing to put into our experiment to give it some comparison.
Which Wavelengths of Light Drive Photosynthesis?
It has been mentioned in the historical outline that photosynthesisis dependent on light. The results of ENGELMANN and SACHS showedthat it is absorbed by chlorophyll. We also got to know that plantshave , chlorophyll a and b and that bothtypes display a characteristic .