Color & Light Effects on Photosynthesis | Hunker

Various other living beings, including humans, are either direct, or indirect beneficiaries of photosynthesis.



Sunlight is one of the basic requirements when it comes to photosynthesis and that explains why plants don't photosynthesize at night.

Effect of colour of light on the rate of photosynthesis

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.


Affect of Different Colored Lights on Photosynthesis

Other than glucose, which is an important source of carbohydrates, even proteins, fats, and water-soluble sugars are the products of photosynthesis.

Five different variables were tested; green light, red light, yellow light, blue light, and regular white light at a controlled distance of approximately 10cm.


How does the level of light affect the rate of photosynthesis

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 wasn’t 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.

Light Color: Number of Bubbles (Light = 6.0 | CO2 = 6.0) 1

Considering that not all light energy is used for photosynthesis we propose an alternative hypothesis. In a previous experiment the pigment xanthophylls absorbed significant amounts of blue light. In new research it is found that this pigment could be an important component in a process called energy dissipation rather than photosynthesis. In order to not overwhelm the plant with photosynthesis and respiration, this photon energy goes to other functions or formations of the plant. Further research on the function of xanthophylls will need to be conducted in order to understand the processes of plant function.

Photosynthesis - light reactions - YouTube

Plants also usemultiple variants of chlorophyll, as well asaccessory pigments such as carotenoids (which givecarrots their orange color) to tune themselves toabsorbing different wavelengths of light. Thatmakes it impossible to assign a single wavelengthof best absorption for all plants. All plants,however, has chlorophyll a, which absorbs moststrongly at ~450 nm, or a bright blue color. Thiswavelength is strong in natural sunlight, andsomewhat present in incandescent lights, but isvery weak in traditional fluorescent lights. Special plant lights increase the amount of lightof this wavelength that they produce. But a400-500 nm wavelength bulb wouldn't be enough,since many plants take cues for germination,flowering, and growth from the presence of redlight as well. Good plant lights produce redlight as well, giving plants all the wavelengthsof light they need for proper growth.