The not so sweet truth about red tomatoes.

The not so sweet truth about red tomatoes.

Alexander Anaya Ashe

American InterContinental University

2/19/2016

The not so sweet truth about red tomatoes.

• Purpose
• Are tomatoes sweetness affected by the green chloroplasts in the fruits?
• Introduction
• Plants are green because of the light being reflected by the chlorophyll pigments inside of chloroplasts. It is these chloroplasts that capture photons from the suns light energy and through the process of photosynthesis turn those photons into glucose. (Editorial Board [EB], 2016, p. 49). Tomatoes originally had green shoulders and where reported to be sweeter. Over the years farmers have cross bred tomatoes to be a uniform red color for aesthetic and harvesting reasons.
  
      “Studies from the University of California, Davis, found that tomatoes need the correct version of a particular gene (one called SlGLK2) to form chloroplasts properly in the fruit.” (Kawok, 2012, para. 5).
  
  The tomatoes without green shoulders are the ones that have been bred to have the wrong version of this SlGLK2 gene which results in smaller and fewer chloroplasts.
• Hypothesis or Predicted Outcome
• I hypothesize that the modified tomatoes are less sweet because of their inability to create a surplus of glucose as a result of having fewer and smaller chloroplasts than those of natural tomatoes and that a restoration of the S1GLK2 gene will in fact result in sweeter tasting tomatoes.
• Methods

 2 variations of tomatoes plants are grown in a completely controlled environment;

(A) Genetically modified to have S1GLK2,

                  (B) Tomato plant without S1GLK2,

3 of each variation of tomato plant are grown simultaneously in individual controlled environments with no variables other than the tomato plants themselves. Glucose measurement takes place at 30, 45, and 60 days of growth for each plant. Glucose measurement takes place by choosing tomatoes from the same location on each plant which are then blended and the glucose levels measured.

• Results or Outcome
  
  

Key:

(A)  Genetically modified to have S1GLK2

(B)   Tomato plant without S1GLK2

	Trial 1 A/B Glucose Level	Trial 2 A/B Glucose Level	Trial 3 A/B Glucose Level	Average A/B Glucose Level
Days of Growth
30days	20 / 18	21 / 18	20 / 18	20 / 18
45 days	28 / 25	30 / 26	29 / 26	29 / 26
60 days	46 / 30	47 / 30	47 / 30	47 /30

Tomato plants (A) on day 30 produced 20, 21, and 20 Glucose Levels [GL] resulting in an average production of 20 GL during the 3 trial study. Tomato plants (B) on day 30 produced 18 GL, 18 GL, and 18 GL resulting in an average production of 18 GL during the 3 trial study.

Tomato plants (A) on day 45 produced 28 GL, 30 GL, and 29 GL, resulting in an average production of 29 GL during the 3 trial study. Tomato plants (B) on day 45 produced 25 GL, 26 GL, and 26 GL resulting in an average production of 26 GL during the 3 trial study.

Tomato plants (A) on day 60 produced 46 GL, 47 GL, and 47 GL, resulting in an average production of 47 GL during the 3 trial study. Tomato plants (B) on day 60 produced 30 GL, 30 GL, and 30 GL resulting in an average production of 26 GL during the 3 trial study.

Discussion and Analysis

Data collected during the experiment lead me to conclude that my hypothesis was correct that the tomato plants with the correct S1GLK2 gene would produce fruits with a higher glucose level than that of the plants without the gene.
If I was to continue the experiment I would perform it again in a manner that I could determine how many chloroplasts each tomato has to give better understanding on the exact nature of the S1GLK2 gene.

References

Kwok, A. (2012). Tomatoes tasteless green gene. Student Science. Retrieved

     from https://student.societyforscience.org/article/tomatoes%E2%80%99-tasteless-green-gene

Kupaferschmidt, K. (2012). How tomatoes lost their taste. Science. Retrieved

     from http://www.sciencemag.org/news/2012/06/how-tomatoes-lost-their-taste

Editorial Board (2016). Biology. Words of Wisdom. Retrieved

 from https://bookshelf.vitalsource.com/#/books/9781934920602/cfi/60!/4/4@0.00:0.00