Project Summary

 Project Information

 Abstract

 Project Summary

 Introduction

 Purpose/Hypothesis

 Materials

 Methodology

 Methodology Diagram

 Data

 Graphed Results

 Results Summarized

 Pictures

 Sources of Error

 Discussion

 Conclusion

 Applications

 Glossary

 References

 Acknowledgements

 Journal

Purpose:          Which type of antioxidant Vitamin will prove to be most effective for protecting plant cells against the harmful effects of free radicals?

Background Introduction:          Free radicals are aggressive, chemically active and unstable molecular complexes that compete with other molecules within cells: extracting from them the missing electron, in order to achieve a more stable configuration. This results in permanent damage to the attacked atomic complex that looses its electron and becomes a free radical itself. A chain reaction is spurred. Free radicals produced within cells can react with membranes, enzymes, and genetic material, damaging or even killing the cell. Thus, the augmentation of free radical formation can cause, over a period of time, widespread cellular destruction, which may translate into cancer, cardiovascular disease, accelerated aging, immune-deficiency diseases, and other degenerative diseases. Free radicals are typically formed as a result of normal cellular metabolism; however, studies have shown that their numbers in the organism greatly increases when its cells are exposed to damaging environmental influences, such as pollutants, sunlight, radiation, emotional stress, smoking, excessive alcohol, infection, and some drugs. New research has established that certain Vitamins can capture these free radicals, and can neutralize them before they cause damage to vital tissue. These Vitamins are classified as antioxidants. By pairing up with free radicals, antioxidants can create non-damaging compounds that can be eliminated by the body as waste. There are several enzyme systems inside of the body that scavenge free radicals; however the best ones include Vitamin E, Vitamin A (beta-carotene), and Vitamin C (Ascorbic Acid). The body cannot make these micronutrients (Vitamins) so they must be supplied or supplemented in the diet. Good sources of antioxidants include fruits and vegetables.

Procedure:          Germinating bean and radish seeds were placed in a hostile, artificial environment containing hydrogen peroxide (H202) as a source of free radicals. Several trials were conducted, where fifteen Petri dishes were lined with filter paper, and divided into five groups of three. Group 1 was saturated with 5 ml of water, Group 2 with 5 ml of 3% H202, Group 3 with the liquid content of a clear gelatin envelope capsule filled with Vitamin A palmitate (10 000IU), Group 4 with the liquid content of a Vitamin E d-alpha tocopheryl acetate (400IU) capsule, and Group 5 with 5 ml of a diluted ascorbic acid solution, obtained after dissolving a 1000mg Redoxon effervescent tablet in 100ml of water. The concentration of antioxidant added to each group was based on the recommended daily allowance for each Vitamin (RDA). These Vitamins were chosen because of their known antioxidant properties; to scavenge free radicals released by the seed’s reactions with hydrogen peroxide.

Either fifty radish seeds or fifty bean seeds were added to each Petri dish. Each Petri dish was then saturated with five ml of H202. All of the groups were placed under a growing light. The percentages of germinating seeds for each individual group were recoded after three days. Several trials were conducted for both the radish and the bean seeds.

Results, Observations, and Discussion:          The results displayed below determined that among the three Vitamins (A, E, and C), Vitamin A consistently promoted the largest percentage of germination to occur. This occurred both with the radish and bean seed trials. Vitamin C, on the other hand, was consistently the Vitamin that germinated the smallest percentage of seeds. The beneficial antioxidant effects of Vitamin E have been publicized; hence why I initially speculated that Vitamin E would prove to be the most beneficial. However, more recent studies are suggesting that Vitamin E may not have all of the benefits attributed to it earlier.

Radish Seed Trials
Average % of Germination

Bean Seed Trials
Average % of Germination

In addition, in the radish seed germination trials, it was the group of H202 that germinated the least amount of seeds. This was expected, as these groups were saturated with the most hydrogen peroxide, and therefore had the most free radicals. However, H202 did not completely inhibit seed germination, as the free radical content was not enough to entirely prevent the germination.

In the bean seed trials, H202 germinated the highest percentage of seeds. The composition, structure, and size of the bean seed may have been a determining factor. It is possible that the H202 helped to dissolve the thick outer epithelial layer of the bean seed, therefore helping it germinate faster. This situation did not occur with the radish seeds as they have a much thinner epithelial layer. Therefore, we can surmise that free radicals will have different effects on different living cells.

As expected, the seeds used up the H2O of the hydrogen peroxide (in order to grow), leaving an oxygen atom by itself: an unstable compound, a free radical. The radical derivatives of oxygen are the most damaging free radicals in the body: known as reactive oxygen species.

In the preliminary trials, the groups saturated with ascorbic acid did not germinate any seeds. Although Vitamin C is an antioxidant, at higher concentrations it has been proven to be a pro-oxidant and thus harmful. Subsequently, the dose of Vitamin C was diluted to approximate the RDA. In spite of this, Vitamin C was the Vitamin that germinated the least amount of seeds in both the radish and bean trials. When exposed to air, Vitamin C solution undergoes oxidation; which increases the formation of free radicals.

Overall, in both the radish and bean seed germination trials, results indicated that the group containing solely 5ml of water, and 5ml of H202 (no antioxidants) germinated a percentage of seeds close to that of Vitamin A. This was very interesting to note. In nature there are various elements that affect seed germination overall such as water supply, temperature, oxygen supply, and light.

Conclusion and Application:          Vitamins generally act as catalysts, combining with proteins to create metabolically active enzymes that in turn, produce hundreds of important chemical reactions in the body. Without Vitamins, many of these chemical reactions would cease. The intricate ways in which Vitamins act on the body and in plants, however, are still far from clear.

Vitamin A, has received particular attention as a disease preventing antioxidant. This coincides with these results, indicating that Vitamin A is the most beneficial antioxidant. Recently, many studies have noted a lower risk of cancer and cardiovascular disease among persons whose diets include a relatively large amount of Beta Carotene. A popular explanation is that Vitamin A can help to prevent carcinogenesis and atherogenesis by interfering passively with oxidative damage to DNA and lipoproteins (involved in cardiovascular disease).

There is little doubt that antioxidants are a necessary component for good health. However, there are still conflicting data as to the most beneficial Vitamin, and its amount for optimal results. In many studies, including this one, some results are distinct and others are more difficult to interpret, possibly because of the many variables involved. However, by studying the effects of antioxidants, such as in a vivo experiment on germinating plant seeds, one may be aided in their quest to find and promote a healthy lifestyle.

Acknowledgements:          The following people are acknowledged for their guidance and support: H. Panzini, MD, FRCPC, and R. Hakim, MD, FRCPS, H. Rees, Dr. Zeman, and BASEF. 

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Edinburgh: Edinburgh University Press

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The Gale Encyclopedia of Science – 2nd Edition, Volume Five

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Effects of a combination of beta carotene and Vitamin A on lung cancer
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