Arduous Learning of English for a Science Student (Appendix)

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Arduous Learning of English for a Science Student (1)
Arduous Learning of English for a Science Student (2)
Arduous Learning of English for a Science Student (3)
Arduous Learning of English for a Science Student (4)
Arduous Learning of English for a Science Student (5)

以下に実際に私が書いた論文を載せる。 ちなみに、73点と評価された。

The difference of the effect of promoting senescence among apple parts

Introduction

It is well known now that ethylene is very important hormone that has various functions in plants (Lelièvere, Jones, Bouzayen, & Pech, 1997). Especially, the production of ethylene has been studied in terms of management of fruit storage (Ketsa, Chidtragool, Klein, & Lurie, 1999 and Riov & Yang, 1982). Ethylene can affect other vegetable and can mature them. Hodge & Forney (2000) found that the more ethylene gas the air around stored apples contains, the more severely they suffer from oxidation.

Some study to determine where vegetables or fruits produce ethylene is already done. Wang & Adams (1980) found that chilled cucumber’s skin tissue had more ACC, which plays important part in ethylene production, than cortex tissue. In addition, as for kiwi fruit, skin produced much more ethylene than any other part (Agar, Massantini, Hess-Pierce, & Kader, 1999).

The amount of ethylene produced under certain environment was different among fruits and vegetables. For example, the reaction to temperature was different among apples, tomatoes and digitatum (Mattoo, Baker, Chalutz, & Lieberman, 1977). ? Thus it is meaningful to study the case of apple. Ethylene synthesis of apple is more active when enough O₂ exists (Lieberman & Kunishi, 1966). Therefore we hypothesized that apples have ethylene synthesis system in skin rather than in core so that they can get enough air efficiently.

Method

Apples

Jonagold was chosen for this study because it produces relatively large amount of ethylene (Yoshioka, Aoba, & Fukumoto, 1989). One apple at commercial maturity was used in this experiment.

The apple was cut into pieces with a knife and the pieces were categorized into three groups: skin, flesh, and core. The pieces of each category were grated into paste to arrange the condition of surface area to the same and because wounding enhances ethylene production (Yu & Yang, 1980).

Procedure

Three Ziplocs were kept in a refrigerator at 0.7ºC for a week. Each bag had 20g of apple paste of three different categories in a small container made from a plastic bottle. The mouths of Ziplocs were kept fastened.

Three pieces of a leave of spinach commercially available was put in each Ziploc. The leaves were chosen so that the sum of the weight of the three is 4.2g. The leaves were put out and taken photo of every night at 0:00 a.m. The speed of the change of their color could be seen as an index of the ethylene amount of each apple paste produced.

 The color of a leave was analyzed with Image J. Leaves of Spinach turn yellow when they get old according to the consumption of sugar [Hisaka, 1989]. So the color can be seen as an index of senescence. The scope of leaves was selected and the mean score of RGB value of the area was calculated.

Result

The experiment was stopped 4 days after the start because the leaves had much fungus on them.

No significant change of color in all situations (Figure 1~4, 95% of confidence interval). However, leaves with skin tended to lose its green color and gain red color rather than leaves with flesh or core. Compared to the controlled group, no other group was likely to lose its green color more remarkably.

Figure 1 The change of each color element of leaves with apple skin in 4 days. Blue bars show the mean of the strength of each color of the three leaves measured on the first day. Red bars show the value of 4^th day.

Figure 2　The result on leaves with apple flesh.

Figure 3 The result on leaves with apple core.

Figure 4 The result on leaves with nothing.

Discussion

 There is no statistically trustworthy evidence on the effect of ethylene. However, this result still contains some suggestions. Yellow color is a combination　of　red and green. In controlled group, there was little change in red color but there seems to be slight decrease in green color. The green color is probably lost by itself as time passes, while red color was held through 4 days. In this view point, the index of ethylene production may be red color, and it is suggested that core produced ethylene most, although we could not find any explanation of the reason for the increase of green color.

 We lacked enough leaves so we could not gain data that is trustworthy, and another experiment using sharper index is needed to prevent precedence of generation of fungus over senescence.

References

Agar, I. T., Massantini, R., Hess-Pierce, B., & Kader, A. A. (1999, May). Postharvest CO2 and Ethylene Production and Quality Maintenance of Fresh-Cut Kiwifruit Slices. Journal of Food Science, 64(3), 433-440.

Hisaka, H. (1989). A relation of Change in Appearance to Cjanges in Sugar Content and Respiration Rate in Spinach during Storage. Nippon Shokuhin Kogyo Gakkaishi, 36(12), 956-963.

Hodge, D. M., & Forney, C. F. (2000, March). The effects of ethylene, depressed oxygen and elevated carbon dioxide on antioxidant profiles of senceing apinach leaves. Journal of Experimental Botany, 51(344), 645-655.

Ketsa, S., Chidtragool, S., Klein, J. D., & Lurie, S. (1999, January). Ethylene synthesis in mango fruit following heat treatment. Postharvest Biology and Technology, 15(1), 65-72.

Lelièvere, J. M., Jones, A. L., Bouzayen, M., & Pech, J. C. (1997, December). Ethylene and fruit ripening. Physiologia Plantarum, 101(4), 727-739.

Lieberman, M., & Kunishi, A. (1966, March). Stimulation of Ethylene Production in Apple Tissue Slices by Methionine. Plant Physiology, 41(3), 376-382.

Mattoo, A. K., Baker, J. E., Chalutz, E., & Lieberman, M. (1977, June). Effect of temperature on the ethylene-synthesizing systems in apple, tomato and Penicillium digitatum. Plant and Cell Physiology, 18(3), 715-719.

Riov, J., & Yang, S. F. (1982, March). Autoinhibition of Ethylene Productioni n Citrus Peel Discs. Plant Physiology, 69(3), 687-690.

Wang, C. Y., & Adams, D. O. (1980, November). Ethylene Production by Chilled Cucumbers (Cucumis sativus L.). Plant Physiology, 66(5), 841-843.

Yoshioka, H., Aoba, K., & Fukumoto, M. (1989). Relationships between qualitative and physiological changes during storage and maturation in apple fruit. Journal of the Japanese Society for Horticultural Science, 58(1), 31-36.
Yu, Y. B., & Yang, S. F. (1980). Biosynthesis of Wond Ethylene. Plant Physiology, 66(2), 281-285.