The Effect of Temperature on Rate of Cellular Respiration in Pea Plants (Pisum sativum) G. Carroll, I. DiBianca, and A. Trumpore Problem Statement: The effect of the temperature of peas and their immediate surroundings is investigated to determine a relationship between temperature and respiration rate of germinated peas.

Background Information and Hypothesis - Pea plants naturally grow in cool temperate spring climates whose temperatures range from 10°C to 20°C - Ideal temperature range for pea plant growth is 13°C to 18°C - Pea plants can tolerate temperatures as low as -10°C, or -30°C if snow- covered - Pea plants do not grow well in warmer temperate or tropical climates It is proposed that the respiration rate of peas will be greatest at the room temperature test point (18°C), with rate decreasing gradually to its second-highest tested rate at 5°C, and dropping off above 18°C to it at slowest tested rate at 35°C.

Procedure - Baseline is conducted at room temperature measured at 18°C according to baseline procedure Colder 1. Test tubes are prepared with basic gas pressure probe setup 2. Large beaker of water is cooled using ice cubes to target temperatures (5°C or 12°C) 3. Ice cubes are removed and beaker is placed in styrofoam box with lid 4. Test tubes are inserted through cardboard holder and placed in the large beaker, as submerged as possible 5. Data is collected for 15 minutes 6. Temperature after trial is verified 6. Setup is disassembled and cleaned Warmer 1. Test tubes are prepared with basic gas pressure probe setup 2. Large beaker of water is heated on hot plate to 35°C 3. Test tubes are inserted through cardboard holder and placed in the large beaker, as submerged as possible 4. Data is collected for 15 minutes 5. Temperature after trial is verified 6. Setup is disassembled and cleaned

Results Slope (kPa/min) Y-Intercept (kPa) Adjusted Slope (kPa/min) 35°C Germinated Germinated Germinated Average Glass Beads N/A Slope (kPa/min) Y-Intercept (kPa) Adjusted Slope (kPa/min) Room Temperature (18°C) Germinated Non-Germinated Glass Beads N/A 5°C Germinated Germinated Germinated Average Glass Beads N/A Slope steepest at 18°C Steeper than that at 35°C by kPa/min

Results Room Temperature (18 °C)5°C 35°C Green - Glass Beads Blue - Ungerminated Peas Red - Germinated Peas Green - Glass Beads Blue - Germinated Peas 1 Red - Germinated Peas 2 Blue - Glass Beads Red - Germinated Peas 1 Green - Germinated Peas 2

Discussion and Conclusion The hypothesis was disproved -- The greatest measured rate of respiration was at 18°C, but only by kPa/min Respiration at 5°C occurred approximately 0.34 times as fast as it did at 18°C and 35 °C Gradualness/suddenness of change in respiration rate as a result of change in temperature was not determined Decreased rate of respiration at 5°C likely resulted simply from lower temperature, less energy, slower reaction 35°C Temperature did not denature respiration enzymes in germinated peas

Discussion and Conclusion Questions for further study: Why do pea plants favor cooler climates even though germinated peas appear to respire faster when warmer? Effects of pea plant age throughout development? Sunlight? Soil? Other parts of the plant - roots, leaves? Other factors? Why can snow-covered pea plants tolerate colder temperatures than non-snow-covered peas?

References "Plants Profile for Pisum Sativum (garden Pea)." Plants Profile for Pisum Sativum (garden Pea). United States Department of Agriculture, n.d. Web. 17 Jan