How Will Plants Survive In Scorching Heat and Crazy Winter Weather?


Colleen Walker and Ashley Stern


CU Boulder, Fall 2006



On this experiment we attempt to test the temperature of the rate of photosynthesis on C3 plants. We wanted to know if the enzymes in the juniper needles were able to consume more CO2 in a warm climate or in a cold climate.  Also, these juniper plants were plucked from Colorado where the weather consistently fluctuates everyday. It was then we hypothesized that the lower the temperature the slowly CO2 will go through photosynthesis but hotter the temperature the faster the CO2 will go through the photosynthesis.

To test our hypothesis we placed juniper leaves in 3 different containers, weighed all 3 containers with a scale with juniper leaves and without. We recorded how much CO2 they consumed with the CO2 gas sensor and recorded them 20 minutes each. Each container was placed in different condition. The 1st container we analyzed in a room temperature, the 2nd container was placed in cold environment, and the 3rd container took place in a boiling environment.  We analyzed the CO2 rating with the CO2 gas chamber to predict the photosynthesis for both light and dark cycles. We then took three trials for each container, analyzed them, and charted them on the graph. Our results showed that the rate of photosynthesis was highest at room temperature and lowest in the cold temperature. The rate or CO2 production in boiling temperature was –15.06 ppm/min, in the cold container our result showed that it was –2.05 ppm/min and the room temperature had the highest rate of –25.21 ppm/min.

Our results were consistent based off our hypothesis in fact the room temperature had the highest rate of photosynthesis and the boiling temperature took second. Results in T. Tromph 2000 on the Cable website supported our result that cold temperature produced a slower photosynthesis compared to room temperature but their major flaws were timing and trials. Our problems were that the temperature for each container was different and the amount of juniper leaves we were using were different. The more junipers we had the more CO2 consumption there were have been. But the fewer junipers we had the slower the consumption would be especially in the cold environment. We also didnŐt use the same temperature on the cold environment the problem were that the ice temperature fluctuated every time we used it so the temperature on the ice on trial one is different then on trial 3.

         We modified our hypothesis knowing that that the higher rate of CO2 production is the result of increase of metabolism and decrease rate of photosynthesis. We hypothesized that the enzymes are adapted to a broad range of temperature. The juniper leaves were adapted to boulderŐs weather in different ways. If we brought a juniper leaver from a different state it will take awhile for them to adapt in our broad range of temperature especially when ColoradoŐs weather is random everyday.