Quercus Berberidifolia) with Brown and Green Leaves During Severe Drought

Pepperdine University Pepperdine Digital Commons

Featured Research Undergraduate Student Research

2013

Difference in Water Status between Oak Trees (Quercus berberidifolia) with Brown and Green Leaves During Severe Drought

Mia Bryant Pepperdine University

Hannah Dario Pepperdine University

Cameron Kline Pepperdine University

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Recommended Citation Bryant, Mia; Dario, Hannah; and Kline, Cameron, "Difference in Water Status between Oak Trees (Quercus berberidifolia) with Brown and Green Leaves During Severe Drought" (2013). Pepperdine University, Featured Research. Paper 127. https://digitalcommons.pepperdine.edu/sturesearch/127

This Research Poster is brought to you for free and open access by the Undergraduate Student Research at Pepperdine Digital Commons. It has been accepted for inclusion in Featured Research by an authorized administrator of Pepperdine Digital Commons. For more information, please contact [email protected], [email protected], [email protected]. Diﬀerence in Water Status between Oak Trees (Quercus berberidifolia) with Brown and Green Leaves During Severe Drought Mia Bryant, Hannah Dario and Cameron Kline Mentor: Dr. Stephen D. Davis Pepperdine University, 24255 Paciﬁc Coast Highway, Malibu, CA 90263

Methods Discussion Abstract • Dry chaparral species that are 1. 2. In this experiment, we examined cavitaon in geng significantly dryer Quercus berberidifolia plants. We hypothesized that as • There was a significant difference the amount of water stress increases, then the between green stems and brown pressure to cause embolism will decrease. We thought stems regarding the atmospheric this because as a plant loses more water, the more air pressure at which the stems fall off bubbles will form within the plant and therefore the • Data showed that the pressure was Figure 1. Data was collected by using the Figure 2. With the use of a parometer, we higher in brown leaves at pre-dawn pressure to cause this will decrease. We tested this Scholander Hammel pressure chamber to measure measured the temperature of the green and hypothesis by comparing dry Quercus berberidifolia to the pressure inside the leaf before it was cut from brown leaves along with their conductance at and mid-day more hydrated Quercus berberidifolia in Tapia Park, the original shrub oak. consistent temperatures. • The pressure at which the stem was near Malibu, California. We measured and compared 3. Fluorescence was also measured using a fluorometer to measure the light reflecon of green and cut is measured in bars at these plants by the use of the Scholander Pressure brown leaves. atmospheric pressure chamber and a parometer. In the end, we discovered Results

9 7 Conclusion that our hypothesis was correct. Our data showed us Predawn Midday 8 that less hydrated plants that had more water stress 6 We have concluded that the 7 atmospheric pressure at which plant had a lower atmospheric pressure than the more 5 6 hydrated plants. * * stems and leaves are falling off to Introducon 5 4 further the plant survival. The plants 4 3 with brown and green leaves show An increasing problem around in the world is 3 2 significantly different pressures. In order drought. This is most evident in the Santa Monica 2

1 to determine whether the change in Mountains. In this Mediterranean style climate, there 1 pressure was significant, we ran tests are consistent periods of drought which are increasing 0 0 Green Brown Green throughout the years. These dry condions cause the Brown and acquired data. As these plants get Figure 3. Mean water potenal at Predawn and Midday comparing shrub oaks with green leaves dryer, the pressure at which they fall off chaparral vegetaon to become less hydrated and as a versus ones with brown leaves, growing at Tapia Park near Malibu, California. Error bars result cavitaon occurs. Cavitaon in a plant is when represent ± 1 SE, n = 6 and an asterisk indicates significant difference between plants with green increased. the loss of water causes an empty space or a low leaves versus brown leaves by Student T-test, p < 0.05. References pressure bubble to form. 110 1 Through invesgang the relaonship between Conductance Fluorescence McDowell, Nate, William T. Pockman, water stress and the amount of pressure for embolism 88 0.8 Craig D. Allen, David D. Breshears, Neil to occur, we can understand more the impact of Cobb, Thomas Kolb, Jennifer Plaut et al. cavitaon of leaves, and the drought impacts on plants 66 0.6 2008. "Mechanisms of plant survival and * in the chaparral environment. In this experiment, we * mortality during drought: why do some observed and tested the extent of cavitaon in 44 0.4 plants survive while others succumb to drought?." New Phytologist 178, no. 4: Quercus agrifolia. We compared dry Quercus agrifolia 22 0.2 with more hydrated Quercus agrifolia. We 719-739. hypothesized that as the amount of water stress 0 0 Green Brown Green Brown increases, then the pressure to cause embolism will Figure 4. The conductance of green leaves Figure 3. Fluorescence comparing shrub oaks decrease. We tested this hypothesis through four compared to brown leaves of the shrub oak, taken with green leaves versus shrub oaks with different tests with the use of a Scholander pressure at Tapia Park near Malibu, California. Error bars brown leaves, taken at Tapia Park near Malibu, chamber, parometer, and a fluorometer. These tests represent ± 1 SE, n = 6 and an asterisk indicates California. Error bars represent ± 1 SE, n = 18 significant difference between plants with green and an asterisk indicates significant difference were all conducted Tapia Park, near Malibu, California. leaves versus plants with brown leaves by Student t- between plants with green leaves versus test, p < 0.05. plants with brown leaves by student t-test, p < 0.05.