Evaluating the Impact of Nighttime Ozone Exposure on Resistant and Sensitive Phaseolus Vulgaris L. Genotypes
Open Access
- Author:
- Isaacs, Emily Grace
- Area of Honors:
- Environmental Resource Management
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Robert David Shannon, Thesis Honors Advisor
Dennis R Decoteau, Thesis Supervisor - Keywords:
- Ozone
Snap Bean
Linear Regression
Air Pollution
Foliar Injury
Pod Yield - Abstract:
- Tropospheric ozone, a common air pollutant, proves harmful to humans and the environment, adversely affecting both plants and animals. Produced through natural and anthropogenic means, ozone enters a plant though the plant’s stomata, resulting in visible foliar injury to sensitive species and triggering the formation of toxins that hasten aging, decrease photosynthesis, and promote necrosis. Consequently, exposure to ozone can reduce crop yield, prompting concern within the agricultural and food production industries. In order to detect damage from ambient ozone, the snap bean (Phaseolus vulgaris L.) genotype pair S156/R123 can be used as a bioindicator of ozone damage, displaying upper leaf stipple, stunted growth, and altered yield after ozone exposure (Burkey et al., 2005; Feng and Kobayashi, 2009; Ladd et al., 2011; Salvatori et al., 2013). Although many studies have presented a correlation between daytime ozone exposure and reductions in yield, limited research has been conducted pertaining to the effects of nighttime ozone exposure (Burkey et al., 2005; Feng and Kobayashi, 2009; Musselman and Minnick, 2000; Salvatori et al., 2013). Ozone production follows diurnal cycles with peak production in the afternoon and diminishment at night. However, ozone levels can remain high during nighttime, potentially inflicting plant injury. This greenhouse study investigated the impact of eleven target ozone concentrations of 0, 50, 75, 100, 125, 150, 175, 200, 225, 250, and 275 ppb upon sensitive and resistant genotypes of snap beans over a three-week, fifteen-day treatment period. Evaluation of the plants for foliar injury occurred throughout the exposure period, and mature pods were dried, counted, and weighed to evaluate yield. Nighttime ozone had a statistically significant effect on pod mass and pod number across the two genotypes. Across the range of nightly ozone exposures, the mean number of injured leaves between genotypes was also statistically significantly different. Moreover, the mean pod mass between genotypes was statistically significantly different relative to the number of injured leaves.