Invasive species, such as Nicotiana glauca, are a prominent part of the Santa Monica Mountains, and could be responsible for displacing native species such as Rhus integrifolia. It was observed in the field that Nicotiana glauca was doing better than Rhus integrifolia, so our group decided to indirectly test this. Because of the invasiveness of its species, it is essential to measure the health of a native species to see if the invasive species is posing as a massive threat. Water potential, stomatal conductance, fluorescence, photosynthetic rates and electron transport rates were compared among the two plants using a pressure chamber and a Li-6400XT. We hypothesized that Nicotiana glauca would have a higher stomatal conductance, fluorescence, photosynthetic rates and electron transport rates as well as a less negative water potential. It was determined that Nicotiana glauca had higher stomatal conductance, photosynthetic rates and electron transport rates compared to Rhus integrifolia. However, Nicotiana glauca did not have a less negative water potential than Rhus integrifolia. Fluorescence was also compared but were too similar to come a solid conclusion on who performed better. Overall, our hypothesis was supported by our data because Nicotiana glauca has a higher stomatal conductance, photosynthetic rate and electron Transport Rate than Rhus integrifolia.
Egbo, Tiffany J.; Navarro, Emma J.; Phillips, MaLaun A.; and Zohary, Cameron I., "Comparison of Photosynthesis, Stomatal Conductance, and Water Potential between Native Rhus integrifolia and Invasive Nicotiana glauca" (2018). Pepperdine University, Featured Research. Paper 210.