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Full-Text Articles in Life Sciences
A Comparison Of Water Potential, Photosynthetic Rate, Electron Transport Rate, And Stomatal Conductance Between Native Malosma Laurina And Exotic Schinus Molle, Karagan L. Smith, Agatha C. Heng, Viridiana Hernandez-Lopez, Stephen D. Davis
A Comparison Of Water Potential, Photosynthetic Rate, Electron Transport Rate, And Stomatal Conductance Between Native Malosma Laurina And Exotic Schinus Molle, Karagan L. Smith, Agatha C. Heng, Viridiana Hernandez-Lopez, Stephen D. Davis
Biology
Schinus molle is a relatively new invasive chaparral shrub in the Santa Monica Mountains and has only recently been observed to displace native shrubs like Malosma laurina. To investigate the probable cause of S. molle’s competitive displacement of M. laurina, we compared their water status, photosynthetic rates, electron transport rates, and stomatal conductance to water vapor diffusion during the fall months of 2016. We hypothesized that S. molle would physiologically outperform M. laurina indicated by higher photosynthetic rates, electron transport rates, stomatal conductance rates, and less negative water potential. We found that there was no significant difference between dry …
The Effect Of Drought On The Comparative Fitness Of Purple Needle Grass (Stipa Pulchra) In The Presence Of An Invasive Weed, Grace M. Palmer, Taylor M. Purdy, Stephen D. Davis
The Effect Of Drought On The Comparative Fitness Of Purple Needle Grass (Stipa Pulchra) In The Presence Of An Invasive Weed, Grace M. Palmer, Taylor M. Purdy, Stephen D. Davis
Biology
Studies on the relative health of Stipa pulchra, a California native perennial bunchgrass, were conducted at the transplant garden on the Drescher campus of Pepperdine University in the Spring semesters of 2016 and 2017. Following the trend of other perennial native grasses, Stipa pulchra is dwindling due to competition with Avena fatua and other invasive species introduced by human activities. In 2016, in the midst of historic five-year drought in California, stomatal conductance, dark adapted fluorescence, water potential, and height of S. pulchra and A. fatua were recorded and compared. As hypothesized, the wild S. pulchra exhibited greater overall fitness-- …
Resistance To Xylem Cavitation In Evergreen Ferns Correlates With Seasonal Dehydration Levels, Not Mechanical Strength, Helen I. Holmlund, Kaitlyn E. Sauer, Breahna M. Gillespie, Jarmila Pittermann, Stephen D. Davis
Resistance To Xylem Cavitation In Evergreen Ferns Correlates With Seasonal Dehydration Levels, Not Mechanical Strength, Helen I. Holmlund, Kaitlyn E. Sauer, Breahna M. Gillespie, Jarmila Pittermann, Stephen D. Davis
Biology
Ferns in the Santa Monica Mountains of southern California display a range of responses to severe drought. In this study, we further characterized the traits that may contribute to fern survival in a mediterranean-type climate. Due to anatomical differences between ferns and angiosperms, we predicted that ferns would exhibit no correlation between stipe mechanical strength and vulnerability to water stress-induced cavitation of stipe xylem. However, we predicted that ferns would show a correlation between seasonal water stress (minimum water potential) and cavitation resistance. Our results support these hypotheses; however, we must increase our sample size of evergreen fern species in …