Presentation Title

Maximum Photosynthetic Rates Correspond to Life History Type among Eight Fern Species in the Santa Monica Mountains

Presentation Type

Poster

Keywords

chaparral, ferns, photosynthetic performance, life history type

Department

Biology

Major

Biology

Abstract

The Santa Monica Mountains of southern California are characterized by a Mediterranean-type climate consisting of hot, dry summers and mild, wet winters. The flora must withstand 6-9 months without rainfall and is most frequently dominated by evergreen, sclerophyllous chaparral. However, various species of ferns are often in the understory of chaparral shrubs. These ferns follow one of four unique life history types relative to frond persistence: evergreen, summer/winter deciduous, or resurrection (desiccation tolerant). The objective of this study was to determine which factors (life history type, microsite, and seasonal activity) might link to maximum photosynthetic performance. Photosynthetic rates were lowest for evergreen species and highest for desiccation-tolerant resurrection plants. Summer and winter deciduous species were intermediate. After comparing maximum photosynthetic performance among our eight species to thirteen fern traits, only Modulus of Elasticity (MOE) had a correlation coefficient approaching significance (r2 = 0.44). Consistent with this observation, maximum stomatal conductance to water vapor diffusion was strongly correlated with MOE (r2 = 0.82). It appears that maximum photosynthetic rates in the eight species examined primarily correlate with frond persistence during summer drought/winter freezing and microsite preference for riparian habitats.

Faculty Mentor

Dr. Stephen D. Davis

Funding Source or Research Program

Academic Year Undergraduate Research Initiative, Keck Scholars Program, Summer Undergraduate Research in Biology

Location

Waves Cafeteria

Start Date

24-3-2017 2:00 PM

End Date

24-3-2017 3:00 PM

This document is currently not available here.

Share

COinS
 
Mar 24th, 2:00 PM Mar 24th, 3:00 PM

Maximum Photosynthetic Rates Correspond to Life History Type among Eight Fern Species in the Santa Monica Mountains

Waves Cafeteria

The Santa Monica Mountains of southern California are characterized by a Mediterranean-type climate consisting of hot, dry summers and mild, wet winters. The flora must withstand 6-9 months without rainfall and is most frequently dominated by evergreen, sclerophyllous chaparral. However, various species of ferns are often in the understory of chaparral shrubs. These ferns follow one of four unique life history types relative to frond persistence: evergreen, summer/winter deciduous, or resurrection (desiccation tolerant). The objective of this study was to determine which factors (life history type, microsite, and seasonal activity) might link to maximum photosynthetic performance. Photosynthetic rates were lowest for evergreen species and highest for desiccation-tolerant resurrection plants. Summer and winter deciduous species were intermediate. After comparing maximum photosynthetic performance among our eight species to thirteen fern traits, only Modulus of Elasticity (MOE) had a correlation coefficient approaching significance (r2 = 0.44). Consistent with this observation, maximum stomatal conductance to water vapor diffusion was strongly correlated with MOE (r2 = 0.82). It appears that maximum photosynthetic rates in the eight species examined primarily correlate with frond persistence during summer drought/winter freezing and microsite preference for riparian habitats.