Presentation Title

Photosynthetic Response of Dryopteris arguta to Extended Drought

Faculty Mentor

Dr. Stephen D. Davis

Start Date

23-11-2019 1:15 PM

End Date

23-11-2019 1:30 PM

Location

Markstein 211

Session

oral 3

Type of Presentation

Oral Talk

Subject Area

biological_agricultural_sciences

Abstract

Ferns were some of the first vascular plants to develop, supposed to have developed on the order of 390 million years ago. Throughout this time period they have evolved unique mechanisms of survival that few would expect of the small and herbaceous plants. Dryopteris arguta is a fern species native to western North America. Known by the common name Coastal Wood Fern, this plant can be found throughout California, further west in Arizona, and as far north as British Columbia in woodlands and chaparral-type regions. These ferns were subjected to a chronic drought over the last several years that has affected the entirety of California natural landscapes causing mass dieback in many native species throughout the state. Starting in Fall 2016, Helen Holmlund began measuring seasonal water potential in the fronds of eight different chaparral fern species and found that D. arguta was definitively the most dehydration resistant of the eight ferns studied, showing an ability to dry down to -8.43 (± 0.21) MPa. This remarkable ability to withstand dehydration even in unusually harsh conditions makes D. arguta an interesting subject for investigating its mechanisms for dehydration resistance and survival during chronic drought.
In order to learn more about the survival methods D. arguta, we conducted A/Ci curves paired with testing water status throughout a summer dehydration process from May through July 2018. The A/Ci curves included two of three usual parameters: Vcmax which measures the efficiency of Rubisco carbon fixing and Jmax which measures the efficiency of the electron transport chain in producing ATP to power the Calvin-Benson cycle. While these months aren’t typically the months during which D. arguta becomes the most dehydrated, it was a dry, hot season during which we were able to monitor water stress increasing and observe the photosynthetic ability of the plant during active dehydration. Our hypothesis was that, contrary to the methods of other dehydration resistant ferns, the photosynthetic activity of Dryopteris arguta would not cease even in its low water potentials. Measuring the dry-down process from -2 Mpa to -4 Mpa saw both the Vcmax and the Jmax decrease approximately by a factor of two, almost precisely mirroring the degree of dehydration.

This document is currently not available here.

Share

COinS
 
Nov 23rd, 1:15 PM Nov 23rd, 1:30 PM

Photosynthetic Response of Dryopteris arguta to Extended Drought

Markstein 211

Ferns were some of the first vascular plants to develop, supposed to have developed on the order of 390 million years ago. Throughout this time period they have evolved unique mechanisms of survival that few would expect of the small and herbaceous plants. Dryopteris arguta is a fern species native to western North America. Known by the common name Coastal Wood Fern, this plant can be found throughout California, further west in Arizona, and as far north as British Columbia in woodlands and chaparral-type regions. These ferns were subjected to a chronic drought over the last several years that has affected the entirety of California natural landscapes causing mass dieback in many native species throughout the state. Starting in Fall 2016, Helen Holmlund began measuring seasonal water potential in the fronds of eight different chaparral fern species and found that D. arguta was definitively the most dehydration resistant of the eight ferns studied, showing an ability to dry down to -8.43 (± 0.21) MPa. This remarkable ability to withstand dehydration even in unusually harsh conditions makes D. arguta an interesting subject for investigating its mechanisms for dehydration resistance and survival during chronic drought.
In order to learn more about the survival methods D. arguta, we conducted A/Ci curves paired with testing water status throughout a summer dehydration process from May through July 2018. The A/Ci curves included two of three usual parameters: Vcmax which measures the efficiency of Rubisco carbon fixing and Jmax which measures the efficiency of the electron transport chain in producing ATP to power the Calvin-Benson cycle. While these months aren’t typically the months during which D. arguta becomes the most dehydrated, it was a dry, hot season during which we were able to monitor water stress increasing and observe the photosynthetic ability of the plant during active dehydration. Our hypothesis was that, contrary to the methods of other dehydration resistant ferns, the photosynthetic activity of Dryopteris arguta would not cease even in its low water potentials. Measuring the dry-down process from -2 Mpa to -4 Mpa saw both the Vcmax and the Jmax decrease approximately by a factor of two, almost precisely mirroring the degree of dehydration.