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Full-Text Articles in Life Sciences
Substrate Type Affects The Drying Speed And Desiccation Tolerance Of Fern Gametophytes, Jordyn D. Regier, Mayra J. Hernandez, Camille K. Sicangco, Stephen D. Davis, Helen I. Holmlund
Substrate Type Affects The Drying Speed And Desiccation Tolerance Of Fern Gametophytes, Jordyn D. Regier, Mayra J. Hernandez, Camille K. Sicangco, Stephen D. Davis, Helen I. Holmlund
Seaver College Research And Scholarly Achievement Symposium
Although most ferns require abundant water to thrive, some ferns can survive in habitats with limited water. Previous studies have examined the adaptations that allow xeric ferns to thrive in mediterranean-type ecosystems such as southern California. However, the large fern sporophyte only represents one stage of the fern life cycle; the independent gametophyte phase must also survive water stress, including the six-month summer drought periods of the Santa Monica Mountains. Some fern gametophytes have been reported to be desiccation tolerant (capable of recovery from near-complete drying), and this trait is believed to be dependent on the plant’s drying speed. In …
Does The Fungal Pathogen (Botryosphaeria Dothidea) Exceed The Dehydration Tolerance Of Its Chaparral Host?, Cristian M. Garcia
Does The Fungal Pathogen (Botryosphaeria Dothidea) Exceed The Dehydration Tolerance Of Its Chaparral Host?, Cristian M. Garcia
Seaver College Research And Scholarly Achievement Symposium
We tested the hypothesis that an opportunistic endophytic fungus Botryosphaeria dothidea that frequently infects and causes dieback in several different species of chaparral shrubs in the Santa Monica Mountains continues to elongate and grow in host tissues at dehydration levels that exceed host survival. This was done by collecting several large branches from the field from three dominant species of co-occurring chaparral shrubs, Malosma laurina, Ceanothus spinosus, and Ceanothus megacarpus. We allowed branches to dehydrate at increasing lengths of time, from a few days to one week, in an air-conditioned laboratory, then sealed in plastic bags to allow tissuewater equilibration, …
Testing For The Presence Of Botryosphaeria Dothidea In Branches Of Ceanothus Spinosus Undergoing Dieback, Katarina Carter
Testing For The Presence Of Botryosphaeria Dothidea In Branches Of Ceanothus Spinosus Undergoing Dieback, Katarina Carter
Seaver College Research And Scholarly Achievement Symposium
Botryosphaeria dothidea is an opportunistic pathogen found in some of the cavitated branches of the chaparral vegetation in the Santa Monica Mountains. In this study, we focused on investigating the presence of Botryosphaeria dothidea in Ceanothus spinosus located on Pepperdine University’s campus. We wanted to test this hypothesis because we had observed a large amount of dieback in the Ceanothus spinosus population and wanted to identify a possible contributor. Because of the large number of cavitated branches in the Ceanothus spinosus we tested, we hypothesized that they contained fungus. To test this, we took twenty samples of twenty different Ceanothus …
Hydraulic Mechanisms Of Fungal-Induced Dieback In A Keystone Chaparral Species During Unprecedented Drought In California, Natalie M. Aguirre, Marissa E. Ochoa, Helen I. Holmlund, Frank E. Ewers, Stephen D. Davis
Hydraulic Mechanisms Of Fungal-Induced Dieback In A Keystone Chaparral Species During Unprecedented Drought In California, Natalie M. Aguirre, Marissa E. Ochoa, Helen I. Holmlund, Frank E. Ewers, Stephen D. Davis
Seaver College Research And Scholarly Achievement Symposium
Between 2012-2016, southern California experienced unprecedented drought that caused dieback in Malosma laurina, a keystone species of chaparral shrub communities. Dieback was especially severe in coastal exposures of the Santa Monica Mountains, leading to whole plant mortality exceeding 50% at some sites. We hypothesized that the endophytic fungus causing the dieback, Botryosphaeria dothidea, was successful in invading the xylem tissue of M. laurina because of protracted water stress, carbon starvation, or a combination of the two. We tested these possibilities in a controlled pot experiment by comparing three treatments, each inoculated with the fungus: (1) irrigated controls (2) …
An Individual-Based Model Of Chaparral Vegetation Response To Frequent Wildfire, Timothy Lucas, Dayna Mann, Reanna Dona
An Individual-Based Model Of Chaparral Vegetation Response To Frequent Wildfire, Timothy Lucas, Dayna Mann, Reanna Dona
Seaver College Research And Scholarly Achievement Symposium
In recent years, the Santa Monica Mountains (SMM) have been plagued by frequent wildfires which threaten the native chaparral species. Nonsprouting chaparral species are completely killed by a fire, but their seeds germinate in response to fire cues. Facultative sprouters both resprout after a wildfire and release seeds that germinate post-fire. This project is based on data collected since 1986 at a biological preserve adjacent to the Malibu campus of Pepperdine University with an average fire return interval of 7.5 years. We present a spatial model that simulates the growth, seed dispersal and resprouting behavior of individual shrubs that compete …