Presentation Type
Oral Presentation
Keywords
Chaparral, Botryosphaeria dothidea, Malosma laurina, drought, hydraulic conductance
Department
Biology
Major
Biology
Abstract
Malosma laurina is a dominant species in coastal chaparral ecosystems The deep root systems of M. laurina provide structural support for the steep Santa Monica Mountains and allow M. laurina to tap into the deep water table. M. laurina dieback is prevalent in coastal exposures of the SMM, presumably due to historic drought predisposing plant tissues to infection by the fungal pathogen Botryosphaeria dothidea. In ecosystems that experience annual dry periods, a high hydraulic conductance in roots is necessary to provide plants with sufficient water. A recent study has examined the effect of Botryosphaeria on the hydraulic conductance of M. laurina stems, but no research has been performed on the roots. This study looks at the effect of Botryosphaeria on the root system of infected M. laurina plants. Our focus was on the roots’ ability to transport water to the shoot and the presence of physical blockage in the xylem vessels. We collected root samples of both plants experiencing severe dieback as well as healthy plants and tested the hydraulic conductivity (Kh) through each root. We then calculated the specific conductivity per unit xylem area (Ks). We found significantly lower Ks in infected plants than in the healthy M. laurina. After testing hydraulic conductivity, we calculated the percent air embolism and physical blockage in the vessels using double-staining. Preliminary double-staining data has corroborated our hydraulic conductance data, indicating increased physical blockage in the vessels of dieback individuals. These data support the hypothesis that infection by Botryosphaeria greatly reduces water transport function in the roots of Malosma laurina.
Faculty Mentor
Dr. Stephen Davis
Funding Source or Research Program
Not Identified
Presentation Session
Session C
Location
Plaza Classroom 190
Start Date
1-4-2016 4:15 PM
End Date
1-4-2016 4:30 PM
Included in
Biology Commons, Botany Commons, Other Ecology and Evolutionary Biology Commons, Plant Pathology Commons
Root Hydraulic Conductance in Malosma laurina Experiencing Severe Dieback in the Santa Monica Mountains
Plaza Classroom 190
Malosma laurina is a dominant species in coastal chaparral ecosystems The deep root systems of M. laurina provide structural support for the steep Santa Monica Mountains and allow M. laurina to tap into the deep water table. M. laurina dieback is prevalent in coastal exposures of the SMM, presumably due to historic drought predisposing plant tissues to infection by the fungal pathogen Botryosphaeria dothidea. In ecosystems that experience annual dry periods, a high hydraulic conductance in roots is necessary to provide plants with sufficient water. A recent study has examined the effect of Botryosphaeria on the hydraulic conductance of M. laurina stems, but no research has been performed on the roots. This study looks at the effect of Botryosphaeria on the root system of infected M. laurina plants. Our focus was on the roots’ ability to transport water to the shoot and the presence of physical blockage in the xylem vessels. We collected root samples of both plants experiencing severe dieback as well as healthy plants and tested the hydraulic conductivity (Kh) through each root. We then calculated the specific conductivity per unit xylem area (Ks). We found significantly lower Ks in infected plants than in the healthy M. laurina. After testing hydraulic conductivity, we calculated the percent air embolism and physical blockage in the vessels using double-staining. Preliminary double-staining data has corroborated our hydraulic conductance data, indicating increased physical blockage in the vessels of dieback individuals. These data support the hypothesis that infection by Botryosphaeria greatly reduces water transport function in the roots of Malosma laurina.