Seminars

May 17 2011

12:00 154 BSRB

Ecolunch Series

Graduate Student Presentations

Summary

Megan Bartlett
Dept of Ecology and Evolutionary Biology
UCLA
"A new solution and global meta-analysis of leaf water relations"

Abstract

Leaf turgor loss point (πtlp), the water potential at which wilting occurs, is a significant determinant of plant water stress response and of species distributions relative to water availability. I will be presenting a new understanding of how variation in other physiological and structural traits determines πtlp, clarifying the ecological significance of these traits and resolving several long-standing controversies concerning drought tolerance in natural and agricultural ecosystems. My co-authors and I developed a model based on a new analytical solution of the fundamental pressure-volume curve equations underlying leaf water relations, allowing the expression of πtlp function of other cellular and structural traits. This model fitted a global dataset of pressure-volume parameters extremely well (r2= 0.99; 89 species). Multiple sensitivity analyses and meta-analyses showed that πo, cell solute concentration, was the primary driver of drought acclimation within given species and the most important determinant of πtlp across species, while shifts in ε, cell wall stiffness, and af, cell wall water content, had negligible direct impacts on πtlp. Our meta-analysis of global data extended these findings, pointing to the importance of πtlp and πo as predictors of drought tolerance and species’ distributions within and across biomes. This work clarifying water stress response and its mechanisms will contribute to the ability to characterize plant and ecosystem resilience to drought in a changing climate regime.

Emily Curd
Dept of Ecology and Evolutionary Biology
UCLA

"A metagenomic study of soil microbial community carbon cycling under several vegetation types"
Abstract

Soil microbial communities play a large role in global carbon cycling. Many aspects of microbial carbon cycling are still unknown. For my dissertation I propose to evaluate the influence of carbon inputs from different types of vegetation on the structure and function of soil microbial communities and their potential role in carbon cycling. Specifically, I plan to determine the composition and function of soil microbial communities under three different vegetation types using metagenome and metatranscriptome analysis. I also propose to experimentally manipulate carbon input into soils. This will allow me to determine the changes to the microbial metagenome and metatranscriptome that are associated with different carbon substrates.

 

 

 

 

 

 



 

 

 

 

 

 

 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



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