B089-04
Varying Impact of Vulnerability Segmentation on Plant Function across Environments and Co-Occurring Traits
Monday, 14 December 2020: 19:12
Virtual
Jean V Wilkening1, Robert Paul Skelton2, Jessica Diaz3, Xue Feng4,5, Todd E Dawson3 and Sally E Thompson1,6, (1)University of California Berkeley, Civil and Environmental Engineering, Berkeley, CA, United States, (2)South African Environmental Observation Network, Fynbos Node, Cape Town, South Africa, (3)University of California Berkeley, Integrative Biology, Berkeley, CA, United States, (4)University of Minnesota Twin Cities, Civil, Environmental, Geo-Engineering, Minneapolis, MN, United States, (5)University of Minnesota Twin Cities, St. Anthony Fall's Laboratory, Minneapolis, MN, United States, (6)University of Western Australia, Department of Civil, Environmental and Mining Engineering, Perth, Australia
Abstract:
Hydraulic vulnerability segmentation has been proposed as an important strategy for mitigating the potential damage of drought-induced embolism. By having relatively lower resistance to embolism in tissues such as leaves, plants are able to avoid damage to more ‘costly’ stem tissues. As methodological advancements have allowed for easier characterization of embolism resistance of different plant tissues, there have been numerous observations of vulnerability segmentation with higher P50 values in leaves than compared to stems. However, there have also been many observations of species which lack vulnerability segmentation, and even some cases of the reverse pattern, with stems having a higher P50 than leaves. In this work, we investigate whether there are scenarios (under certain environmental conditions and/or co-occurring traits) where a lack of vulnerability segmentation or even reverse vulnerability segmentation (more vulnerable stems) could be advantageous for plant function.
We present a plant hydraulic model with separate representation of resistance to embolism in stem and leaf tissues. Using published data from the Xylem Functional Traits Database, we apply statistical methods to generate parameter sets for the model which are characteristic of observed distributions of plant hydraulic traits (stem P50, stem specific conductivity, Huber value, etc.). We then impose different segmentation patterns and compare the impact on plant conductance and embolism of tissues across different environmental conditions, such that we can broadly examine the impact of vulnerability segmentation for different environments while considering the range and variability of co-occurring functional traits. From this large-scale analysis, we then consider a specific case study of two species native to California, but which exhibit contrasting vulnerability segmentation. The modeled outcomes from this study reveal the complex role of vulnerability segmentation, emphasizing the need for more holistic analysis of plant hydraulic traits and offering a framework for interpreting observed variability within and across environments.
