Modeling and Analyzing Xylem Vulnerability to Embolism as an Epidemic Process.

Area of Science:

• Plant Physiology
• Biophysics
• Forest Ecology

Background:

• Xylem vulnerability to embolism is crucial for plant survival, impacting water transport.
• Vulnerability curves (VC) quantify embolism by measuring hydraulic conductivity loss under negative water potential.
• Current empirical methods for VC analysis have limitations in mechanistic understanding.

Purpose of the Study:

• To introduce and compare mechanistic approaches for simulating embolism propagation in xylem.
• To explore the application of network theory and epidemic modeling for understanding xylem vulnerability.
• To provide a framework for mechanistic simulation of embolism spread in plant water transport systems.

Main Methods:

• Network theory: Xylem conduits modeled as graphs with nodes representing conduits and edges representing connections.
• Epidemic modeling: Embolized conduits treated as 'infected' with 'infection' spreading to neighboring conduits.
• Both methods simulate the transmission of gas (embolism) between interconnected xylem elements.

Main Results:

• Mechanistic approaches, including network theory and epidemic modeling, offer a way to simulate embolism propagation.
• These models allow for spatial tracking of embolism spread (network theory) and transmission dynamics (epidemic modeling).
• Both approaches provide a mechanistic understanding of how xylem vulnerability to embolism develops.

Conclusions:

• Network theory and epidemic modeling provide powerful tools for mechanistic simulation of xylem embolism.
• These approaches enhance our understanding of plant water transport vulnerability beyond empirical curve fitting.
• Mechanistic simulations offer a promising avenue for future research on plant hydraulic function and drought response.