Catastrophic hydraulic failure and tipping points in plants. (27th May 2022)

• Record Type: Journal Article
• Authors: Johnson, Daniel M.; Katul, Gabriel; Domec, Jean‐Christophe
• Is Part Of: Plant, cell and environment. Volume 45:Number 8(2022)
• Page Start: 2231
• Page End: 2266
• Publication Date: 2022-05-27
• Subjects: bifurcation -- cavitation -- cusp -- embolism -- fold -- r‐shaped curves -- soil -- s‐shaped curves -- transpiration -- water potential -- xylem; Plant physiology -- Periodicals; Plant cells and tissues -- Periodicals; Plant communities -- Periodicals; 581.105
• DOI: 10.1111/pce.14327
• Languages: English
• ISSNs: 0140-7791

Abstract

Abstract: Water inside plants forms a continuous chain from water in soils to the water evaporating from leaf surfaces. Failures in this chain result in reduced transpiration and photosynthesis and are caused by soil drying and/or cavitation‐induced xylem embolism. Xylem embolism and plant hydraulic failure share several analogies to 'catastrophe theory' in dynamical systems. These catastrophes are often represented in the physiological and ecological literature as tipping points when control variables exogenous (e.g., soil water potential) or endogenous (e.g., leaf water potential) to the plant are allowed to vary on time scales much longer than time scales associated with cavitation events. Here, plant hydraulics viewed from the perspective of catastrophes at multiple spatial scales is considered with attention to bubble expansion within a xylem conduit, organ‐scale vulnerability to embolism, and whole‐plant biomass as a proxy for transpiration and hydraulic function. The hydraulic safety‐efficiency tradeoff, hydraulic segmentation and maximum plant transpiration are examined using this framework. Underlying mechanisms for hydraulic failure at fine scales such as pit membranes and cell‐wall mechanics, intermediate scales such as xylem network properties and at larger scales such as soil–tree hydraulic pathways are discussed. Understudied areas in plant hydraulics are also flagged where progress is urgently needed. Summary statement: Hydraulic failure in plants and tipping points in ecosystem processes are examples of catastrophes in dynamical systems. Here, these phenomena are reviewed at bubble, xylem network and whole‐plant scales and the underlying mechanisms that result in these catastrophes are explored.