Xylem embolism in leaves does not occur with open stomata: evidence from direct observations using the optical visualization technique

Drought represents a major abiotic constraint to plant growth and survival. On the one hand, plants keep stomata open for efficient carbon assimilation while, on the other hand, they close them to prevent permanent hydraulic impairment from xylem embolism. The order of occurrence of these two processes (stomatal closure and the onset of leaf embolism)…

Xylem Embolism Spreads by Single-Conduit Events in Three Dry Forest Angiosperm Stems

Xylem cavitation resulting in air embolism is a major cause of plant death during drought, yet the spread of embolism throughout the plant water transport system is poorly understood. Our study used optical visualization and X-ray microcomputed tomography imaging to capture the spread of emboli in stems of three drought-resistant angiosperm trees: Drooping she-oak (Allocasuarina…

In vivo monitoring of drought-induced embolism in Callitris rhomboidea trees reveals wide variation in branchlet vulnerability and high resistance to tissue death

Damage to the plant water transport system through xylem cavitation is known to be a driver of plant death in drought conditions. However, a lack of techniques to continuously monitor xylem embolism in whole plants in vivo has hampered our ability to investigate both how this damage propagates and the possible mechanistic link between xylem damage…

An increase in xylem embolism resistance of grapevine leaves during the growing season is coordinated with stomatal regulation, turgor loss point and intervessel pit membranes

Although xylem embolism resistance is traditionally considered as static, we hypothesized that in grapevine (Vitis vinifera) leaf xylem becomes more embolism-resistant over the growing season. We evaluated xylem architecture, turgor loss point (ΨTLP) and water potentials leading to 25% of maximal stomatal conductance (gs25) or 50% embolism in the leaf xylem (P50) in three irrigation…

Mapping xylem failure in disparate organs of whole plants reveals extreme resistance in olive roots

The capacity of plant species to resist xylem cavitation is an important determinant of resistance to drought, mortality thresholds, geographic distribution and productivity. Unravelling the role of xylem cavitation vulnerability in plant evolution and adaptation requires a clear understanding of how this key trait varies between the tissues of individuals and between individuals of species….

Stomatal Closure, Basal Leaf Embolism, and Shedding Protect the Hydraulic Integrity of Grape Stems

The time scale of stomatal closure and xylem cavitation during plant dehydration, as well as the fate of embolised organs, is under debate, largely due to methodological limitations in the evaluation of embolism. While some argue that complete stomatal closure precedes the occurrence of embolism, others believe that the two are contemporaneous processes that are…

Optical Measurement of Stem Xylem Vulnerability

The vulnerability of plant water transport tissues to a loss of function by cavitation during water stress is a key indicator of the survival capabilities of plant species during drought. Quantifying this important metric has been greatly advanced by non-invasive techniques that allow embolisms to be directly viewed in the vascular system. Here we present…

Casting light on xylem vulnerability in an herbaceous species reveals a lack of segmentation

Finding thresholds at which loss of plant functionality occurs during drought is critical for predicting future crop productivity and survival. Xylem resistance to embolism has been suggested as a key trait associated with water-stress tolerance. Although a substantial literature exists describing the vulnerability of woody stems to embolism, leaves and roots of herbaceous species remain…

Revealing catastrophic failure of leaf networks under stress

The intricate patterns of veins that adorn the leaves of land plants are among the most important networks in biology. Water flows in these leaf irrigation networks under tension and is vulnerable to embolism-forming cavitations, which cut off water supply, ultimately causing leaf death. Understanding the ways in which plants structure their vein supply network…

Visual quantification of embolism reveals leaf vulnerability to hydraulic failure

Vascular plant mortality during drought has been strongly linked to a failure of the internal water transport system caused by the rapid invasion of air and subsequent blockage of xylem conduits. Quantification of this critical process is greatly complicated by the existence of high water tension in xylem cells making them prone to embolism during…

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New hand-lens clamp for stem and leaves nearly ready!

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eucryphia-leaf-2 Play

Eucryphia lucida leaf 2
Captured by Jen Peters from Western Sydney University visiting the Brodribb Lab in Hobart.