scholarly journals Testing the plant pneumatic method to estimate xylem embolism resistance in stems of temperate trees

2018 ◽  
Vol 38 (7) ◽  
pp. 1016-1025 ◽  
Author(s):  
Ya Zhang ◽  
Laurent J Lamarque ◽  
José M Torres-Ruiz ◽  
Bernhard Schuldt ◽  
Zohreh Karimi ◽  
...  
Keyword(s):  
Xylem Embolism ◽  
Temperate Trees ◽  
Embolism Resistance ◽  
Pneumatic Method

scholarly journals No gas source, no problem: proximity to pre-existing embolism and segmentation affect embolism spreading in angiosperm xylem by gas diffusion

2020 ◽  
Author(s):  
Xinyi Guan ◽  
Luciano Pereira ◽  
Scott McAdam ◽  
Kun-Fang Cao ◽  
Steven Jansen
Keyword(s):  
Pressure Difference ◽  
Gas Diffusion ◽  
Difference Threshold ◽  
Xylem Embolism ◽  
Gas Source ◽  
Reducing Gas ◽  
Detached Leaves ◽  
Embolism Resistance ◽  
Pneumatic Method ◽  
Strong Agreement

Embolism spreading in dehydrating angiosperm xylem is driven by gas movement between embolised and sap-filled conduits. Here, we examine how proximity to pre-existing embolism and hydraulic segmentation affect embolism propagation. Based on the optical method, we compared xylem embolism resistance between detached leaves and leaves attached to branches, and between intact leaves and leaves with cut minor veins for six species. Moreover, we directly compared the optical and pneumatic method on detached leaves. Embolism resistance of detached leaves was significantly lower than leaves attached to stems, except for two species with all vessels ending in their petioles. Cutting of minor veins showed limited embolism spreading in minor veins near the cuts prior to major veins. Moreover, there was strong agreement in embolism resistance between the optical and pneumatic method, with minor differences occurring during early stages of embolism formation. We conclude that embolism resistance may represent a relative trait, depending on the proximity and connectivity to pre-existing embolism as a gas source. Since embolism formation may not rely on a certain pressure difference threshold between functional and embolised conduits, we suggest that embolism is facilitated by pressure-driven gas diffusion, while hydraulic segmentation can prevent embolism propagation by reducing gas diffusion.

scholarly journals Pore constrictions in intervessel pit membranes provide a mechanistic explanation for xylem embolism resistance in angiosperms

2021 ◽  
Vol 230 (5) ◽  
pp. 1829-1843 ◽  
Author(s):  
Lucian Kaack ◽  
Matthias Weber ◽  
Emilie Isasa ◽  
Zohreh Karimi ◽  
Shan Li ◽  
...  
Keyword(s):  
Mechanistic Explanation ◽  
Xylem Embolism ◽  
Embolism Resistance

scholarly journals Climatic limits of temperate rainforest tree species are explained by xylem embolism resistance among angiosperms but not among conifers

2020 ◽  
Vol 226 (3) ◽  
pp. 727-740 ◽  
Author(s):  
Daniel C. Laughlin ◽  
Sylvain Delzon ◽  
Michael J. Clearwater ◽  
Peter J. Bellingham ◽  
Matthew S. McGlone ◽  
...  
Keyword(s):  
Tree Species ◽  
Xylem Embolism ◽  
Temperate Rainforest ◽  
Embolism Resistance

scholarly journals A Unit Pipe Pneumatic model to simulate gas kinetics during measurements of embolism in excised angiosperm xylem

2021 ◽  
Author(s):  
Dongmei Yang ◽  
Luciano Pereira ◽  
Guoquan Peng ◽  
Rafael V. Ribeiro ◽  
Lucian Kaack ◽  
...  
Keyword(s):  
Gas Diffusion ◽  
Ideal Gas ◽  
Striking Similarity ◽  
Measuring Error ◽  
List Type ◽  
Gas Phases ◽  
Ideal Gas Law ◽  
Embolism Resistance ◽  
Physical Laws ◽  
Pneumatic Method

AbstractThe Pneumatic method has been introduced to quantify embolism resistance in plant xylem of various organs. Despite striking similarity in vulnerability curves between the Pneumatic and hydraulic methods, a modeling approach is highly needed to demonstrate that xylem embolism resistance can be accurately quantified based on gas diffusion kinetics.A Unit Pipe Pneumatic (UPPn) model was developed to estimate gas diffusion from intact conduits, which were axially interconnected by interconduit pit membranes. The physical laws used included Fick’s law for diffusion, Henry’s law for gas concentration partitioning between liquid and gas phases at equilibrium, and the ideal gas law.The UPPn model showed that 91% of the extracted gas came from the first two series of embolized, intact conduits, and only 9% from the aqueous phase after 15 s of simulation. Embolism resistance measured with a Pneumatic apparatus was systematically overestimated by 2 to 17%, corresponding to a typical measuring error of 0.11 MPa for P50 (the water potential equivalent to 50% of the maximum amount of gas extracted).Because results from the UPPn model are supported by experimental evidence, there is a good theoretical and experimental basis for applying the pneumatic method to research on embolism resistance of angiosperms.

The Pneumatron estimates xylem embolism resistance in angiosperms based on gas diffusion kinetics: a mini-review

2020 ◽  
pp. 193-200
Author(s):  
S. Jansen ◽  
X. Guan ◽  
L. Kaack ◽  
C. Trabi ◽  
M.T. Miranda ◽  
...  
Keyword(s):  
Gas Diffusion ◽  
Diffusion Kinetics ◽  
Xylem Embolism ◽  
Embolism Resistance

scholarly journals Embolism resistance in petioles and leaflets of palms

2019 ◽  
Vol 124 (7) ◽  
pp. 1173-1183 ◽  
Author(s):  
Thaise Emilio ◽  
Laurent J Lamarque ◽  
José M Torres-Ruiz ◽  
Andrew King ◽  
Guillaume Charrier ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Xylem Embolism ◽  
Phylogenetic Relatedness ◽  
X Ray ◽  
Xylem Pressure ◽  
Palm Species ◽  
Embolism Resistance ◽  
Increasing Temperature

Abstract Background and aims Hydraulic studies are currently biased towards conifers and dicotyledonous angiosperms; responses of arborescent monocots to increasing temperature and drought remain poorly known. This study aims to assess xylem resistance to drought-induced embolism in palms. Methods We quantified embolism resistance via P50 (xylem pressure inducing 50 % embolism or loss of hydraulic conductivity) in petioles and leaflets of six palm species differing in habitat and phylogenetic relatedness using three techniques: in vivo X-ray-based microcomputed tomography, the in situ flow centrifuge technique and the optical vulnerability method. Key results Our results show that P50 of petioles varies greatly in the palm family, from −2.2 ± 0.4 MPa in Dypsis baronii to −5.8 ± 0.3 MPa in Rhapis excelsa (mean ± s.e.). No difference or weak differences were found between petioles and leaf blades within species. Surprisingly, where differences occurred, leaflets were less vulnerable to embolism than petioles. Embolism resistance was not correlated with conduit size (r = 0.37, P = 0.11). Conclusions This study represents the first estimate of drought-induced xylem embolism in palms across biomes and provides the first step towards understanding hydraulic adaptations in long-lived arborescent monocots. It showed an almost 3-fold range of embolism resistance between palm species, as large as that reported in all angiosperms. We found little evidence for hydraulic segmentation between leaflets and petioles in palms, suggesting that when it happens, hydraulic segregation may lack a clear relationship with organ cost or replaceability.

scholarly journals Linking drought‐induced xylem embolism resistance to wood anatomical traits in Neotropical trees

2020 ◽  
Vol 229 (3) ◽  
pp. 1453-1466
Author(s):  
Sébastien Levionnois ◽  
Steven Jansen ◽  
Ruth Tchana Wandji ◽  
Jacques Beauchêne ◽  
Camille Ziegler ◽  
...  
Keyword(s):  
Xylem Embolism ◽  
Neotropical Trees ◽  
Embolism Resistance

scholarly journals Xylem embolism spread is largely prevented by interconduit pit membranes until the majority of conduits are gas-filled

2021 ◽  
Author(s):  
Rodrigo Avila ◽  
Xinyi Guan ◽  
Cade Kane ◽  
Amanda Cardoso ◽  
Timothy Batz ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Water Potential ◽  
Small Degree ◽  
Conifer Species ◽  
Local Pressure ◽  
Xylem Embolism ◽  
Embolism Resistance ◽  
Potential Threshold ◽  
Xylem Conduits

Xylem embolism resistance varies across species influencing drought tolerance, yet little is known about the determinants of the embolism resistance of an individual conduit. Here we conducted an experiment using the optical vulnerability method to test whether individual conduits have a specific water potential threshold for embolism formation and whether pre-existing embolism in neighbouring conduits alters this threshold. Observations were made on a diverse sample of angiosperm and conifer species through a cycle of dehydration, rehydration and subsequent dehydration to death. Upon rehydration after the formation of embolism, no refilling was observed. When little pre-existing embolism was present, xylem conduits had a conserved, individual, embolism resistance threshold that varied across the population of conduits. The consequence of a variable conduit-specific embolism threshold is that a small degree of pre-existing embolism in the xylem results in an apparently more resistant xylem in a subsequent dehydration, particularly in angiosperms with vessels. While our results suggest that pit membranes separating xylem conduits are critical for maintaining a conserved individual embolism threshold for given conduit when little pre-exisiting embolism is present, as the percentage of embolized conduits increases, gas movement, local pressure differences, and connectivity between conduits increasingly contribute to embolism spread.

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

2019 ◽  
Vol 71 (3) ◽  
pp. 1151-1159 ◽  
Author(s):  
Danielle Creek ◽  
Laurent J Lamarque ◽  
José M Torres-Ruiz ◽  
Camille Parise ◽  
Regis Burlett ◽  
...  
Keyword(s):  
Water Stress ◽  
Stomatal Closure ◽  
Safety Margin ◽  
Carbon Assimilation ◽  
Xylem Embolism ◽  
Growth And Survival ◽  
Direct Observations ◽  
Optical Visualization ◽  
Embolism Resistance ◽  
The One

Abstract 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) during plant dehydration has remained controversial, largely due to methodological limitations. However, the newly developed optical visualization method now allows concurrent monitoring of stomatal behaviour and leaf embolism formation in intact plants. We used this new approach directly by dehydrating intact saplings of three contrasting tree species and indirectly by conducting a literature survey across a greater range of plant taxa. Our results indicate that increasing water stress generates the onset of leaf embolism consistently after stomatal closure, and that the lag time between these processes (i.e. the safety margin) rises with increasing embolism resistance. This suggests that during water stress, embolism-mediated declines in leaf hydraulic conductivity are unlikely to act as a signal for stomatal down-regulation. Instead, these species converge towards a strategy of closing stomata early to prevent water loss and delay catastrophic xylem dysfunction.

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