Impact of Electroviscosity on the Hydraulic Conductance of the Bordered Pit Membrane: A Theoretical Investigation

Santiago, Michael; Pagay, Vinay; Stroock, Abraham D.

doi:10.1104/pp.113.219774

Cited by 43 publications

(32 citation statements)

References 70 publications

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“…The coating of gold particles by amphiphilic lipids could affect the size and penetration capacity of pit membranes pores. Besides the hydrophobic and charged nature of the colloidal gold particles, their perfusion may also be affected by electroviscosity (Santiago, Pagay, & Stroock, ) and impenetrable boundary layers (Sulbaran, Toriz, Allan, Pollack, & Delgado, ). Therefore, our TEM observations of gold perfused xylem may represent a relative indication of pore constriction sizes, and it is possible that pore constrictions are slightly larger than what we experimentally measured.…”

Section: Discussionmentioning

confidence: 99%

High porosity with tiny pore constrictions and unbending pathways characterize the 3D structure of intervessel pit membranes in angiosperm xylem

Zhang

Carmesin

Kaack

et al. 2019

Plant Cell & Environment

108

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Pit membranes between xylem vessels play a major role in angiosperm water transport. Yet, their three‐dimensional (3D) structure as fibrous porous media remains unknown, largely due to technical challenges and sample preparation artefacts. Here, we applied a modelling approach based on thickness measurements of fresh and fully shrunken pit membranes of seven species. Pore constrictions were also investigated visually by perfusing fresh material with colloidal gold particles of known sizes. Based on a shrinkage model, fresh pit membranes showed tiny pore constrictions of ca. 20 nm, but a very high porosity (i.e. pore volume fraction) of on average 0.81. Perfusion experiments showed similar pore constrictions in fresh samples, well below 50 nm based on transmission electron microscopy. Drying caused a 50% shrinkage of pit membranes, resulting in much smaller pore constrictions. These findings suggest that pit membranes represent a mesoporous medium, with the pore space characterized by multiple constrictions. Constrictions are much smaller than previously assumed, but the pore volume is large and highly interconnected. Pores do not form highly tortuous, bent, or zigzagging pathways. These insights provide a novel view on pit membranes, which is essential to develop a mechanistic, 3D understanding of air‐seeding through this porous medium.

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Section: Discussionmentioning

confidence: 99%

High porosity with tiny pore constrictions and unbending pathways characterize the 3D structure of intervessel pit membranes in angiosperm xylem

Zhang

Carmesin

Kaack

et al. 2019

Plant Cell & Environment

108

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“…During water transport in xylem, the ionic effect, i.e., variation of cation concentration in xylem sap alters xylem hydraulic efficiency (no increase to >30%) compared with distilled water has been frequently reported in recent years [100][101][102][103][104][105][106]. It was suggested that electroviscosity is partially responsible for variation of hydraulic conductance of bordered pit membranes, which were reported to be attributed to shrinkage and swelling of hydrogel on the pit membranes [107][108][109] or pit membrane polymers instead of pectin [88]. Seasonal changes of ionic effect [110] might also be due to seasonal changes of pit membranes.…”

Section: The Ionic Effect and Controversy Of Pectin Presence In Pit Mmentioning

confidence: 99%

Investigating Effects of Bordered Pit Membrane Morphology and Properties on Plant Xylem Hydraulic Functions—A Case Study from 3D Reconstruction and Microflow Modelling of Pit Membranes in Angiosperm Xylem

Wang

Yin

et al. 2020

Plants

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Pit membranes in between neighboring conduits of xylem play a crucial role in plant water transport. In this review, the morphological characteristics, chemical composition and mechanical properties of bordered pit membranes were summarized and linked with their functional roles in xylem hydraulics. The trade-off between xylem hydraulic efficiency and safety was closely related with morphology and properties of pit membranes, and xylem embolism resistance was also determined by the pit membrane morphology and properties. Besides, to further investigate the effects of bordered pit membranes morphology and properties on plant xylem hydraulic functions, here we modelled three-dimensional structure of bordered pit membranes by applying a deposition technique. Based on reconstructed 3D pit membrane structures, a virtual fibril network was generated to model the microflow pattern across inter-vessel pit membranes. Moreover, the mechanical behavior of intervessel pit membranes was estimated from a single microfibril's mechanical property. Pit membranes morphology varied among different angiosperm and gymnosperm species. Our modelling work suggested that larger pores of pit membranes do not necessarily contribute to major flow rate across pit membranes; instead, the obstructed degree of flow pathway across the pit membranes plays a more important role. Our work provides useful information for studying the mechanism of microfluid flow transport across pit membranes and also sheds light on investigating the response of pit membranes both at normal and stressed conditions, thus improving our understanding on functional roles of pit membranes in xylem hydraulic function. Further work could be done to study the morphological and mechanical response of bordered pit membranes under different dehydrated conditions, as well as the related microflow behavior, based on our constructed model.

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“…It is interesting in this context to mention that recent theoretical estimates show relative changes of 20% in the sap flow through bordered pit membranes when electroviscous effects are included from ions in and just outside the membrane (Santiago, Pagay, and Stroock, 2013).…”

Section: Phloem Xylem Human Aortamentioning

confidence: 99%

“…In most plants, the pit membrane appears relatively featureless, with atomic force microscopy indicating the presence of a soft surface layer that covers the cellulose network (Lee, Holbrook, and Zwieniecki, 2012). The presence of hydrogels in pit membranes is indicated by the effect of cations on hydraulic resistance (Zwieniecki, Melcher, and Holbrook, 2001;Santiago, Pagay, and Stroock, 2013).…”

Section: Xylem Anatomymentioning

confidence: 99%

Sap flow and sugar transport in plants

et al. 2016

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Green plants are Earth's primary solar energy collectors. They harvest the energy of the Sun by converting light energy into chemical energy stored in the bonds of sugar molecules. A multitude of carefully orchestrated transport processes are needed to move water and minerals from the soil to sites of photosynthesis and to distribute energy-rich sugars throughout the plant body to support metabolism and growth. The long-distance transport happens in the plants' vascular system, where water and solutes are moved along the entire length of the plant. In this review, the current understanding of the mechanism and the quantitative description of these flows are discussed, connecting theory and experiments as far as possible. The article begins with an overview of low-Reynolds-number transport processes, followed by an introduction to the anatomy and physiology of vascular transport in the phloem and xylem. Next, sugar transport in the phloem is explored with attention given to experimental results as well as the fluid mechanics of osmotically driven flows. Then water transport in the xylem is discussed with a focus on embolism dynamics, conduit optimization, and couplings between water and sugar transport. Finally, remarks are given on some of the open questions of this research field.

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Impact of Electroviscosity on the Hydraulic Conductance of the Bordered Pit Membrane: A Theoretical Investigation

Cited by 43 publications

References 70 publications

High porosity with tiny pore constrictions and unbending pathways characterize the 3D structure of intervessel pit membranes in angiosperm xylem

High porosity with tiny pore constrictions and unbending pathways characterize the 3D structure of intervessel pit membranes in angiosperm xylem

Investigating Effects of Bordered Pit Membrane Morphology and Properties on Plant Xylem Hydraulic Functions—A Case Study from 3D Reconstruction and Microflow Modelling of Pit Membranes in Angiosperm Xylem

Sap flow and sugar transport in plants

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