Xylem network connectivity and embolism spread in grapevine(Vitis vinifera L.)

Abstract Xylem networks are vulnerable to the formation and spread of gas embolisms that reduce water transport. Embolisms spread through interconduit pits, but the three-dimensional (3D) complexity and scale of xylem networks means that the functional implications of intervessel connections are not well understood. Here, xylem networks of grapevine (Vitis vinifera L.) were reconstructed from 3D high-resolution X-ray micro-computed tomography (microCT) images. Xylem network performance was then modeled to simulate loss of hydraulic conductivity under increasingly negative xylem sap pressure simulating drought stress conditions. We also considered the sensitivity of xylem network performance to changes in key network parameters. We found that the mean pit area per intervessel connection was constant across 10 networks from three, 1.5-m stem segments, but short (0.5 cm) segments fail to capture complete network connectivity. Simulations showed that network organization imparted additional resistance to embolism spread beyond the air-seeding threshold of pit membranes. Xylem network vulnerability to embolism spread was most sensitive to variation in the number and location of vessels that were initially embolized and pit membrane vulnerability. Our results show that xylem network organization can increase stem resistance to embolism spread by 40% (0.66 MPa) and challenge the notion that a single embolism can spread rapidly throughout an entire xylem network.

Download Full-text

Scion photosynthesis and leaf gas exchange in Vitis vinifera L. cv. Shiraz: Mediation of rootstock effects via xylem sap ABA

Australian Journal of Grape and Wine Research ◽

10.1111/j.1755-0238.2006.tb00047.x ◽

2006 ◽

Vol 12 (2) ◽

pp. 82-96 ◽

Cited By ~ 69

Author(s):

C.J. SOAR ◽

P.R. DRY ◽

B.R. LOVEYS

Keyword(s):

Gas Exchange ◽

Vitis Vinifera ◽

Leaf Gas Exchange ◽

Xylem Sap ◽

Vitis Vinifera L

Download Full-text

Effects of three esca-associated fungi on Vitis vinifera L.: V. Changes in the chemical and biological profile of xylem sap from diseased cv. Sangiovese vines

Physiological and Molecular Plant Pathology ◽

10.1016/j.pmpp.2008.02.005 ◽

2007 ◽

Vol 71 (4-6) ◽

pp. 210-229 ◽

Cited By ~ 38

Author(s):

Giovanni Bruno ◽

Lorenzo Sparapano

Keyword(s):

Vitis Vinifera ◽

Xylem Sap ◽

Vitis Vinifera L ◽

Biological Profile

Download Full-text

Effects of three esca-associated fungi on Vitis vinifera L.: II. Characterization of biomolecules in xylem sap and leaves of healthy and diseased vines

Physiological and Molecular Plant Pathology ◽

10.1016/j.pmpp.2007.04.007 ◽

2006 ◽

Vol 69 (4-6) ◽

pp. 195-208 ◽

Cited By ~ 32

Author(s):

Giovanni Bruno ◽

Lorenzo Sparapano

Keyword(s):

Vitis Vinifera ◽

Xylem Sap ◽

Vitis Vinifera L

Download Full-text

Three‐dimensional reconstruction of Vitis vinifera (L.) cvs Pinot Noir and Merlot grape bunch frameworks using a restricted reconstruction grammar based on the stochastic L‐system

Australian Journal of Grape and Wine Research ◽

10.1111/ajgw.12444 ◽

2020 ◽

Vol 26 (3) ◽

pp. 207-219

Author(s):

B. Xin ◽

S. Liu ◽

M. Whitty

Keyword(s):

Vitis Vinifera ◽

Three Dimensional ◽

Pinot Noir ◽

Vitis Vinifera L ◽

Three Dimensional Reconstruction ◽

L System ◽

Dimensional Reconstruction

Download Full-text

Ultrastructure of pit membrane dissolution and movement of Xylella fastidiosa through pit membranes in petioles of Vitis vinifera

Botany ◽

10.1139/b10-025 ◽

2010 ◽

Vol 88 (6) ◽

pp. 596-600 ◽

Cited By ~ 4

Author(s):

E. Ann Ellis ◽

George Ray McEachern ◽

Samantha Clark ◽

B. Greg Cobb

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Vitis Vinifera ◽

Causative Agent ◽

Xylella Fastidiosa ◽

Vitis Vinifera L ◽

Cabernet Sauvignon ◽

Transmission Electron ◽

Pit Membrane ◽

Xylem Element

Xylella fastidiosa is the causative agent in Pierce’s disease (PD) in Vitis vinifera L. (grape) vines. Xylella fastidiosa colonizes and disseminates itself from one xylem element to another by dissolution and breach of pit membranes. These studies on naturally infected V. vinifera grown under vineyard conditions document by transmission electron microscopy that there is dissolution and breach of pit membranes by X. fastidiosa in vertical and lateral colonization in PD. These processes were documented in two cultivars of V. vinifera: ‘Syrah’ and ‘Cabernet Sauvignon.’

Download Full-text

Gradients in stomatal conductance, xylem sap ABA and bulk leaf ABA along canes of Vitis vinifera cv. Shiraz: molecular and physiological studies investigating their source

Functional Plant Biology ◽

10.1071/fp03238 ◽

2004 ◽

Vol 31 (6) ◽

pp. 659 ◽

Cited By ~ 74

Author(s):

Christopher J. Soar ◽

Jim Speirs ◽

Suzanne M. Maffei ◽

Brian R. Loveys

Keyword(s):

Stomatal Conductance ◽

Vitis Vinifera ◽

Biosynthetic Pathway ◽

Xylem Sap ◽

Leaf Age ◽

Vitis Vinifera L ◽

Local Synthesis ◽

Cdna Sequences ◽

Genes Encoding ◽

Induced Changes

Gradients were observed in xylem sap ABA and in stomatal conductance along canes of Vitis vinifera L. cv. Shiraz. To investigate the source of the ABA responsible for these gradients a series of girdling and decapitation experiments were carried out. Leaf stomatal conductance and bulk ABA of leaves and apices were measured in control plants and in response to apex removal or girdling. Gradients in leaf ABA were observed over the first eight expanded leaves of field-grown Shiraz, with higher concentrations of ABA observed towards the apex. Gradients in stomatal conductance that correlated negatively with the concentration of ABA in the leaf ([ABA]leaf) were also observed over the first eight leaves. No significant effect of decapitation was observed on either leaf ABA or stomatal conductance except for the leaf immediately below the apex where a transient increase in [ABA]leaf was observed after 24 h with no corresponding decrease in conductance. Girdling resulted in an increase in [ABA]leaf in leaves distal to the girdle without the corresponding effect on conductance. These effects were further studied at the level of gene activity. To facilitate this, gene sequences encoding two key enzymes involved in the biosynthetic pathway of ABA in grape, zeaxanthin epoxidase (Zep) and 9-cis-epoxycarotenoid dioxygenase (NCED), were isolated and characterised. The cDNA sequences were used as probes to measure the abundances of their respective mRNAs in the leaf and apical material. Levels of expression of one of the two genes encoding NCED, VvNCED1, reflected the gradients in [ABA]leaf in control vines, however treatment-induced changes in ABA were not always associated with corresponding changes in VvNCED1 expression. The abundances of both the VvNCED2 mRNA and Zep mRNA increased with increasing leaf age and did not appear to be associated with either the [ABA]leaf or the expression of VvNCED1. Our results indicate that observed gradients in g s are correlated with [ABA] gradients in mature leaves and xylem sap and that these [ABA] gradients are not derived directly from the apical tissues but, at least partially, from local synthesis.

Download Full-text

Three-dimensional imaging of xylem at cell wall level through near field nano holotomography

Scientific Reports ◽

10.1038/s41598-021-83885-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tim Koddenberg ◽

Imke Greving ◽

Johannes Hagemann ◽

Silja Flenner ◽

Andreas Krause ◽

...

Keyword(s):

Cell Wall ◽

Pinus Sylvestris ◽

Fagus Sylvatica ◽

Ion Beam ◽

Near Field ◽

Three Dimensional ◽

Imaging Method ◽

Micro Computed Tomography ◽

X Ray ◽

Pit Membrane

AbstractDetailed imaging of the three-dimensionally complex architecture of xylary plants is important for studying biological and mechanical functions of woody plants. Apart from common two-dimensional microscopy, X-ray micro-computed tomography has been established as a three-dimensional (3D) imaging method for studying the hydraulic function of wooden plants. However, this X-ray imaging method can barely reach the resolution needed to see the minute structures (e.g. pit membrane). To complement the xylem structure with 3D views at the nanoscale level, X-ray near-field nano-holotomography (NFH) was applied to analyze the wood species Pinus sylvestris and Fagus sylvatica. The demanded small specimens required focused ion beam (FIB) application. The FIB milling, however, influenced the image quality through gallium implantation on the cell-wall surfaces. The measurements indicated that NFH is appropriate for imaging wood at nanometric resolution. With a 26 nm voxel pitch, the structure of the cell-wall surface in Pinus sylvestris could be visualized in genuine detail. In wood of Fagus sylvatica, the structure of a pit pair, including the pit membrane, between two neighboring fibrous cells could be traced tomographically.

Download Full-text

Naturally Occurring Periderm Tubes Around Secondary Phloem Fibres in the Bark of Vitis Vinifera L.

IAWA Journal ◽

10.1163/22941932-90001203 ◽

1991 ◽

Vol 12 (1) ◽

pp. 57-61 ◽

Cited By ~ 1

Author(s):

Roni Aloni ◽

Carol A. Peterson

Keyword(s):

Vitis Vinifera ◽

Three Dimensional ◽

Full Length ◽

Dimensional Structure ◽

Vitis Vinifera L ◽

Secondary Phloem ◽

Three Dimensional Structure ◽

Naturally Occurring ◽

Surrounding Atmosphere ◽

Parenchyma Cells

The three-dimensional structure of periderm tubes, which normally occur in the bark of intact Vitis vinifera L. stems, is described. Each tube, which possesses several layers of mature phellem cells, differentiated around an individual strand of secondary phloem fibres within the bark. Following these peridermenclosed strands for their full length revealed that at one or two points the strand passed through a sheet of periderm and was exposed to the surrounding atmosphere. The tubes of suberised phellern within the bark isolated these strands of air-dried fibres from the living parenchyma cells around them and thus protected the bark from desiccation and pathogen attack.

Download Full-text