Aquaporin-facilitated water uptake in barley (Hordeum vulgare L.) roots

It is not known to what degree aquaporin-facilitated water uptake differs between root developmental regions and types of root. The aim of this study was to measure aquaporin-dependent water flow in the main types of root and root developmental regions of 14- to 17-d-old barley plants and to identif...

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Main Authors:	Knipfer, Thorsten, Besse, Matthieu, Verdeil, Jean-Luc, Fricke, Wieland
Format:	Online
Language:	English
Published:	Oxford University Press 2011
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3153672/

id	pubmed-3153672
recordtype	oai_dc
spelling	pubmed-31536722011-08-15 Aquaporin-facilitated water uptake in barley (Hordeum vulgare L.) roots Knipfer, Thorsten Besse, Matthieu Verdeil, Jean-Luc Fricke, Wieland Research Papers It is not known to what degree aquaporin-facilitated water uptake differs between root developmental regions and types of root. The aim of this study was to measure aquaporin-dependent water flow in the main types of root and root developmental regions of 14- to 17-d-old barley plants and to identify candidate aquaporins which mediate this flow. Water flow at root level was related to flow at cell and plant level. Plants were grown hydroponically. Hydraulic conductivity of cells and roots was determined with a pressure probe and through exudation, respectively, and whole-plant water flow (transpiration) determined gravimetrically in response to the commonly used aquaporin inhibitor HgCl2. Expression of aquaporins was analysed by real-time PCR and in situ hybridization. Hydraulic conductivity of cortical cells in seminal roots was largest in lateral roots; it was smallest in the fully mature zone and intermediate in the not fully mature ‘transition’ zone along the main root axis. Adventitious roots displayed an even higher (3- to 4-fold) cortical cell hydraulic conductivity in the transition zone. This coincided with 3- to 4-fold higher expression of three aquaporins (HvPIP2;2, HvPIP2;5, HvTIP1:1). These were expressed (also) in cortical tissue. The largest inhibition of water flow (83–95%) in response to HgCl2 was observed in cortical cells. Water flow through roots and plants was reduced less (40–74%). It is concluded that aquaporins contribute substantially to root water uptake in 14- to 17-d-old barley plants. Most water uptake occurs through lateral roots. HvPIP2;5, HvPIP2;2, and HvTIP1;1 are prime candidates to mediate water flow in cortical tissue. Oxford University Press 2011-08 2011-03-25 /pmc/articles/PMC3153672/ /pubmed/21441404 http://dx.doi.org/10.1093/jxb/err075 Text en © 2011 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.5), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. This paper is available online free of all access charges (see http://jxb.oxfordjournals.org/open_access.html for further details)
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Knipfer, Thorsten Besse, Matthieu Verdeil, Jean-Luc Fricke, Wieland
spellingShingle	Knipfer, Thorsten Besse, Matthieu Verdeil, Jean-Luc Fricke, Wieland Aquaporin-facilitated water uptake in barley (Hordeum vulgare L.) roots
author_facet	Knipfer, Thorsten Besse, Matthieu Verdeil, Jean-Luc Fricke, Wieland
author_sort	Knipfer, Thorsten
title	Aquaporin-facilitated water uptake in barley (Hordeum vulgare L.) roots
title_short	Aquaporin-facilitated water uptake in barley (Hordeum vulgare L.) roots
title_full	Aquaporin-facilitated water uptake in barley (Hordeum vulgare L.) roots
title_fullStr	Aquaporin-facilitated water uptake in barley (Hordeum vulgare L.) roots
title_full_unstemmed	Aquaporin-facilitated water uptake in barley (Hordeum vulgare L.) roots
title_sort	aquaporin-facilitated water uptake in barley (hordeum vulgare l.) roots
description	It is not known to what degree aquaporin-facilitated water uptake differs between root developmental regions and types of root. The aim of this study was to measure aquaporin-dependent water flow in the main types of root and root developmental regions of 14- to 17-d-old barley plants and to identify candidate aquaporins which mediate this flow. Water flow at root level was related to flow at cell and plant level. Plants were grown hydroponically. Hydraulic conductivity of cells and roots was determined with a pressure probe and through exudation, respectively, and whole-plant water flow (transpiration) determined gravimetrically in response to the commonly used aquaporin inhibitor HgCl2. Expression of aquaporins was analysed by real-time PCR and in situ hybridization. Hydraulic conductivity of cortical cells in seminal roots was largest in lateral roots; it was smallest in the fully mature zone and intermediate in the not fully mature ‘transition’ zone along the main root axis. Adventitious roots displayed an even higher (3- to 4-fold) cortical cell hydraulic conductivity in the transition zone. This coincided with 3- to 4-fold higher expression of three aquaporins (HvPIP2;2, HvPIP2;5, HvTIP1:1). These were expressed (also) in cortical tissue. The largest inhibition of water flow (83–95%) in response to HgCl2 was observed in cortical cells. Water flow through roots and plants was reduced less (40–74%). It is concluded that aquaporins contribute substantially to root water uptake in 14- to 17-d-old barley plants. Most water uptake occurs through lateral roots. HvPIP2;5, HvPIP2;2, and HvTIP1;1 are prime candidates to mediate water flow in cortical tissue.
publisher	Oxford University Press
publishDate	2011
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3153672/
_version_	1611470193944428544

Aquaporin-facilitated water uptake in barley (Hordeum vulgare L.) roots

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