Complete mechanical impedance increases the turgor of cells in the apex of pea roots |
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Authors: | LJ CLARK WR WHALLEY AR DEXTER PB BARRACLOUGH RA LEIGH |
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Institution: | Biochemistry and Physiology Department, IACR-Rothamsted, Harpenden, Hertfordshire AL5 2JQ, UK.;Silsoe Research Institute, Wrest Park, Silsoe, Bedford MK45 4HS, UK;Crop and Disease Management Department, IACR-Rothamsted, Harpenden, Hertfordshire AL5 2JQ, UK |
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Abstract: | In this paper we describe an experimental approach which allows turgor (p) in an impeded root to be measured without the need to remove the root from the impeding environment. The maximum axial growth pressure (σmax) generated by completely impeded pea (Pisum sativum L.) roots was measured using a novel apparatus incorporating a force transducer. The apparatus was designed so that it was possible to gain access to the impeded root with the microcapillary of a pressure probe and so obtain in situ measurements of P. Turgor in cells in the apical region of impeded roots was 0.78 MPa, compared with 0.55 MPa in unimpeded roots. In impeded roots, σmax was 0.52 MPa, showing that the pressure component resulting from cell wall tension (W, where W=P–σ) decreased from 0.55 to 0.26 MPa as the roots became impeded. When impeded roots were removed from the apparatus, there was no decrease in P over the following 90 min. Impedance did not cause P to change in the non-elongating part of the roots further from the apex. |
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Keywords: | Pisum sativum L pea mechanical impedance pressure probe root growth pressure turgor |
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