Xylem sap calcium concentrations do not explain liming-induced inhibition of legume gas exchange

Rothwell, Shane A. and Dodd, Ian C. (2014) Xylem sap calcium concentrations do not explain liming-induced inhibition of legume gas exchange. Plant and Soil, 382 (1-2). pp. 17-30. ISSN 0032-079X

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Abstract

Liming is considered normal agricultural practise for remediating soil acidity and improving crop productivity; however recommended lime applications can reduce yield. We tested the hypothesis that elevated xylem sap Ca2+ limited gas exchange of Phaseolus vulgaris L. and Pisum sativum L. plants that exhibited reduced shoot biomass and leaf area when limed. We used Scholander and whole-plant pressure chamber techniques to collect root and leaf xylem sap, a calcium-specific ion-selective electrode to measure xylem sap Ca2+, infra-red gas analysis to measure gas exchange of limed and unlimed (control) plants, and a detached leaf transpiration bioassay to determine stomatal sensitivity to Ca2+. Liming reduced shoot biomass, leaf area and leaf gas exchange in both species. Root xylem sap Ca2+ concentration was only increased in P. vulgaris and not in P. sativum. Detached leaves of both species required 5 mM Ca2+ supplied to via the transpiration stream to induce stomatal closure, however, maximum in vivo xylem sap Ca2+ concentrations of limed plants was only 1.7 mM and thus not high enough to influence stomata. We conclude that an alternative xylem-borne antitranspirant other than Ca2+ decreases gas exchange of limed plants.

Item Type:
Journal Article
Journal or Publication Title:
Plant and Soil
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1100/1111
Subjects:
ID Code:
72113
Deposited By:
Deposited On:
11 Dec 2014 09:08
Refereed?:
Yes
Published?:
Published
Last Modified:
22 Apr 2020 03:21