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The stomatal physiology of calcicoles in relation to calcium delivered in the xylem sap.

de Silva, D. L. R. and Mansfield, T. A. (1994) The stomatal physiology of calcicoles in relation to calcium delivered in the xylem sap. Proceedings of the Royal Society B: Biological Sciences, 257 (1348). pp. 81-85.

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Abstract

Physiological mechanisms in calcicoles in simulated highly calcareous habitats have been investigated using Campanula glomerata, Centaurea scabiosa and Leontodon hispidus. Diffusion resistance of the leaves was unaffected by high concentrations (15 mol m-3) of rhizospheric calcium in all three species, and in C. scabiosa and L. hispidus there was no inhibition of leaf extension even at 20 mol m-3. Free calcium concentrations in samples of xylem sap taken from the roots were found to be very close to those in the rhizosphere. However, stomata on isolated epidermis of C. scabiosa and L. hispidus closed in response to elevated free calcium in the same manner as those of Commelina communis, a calcium-neutral plant. It is concluded that the calcicoles must possess an efficient mechanism to remove high concentrations of free calcium delivered into the leaf's apoplast by the transpiration stream. If the xylem sap reached the apoplast around the stomata containing even 5-10% of its free calcium, stomatal function would be disturbed. If these species are representative of calcicoles in general, the leaf's mechanism for preventing excess calcium from reaching the stomatal guard cells may be indispensable. The capacity to remove or sequester most of the calcium delivered in the xylem may be a key factor in determining whether a plant is a calcicole or not.

Item Type: Article
Journal or Publication Title: Proceedings of the Royal Society B: Biological Sciences
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Departments: Faculty of Health and Medicine > Medicine
Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 22416
Deposited By: ep_ss_importer
Deposited On: 03 Feb 2009 10:09
Refereed?: Yes
Published?: Published
Last Modified: 26 Jul 2012 16:00
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/22416

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