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Light-induced changes in hydrogen, calcium, potassium, and chloride ion fluxes and concentration from mesophyll and epidermal tissues of bean leaves. Understanding the ionic basis of light-induced bioelectrogenesis

Citation

Shabala, SN and Newman, IA, Light-induced changes in hydrogen, calcium, potassium, and chloride ion fluxes and concentration from mesophyll and epidermal tissues of bean leaves. Understanding the ionic basis of light-induced bioelectrogenesis, Plant Physiology, 119, (3) pp. 1115-1124. ISSN 0032-0889 (1999) [Refereed Article]

DOI: doi:10.1104/pp.119.3.1115

Abstract

Noninvasive, ion-selective vibrating microelectrodes were used to measure the kinetics of H+, Ca2+, K+, and Cl- fluxes and the changes in their concentrations caused by illumination near the mesophyll and attached epidermis of bean (Vicia faba L.). These flux measurements were related to light-induced changes in the plasma membrane potential. The influx of Ca2+ was the main depolarizing agent in electrical responses to light in the mesophyll. Changes in the net fluxes of H+, K+, and Cl- occurred only after a significant delay of about 2 min, whereas light-stimulated influx of Ca2+ began within the time resolution of our measurements (5 s). In the absence of H+ flux, light caused an initial quick rise of external pH near the mesophyll and epidermal tissues. In the mesophyll this fast alkalinization was followed by slower, oscillatory pH changes (5-15 min); in the epidermis the external pH increased steadily and reached a plateau 3 min later. We explain the initial alkalinization of the medium as a result of CO2 uptake by photosynthesizing tissue, whereas activation of the plasma membrane H+ pump occurred 1.5 to 2 min later. The epidermal layer seems to be a substantial barrier for ion fluxes but not for CO2 diffusion into the leaf.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Plant Physiology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Environmental Sciences
Author:Shabala, SN (Professor Sergey Shabala)
Author:Newman, IA (Dr Ian Newman)
ID Code:17675
Year Published:1999
Web of Science® Times Cited:70
Deposited By:Agricultural Science
Deposited On:1999-08-01
Last Modified:2000-06-06
Downloads:0

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