Relative quantification of membrane-associated calcium in red spruce mesophyll cells

• Published in: Trees (Berlin, West) West), 1997-12, Vol.12 (1), p.21-26
• Main Authors: BORER, C. H, DEHAYES, D. H, SCHABERG, P, CUMMING, J. R
• Format: Article
• Language: English
• Subjects: Absorption. Translocation of ions and substances. Permeability; Agronomy. Soil science and plant productions; Biological and medical sciences; Calcium; Cell physiology; Economic plant physiology; Foliage; Fundamental and applied biological sciences. Psychology; Membranes; Nutrition. Photosynthesis. Respiration. Metabolism; Plant physiology and development; Plant tissues; Plasma membrane and permeation; Seedlings; Trees; Woody plants
• ISSN: 0931-1890; 1432-2285
• DOI: 10.1007/s004680050117

We describe a method for localizing and comparing relative amounts of plasma membrane-associated calcium ions (mCa) in complex tissues and verify the procedure for mesophyll cells of red spruce (Picea rubens Sarg.) needles. This technique incorporates epifluorescence microscopy using the fluorescent probe chlorotetracycline (CTC) with computer image processing and analysis. Using an appropriate standardization for image brightness, the procedure allows relative quantitative comparison of CTC-fluorescence in the plasma membrane-cell wall region that corresponds to relative amounts of mCa. The technique effectively discerned mCa differences among red spruce needle sections exposed to treatments designed to alter mCa levels in vitro. Estimates of mCa for nine red spruce seedlings, were highly repeatable over a 6 week period in late summer. This repeatability verifies that the described methods produce reliable and reproducible estimates of foliar mCa in woody plant foliage. By incorporating image analysis, this technique allows for relative quantitative estimates of mCa specific to the physiologically-important and labile pool of Ca associated with the plasma membrane-wall complex. Such measurements have not previously been reported for woody plant tissues and thus may provide new insights into the relative roles and responsiveness of mCa vs total foliar Ca pools.[PUBLICATION ABSTRACT]