Quantitative ion localization within Suaeda maritima leaf mesophyll cells

Abstract

Grown under saline conditions, Suaeda maritima accumulates Na(+) and Cl(-) into its leaves, where individual mesophyll cells behave differently in their compartmentation of these ions. Measurements of ion concentrations within selected subcellular compartments show that freeze-substitution with dry sectioning is a valuable preparative technique for analytical electron microscopy of highly vacuolate plant material. Using this approach, absolute estimates were made of Na(+), K(+) and Cl(-) concentrations in the cytoplasm, cell walls, chloroplasts and vacuoles of leaf mesophyll cells.

Osmoregulation in the Extremely Euryhaline Marine Micro-Alga Chlorella autotrophica

“…Glucose-6-P dehydrogenase, an enzyme involved in the oxidative pentose-P cycle of the chloroplast, when isolated from the leaves of Suaeda maritima was strongly inhibited by 167 mm NaCl (8). The chloroplasts in the leaves of this angiosperm halophyte growing under optimum growth conditions may, however, have chloride concentrations of up to 210 mm (13). These studies, therefore, point out the limits to which reliance can be placed on in vitro studies of enzymes to determine the salt tolerance ofhighly organized intact cytoplasmic machinery of plant cells.…”

Quntitative Ion Distribution Within Root Cells of Salt‐sensitive and Salt‐tolerant Maize Varieties

“…The segments were gently blotted and prepared for analysis by freeze-substitution in acetone as described by Harvey, Hall & Flowers (1976), and analytical concentration calibration standards were prepared as described by Harvey, Flowers & Kent (1984). Analysis of thin sections was performed with an EMMA-4/Link systems energy dispersive system as previously described (Harvey et aL, 1981;Harvey, 1985). Ion concentrations at the analyzed sites were determined by comparison of R values (R = elemental peakbackground/continuum) with those obtained from the appropriate calibration standard (Harvey et aL, 1984).…”

Quantification of Apoplastic Potassium Content by Elution Analysis of Leaf Lamina Tissue from Pea (Pisum sativum L. cv Argenteum)

“…Several indirect approaches have been reported for collection of apoplastic sap and estimation of ionic concentrations including analysis of xylem exudates, vacuum perfusion of leaf lamina discs (1), and pressure dehydration of leaves (14). X-ray microanalysis (7,9,12) and ion-sensitive microelectrodes have been used to measure directly extracellular ion concentrations ofepidermal guard cells (2) and the extensor and flexor cells within the pulvinus of legume leaves (26). The primary limitation of these procedures is the inability to estimate the ionic content within the apoplastic reservoir of the mesophyll.…”