ISSN:
1432-2048
Keywords:
9-Aminoacridine
;
Avena (plasmalemma)
;
Bound divalent cations
;
Plasmalemma (electrostatic surface properties)
;
Triticum (plasmalemma)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Right-side-out and sealed plasmalemma vesicles were isolated from roots of spring wheat (Triticum aestivum L. cv. Drabant) and oat (Avena sativa L. cv. Brighton) by two-phase partition in a medium containing sucrose (0.25 mol l-1). Oat root plasmalemma vesicles were discovered to contain a strongly fluorescent compound with an emission maximum at 418 nm. The surface potential of the membranes was monitored by 9-aminoacridine fluorescence and the effect of protein concentration, mannitol versus sucrose, absence of osmoticum, concentrations of salt, and titrations with chelators investigated. It is concluded that i) protein concentrations of less than 50 μg ml-1 for oat and 100 μg ml-1 for wheat plasmalemma vesicles should be used to avoid serious problems with non-linearity of response of 9-aminoacridine fluorescence, ii) mannitol can be used instead of sucrose as the osmoticum, iii) the vesicles were ruptured in the absence of osmoticum allowing us to monitor both sides of the membranes, iv) plasmalemma vesicles from oat roots are more negative than vesicles from wheat roots, and v) oat and wheat root plasmalemma vesicles are isolated with about the same amounts of bound Ca2+ and Mg2+. These bound divalent cations may not, however, reflect the in-vivo conditions since the tissues were homogenised in the presence of ethylenediaminetetraacetic acid.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00402946
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