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Quantitative Stress Responses of the V 0 V 1 ‐ATPase of Higher Plants Detected by Immuno‐electron Microscopy
Author(s) -
Ratajczak R.,
Hille Angela,
Mariaux J.B.,
Lüttge U.
Publication year - 1995
Publication title -
botanica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0932-8629
DOI - 10.1111/j.1438-8677.1995.tb00528.x
Subject(s) - vacuole , mesembryanthemum crystallinum , hordeum vulgare , vesicle , atpase , membrane , biology , biophysics , biochemistry , botany , enzyme , poaceae , cytoplasm , crassulacean acid metabolism , photosynthesis
Immuno‐electron microscopy of negatively stained isolated tonoplast vesicles was used to quantify stress responses of the H + ‐transporting tonoplast ATPase (V 0 V 1 ‐ATPase; EC 3.6.1.1) of the C 3 /CAM intermediate Mesembryanthemum crystallinum L. and the C 3 plant Hordeum vulgare L. This approach has the advantage that it relates quantitative adaptations at the level of membrane enzymes directly to membrane area and thus is independent of concomitant changes of relative amounts of other membrane proteins which may perturb conclusions when data are expressed on a tonoplast protein basis. It was shown that in M. crystallinum the amount of V 0 V 1 ‐ATPase per unit membrane area increased slightly with ageing and pronouncedly with salinity stress. In H. vulgare under salt stress there was an increase in V 0 V 1 ‐ATPase amount only in the highly salt tolerant cv. California Mariout and not in the moderately tolerant cv. Carina. This corroborates conclusions from earlier work, where results were expressed on a protein basis, although this was not to be expected a priori . In all comparative ecophysiological studies using tonoplast vesicles at least some key‐point tests with the immunonegative staining technique should be included for the sake of prudence. The data obtained here via immunonegative staining of isolated tonoplast vesicles are in very close agreement with much earlier assessments of area and whole cell‐related activities given by measurements of entire isolated vacuoles and morphometric analysis, which further corroborates the suitability of the approaches. The data presented here for the first time allow calculations of the coverage of the tonoplast surface of M. crystallinum with V 0 V 1 ‐ATPase holoenzyme protein and with total tonoplast protein, i.e. 1.5 to 2.3 . 10 −15 g V 0 V 1 ‐ATPase per μm 2 and 7.4 to 8.8 . 10 −15 g protein per μm 2 , respectively.