ISSN:
1432-2048
Keywords:
Chlorophyll fluorescence
;
Commelina
;
Guard cell
;
Oxygen evolution (guard cell)
;
Photosystem II
;
Protoplast
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Guard-cell protoplasts were isolated by enzymic digestion of the epidermis peeled from the abaxial surface of leaves from Commelina communis L. The protoplasts were separated from mesophyll-cell protoplasts and other contaminants by density-gradient centrifugation, and the purity of the preparations carefully and quantitatively assessed by light microscopy. The preparations of guard-cell protoplasts were then compared with mesophyll-cell protoplasts in terms of the activity of photosystem II as assessed by a) the light-induced evolution of oxygen under both steady-state and flashing light and b) the characteristics of photosystem-II chlorophyll fluorescence. In all experiments, clear photosystem-II activity was found in guard-cell protoplasts, although some subtle distinctions between guard-cell and mesophyll-cell protoplasts were found. The contribution of any contaimination by mesophyll-cell chlorophyll to guard-cell-protoplast signals was estimated to be less than 3% in all cases. The results indicate that photosystem II is present and active in guard cells of Commelina.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00409145
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