ISSN:
1573-5079
Keywords:
Beta vulgaris
;
calcium oxalate
;
CO2 fixation
;
isolated chloroplasts
;
sugarbeet
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Intact chloroplasts were isolated from sugarbeet leaves by the mechanical disruption technique normally used for spinach. The chloroplast pellet contained a ring of white irregularly shaped crystals which were identified as calcium oxalate. The chloroplasts were greater than 90% intact yet good rates of CO2 fixation were only obtained when inorganic pyrophosphate or 3-phosphoglycerate were added to the assay medium. Chloroplasts free of calcium oxalate were prepared by purification on a three step Percoll gradient. These purified chloroplasts were highly intact and showed high rates of CO2 fixation without adding inorganic pyrophosphate or 3-phosphoglycerate. With optimal assay conditions (0.2 mM orthophosphate and pH 8.0) rates of 110–130 μ mole per milligram chlorophyll per hour were routinely obtained. It is concluded that intact chloroplasts capable of high rates of CO2 fixation can be prepared from sugarbeet leaves using a simple three step Percoll gradient.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00052132
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