A quick method for assessing chloroplastic starch granules by flow cytometry

A crude but rapid method for assessing chloroplastic starch granules by flow cytometry is introduced. It yields information on the average number of starch granules in chloroplasts within minutes. Two species of beans, Phaseolus vulgarisandPhaseolus acutifolius, were used to develop the tech nique. This new technique cannot replace the conventional enzymatic method when absolute quantification of starch (in glucose equivalents) is required. However, if a quick check of relative starch content is sufficient when addressing issues such as stress and photosynthetic regulation through large-scale screening of plants, the new technique may be the method of choice.