Measurements of starch (e.g. amyloplasts in stomatal guard cells, sieve ele
ments, root tips or the starch sheath) is often very difficult using most a
nalytical methods. An evaluation was made of interactive computer image ana
lysis of starch measurements in apple fruits. The results obtained indicate
that quantitative histochemistry can be an appropriate method to quantify
starch. Correlations for starch values between the image analysis system an
d a colorimetric system were quantified. The thickness of plastic-embedded
slices had no influence on the accuracy of the area occupied by image-quant
ified starch (starch/slice) or on its variance. The magnification of the ob
jective also had no effect on measured starch-occupied areas (starch/slice)
, but there were big differences in variance. The number of replications re
quired to establish statistically significant differences were calculated.