Histochemical and electron microscopic studies on the granular materials associated with swollen rachises of 'Muscat of Alexandria' grape

To identify granules present in abnormally swollen rachises of 'Muscat of Alexandria' grape, six kinds of histochemical tests as well as SEM and TEM observations were made. Most of the granules with the diameter ranging from 1 to 2 μm were supposed to be not starch grains but mainly polyphenol substances, based on the staining reactions with iodine. Sudan black and vanillin. Smaller granules (0.1 to 0.5 μm diameter) were suggested to be vesicles from their irregular size, non-staining reaction to hematoxilin, eosin and Bismark brown, lack of ribosome-like particles, and double membrane structure. They may be not the cause of the abnormal cell division but are produced as a result of unusual cell physiology.