Varietal Difference in Distribution of Calcium Oxalate Crystal Idioblasts in Tissue of Taro (Colocasia esculenta Schott)

　The presence of calcium oxalate crystal in the petioles and corms is associated with acridity. In this study, varietal difference in the distribution of calcium oxalate crystal idioblasts in taro (Colocasia esculenta Schott) were investigated. Crystals of two forms were found: bundles of needle-like crystals (raphides) and aggregates of sand-like crystal (druses). Generally, the density of druse was higher than that of raphide, and there were few raphide idioblasts in the corm. The density of oxalate crystal was low in the edible petiole of cv. Yatsugashira and the edible corms of cvs. Yatsugashira, Akame-daikichi, Takenokoimo and Malaysia No. 1. There were few oxalate crystals in the cormels of all cultivars. There was no correlation between the density of oxalate crystal and the concentration of insoluble oxalate. These results suggest that the edible quality is not related to the insoluble oxalate concentration but to the density of oxalate crystal.