Histological Analysis of Concavity Induced on Surface of Garlic Scales after Harvest

Abstract

Concavities often develop on the scales of garlic bulbs stored for long periods in sub-zero conditions. Previous studies indicated that curing methods and the temperature and duration of sub-zero storage affect the occurrence of such concavities. In this study we histologically analyzed the developmental process of concavities to elucidate the causative mechanism. Striped depressions in a vertical direction were observed on the surface of the tip of garlic scales with mild symptoms. The depression parts expanded to near the base of scales in garlic with severe symptoms. Cell collapse was observed in a few cell layers near the epidermis in scales with mild symptoms. The more severe the concavity symptoms, the more cell layers showed collapse. No evidence of ice crystal formation was found in the internal tissue of scales with severe symptoms. This histological study suggests that the concavity on garlic scales is induced by factors other rather than ice crystal formation.