Difference in Sugar Accumulation and Metabolism Between Red Flesh and White Flesh Cultivar in Loquat(Eriobotrya japonica Lindl.) Changes in cell ultra-structure, membrane permeability and protective enzyme activity in Eriobotrya japonica Lindl. leaves under cold stress Difference in Sugar Accumulation and Metabolism Between Red Flesh and White Flesh Cultivar in Loquat(Eriobotrya japonica Lindl.)