Studies on the Sucrose-metabolizing Enzymes in Navel Orange Fruit from Different Habitats Studies on the Sucrose-metabolizing Enzymes in Navel Orange Fruit from Different Habitats Effects of Different Planting Densities on Sugar Accumulation and Activities of Sucrose Synthase and Sucrose Phosphate Synthase of Sweet Sorghum bicolor (L.) Moench Cloning and Tissue Expression Analysis of Sucrose Phosphate Synthase Gene from Lycium barbarum L.