2.Plant Growth and development 种皮seed capsule保护层 胚根radicel A.seed structure) 胚一未来新植株的雏体胚轴hypocotyl (占种子重的2-3%) 胚芽embryo 子叶cotyledon 胚乳endosperm—store energy For grass,the endosperm in the caryopsis is relatively small,so there is little stored enery.Shallow planting is critical so seedlings can emerge and develop quickly before the reserves are used up. ■RA Copyright reseved by Long Mi College of animal science,Northwest Agriculture Forestry University 西北农林科技大学动物科技学院草业科学系__________________________________________________________________ College of animal science, Northwest Agriculture & Forestry University  西北农林科技大学动物科技学院草业科学系 Copyright reseved by Long Mingxiu  种皮seed capsule——保护层 胚根radicel  A.seed structure  胚——未来新植株的雏体 胚轴hypocotyl  （占种子重的2­3%） 胚芽embryo  子叶cotyledon  胚乳endosperm——store energy For grass,the endosperm in the caryopsis颖 果 is relatively small,so there is little stored  enery.Shallow planting is critical so seedlings can emerge and develop quickly before the  reserves are used up.  2.Plant Growth and development