Dicot Seed Structure Seed Coat Cotyledon Epicotyl Embryo Hypocotyl 把子叶分开 图2菜豆种子 果皮和种皮 胚乳 Monocot Seed Structure 子P叶的维管束 子叶 种子 Seed Coat 全部 胚芽销 液叶 Endosperm 胚芽 Cotyledon 子叶的表皮 外胚叶 Epicotyl 胚根 胚根鞘 Radicle 胚 图4小麦麦粒（果实）织切面
__________________________________________________________________ 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
2.Plant Growth and development B.Requirements for seed germination The germination of seeds is dependent on both internal and external conditions. The most important external factors include: temperature-affects cellular metabolic and growth rates. water-is required before cellular metabolism and growth can resume. oxygen-is required by the germinating seed for metabolism. light or darkness(sometimes)-can be a type of environmental trigger for germination in seeds. ■▣RA opyright reseved by Long M 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 B.Requirements for seed germination • The germination of seeds is dependent on both internal and external conditions. • The most important external factors include: temperature affects cellular metabolic and growth rates. wateris required before cellular metabolism and growth can resume. oxygen is required by the germinating seed for metabolism . light or darkness (sometimes) can be a type of environmental trigger for germination in seeds . 2.Plant Growth and development
几种主要牧草及饲料作物种子萌发时需要的温度 浪度(C) 种炎 虽低 最通 最高 紫花档若 0-4.8 36-37 37-44 红且单 2-4 20-25 32-35 三叶皂 2-4 20-25 32-35 箭舌嫡且 2-4 20-25 32-35 绮且 1-2 20 无芒鲨多 5-6 25-30 35-37 猫尾皇 5-6 25-30 35-37 单芽 5-6 25-30 35-37 黑麦电 2-4 25-30 35-37 苏开自 8-10 20-30 40-50 FORAG 玉米 5-10 37-44 44-50 胡整卜 10 15-25 30 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
Germination and Emergence When water is absorbed,radicle胚根grows through the coleorhiza胚根鞘，seminal roots develop Epicotyl上胚轴elongates and grows toward the soil surface Coleoptile胚芽鞘(tip)pushes through the soil and reaches surface,then opens for true leaves to emerge Germination Events 4DAP Plumule Lateral seminal Radicle root roots F■RAEE Tip of kernel RLNiolsen,Purdue Univ..2000 PLong Mg College of animal science,Nornwest Agrcunure rorestry oniversity 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 Germination and Emergence • When water is absorbed, radicle 胚根grows through the coleorhiza胚根鞘, seminal roots develop • Epicotyl上胚轴 elongates and grows toward the soil surface • Coleoptile 胚芽鞘(tip) pushes through the soil and reaches surface, then opens for true leaves to emerge
2.Plant Growth and development The uptake of water by seeds is called imbibition. Foliage leaves Cotyledon Foliage leaves Hypocotyl Epicotyl Cotyledon Coleoptile Hypocotyl Coleoptile Hypocotyl Radicle Seed coat Radicle (a)Bean (c)Corn Bean is epigeal Foliage leaves 子叶出土 Hypocotyl -Epicotyl Pea and Corn are hypogeal Cotyledon FORAGES 子叶留土 Hypocotyl Radicle (b)Pea CopyrightPearson Education.Inc publishing as Benjamin Cummings
__________________________________________________________________ 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 Bean is epigeal 子叶出土 Pea and Corn are hypogeal 子叶留土 The uptake of water by seeds is called imbibition. 2.Plant Growth and development