细胞全能性及其应用

• The endosperm
– The endosperm is the food reserve that the embryo uses during the early stages of germination. Before the embryo is able to produce its own food through photosynthesis, the endosperm provides vital nutrients to the embryo.
内容简介
什么是细胞全能性？ 什么叫人工种子？ 人工种子具有哪些特点？
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一、细胞全能性（Totipotency）
指细胞能够发展成为一棵完整植株的能力
基于：
细胞学说：细胞是生物体结构和功能 的基本单位 遗传学理论：每一个细胞都具有生物 体全部的遗传物质
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二、人工种子(Synthetic seeds)
• Advantages of artificial seeds
– Artificial seeds have the potential for providing an inexpensive plant delivery system. The process of planting can be easily mechanised and this allows the direct delivery of tissue cultured plant propagules to the field. It also provides rapid bulking up for the production of individual genetically engineered plants.
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• Artificial Seeds • Concept
– Artificial seeds were first introduced in the 1970s as a novel analogue to the plant seeds. The production of artificial seeds is especially useful for plants which do not produce viable seeds. It represents a method to propagate these plants. Artificial seeds are small sized and this provides further advantages in storage, handling, shipping and planting.
1、基本概念
将组织培养产生的体细胞胚或不定芽 包裹在能提供养分的胶囊里，再在胶 囊外面包上一层具有保护功能和防止 机械损伤的外膜，形成一种类似于自 然种子的结构。
4ቤተ መጻሕፍቲ ባይዱ
– In the production of artificial seeds, an artificial endosperm can be created within the encapsulation matrix. The encapsulation matrix is a hydrogel made of natural extracts from seaweed (agar, carageenan or alginate), plants (arabic or tragacanth), seed gums (guar, locust bean gum or tamarind) or microrganisms (dextran, gellan or xanthan gum黄原胶.). These compounds will gel when mixed with or dropped into an appropriate electrolyte (copper sulphate, calcium chloride or ammonium chloride). Ionic bonds are formed to produce stable complexes. Useful adjuvants such as nutrients, plant growth regulators, pesticide and fungicide can be supplied to the plant propagule within the encapsulation matrix. In most cases, a second coat covering the artificial endosperm is required to simulate the seed coat..
• The testa
– The testa protects the embryo from injury and drying out. It also
makes sure that the embryo remains viable before germination. As germination occurs, water is absorbed and the seed coat breaks 3 allowing the radicle to first emerge from the seed.
• Plant Seeds
– A plant seed consists of an embryo and its food store (endosperm), surrounded by a seed coat (testa). The seed ensures that the next generation of plants exists.
• The embryo
– The embryo is made up of one or two cotyledons attached to a central axis. The upper part of the axis contains a plumule at its tip. The plumule grows into the shoot system. The lower part of the axis consists of the hypocotyl and a radicle. The radicle grows into the root system.