哺乳动物的受精

受精是单倍体配子（精子和卵子）融合产生新生命的过程,是有性生殖个体发育的起点。根据动物种类的不同,受精可以发生在体内,也可以发生在体外。它一方面恢复了染色体双倍体数目,保证了双亲的遗传作用;另一方面,受精可以把生殖细胞通过减数分裂同源重组获得遗传物质变化和个体发生过程中产生的变异遗传下去,保证了物种的遗传多样性,在生物进化上具有重要意义。     

哺乳动物的受精

受精过程包含着两性配子间一系列复杂且十分协调的相互作用.本文概述了近年来有关受精过程和机理的新发现,对建立比较完整的关于受精的新概念无疑是有益的.     

鱼类的受精

关于动物的受精,特别是海胆和哺乳类已有大量文献和专著问世,但对鱼类却知之甚少。自1979年以来从亚显微结构方面对几种鱼类受精过程作了报道,在此作一综合介绍。 (一)精子 硬骨鱼类的精子没有顶体,但圆口纲的七鳃鳗,板鳃纲的鲨鱼(Squalus suckleyi)和鲟     

植物的受精作用 第五讲 受精的控制

自本世纪二十年代开始,已开展了一些有关人工控制受精的试验。1950年以前的工作,Maheshwari (1950)已收集在他所著的《被子植物胚胎学引论》一书中。在最近的三十多年,由于对不亲和性饥理的知识的提高,创立了更多的克服不亲和性的有效方法。本文选择蒙导花粉法、蕾期授粉、电助授     

被子植物的受精工程技术

被子植物的受精工程技术何龙飞,王爱勤（广西农业大学农学系,南宁５３０００５）被子植物受精工程是利用分离的精子和卵细胞进行体外受精,形成人工合子,再培养成植株而进行品种改良或物种创造的过程,具有重要的理论和实践意义。近年来取得了重大的进展,如雄性生殖单...     

哺乳动物受精的生物学

哺乳动物的受精(Mammalian Fertilization)是两性配子(精子和卵子)相结合而形成合子的过程,它标志着胚胎发育的开始,也即是一个新生命的起点。受精是生物学家饶有兴味的课题。因为它不仅涉及到一个理论问题,更重要的是当今节育和不育的世界性问题尚未解决,因此,受精的重要性是不言而喻的。当然,受精是一个极其复杂的生命现象,涉及到两性配子的发育和成熟、精子获能、顶体反应、精卵激活、精子     

两栖动物的受精方式

在1991年豫、鄂、湘、粤、桂、鲁、赣专科起点本科招生统考的动物学试题中有一个选择题是:两栖动物的受精方式为:A.体内受精 B.多数种类为体内受精C.体外受精 D.多数种类为体外受精试题答案及评分标准要求的答案是 C,即两栖动物的受精方式为体外受精。初看起来这答案没有问题,因为我国常见的无尾两栖动物的受精方式都是体外受精。但对两栖动物的受精方式进行全面分析,就发现选择 C 不对。而正确的答案应选 D,即多数种类为体外受精。为了说明答案是 C 还是 D,必须了解现存三个目两栖动物的受精方式。     

果树的授粉受精

果树的产量与果实的品质,除决定于各种栽培管理措施外,是否有良好的授粉树,能否顺利完成授粉、受精过程也是一个十分重要的因素。大多数果树,特别是仁果类的果树通常是自花不实或微量结实的,即栽植单一品种的果树是不会有经济产量的。但自花结实的树种配置不同品种的授粉树后,也可显著增产。影响授粉受精的因素很多,主要有以下几方面。 (一)亲和力首先要考虑授粉品种与主栽品种要有良好的亲和力。花粉落到柱头上后,要经过二者的互相识别和选择,并非落到柱头上的花粉都能萌发。如果二者亲合,花粉吸水膨     

植物的多重受精

在以日丹诺夫命名的国立列宁格勒大学遗传学教研组所作的研究结果中,已经获得了许多资料,都证明在混合花粉授粉的条件下,可以产生一些遗传若干个共同授粉品种的性状的植物杂种。我们在番茄、豌豆、小麦和萝蔔的试验中,就曾获得有这样的结果。而在玉米、小麦、棉花以及他种作物的许多试验研究中,也得到过类似的结论。所以说杂种体能够遗传若干个共同授粉品种的性状的事实,乃是千真万确的。     

Fertilization in Fucus

Summary Methods are described for the collection, treatment and uniform discharge of large quantities of gametes, and a measure of fertilization control in the monoecious brown alga, Fucus distichus. Fertilization was examined using the techniques of blister-formation, gamete separation experiments, and electron microscopy. Sperm enter the freshly-discharged egg packets through a mesochite pore and juxtaposition with the eggs early. However, experimental and thinsection data indicate that fertilization does not occur until the eggs dissociate from the mesochite and round up. Hence, the egg surface appears to undergo three functional changes following its release from the thallus: (1) a pre-dissociation state which inhibits fertilization within the mesochite; (2) a dissociation state when fusion of gametes is possible; and (3) a post-fertilization state characterized by the formation of extraneous coats. As the egg is activated by the sperm a nonmembranous layer appears to detach from the egg surface to form an activation layer. This is augmented by fibrous units to function as a fertilization barrier which ultimately thickens to form the cell wall. The area between the eggs within the egg packet is characterized by the presence of fibrous and particulate substances which are continuously given off through the egg surface. These apparently play a functional role in the sequential stages of fertilization in Fucus. These observations are discussed in terms of analogies with fertilization in the sea urchin.This work was supported by a Lalor Foundation Research Fellowship at Friday Harbor Biological Laboratories, University of Washington, and by a National Science Foundation Science Faculty Fellowship to the Swiss Federal Institute of Technology, Zürich, Switzerland.     

Fertilization in Animals

Fertilization in mammalian and nonmammalian organisms has many features in common. These features include a final maturation phase for sperm and eggs, species‐specific binding of sperm to eggs, penetration by sperm of one or more extracellular coats surrounding eggs, fusion of sperm and eggs, and activation of eggs. Implicit in this are a variety of basic molecular events, including receptor‐ligand interactions, signalling cascades, specific proteolysis, and nuclear transformations. Here, several of these events are addressed for fertilization in animals as diverse as starfish and mice. Dev. Genet. 25:83–86, 1999. © 1999 Wiley‐Liss, Inc.     

Fertilization in echinoderms

For more than 150years, echinoderm eggs have served as overly favored experimental model systems in which to study fertilization. Sea urchin and starfish belong to the same phylum and thus share many similarities in their fertilization patterns. However, several subtle but fundamental differences do exist in the fertilization of sea urchin and starfish, reflecting their phylogenetic bifurcation approximately 500 million years ago. In this article we review some of the seminal and recent findings that feature similarities and differences in sea urchin and starfish at fertilization.