Be fertilized

The fertilized eggs and is sperm The fusion is a process of the zygote. It is sexual reproduction The basic characteristics, widely exists in animals and plants, but people usually mention most is the animal. Animal fertilization at the cellular level, including the process of fertilization Egg Activation, adjustment and gender Prokaryotic fusion The 3 main stages. Activation can be regarded as Individual development The starting point, mainly for the egg plasma membrane The permeability change, Cortical granule Efflux, Fertilization membrane In formation; adjustment occurs after activation, is to ensure that the first change required to split the normal fertilized egg egg; amphoteric prokaryotic fusion ensure parental genetic effect, and restore the body double fertilization, not only start DNA Replication and egg activation within the mRNA, rRNA etc. genetic information The synthesis of. embryonic development The need for protein.
Be fertilized

Be fertilized The process of fertilization

Be fertilized 6~7 days after the late blastocyst Transparent tape After being buried and gradually disappear Endometrium The coverage of the process, called the implantation of the fertilized egg. To go through three processes: 1 2 3 penetration location; adhesion. Occurs rapidly after implantation Metamorphosis .
Animal sperm as low plants such as bryophytes sperm has obvious Chemotaxis But, on its own Active movement Or rely on genital epithelial cells. Ciliary movement Arrive Egg Nearby. Human fertilization time: ovulation After 24 hours. Fertilization site: Fallopian tube Ampulla.

Be fertilized Sperm capacitation

Many known mammalian sperm through the female reproductive tract or through Cumulus When the exogenous protein was removed sperm package, sperm plasma membrane The physicochemical and biological characteristics of the change. Sperm capacitation In the process of fertilization.
Mammals Capacitation Sperm egg contact week Egg membrane With a specific or transparent, and egg membrane. glycoprotein Combined excitation of sperm production Acrosome reaction Lost on the plasma membrane of acrosome outer periphery of the outer acrosomal membrane invagination, vesicles, the contents in the acrosome including some exo hydrolase. The top of the body The reaction is helpful to further sperm through the egg membrane. In the sea urchin eggs, sperm acrosome reaction is a perivitelline film in polysaccharides provoked. Most of the eggs are eggs peripheral membrane, a variety of different thickness of egg membrane, the main component is mucin or mucopolysaccharide; only a few are naked eggs, such as animal coelenterate eggs.

Be fertilized Acrosome reaction

Sperm through the egg membrane, after combining the first adhesion process. The former is a loose attachment, without outside interference temperature, specificity, no adhesion during the acrosome membrane. Acroblast Protein into acrosomal protein, acrosome proteins accelerate the sperm through the egg membrane; the latter is firmly combined by low temperature interference, is species specificity. In the sea urchin sperm plasma membrane Have isolated a specific binding with egg membrane glycoprotein protein, called binding protein, molecular weight of about 30000.

Be fertilized transport of ovum

In the metaphase of second meiosis in the ovulation The secondary oocyte Together with the surrounding Transparent tape and Radiata Because. Fallopian tube epithelial cells cilia The swing and muscle contraction rapidly through the abdominal cavity into the ampulla of fallopian tube. If the egg and sperm cells failed to meet, usually in the 12 - 24 hours to degeneration and death.

Be fertilized Egg activation

Once the sperm and egg, the egg is also activated a series of changes. In mammalian eggs, is shown as Cortical reaction The egg. plasma membrane Reaction and Zona reaction And thus play a role in blocking the fertilized egg and stimulate further development of the. Cortex in response to fine Egg cell Fusion of the fusion point, since the beginning, the cortical granule rupture. Inclusion Efflux, which affected the whole egg cortex. Egg membrane reactor is the recombination process of egg quality and cortical granule capsule. Transparent tape The reaction for cortical granule efflux formed together with transparent tape Fertilization membrane In the process of, Egg membrane With membrane separation, zona pellucida sperm receptor disappeared, zona hardening.

Be fertilized Fertilization

Only to sperm acrosome reaction and egg fusion. In the acrosomal enzyme, sperm through the zona radiata, and the effect on sperm receptor glycoprotein ZP3, the sperm acrosin release, through the transparent belt into the perivitelline space. Fertilization, sperm head capsule equator side contact with the egg cell membrane, cytoplasm and nucleus and sperm into the egg. The sperm into the egg, the egg shallow in the cytoplasm of cortical granules immediately release their content into the film around the gap, caused the changes of ZP3 in the zona pellucida glycoprotein, the zona pellucida lost accept sperm through the function. At the same time, with the cortical granule membrane fuses with the egg cell, the cell surface charge increased, thus stopping the fusion of the sperm plasma membrane and egg membrane, called the cortical reaction (cortical reaction). The transparent band structure changes, called the zona reaction (zona reaction). At this time, the sperm zona binding ability to reduce, prevent polyspermy (polyspermy) occurs, ensure human monospermy (monospermy) biological characteristics.
The contents of cortical granules (a trypsin like protease) can destroy or inactivate ZP and sperm receptor, can make the transparent zone between peptide cross-linking increased, decreased sensitivity to acrosin, prevent sperm penetration. Normally, although some sperm through the zona pellucida, but only one sperm into the egg cells fertilized. In exceptional circumstances, there can be two sperm in fertilization, namely double fertilization. At the same time two sperm into the egg to form the triploid cell of the embryo, the embryo died soon after birth or abortion. After the sperm entered the egg, the egg quickly completed second meiosis, when sperm and egg nuclei are called male pronucleus and female pronucleus. Two prokaryotic gradually move closer, the nuclear membrane disappeared, chromosome fusion, to form a diploid zygote.

Be fertilized Sperm egg fusion

Sperm oocyte fusion can be seen on the surface of the egg first microvilli Surrounded by sperm may play a directional role; then eggs and sperm membrane The top of the body The membrane fusion. Many animal sperm into the egg cytoplasm after rotating 180 degrees, the middle and the head of the sperm to rotate together, so that the center toward the central grain of eggs. Then the male pronucleus formed gradually, at the same time the particle center around a star, together with the male pronucleus transfer to the female star with prokaryotic. The sperm midpiece and tail soon degraded and absorbed. The egg nucleus after the completion of the two meiosis, the formation of female Prokaryotic . Two female and male pronucleus meet, or fusion, two Nuclear membrane Into a; or in combination, the two nuclear compound, the nuclear membrane disappeared, only Chromosome set Together, in order to establish zygotic genome, thus completing fertilization.

Be fertilized After the change

Be fertilized Sperm egg binding

The eggs before the metabolic level is very low, the synthetic activities of DNA, RNA and protein synthesis are very few. So from the eggs, if not fertilized, soon died.
When the surface of sperm and eggs, eggs rapidly increasing rate of metabolism, and the synthesis of DNA. Details of the egg activation mechanism is not clear, only know how to open the sperm only played the role of switching procedures. In addition to sperm, some other non-specific chemical or physical treatment, also can make the egg activation, such as acupuncture frogspawn, also make the excitement. The initial excitement without any new protein synthesis.
 In vivo by ovulation, fertilization, implantation to the process In vivo by ovulation, fertilization, implantation to the process

Be fertilized The mechanism of fertilization

In the early stages of the sea urchin egg activation, increased membrane permeability to sodium ions, sodium ion influx, resulting in membrane depolarization in seconds; calcium ion Since the release of the cell in the inventory, the 20 ~ 30 seconds eggs free calcium increased up to 100 times; with the sodium ion influx, hydrogen ion efflux, resulting in a minute egg pH value increased significantly. These changes induced by ion. Cortical reaction The result of blocking, excess sperm into the egg, egg and stir up the further development. The increase of intracellular free calcium ion, arrived in egg activation Calmodulin The effect, which further activate other proteins in the eggs. Then increased protein synthesis, DNA also began to copy.
In the sea urchin eggs, calcium may also be by calmodulin, activation of certain specific transport proteins on the egg plasma membrane, hydrogen ions to the output cell. The pH value increased in the eggs, will lead to increased protein synthesis and replication of DNA. The outflow of sodium ions flow depends on the hydrogen ion. The new synthesis of these proteins is not dependent on RNA, but stored in eggs of mRNA to cover and ribosome activation results.
Study on the mechanism of fertilization, is one of the basic guarantee for the effective control and sexual reproduction of animal breeding and breeding. Human" Tube baby "The birth of only a few success stories. Because of the many problems still exist in suspense and the further development of normal fertilization mechanism, IVF of many animal fail. These failures show that The basic theory research The important.

Be fertilized Fertilization method

Be fertilized In vivo fertilization

Where the female and male parent mating, sperm From the male to female transmission of genital tract, and gradually reach the place (such as fertilization uterus Or, fallopian tubes) where sperm egg fusion met and said, In vivo fertilization .
Occurred in the The higher animal Such as reptiles, birds, Mammals Some of the software, animal and insects and some fish and a few Amphibian .

Be fertilized In vitro fertilization

Where the sperm and egg also excreted in the vicinity of female laying holes or in water and fertilization, said In vitro fertilization . The common mode of reproduction of aquatic animal, such as some fish and some amphibians.
 In vitro fertilization In vitro fertilization
Autofertilization and Cross fertilization Most of the animal is female and male allogeneic, male and female are separated. Some animal is male and female body, the same individual can produce eggs, can also produce sperm. In hermaphroditic animal, some are self fertilization, namely the same individual sperm and egg fusion, such as a tapeworm; some are two different fertilization, namely individual sperm and egg combination, such as earthworms.

Be fertilized Monospermy

Usually, only one sperm into the fertilized eggs, said Monospermy . Such as coelenterate animal, Echinoderm animal , Part of animal Bony fish, amphibians and Mammal . This kind of egg and sperm once contact, immediately be activated and produce a series of changes, to prevent other sperm into the egg.

Be fertilized Polyspermia

If the degree of maturity of the egg through because of inappropriate reasons, but there is more than one sperm into the egg, the so-called pathological Polyspermia Then, cleavage Abnormal, embryo Deformity, sooner or later will die of shame. Some eggs in the normal fertilization conditions, there may be more than one sperm enters the egg, but only one of the original male sperm nuclear and egg pronuclei of zygotes, become the nucleus, the rest of the sperm gradually disappear, called physiologic polyspermy. Such as insects, soft animal, fish cartilage, amphibians, reptiles and birds.

Be fertilized A brief history of fertilization

1875
Germany Biologist O. the Hutt first in Vichy Sea urchin Found from sperm Into the egg to two female prokaryotic fusion process of fertilization, embryology Over 200 years of eggs and sperm only only doctrine, so far only get the truth
 Sperm reaching the egg Sperm reaching the egg
Answer。 1883 Belgium Biologist E.van Beneden Edouard van Two: price horse side Ascaris Study on fertilization cytology, confirms Hertwig's parents in the genetic contribution equality theory, and make the study of sperm and egg for the more in-depth. In the first division spindle parascaris equorum zygote, can see four chromosomes, of which two were from the father, the mother from two. Therefore, he believes that there is a qualitative, chromosome setting, and have a certain number of chromosomes of the parent system, through the fusion of sperm and egg to their offspring. Later, the German biologist T.H. boverie in parascaris equorum on work to further consolidate the above theory, the chromosome is regarded as the carrier of genetic information.
Since twentieth Century
To explore gender fertilization research gamete Binding mechanism. According to the American scholar F.R Lili Nereis And sea urchins on the study, first of all that egg production and accept the material related to sperm, he called on fertilization. After 40s, another American scholar A. Taylor launched a series of work on the biology, chemical and immunological characteristics of fertilized pigment, further emphasizes the importance of egg maturation during the discharge of fertilization. At the same time, the German scholar M. Hartmann In the process of fertilization of sea urchin eggs, not only can discharge the female hormone, sperm can discharge the male gamone, they contend with each other determines the extent of the fertilization success. Soon, in amphibians, found the eggs outside the film role in fertilization.
1956
According to the China experimental cell scientist Zhu Xideng Bufogargarizans The experiments presented Fallopian tube Egg shell secretion, for male and female gametes needed to achieve fertilization. In mammals.
One thousand nine hundred and fifty-one
Min Chueh Chang And C.R. Austen At the same time put forward respectively the female reproductive tract in sperm must stay for a period of time, get through Egg The ability of capacitation, can fertilize the egg effectively. Sperm capacitation The discovery of the mammalian egg from the past people find reason of fertilization failure, thus the higher mammals and human eggs research to a new stage.

Be fertilized Answer questions

Why is the difference between individual sperm and eggs
The number of different
According to the " Encyclopedia of China "The medical volume contained human eggs, visible to the naked eye, about 0.2 mm in diameter, is the largest cell in the human body, and even with the sperm length meter is only 0.06 mm, if the volume is only 1/1000 eggs. Because of this layer between them appeared far from the chance, about one egg a month from one, without time limit for sperm from 200 million people at a time.
The egg cell also has reproductive mission, their individual why such disparity? We must first understand why the animal were divided into two types of sex. Perhaps someone will say, is to limit the mating success rate, stable number. But why is the location choice in sperm? This is a big topic in the field of evolutionary biology. There are many methods to define, here is the sexual reproductive biology, has produced eggs, such as ovary Macrogamete The function of the individual as female, and those who produce sperm, pollen etc. Microgamete It is called the male.
What kind of swimming sperm to produce gametes breeding success rate is high, but also can improve the combination of the Offspring The survival rate? By calculation to find out the answer, this way in 1970s, it is called "the rules of the game". The popular explanation is: pay after the formation of small if all the nutrients can produce a large number of gametes offspring, but the combination between microgamete, caused by individual nutrient deficiency, survival difficulties. Conversely, if all the individual generation of gametes, although the survival rate can be increased, and the number of offspring was significantly reduced. In order to solve this problem, usually by a sex act as gametes, the smallest individual used to have a lot to meet the basic functions; another gender to generate a large number of larger individuals, towards the direction of evolution on the results of a large egg, sperm.
Sperm egg encounter
When the egg and sperm. In addition, small individuals have better athletic ability, to find the best places to accommodate their large parasitic individual, gamete is conducive to survival. So the two different individual form of male and female, and to group. By the late 90s, the University of Oxford Harbin Milton Professor of the cytoplasmic asymmetry, and made a new interpretation, he believes that the individual differences in order to avoid eggs and sperm downtown "dispute", the specific reasons in the sperm body, because they lost to Mitochondrial DNA Led by the cytoplasm Genetic genes . If Egg Sperm are cytoplasmic genes, with each other when the genetic onslaught of the other party, before combining to avoid this confusion, sperm magnanimously lifted their genetic advance of cytoplasm, and only with nuclear genes.

Be fertilized Plant fertilization

Fertilization is a fusion of two gametes homozygous process. The zygote develops into a new individual with a hereditary parents. Fertilization is the central link of sexual reproduction.
 The double fertilization of angiosperms The double fertilization of angiosperms
The plants of the male and female parents of higher animals (i.e. male and female) genetic characteristics, is reached by the chromosomes in sperm and egg fertilized by Offspring The. The new individual generated by the sperm and egg fusion, recovered two times the number the same as the parental chromosome, inherited genetic, parental both sides at the same time, because of both parents genetic material The re combination, and may show new characters. So fertilized by the offspring, both pro and genetic characteristics, but also a specific individual. Therefore, fertilization not only has an important significance in continuing to maintain the species, but also one of the important factors is the biological evolution.

Be fertilized The basic way

There are three types: isogame (identical gametes); the heterogamy (anisogametism); the reproductive egg (sperm with).
Three kinds of fertilization reflects the fusion of two gametes from the division that there is little obvious differentiation of the evolutionary process.

Be fertilized Isogame

The fusion of two gametes are quite similar in shape and size, there are two situations: the clan of the individual (by one individual by asexual reproduction or Gamogenesis Offspring) gametes can cooperate with each other, called homothallic; with the Jia Zong gametes with only quinethazone, called Heterothallism . Although the latter gamete size and shape of the same, but there is a difference in physiology. Are generally used a "+" and "-" minus two cases with different gametes and their plants. Green algae in Chlamydomonas Some of the species is heterothallic. These kinds of gametes "+" and "-" different Mating type Only, between different mating type of gametes lectin can occur and further integration. The black fungus Rhizopus and 6 Some species can also see the heterothallic reproduction. When the "+" and "-" meeting of the mycelium, in the relative position can be put Ascus Then, the different mating type of gametes capsule Protoplast fusion .

Be fertilized Heterogamy

The fusion of two gametes have fixed the size difference, which is further cell differentiation performance. For example, the typical algae genera, two kinds of gametangia in a repeated bifurcation of the individual, in a large body with two flagellate gametes gametangial, similar with the former form and form a much smaller gamete another gametangia, known as big Female gamete Little is known, Male gamete .

Be fertilized Egg reproduction

The fusion of two gametes have significant differences in the structure, activity and size. Male gametes are usually referred to as sperm, many groups of plants is a flagellum and sperm Exercise capacity The. The sperm nucleus and little cytoplasm; highly differentiated female gametophyte known as eggs or egg balls, Egg cell The cytoplasm is very rich. From the low of algae and fungi to Seed plant There are Egg reproduction But, Isogame , Heterogamy Only in algae and fungi. In the same type of gametes and special-shaped gametes fertilization methods, cells have flagella, the fusion of two gametes meet and achieve fertilization in the water swimming. In reproductive egg, fertilization of the female gametophyte is generally fixed cells, the structure of sexual organs more complex. Complete fertilization have many different ways. Volvox The sperm with the egg reproduction is simple.
stay Volvox Multicellular individuals can be formed in the male and female gametes two. By a male after several primitive cells produce many vertical split with two slender and the sperm flagellum; egg is composed of a female original cell enlargement and maturity is spherical, no flagella, motile sperm swim to be Colloid Sheath eggs, by a sperm and egg fusion Fertilization .

Be fertilized Fertilization classification

Algae and fungi
Algae and fungi there are other ways for sperm egg fusion. For example, the fungus Saprolegnia, female organ - oocysts in mycelium At the end of the formation, development of a plurality of eggs in the oocysts in sperm producing; The sperm is In the vicinity of the oocysts, number of sperm, can not swim. During fertilization, the sperm for fertilization of the growing tube into oocysts and sperm injection to achieve fertilization and egg side. No green organs and water mildew algae species is basically similar, but active sperm, only one egg mature oocysts in. Sperm from the sperm is released after through oocysts into oocysts and egg fusion beak opening.
In moss and Fern In the sperm and egg are wrapped up in the multicellular The sexual organs, fertilization can not leave the water conditions. Female organ money like bottle shape, called The archegonium . Archegonia and antheridia were born in leafy Gametophyte The support. The money is Gonochorism The. Only one egg in the archegonium, produced many long, curly and two of the sperm flagellum in sperm. When the sperm is mature, sperm release, if the back of a water plant, sperm can swim to the archegonium and eggs to achieve fertilization. Fern archegonia and antheridia are produced in the lower surface of the same gametophyte, the sperm can swim through the surface layer of gametophyte swim into the archegonium in.
The structure of reproductive organs of seed plants are more complex, the pollen tube, in the process of sexual reproduction by pollen tube, fertilization is no longer dependent on water conditions, this is one of the important factors to adapt to life on land seed plants. Female gametophyte of the female gametophyte in the sporangium is ovule The development of the department. Most gymnosperms retain archegonia structure, formed in the neck of the egg inside egg. stay microspore In the development of pollen sac, the male gametophyte stage. In the male Gametophyte In the formation of two sperm. No more than sperm Flagellum But, in cycads and ginkgo head is still swimming sperm. Angiosperm The female gametophyte is called embryo sac The egg, in which produce sperm directly; complete loss of flagella. These characteristics determine the seed plants fertilized by pollination. The gymnosperm ovule is exposed, after pollination, pollen ovule was sent to Micropyle But, in angiosperms, ovules in the pistil ovary, pollen ovule but can not directly fall on the stigma, the germination and growth of pollen tube sperm into the female gamete nearby. In gymnosperms, two sperm into the archegonium and only one egg fusion. Two sperm but in angiosperms into embryo sac respectively and eggs and Polar nuclei Fusion. This is unique to angiosperms Double fertilization .
To identify the role in fertilization.
1940s is known to Chlamydomonas mating is a kind of control called gamone material. The test then cultured to further clarify the status of gametes to release the material can lead to medium relative Mating type Gamete agglutination; from the "+" cells release substances so that "-" the cell agglutination, on the contrary, agglutinable "+" cells from cell "-" the release of substances in the same lectin, does not occur cell fusion . This material is called the same lectin It is a kind of water. glycoprotein The substance that exists in the Flagellum Micro bubble surface, its specificity not only sexual, and species specificity, is undoubtedly the adhesion and recognition reaction involving gamete material.
There is a similar reaction in recognition of the fungus Mucor purpose of sexual reproduction. For example, Mucor Heterothallism When is the "+" and "-" Gametangial The fusion, artificial cultivation experiments have demonstrated that fusion control heterothallic ascomycetes is divided into two steps. First of all to three induced by abscisic acid produced two Mating type Ascomycetes, three to abscisic acid exist only in two mating types under the condition of formation of precursor only because of a mating type has been changed to three relative mating type of abscisic acid, namely "+" the precursor can be transformed into "-" three "- spore acid." produced by another precursor can only be "+" into three spore acid. Then different mating type ascomycetes encounter occurred before fusion. Recognition of this reaction, presumably due to the existence of a contained in the gametangial region with the top of the wall glycoprotein The identification of substances.
Moss and ferns eggs wrapped up in the archegonium, swimming sperm egg binding and reach the archegonium must travel to a certain distance, sperm can "discover" eggs, apparently there are some interactions of the material. In these two groups of plants, the sperm to the resistance has been affirmed. To the trend of chemical produced eggs or sperm archegonium. The earliest study of W.F.P. Pfeiffer fil Bracken (Pteridium aquilinum) sperm chemotaxis experiments proved that L- malic acid produced by the archegonium is effective to attract agents. It will contain the tap water (containing 10% agar) 10%L- dropper sodium malate into the sperm suspension, malate ion immediately from the dropper in differential diffusion into the surrounding medium, the sperm in a second will move to the dropper mouth, is moving to malate source direction. In the absence of malate in tap water, sperm is free if in action; Homogeneous The solution of malate, which does not exist in graduation, sperm also maintained evenly distributed in solution. In Equisetum has tested 12 kinds of organic acids, the sperm only L- malic acid and tartaric acid sensitive.
Angiosperm
In angiosperms, the sperm from the tube is transmitted to the embryo sac. The directional growth of pollen tube by reason of the style, there have been various interpretations. Some speculation is to control factors, that is calcium factors to attract pollen tube growth; some believe that the early growth of pollen tube Vegetative nucleus In the control of DNA transcription mRNA hypothesis; pollen tube orientation are determined by the growth of the stigma and ovary potential difference etc.. This is an inconclusive problem.
Mutual recognition of pollen and pistil of angiosperm achieve fertilization plays a decisive role. Because the choice of male gametes pistil is the first organization, rather than eggs.
 Double fertilization model Double fertilization model
In angiosperms, the stigma and style of "screening" out of their most suitable pollen effect. Most of the plants are widely for the same species Cross fertilization If, genetic differences (such as a relationship or species) or genetic difference is too small (like a flower, with a different individual among the flowers Self The mating between individuals) is not compatible, the Distant hybridization Incompatibility and self incompatibility phenomenon is developed during the long-term evolution of angiosperms in both species is conducive to maintaining stability and an adaptation characteristic can maintain its life force.
Pollen on the stigma of the fall was "acceptable" or was "rejected" the decision on mutual recognition between them. If it is compatible, plant pollen grains on the stigma and the pollen tube grew into a adorable stigma, and along a certain way through style to release the sperm sac there; if the pollen and stigma of plants is incompatible, pistil will inhibit pollen germination and pollen tube growth and fertilization hinder.
Plant fertilization incompatibility is determined by the genotype of the two parents, and showed inhibition of physiological reactions. Self incompatibility According to the study on the physiological basis of some plants of the Compositae and Cruciferae, is that pollen and pistil tissue identification results. With the identification of related substances in pollen is present in the side wall of the pollen protein; in the pistil of the party have been identified to be covered in the stigma surface protein film.
Pollen wall and inner wall. The material is composed of outer wall of carotenoids and carotenoid esters oxidation polymerization and the formation of Sporopollenine . Synthesis and transport into the tapetal protein structure formed between the outer wall of the inner wall material, when the development of pectin cellulose deposition, the pollen itself cytoplasmic protein synthesis incorporated therein. So, when the mature pollen, the outer wall of a spore (tapetum cells) genotype control of the protein wall; Gametophyte (in pollen cells) genotype control of the protein, these are To identify the role of Protein.
On the recognition of pollen pistil, now the stigma of dry (stigma maturity liquid secretion) understanding more clearly. For example, in the Compositae and cruciferous plants, produce the stigma surface papilla The shape of a single cell, it pectin cellulose with a layer of the wall and not for the cuticle. Papillary cells during development, through the wall and cuticle also secrete some substances to form a layer of film on the surface, the main component of this film is a protein, it not only provides a surface to capture the sticky pollen, but also has the recognition" Receptor "Features. When combined with the pollen wall and then after "accept" or "reject" response.
The pollen on the stigma, from stigma swollen, in contact after a few minutes, the pollen wall protein is released with the stigma surface protein film, if it is compatible with the pollen germination, due to the action of the enzyme, the cuticle of stigma were dissolved into the stigma and pollen tube growth smoothly in the style. In the case of incompatible pollen tube growth stagnation, or can not enter the stigma (spore control system), or tube in the style of growth stalled and broken ( Gametophyte Control system). Radish, cabbage, and cosmos Sunflower The plant self incompatibility, a few hours after pollination, which produce lenticular structure callose stigma papillae cells; and in affinity is not mating callose reaction. This can be used to test the callose reaction affinity index in a certain relationship within the scope of. A stigma to be able to germinate, and also induce the papillary cells callose formation (Gramineae formation of callose in pollen tube is the top) Incompatibility The reaction. Intraspecific incompatibility and interspecific incompatibility occurred in this reaction, the reaction marks between the two parents, there is a certain relationship; if neither pollen germination, and not cause the mastoid cells showed the callose reaction reflects, no relationship between the two parents can not Hybrid This is often, distant hybridization between the different families.
Interspecific hybridization
Some of the experiments to prove the existence of recognition between pollen and stigma. Interspecific hybridization of Populus alba and Canada poplar is usually Sterile The alien pollen on the stigma of stagnation. But from Populus alba pollen extract its surface proteins and incompatibility of Canada poplar pollen together with Yang Zhu in the white head, you can get a certain number of hybrid seeds; used to kill the Alba pollen mixed with Canada poplar pollen on Populus alba, also get the same results. This indicates that the wall protein of female pollen and stigma To identify the role of That can make the incompatibility of alien pollen is accepted. A method of affinity dissidents and pollen and pollen mixed pollination that has been in production as hybrids.
In vitro pollination and fertilization
In 1960s the band, the placenta angiosperm ovule pistil or ovary in vitro conditions to achieve pollination and fertilization.
1962 K. Ganda and collaborators reported their poppy as materials under aseptic conditions, there will be no fertilization with the placenta in a poppy ovule, disinfection of the nutrient medium test tube At the same time, with a sterile needle from anther removed pollen ovule scattered on the surface, the results were similar with normal fertilization, finally produce a life of the seeds. These seeds can grow into healthy seedlings in the tube, this is the first experiment of isolated pollination and fertilization success. There are 40 kinds of plants have been reported successful, mainly (such as thistle poppy, poppy, Corn poppy Solanaceae (tobacco), Petunia hybrida ), Shi Zhuke (such as carnation, dioecious melandrium) and cruciferous plants (such as cabbage), in recent years in gramineous corn and wheat in success.
In vitro pollination
In vitro pollination and fertilization technology in the breeding process may be overcome sexual reproduction Incompatibility barrier means exist in selfing or crossing. Self incompatibility barrier plants during fertilization, usually occurs in the stigma or style, that is because the pollen stigma recognition reaction resulting in pollen tube growth is inhibited, can not enter the stigma or growth in the style of stagnation that fertilization failure. It is likely to use the body from pollination fertilization successful completion. It has been successfully tested Petunia plants. For example, all ovules self incompatibility in Petunia axillaris with a child seat of the ovary were cultured in vitro and granted to self pollen. The results of pollen tube growth is normal, with normal development of the final formation of the embryo and endosperm of seeds. Grown by in vitro fertilization are the seeds of the first generation plants as its parent, is diploid The fertile and self incompatibility. On the other hand, in some plant trial Caryophyllaceae, Papaveraceae and Solanaceae and Gramineae in vitro pollination and fertilization technology to overcome hybridization Incompatibility . Although many of these combinations to achieve fertilization, but failed to obtain a life of seeds.
 In vitro pollination by bees In vitro pollination by bees
But a small number of hybrid seeds and seedlings. Such as: the cultivation of tobacco (2n=28) and Deshi tobacco or tobacco rosette (2n=40) hybrid, which is a hybrid method can be successful, however, with the method of in vitro pollination, the hybrid seeds and seeds in in vitro culture medium On Germination and seedling; corn and corn in Mexico in vitro hybridization, was developed with a good embryo and endosperm of seeds; the wheat (2n=42) ovary in vitro (2n=14) granted to rye pollen, with organ differentiation of embryo and endosperm containing caryopsis. Such hybrid embryos from caryopsis out in the anatomy of embryo culture, the results of a hybrid seedlings. Seedling root tip For the number of chromosomes of wheat and rye chromosomes and a half, which is a 28 (21+7).
Artificial fertilization conditions
artificial insemination Must have certain conditions, which is the most basic conditions of the at least one side of the fallopian tube is the end
 Artificial fertilization process diagram Artificial fertilization process diagram
The smooth (by hysterosalpingography or Laparoscopy surgery The woman has confirmed), or by spontaneous ovulation ovulation treatment can ovulation; men sperm There must be a certain number of live sperm, only these two conditions are met, can be a successful pregnancy.