| 单词 | fertilisation |
| 例句 | The fertilisation of a human egg cell by a sperm was first observed under the microscope 99 years before Louise Brown was born, by the Swiss zoologist Hermann Fol. Seven ways IVF changed the world – from Louise Brown to stem-cell research 2018-07-08T04:00:00Z Our analysis showed 68% of recorded flowers received the minimum number of four insect visits required for full fertilisation during the monitoring period. AI can track bees on camera. Here’s how that will help farmers 2023-03-07T05:00:00Z The report of her committee on in vitro fertilisation, published in 1984, clarified the standing of IVF and paved the way for stem cell research. Mary Warnock 2011-03-08T00:05:44Z Standard IVF means an embryologist mixes harvested eggs and sperm and leaves them alone to allow fertilisation to occur. Four years, 40 negative tests: why being young and infertile sucks 2015-06-06T04:00:00Z The technique was pioneered by the Cambridge physiologist Robert Edwards, working with obstetrician Patrick Steptoe of Oldham general hospital, who first reported successful fertilisation of a human egg cell in vitro in 1969. Seven ways IVF changed the world – from Louise Brown to stem-cell research 2018-07-08T04:00:00Z In vitro fertilisation, fertility drugs, donor eggs and embryos, surrogacy – these things are no joke. Laurie Frankel: We adopted by choice not necessity 2017-03-18T04:00:00Z This was before the first child was conceived through in vitro fertilisation in Manchester in 1978. I was taunted for having two mums in the 1980s 2018-07-22T04:00:00Z In the reproductive system, prostaglandin is an important mediator of processes like ovulation, fertilisation and embryo implantation. Morning-after pill more effective when taken with an anti-inflammatory painkiller, researchers find 2023-10-20T04:00:00Z In the case of sexual fertilisation, the simple chromosome sets from the egg and sperm cells come together to create a double -- diploid -- chromosome set. Proteins roll the dice to determine bee sex 2023-10-04T04:00:00Z The embryo models were allowed to grow and develop until they were comparable to an embryo 14 days after fertilisation. Scientists grow whole model of human embryo, without sperm or egg 2023-09-06T04:00:00Z But if life is considered to start at the moment of fertilisation, doctors and patients like Julie fear this could have implications for the IVF process. Roe v Wade: ‘Could abortion bans put my IVF at risk?’ 2023-08-08T04:00:00Z Stories of virgin births, where young are produced without fertilisation, have been told throughout history. Crocodile’s ‘Virgin Birth’ Is a First for Science’s History Books 2023-06-09T04:00:00Z After fertilisation with prized sperm, multiple embryos can be transferred to surrogate camels. Dubai camel cloning caters to races, beauty pageants 2023-05-25T04:00:00Z He says his years studying embryology left him with the belief that life begins at fertilisation. Abortion may be legal in Argentina but women still face major obstacles 2023-03-04T05:00:00Z As stimulation results in contractions of the reproductive tract, it is likely that sperm is then drawn further in to the uterus, increasing fertilisation success. Why Snakes Have Two Clitorises and Other Mysteries of Female Animal Genitalia 2023-02-16T05:00:00Z Legislation defining life as beginning at conception or fertilisation is sometimes called a "personhood law", because it confers the rights of a person on a foetus or embryo. Roe v Wade: ‘Could abortion bans put my IVF at risk?’ 2023-08-08T04:00:00Z In May, Oklahoma passed one of the most restrictive abortion laws in the country, banning abortion from the moment of fertilisation. Supreme Court: Where would abortions be illegal in the US? 2022-06-20T04:00:00Z This is known as the "CO2 fertilisation effect". Friendly fungi help forests fight climate change 2022-06-18T04:00:00Z "It is Catholic understanding that a baby exists from the moment of fertilisation," they said. New sex education programme for Catholic primaries 2022-05-19T04:00:00Z The Oklahoma measure defines fertilisation as the "fusion of a human spermatozoon with a human ovum". Oklahoma passes bill banning most abortions after conception 2022-05-19T04:00:00Z She says that many of these bills are written by people who do not have a medical background, using words such as "fertilisation" and "implantation" which have a very specific meaning in a scientific context. Roe v Wade: ‘Could abortion bans put my IVF at risk?’ 2023-08-08T04:00:00Z Our reporter points out that the same argument could be used in the case of gay marriage, in vitro fertilisation or certain forms of contraception. Abortion ruling: US Supreme Court says leak is real as investigation launched 2022-05-03T04:00:00Z "It was our dream that we both be her parents," says Consuelo, explaining that they had Josefa through reciprocal in vitro fertilisation. Chile couples' joy as first same-sex marriages held 2022-03-10T05:00:00Z The eggs are then sent to an Italian lab for fertilisation, using sperm from two deceased males. One of world's last northern white rhinos retired from breeding scheme 2021-10-21T04:00:00Z The earth can be protected from the elements by planting cover crops, such as clover, and use grazing animals for natural fertilisation. 'Farmers can't forget what our grandparents taught us' 2021-07-08T04:00:00Z Individual states can now ban or restrict access to terminations and in the process of rewriting the rules, some lawmakers drew up legislation defining life as beginning at fertilisation. Roe v Wade: ‘Could abortion bans put my IVF at risk?’ 2023-08-08T04:00:00Z In vitro fertilisation, hormone therapy and cryopreservation are increasingly being used as tools for conservation – for amphibians and beyond. A tiny, ugly scientific marvel: Olaf the IVF toad brings hope to at-risk species 2020-04-22T04:00:00Z She said these involve the woman going through a "quite involved" medical process of hormone injections, a minor surgical procedure and then a fertilisation procedure. The doctor trying to solve male infertility 2019-10-28T04:00:00Z And after fertilisation, there are surgical interventions, biological replacements, personally tailored pharmaceuticals. Will this be the last generation to have bodies that are familiar to us? | Susie Orbach 2019-08-23T04:00:00Z Sir Robert Edwards and Patrick Steptoe are known as the pioneers of in vitro fertilisation, which led to the world's first test tube baby, born in 1978. Female scientist's IVF work 'unrecognised' 2019-06-10T04:00:00Z Mr Karbaat called himself "a pioneer in the field of fertilisation". Dutch fertility doctor fathered 49 children 2019-04-12T04:00:00Z A 2016 study found that about 1.4bn jobs and three-quarters of all crops depend on pollinators, mainly bees, which provide free plant fertilisation services worth billions of dollars. Bavaria to pass 'save the bees' petition into law in landmark move 2019-04-03T04:00:00Z "It was something of a natural fertilisation experiment." Tossing dead salmon is good for plants 2018-11-25T05:00:00Z President Trump has supported a proposed federal ban on abortions after 20 weeks after fertilisation, but the bill was blocked in the Senate in January. US state backs abortion ban after 15 weeks 2018-03-07T05:00:00Z Sexual reproduction provides lots of scope to generate genetic variability; when pieces of individual chromosomes recombine as the eggs and sperm are formed and when the unique combinations of chromosomes are merged at fertilisation. Amazon fish challenges mutation idea 2018-02-13T05:00:00Z The embryos were modified shortly after fertilisation and allowed to develop for seven days. UK scientists edit DNA of human embryos 2017-09-20T04:00:00Z The company's latest annual report is full of commitments to grow back more ethically - literally, it uses water and seeds and fertilisation as metaphors. Politicians suspected in bribery scandal 2017-09-14T04:00:00Z The eggs have now been rushed back to the Avantea clinic in Italy, a lab that specialises in assisted reproduction in animals, where they will be prepared for fertilisation. UK rhino eggs 'could save last northern whites' - BBC News 2017-07-19T04:00:00Z Jan Karbaat called himself "a pioneer in the field of fertilisation". Dutch families win right to test DNA of sperm bank doctor - BBC News 2017-06-02T04:00:00Z The space-preserved samples showed evidence of slightly increased DNA damage compared with control samples preserved on Earth, but this was found to be largely repaired in embryos following fertilisation. Space sperm produces healthy mice, raising prospect of future human settlement 2017-05-22T04:00:00Z Now, Californian researchers have found they can also block fertilisation. Plant chemicals hope for 'alternative contraceptives' - BBC News 2017-05-15T04:00:00Z The zoo said Tuesday experts would try to remove eggs from the two females at Ol Pejeta this year to save the subspecies by means of in-vitro fertilisation and embryo transfer to surrogate mothers. Czech zoo to remove horns of 18 white rhinos following French attack 2017-03-14T04:00:00Z For now, the work helps to explain some of the details of fertilisation. Making babies without eggs may be possible, say scientists - BBC News 2016-09-13T04:00:00Z "We believe the Bible has several passages that speak to the fact that life begins at fertilisation," says Aaron. The Americans who 'adopt' other people's embryos - BBC News 2016-07-17T04:00:00Z This now looks set to change following two studies published last month, showing that it is possible to keep human IVF embryos alive and developing for up to 13 days after fertilisation. Inside the ‘black box’ of human development 2016-06-05T04:00:00Z In tests, chemicals called pristimerin and lupeol stopped fertilisation by preventing human sperm from whipping its tail and propelling itself towards and into the woman's egg. Plant chemicals hope for 'alternative contraceptives' - BBC News 2017-05-15T04:00:00Z The Netherlands will change its laws on embryonic research, which until now only allowed tests to be conducted on leftover embryos procured from in vitro fertilisation processes. Netherlands gives green light for growing human embryos 2016-05-27T04:00:00Z Chinese scientists injected the Asian strain of Zika, which is closely related to the one circulating in south America, into the brains of mice foetuses 13 days after fertilisation. Zika virus 'shrinks brains' in tests - BBC News 2016-05-11T04:00:00Z But the researchers say the fertilisation effect diminishes over time. Rise in CO2 has 'greened Planet Earth' - BBC News 2016-04-25T04:00:00Z On the days when fertilisation might occur, it stretches into tubes that look, and act, like tiny, high-speed rail tunnels. ‘Fitbit for your period’: the rise of fertility tracking | Moira Weigel 2016-03-23T04:00:00Z "This is a very interesting study which shows that two natural compounds can knock out a key molecule on sperm that regulates how they swim in the final moments before fertilisation. " Plant chemicals hope for 'alternative contraceptives' - BBC News 2017-05-15T04:00:00Z The scientists, who are searching for clues to what happens in the first seven days after fertilisation and want to investigate miscarriage, will not be able to implant the embryos into women. Researchers get green light to genetically modify human embryos 2016-02-01T05:00:00Z Doctors hope that making fertilisation more natural will mean healthier pregnancies. 'Natural' fertilisation device for IVF - BBC News 2016-01-18T05:00:00Z The next hurdle was mimicking the effect of the female reproductive tract, which prepares incoming sperm for fertilisation. Litter of seven puppies are first born through IVF 2015-12-09T05:00:00Z The process usually involves in-vitro fertilisation and embryo transfer, leading to a rise in fertility centres offering such services. India bans foreigners from hiring surrogate mothers 2015-10-28T04:00:00Z There are different procedures but they work in a similar way - by preventing eggs from travelling down the fallopian tubes so that fertilisation can't happen. Essure implant study finds safety concerns - BBC News 2015-10-13T04:00:00Z Niakan wants to use the procedure to find which genes are at play in the first few days of human fertilisation, when an embryo develops a coating of cells that later form the placenta. Researchers get green light to genetically modify human embryos 2016-02-01T05:00:00Z But the meteorological satellite operator knew that she wanted a child with her new husband, and in vitro fertilisation was necessary. Fertility treatments give birth to dilemma for parents 2015-05-23T04:00:00Z With those two changes, the scientists achieved fertilisation rates of better than 80%. Litter of seven puppies are first born through IVF 2015-12-09T05:00:00Z And in the modern technological age, that cross fertilisation of ideas also unites once-disparate industries. F1 tech shaping tomorrow's transport 2015-03-08T05:00:00Z The House of Lords approved the novel form of in vitro fertilisation last week despite opposition from the clergy and pro-life groups. Three-Parent Babies Raise Ethical Alarms 2015-02-28T05:00:00Z The next step might be IVF - fertilisation in a test tube. David Shukman: Should we try to halt extinction? 2015-01-21T05:00:00Z When that didn’t work, they moved on to a round of in vitro fertilisation that resulted in nine fertilised embryos. Fertility treatments give birth to dilemma for parents 2015-05-23T04:00:00Z This autumn, the zoo began a project to harvest eggs from her for in vitro fertilisation. Race on to save rare white rhino 2014-12-16T05:00:00Z In vitro fertilisation efforts will now reportedly be undertaken to keep the species from extinction. Rare northern white rhino dies in US 2014-12-15T05:00:00Z “We’ve defined the point in evolution when the origin of internal fertilisation in all animals began and that’s a really big step,” said Long. First act of sexual intercourse ‘was done sideways, square-dance style’ 2014-10-19T04:00:00Z It’s a chance for companies put their work on display, but there is also plenty of scope for discussion and cross fertilisation of ideas. UK Tech Companies Play Open House As OpenCo Spreads Its Wings 2014-09-25T04:00:00Z Not long after fertilisation, the embryo consists of a tiny sphere of identical, non-specialised cells, referred to as pluripotent stem cells. The man who grew eyes 2014-08-26T04:00:00Z Mr Stejskal emphasises that in vitro fertilisation was just one of the options on the table. Race on to save rare white rhino 2014-12-16T05:00:00Z For those who believe that life begins at the moment of fertilisation, this can be deeply troubling. How Women Are 'Freezing' The Biological Clock “Now we know that internal fertilisation is the general condition for placoderms, and is the most primitive type of reproduction for vertebrates,” she added. First act of sexual intercourse ‘was done sideways, square-dance style’ 2014-10-19T04:00:00Z Over 10 years ago, I underwent 2 cycles of in-vitro fertilisation. Quora Question: How Important Are Women’s Reproductive Rights to Voters? "It opens up a lot of applications, from targeted drug delivery to in vitro fertilisation - where you want to reach precise locations," Dr Misra said. 'Robot sperm' controlled by magnets 2014-06-02T04:00:00Z Swimming as a shoal may boost the odds of fertilisation, the scientists say. Sperm swim upstream 'in a shoal' 2014-05-27T04:00:00Z It is much less common in plants with separate male and female flowers, because the same pollinator needs to visit both sexes to ensure fertilisation. Single sex flowers differ by scent 2013-10-23T04:36:33Z "The ones that succeeded in fertilisation were the ones with better offspring survival." Sex is deadly for male marsupials 2013-10-08T12:58:35Z Ocean fertilisation involves huge interference with the ecosystem. Geoengineering: Are we there yet? 2013-09-20T11:56:51Z Their research led to the successful fertilisation of a human egg outside the body and the transfer of the resulting embryo to the womb. 'Test-tube baby' Brown hails doctors 2013-07-25T10:21:50Z "So much of what they like is networking, and the cross fertilisation of ideas," he says. 'Everyone knows I'm not in the Trampery to make a pile of money' 2013-02-24T15:50:29Z Who would ever believe that the church had supported both of Berlusconi’s last governments because of their stance on issues such as in-vitro fertilisation and gay marriage? Eurozone crisis live: Mario Monti's resignation pledge spooks markets 2012-12-10T15:43:00Z They believe the huddling process is necessary to ensure the egg's healthy development and fertilisation. 'Huddle' gene link to infertility 2012-11-26T11:52:40Z But another showed that little CO2 was taken up by the organisms and that the potential for iron fertilisation may depend strongly on the location where it is attempted. Geoengineering: Are we there yet? 2013-09-20T11:56:51Z Italian scientists have been investigating the sex lives of Hermann's tortoises Baby tortoises have been given paternity tests to find out whether sperm storage affects fertilisation. Paternity testing for tortoises 2012-11-16T04:00:27Z There was once opposition to in vitro fertilisation, with pejorative terms like “test-tube baby” being bandied about. Gene therapy: Hello mothers, hello father 2012-10-25T15:00:58Z During a press conference on Monday, zoo director Dennis Kelly said he did not think the panda fertilisation programme contributed to the cub's death. Dead US panda cub's health issues 2012-09-24T15:47:31Z Both women started in-vitro fertilisation before the surgery, he said, adding that their frozen embryos will be thawed and transferred if the women are considered in good enough health after a year-long observation period. Sweden hails uterus transplants 2012-09-18T13:38:53Z The move outraged environmentalists opposed to ocean fertilisation. Geoengineering: Are we there yet? 2013-09-20T11:56:51Z Scientists found that in egg clutches with multiple fathers, mating order did not affect males' fertilisation success. Paternity testing for tortoises 2012-11-16T04:00:27Z Activists have also tried to get “personhood” measures—defining life as beginning at fertilisation—on to the ballots of several states in recent election cycles. Abortion laws: And then there was one 2012-09-06T15:03:18Z By far the most researched technology is ocean fertilisation, where iron is used to stimulate plankton growth in the ocean, increasing uptake of carbon dioxide. Geoengineering: Risks and benefits 2012-08-24T17:15:16Z This method of internal fertilisation is extremely rare in fish, as the eggs of over 90% of known bony fish species are fertilised outside the female’s body. Get on your bike, Phallostethus cuulong 2012-07-25T17:45:06.547Z Iron fertilisation is one of the oldest ideas for a climate "technical fix". Climate ocean tech fix 'can work' 2012-07-18T17:21:43Z Normal twins may arise from the fertilisation of one ovum and of two distinct ova. Essays In Pastoral Medicine 2012-03-05T03:00:09.993Z This would be the place to introduce an account of the enormous advances made by the botanists of the last decade or two in the study of the microscopic phenomena of fertilisation. Disease in Plants 2012-03-01T03:00:22Z First there is heterogeneity among progenitors which "generates new deviations by composition of forces"; in other words new patterns arise from the mingling of diverse hereditary contributions in fertilisation. Herbert Spencer 2012-02-29T03:00:20.773Z This bird, which announced or caused the fertilisation or new life of the land, could not but belong to the god of life. The History of Antiquity, Vol. I (of VI) 2012-01-28T03:00:28.213Z The biggest experiment of all, Lohafex, dealt a blow to hopes of utilising ocean fertilisation when that six tonnes of iron produced little extra plankton growth. Climate ocean tech fix 'can work' 2012-07-18T17:21:43Z The earliest stage in the development of a human double monster observed was at the fourth week after fertilisation—Ahlfeld's case. Essays In Pastoral Medicine 2012-03-05T03:00:09.993Z The crossing of varieties of wheat, etc.—The essentials of fertilisation—Rimpau's experiments—Hybrids and selected varieties. Disease in Plants 2012-03-01T03:00:22Z From this speculation Spencer passes to a brief consideration of what occurs before and during the fertilisation of the ovum. Herbert Spencer 2012-02-29T03:00:20.773Z The aphorism, 'Nature abhors close fertilisation,' and the demonstration of the principle, belong to our age and to Mr. Darwin. Charles Darwin: His Life in an Autobiographical Chapter, and in a Selected Series of His Published Letters 2012-01-22T03:00:19.733Z Such differences will, of course, be introduced at the time of fertilisation. Embryology The Beginnings of Life 2011-09-12T02:00:28.483Z It appears that the same condition of things occurs as when, in ordinary fertilisation, sexual cells from different varieties, or species, are united. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z When helping couples conceive, doctors may consider using more direct interventions such as in vitro fertilisation or intrauterine insemination if they find that the male partner has this gene mutation, Tollner said. Mutant gene reduces male fertility: study 2011-07-20T18:32:55Z Before fertilisation is accomplished the nucleus of the ovum normally divides twice in rapid succession, and gives off two abortive cells—known as polar bodies—which come to nothing. Herbert Spencer 2012-02-29T03:00:20.773Z The condition and needs of the soil were studied, its strength replenished by careful fertilisation, and it was worked with care. Inventions in the Century 2011-07-20T02:00:14.643Z Evolution in fertilisation has the following steps:— I. Formation of plasmodia. Degeneracy Its Causes, Signs and Results 2011-05-02T02:00:17.657Z The process begins with the fertilisation of the egg-cell by the fusion with its nucleus of the nucleus or head of a male-cell or spermatozoon. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z A small number of cells are removed from the growing embryo five days after fertilisation and the DNA in them is scanned for any clear problems. Life screening 2011-02-19T00:17:36Z In the history of the male element or spermatozoon, there is an analogous reduction, so that when spermatozoon and ovum unite in fertilisation the normal number is restored. Herbert Spencer 2012-02-29T03:00:20.773Z Taraxacum decastroi and Taraxacum lacianense are plants with long leaves and little pollen, because they reproduce by means of seeds without fertilisation. 2 New Plants Discovered in Spain 2011-02-16T15:43:00Z On the other hand, Dr. Wallace believes that with moths the progeny from a second or third fertilisation is apt to be weakly, and therefore would not have so good chance of surviving. The Descent of Man and Selection in Relation to Sex, Vol. I 2011-01-17T03:00:49.523Z But before or during the process of fertilisation, changes take place, the result of which is that the fusing nuclei are exactly alike in morphological character. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z In other countries the rules are less strict and sex selection takes place, particularly in case of in-vitro fertilisation. Are the Beckhams more likely to have another boy? 2011-01-10T13:03:25Z Now, while Spencer was probably right in saying that fertilisation promotes change, we cannot think that he succeeded in finding what he was seeking, namely a primary physiological reason why sexual reproduction should occur. Herbert Spencer 2012-02-29T03:00:20.773Z The same neglect also overtook Sprengel's immensely interesting and curious work on fertilisation of flowers. Charles Darwin 2010-12-24T03:00:33.847Z The Human Fertilisation and Embryology Authority plans to allow payment for donated eggs and sperm for in vitro fertilisation. In the name of purity, public funds are wasted on the rich 2010-08-24T19:00:00Z Taking frogs' eggs immediately after fertilisation, I compressed them strongly between parallel, horizontally placed glass plates. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z Whether iron fertilisation ever will be deployed as a "climate fix" is unclear. Toxic troubles for climate 'fix' 2010-03-16T03:04:00Z He said: "All of these events are essential to fertilisation - you can imagine now that we know the molecule responsible we could block it to prevent activation and fertilisation as a kind of male contraception." 2010-02-05T00:08:00Z The fertilisation ritual must be quite some sight. 2010-02-04T01:02:00Z The adaptations found in the female organs are chiefly such as increase the surface capable of receiving the pollen, and therefore increase the chance of fertilisation. Springtime and Other Essays In the case of many insects in which parthenogenesis occurs, the determination of sex depends upon fertilisation. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z This operation exposes the various organs that are concerned in the fertilisation of the flower. Orchids Being mainly dependent upon the wind for their fertilisation, they have none of the varied or bright colours that are characteristic of flowers fertilised by insect agency. Trees and Shrubs for English Gardens They gave the soil a square deal in the matter of fertilisation. The Romance of the Reaper Its anatomy forbids fertilisation by wind, or even, one may say, by accident. The Woodlands Orchids Cross fertilisation has made stronger individuals and types, and likewise it has maintained them. The Kempton-Wace Letters Have hives of bees at no great distance to promote fertilisation. The Book of Pears and Plums Those methods of fertilisation, with which the flower-gardener has in recent years worked such wonders, can undoubtedly be utilised for many objects besides those of the variation of form and hue in ornamental plants. Twentieth Century Inventions A Forecast In these unicellular organisms reproduction is known as asexual, because there are no special germ-cells, nor is there anything corresponding to fertilisation. The Truth About Woman After fertilisation, the couple, as is rarely found among fish, remain in the neighbourhood of their offspring to assist them if necessary. The Industries of Animals It is probable that this occurs with many plants during fertilisation, but can only be detected when distinct forms are crossed. The Variation of Animals and Plants Under Domestication, Volume II (of 2) Owing to the minute size of their florets, these plants offer very considerable technical difficulties in the way of cross fertilisation. Mendelism Third Edition After the fertilisation of the ovum, during pregnancy, that is to say, menstruation usually ceases until after the birth of the child, and often until the completion of lactation. The Sexual Life of the Child In favourable environmental conditions of abundant nutrition this state of affairs continues, and the colony increases only by multiplication and without fertilisation. The Truth About Woman The whole structure of orchids, as modified to secure insects’ visits and cross fertilisation, was now expounded, and the benefits shown by cases where insects’ visits were prevented, and no seed was set. Life of Charles Darwin Certain bodies, which during their early development cannot be distinguished by any external character from true ovules, nevertheless must be classed as buds, for though formed within the ovarium they are incapable of fertilisation. The Variation of Animals and Plants Under Domestication, Volume II (of 2) When this, the normal mode of fertilisation, takes place, the flower is said to be selfed. Mendelism Third Edition I have already alluded to the various ways in which flowers are adapted to fertilisation by insects. The Beauties of Nature and the Wonders of the World We Live In And when plants have attained maturity and flowered, the flowers employ numberless ways of attracting insects for the purpose of fertilisation. The Heart of Nature or, The Quest for Natural Beauty In the great group of the Vandeæ, relative position of parts, friction, viscidity, elastic and hygrometric movements were all found to be nicely related to one end—the aid of insects in fertilisation. Life of Charles Darwin This process may be compared with the ordinary act of fertilisation, during which the contents of the pollen-tubes penetrate the closed embryonic sack within the ovule, and determine the development of the embryo. The Variation of Animals and Plants Under Domestication, Volume II (of 2) The bag may be removed in about a week after fertilisation. Mendelism Third Edition A second and scarcely less important is that they tend to secure "cross fertilisation"; that is to say, that the seed shall be fertilised by pollen from another plant. The Beauties of Nature and the Wonders of the World We Live In The tadpoles and young frogs so produced are examples of what is called "parthenogenesis"—that is to say, virginal reproduction—reproduction without fertilisation by material derived from a male parent! More Science From an Easy Chair The strange structures of Cypripedium, or the Lady’s Slipper, were then analysed, and the mode of fertilisation by small bees was discovered. Life of Charles Darwin Munro, R., on the fertilisation of orchids, ii. The Variation of Animals and Plants Under Domestication, Volume II (of 2) A hardy annual, prolific, easily worked, Pisum has a further advantage in that the insects which normally visit flowers are unable to gather pollen from it and so to bring about cross fertilisation. Mendelism Third Edition But this idea, great and promising as it was, required further fertilisation, and got it from another. A History of the French Novel, Vol. 1 From the Beginning to 1800 There have, however, been important experiments on the subject of the development of eggs without fertilisation in recent years, prior to these discoveries as to the frog's egg. More Science From an Easy Chair That the action is anomalous in appearance is true, but hardly so in reality, for apparently it plays the same part in the ordinary fertilisation of many flowers. The Variation of Animals and Plants Under Domestication, Vol. I. It is quite evident that an artificial stimulus can in certain cases set up segmentation, but never can it cause the fertilisation of the ovum. Science and Morals and Other Essays Owing in part to the great technical difficulties attending the cross fertilisation of these flowers he succeeded in obtaining very few hybrids. Mendelism Third Edition It is obvious, from what has been before said, that the process of fertilisation is in many cases interfered with and altered by the change in the conformation or the flower. Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants We know of many lower animals in which the egg-cells produced by the females do regularly and naturally develop without the intervention of a male and without fertilisation. More Science From an Easy Chair It is independent of external conditions, e.g. fertilisation and atmospheric oxidations, and is probably therefore a process of internal rearrangement of the character of an oxidation. Researches on Cellulose 1895-1900 We have thus an elucidation of the puzzling fact that in these forms fertilisation results in the formation of females only. Evolution in Modern Thought From the union of two such gametes, provided that they are still capable of fertilisation, comes the zygote which in course of growth develops the new character. Mendelism Third Edition Then artificial fertilisation with pollen was successfully attempted, and now Réunion supplies most of the vanilla in the world's markets. From Pole to Pole A Book for Young People Clover depends on bees for its fertilisation and seeding. More Science From an Easy Chair After this she applies the pollen to the tip of the pistil, thus securing the fertilisation of the flower and the growth of the ovules in the pod. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told Darwin was the first to explain that this diversity of structure ensures cross fertilisation by bees and allied insects. Herbal Simples Approved for Modern Uses of Cure The interval between emasculation and fertilisation must be rather longer. Mendelism Third Edition Dr. von Faber of Java has recently shown that whilst self-pollination is the rule, cross fertilisation occurs between the flowers on adjacent or interlocking trees. Cocoa and Chocolate Their History from Plantation to Consumer She represented earth, bringing forth fruit without fertilisation. The Evolution of Love It has more possibilities in it than any other thing, yet without fertilisation it will die. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told The precious hour of fertilisation was already wasted, so there and then I escorted Suzanne to the Bank. Punch, or the London Charivari, Volume 158, March 3rd, 1920 Having a circle of good customers upon whom they can depend with certainty for fertilisation, they have no need to waste any large proportion of their substance upon expensive advertisements or gaudy petals. Science in Arcady A physiological law makes it possible, in a large proportion of strictly normal women, for union to take place without fertilisation. The Fertility of the Unfit A rather higher temperature than usual combined with free movement of the atmosphere is generally sufficient to insure fertilisation. The Culture of Vegetables and Flowers From Seeds and Roots 16th Edition For these reasons a woman cannot be quite sure of the exact time of fertilisation, and hence cannot predict exactly the date of the child-birth. Safe Marriage A Return to Sanity Certain volatile oils may attract insects, and in obtaining nectar from flowers insects assist fertilisation. The Chemistry of Food and Nutrition A considerable number of plants which have evidently been specially modified for insect fertilisation have, by further modification, become quite self-fertile. Darwinism (1889) Later a little knowledge of Botany and Zoology will enable a parent to sketch briefly the outlines of fertilisation and reproduction. The Nervous Child Wagner's luminous phrase, "the fertilisation of music by poetry," would have implied for him no mere æsthetic abstraction, but an intimate and ever-present ideal. Edward MacDowell Now fertilisation does not necessarily occur whenever the male organ comes in contact with the female organ. Safe Marriage A Return to Sanity The fertilisation of the ovules by pollen which falls directly from the anthers on to the stigma can be used as a representation of similar facts in animal physiology. Youth and Sex Again, in parthenogenetic females the complete apparatus for fertilisation remains unreduced; but if these varied as do sexually produced animals, the organs referred to, being unused, would become rudimentary. Darwinism (1889) Another plant which performs an important function in the fertilisation of these arid formations, is the Spinifex squarrosus, the "water pink," as it is sometimes called by Europeans. Ceylon; an Account of the Island Physical, Historical, and Topographical with Notices of Its Natural History, Antiquities and Productions, Volume 1 A warm, sunny morning is the most suitable time for this operation, as fertilisation takes place much more readily under the influence of bright sunshine than at any other time. Cactus Culture for Amateurs Being Descriptions of the Various Cactuses Grown in This Country, With Full and Practical Instructions for Their Successful Cultivation Generally the pregnancy lasts nine months, but it may last longer—say ten months on rare occasions; and it may be extended apparently by a delay in fertilisation. Safe Marriage A Return to Sanity You know, Darwin studied their fertilisation, and showed that the whole structure of an ordinary orchid-flower was contrived in order that moths might carry the pollen from plant to plant. The Stolen Bacillus and Other Incidents Then there is another source of fertilisation nearly as productive and valuable. A Walk from London to John O'Groat's You know, Darwin studied their fertilisation, and showed that the whole structure of an ordinary orchid flower was contrived in order that moths might carry the pollen from plant to plant. The Country of the Blind, and Other Stories Now the fertilisation involved by the existence of two sexes is, as Weismann insisted, simply an arrangement which renders possible the intermingling of two different hereditary tendencies. Essays in War-Time Further Studies in the Task of Social Hygiene She is the one fertilised, and therefore she is the one to guard herself against fertilisation. Safe Marriage A Return to Sanity But, for the settlement of this momentous question, the discoveries of the last ten years with regard to the more minute occurrences in the process of fertilisation are of decisive importance. Monism as Connecting Religion and Science A Man of Science When fertilisation occurs the zygote therefore contains 2N chromosomes and becomes female. Hormones and Heredity Only one-seventh of a foot of water, accordingly, could possibly be made available for their fertilisation, supposing them to get the entire advantage of the spring freshet. Is Mars habitable? A critical examination of Professor Percival Lowell's book "Mars and its canals," with an alternative explanation For the ladies keep cats, and the cats destroy the field-mice, which prey on the bees, which, in their turn, are all-important agents in the fertilisation of the clover flowers. Deductive Logic But—if the two methods are combined, the chemical method and the mechanical method, then the protection against fertilisation may be regarded as almost absolute. Safe Marriage A Return to Sanity As the two polar cells are extruded and lost, and have no further part in the fertilisation of the ovum, we need not discuss them any further. The Evolution of Man — Volume 1 The smaller eggs develop without fertilisation, by parthenogenesis, and become males. Hormones and Heredity You learn how the natives obtain sugar, palm-wine, and rubber; what is the use of the toucan's huge beak, and how plants secure the fertilisation of their flowers. The Naturalist in Nicaragua The closure of the flowers will also exclude nocturnal insects which may be ill-adapted for their fertilisation, and the well-adapted kinds at periods when the temperature is not favourable for fertilisation. The Power of Movement in Plants Many horticulturists have sought by the selection of seeds and by artificial fertilisation to control the sex of the plant so that the fruit-bearing females shall be the more numerous, but in vain. Confessions of a Beachcomber In all these animals the mature ovum, and the stem-cell that arises from it in fertilisation, consist of two different and separate parts, which we have called formative yelk and nutritive yelk. The Evolution of Man — Volume 1 Every zygote after conjugation or fertilisation may be said to be bisexual or hermaphrodite. Hormones and Heredity Dependence of flowers on insects for their fertilisation. The Naturalist in Nicaragua Her concern, as we have said, was merely to improve the race by means of crossed fertilisation. The Life of the Bee Sprengel, in which he clearly proved by innumerable observations, how essential a part insects play in the fertilisation of many plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In many of the lower animals the ovum retains its original naked form until fertilisation, develops no membranes, and is then often indistinguishable from the ordinary amoeba. The Evolution of Man — Volume 1 When a gamete with 8 chromosomes unites in fertilisation with a normal gamete with 7 the zygote has 15. Hormones and Heredity Darwin on animals and plants. on the effects of slight differences of colour. on fertilisation of scarlet runner. on fossil maize in Peru. on fresh-water mollusks. on the bumble bee. on the migration of butterflies. The Naturalist in Nicaragua Here it is evidently nature's wish, in the interests of crossed fertilisation, that the union of the drone and the queen-bee should be possible only in the open sky. The Life of the Bee Moreover, the fertilisation of a flower by its own pollen corresponds to a closer form of interbreeding than is possible with ordinary bi-sexual animals; so that an earlier result might have been expected. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The process of fertilisation by sexual conception consists, therefore, essentially in the coalescence and fusing together of two different cells. The Evolution of Man — Volume 1 When two such gametes unite in fertilisation the resulting organism will be a homozygous recessive, and the corresponding character will be absent. Hormones and Heredity If the humble-bee went first to the upper flowers of the spike and proceeded downwards, the whole economy of this plant to procure cross fertilisation would be upset.* The Naturalist in Nicaragua They are manifestly adapted for self- fertilisation, which is effected at the cost of a wonderfully small expenditure of pollen; whilst the perfect flowers produced by the same plant are capable of cross-fertilisation. The Different Forms of Flowers on Plants of the Same Species But it is more probable that their fertilisation is effected, as Mr. Bennett suggests, by Thrips and certain minute beetles which haunt the flowers, and which cannot be excluded by any net. Effects of Cross and Self Fertilisation in the Vegetable Kingdom These ova that do not need fertilisation are called "false ova," pseudova or spores. The Evolution of Man — Volume 1 In the majority of fishes, in which fertilisation is external and no care is taken of the eggs or young, there are no somatic sexual differences. Hormones and Heredity With respect to the common pea, I have ascertained that it is rarely crossed in this country owing to premature fertilisation. The Variation of Animals and Plants under Domestication — Volume 2 Therefore I have called the former method of fertilisation a legitimate union, and the latter, as it fails to yield the full complement of capsules and seeds, an illegitimate union. The Different Forms of Flowers on Plants of the Same Species The common carnation is strongly proterandrous, and therefore depends to a large extent upon insects for fertilisation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The splendid studies of Charles Darwin and Hermann Muller on the fertilisation of flowers by insects have given us very interesting particulars of this.* The Evolution of Man — Volume 1 When we examine these somatic differences we find that they can be classified according to their relation to fertilisation and reproduction, including the care or protection of the offspring. Hormones and Heredity Nor can pseudova which do not need fertilisation, be distinguished from true ova, as was first shown by Sir J. Lubbock, and is now admitted by Siebold. The Variation of Animals and Plants under Domestication — Volume 2 But there is no evidence that two sets of individuals exist, which differ slightly in function and are adapted for reciprocal fertilisation; and this is the essence of heterostylism. The Different Forms of Flowers on Plants of the Same Species For complete fertilisation it is necessary that pollen from the one form should be applied to the stigma of the other form; and this is effected under nature by insects. Effects of Cross and Self Fertilisation in the Vegetable Kingdom But this direct action of the male element is not so anomalous as it at first appears, for it comes into play in the ordinary fertilisation of many flowers. The Variation of Animals and Plants under Domestication — Volume 1 The view above suggested merely attempts to bring our real knowledge of the difference between ovum and sperm into relation with our real knowledge of the sex-chromosomes and their behaviour in reduction and fertilisation. Hormones and Heredity I did think it possible or probable that perfect fertilisation might have been effected through rostellum. More Letters of Charles Darwin — Volume 2 As both species are heterostyled, their complete fertilisation depends on insects. The Different Forms of Flowers on Plants of the Same Species Consequently the pollen and stigma of the same flower are adapted for complete mutual fertilisation, instead of its being necessary that pollen should be brought from one form to another, as in the common cowslip. Effects of Cross and Self Fertilisation in the Vegetable Kingdom I am particularly glad that you are ruminating on the act of fertilisation: it has long seemed to me the most wonderful and curious of physiological problems. More Letters of Charles Darwin — Volume 1 On fertilisation half the zygotes have XX and half XY, whether Y is absence of a sex-chromosome, or one of the other Y forms above mentioned. Hormones and Heredity Cruger's case here referred to is doubtless the cleistogamic fertilisation of Epidendrum, etc. More Letters of Charles Darwin — Volume 2 It had the appearance of having suffered from hyperthrophy, and is probably incapable of fertilisation. The Different Forms of Flowers on Plants of the Same Species The self-fertility of Primula veris increased after several generations of illegitimate fertilisation, which is a process closely analogous to self-fertilisation, but only as long as the plants were cultivated under the same favourable conditions. Effects of Cross and Self Fertilisation in the Vegetable Kingdom My blessed little Scaevola has come into flower, and I will try artificial fertilisation on it. More Letters of Charles Darwin — Volume 1 There are a great many animals, from jelly-fishes to fishes and frogs, in which fertilisation is external, and there are no intromittent organs at all. Hormones and Heredity Scott points out that the viscid matter is produced in large quantity only after the pollen-grains have penetrated the stigma, and that it is, in fact, a consequence, not a preliminary to fertilisation. More Letters of Charles Darwin — Volume 2 In all the several foregoing points the parallelism is wonderfully close between the effects of illegitimate and hybrid fertilisation. The Different Forms of Flowers on Plants of the Same Species But we should remember that if bees had been permitted to visit these flowers, they would have visited them at the best time for fertilisation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Your brother also continues to do fine work on the fertilisation of flowers and allied subjects. More Letters of Charles Darwin — Volume 1 Plants, cultivated, more fertile than wild; Nageli, on natural selection in; male flowers of, mature before the female; phenomena of fertilisation in. The Descent of Man I am working away on some points in vegetable physiology, but though they interest me and my son, yet they have none of the fascination which the fertilisation of flowers possesses. More Letters of Charles Darwin — Volume 2 Every known heterostyled plant, however, depends on insects for its fertilisation, and not on the wind; so that it is a rather surprising fact that only one genus, Pontederia, has a plainly irregular corolla. The Different Forms of Flowers on Plants of the Same Species In order to compensate the loss of pollen in so many ways, the anthers produce a far larger amount than is necessary for the fertilisation of the same flower. Effects of Cross and Self Fertilisation in the Vegetable Kingdom So a previous fertilisation apparently gives to the subsequent offspring a tendency to certain characters, as well as characters actually possessed by the first male. More Letters of Charles Darwin — Volume 1 Sachs, Prof., on the behaviour of the male and female elements in fertilisation. The Descent of Man They are wonderful creatures, these orchids, and I sometimes think with a glow of pleasure, when I remember making out some little point in their method of fertilisation. More Letters of Charles Darwin — Volume 2 There can therefore be little doubt that this plant generally propagates itself throughout an immense area by cleistogamic seeds, and that it can hardly ever be invigorated by cross- fertilisation. The Different Forms of Flowers on Plants of the Same Species Hermann Muller and Delpino have now shown that some other plants have thickened petals which are sucked or gnawed by insects, their fertilisation being thus aided. Effects of Cross and Self Fertilisation in the Vegetable Kingdom This process I have actually compared with ordinary fertilisation. More Letters of Charles Darwin — Volume 1 The last method of fertilisation is the more common. The Crime of Sylvestre Bonnard And this very example serves to show the falseness of Nageli's view, since a pollen-grain is an adaptation to aerial as opposed to aquatic fertilisation. More Letters of Charles Darwin — Volume 2 We thus see that the visits of insects are absolutely necessary for the fertilisation of Primula veris. The Different Forms of Flowers on Plants of the Same Species So that the relationship between hermaphroditism and fertilisation by means of insects is likewise to a certain extent intelligible. Effects of Cross and Self Fertilisation in the Vegetable Kingdom It is curious that he should not have thought of the endless adaptations for the dispersal of seeds and the fertilisation of flowers. More Letters of Charles Darwin — Volume 1 He found that a wonderfully close parallelism exists between hybridisation and certain forms of fertilisation among heterostyled plants. Life and Letters of Charles Darwin — Volume 2 The great difference in structure for fertilisation within the same genus makes one believe that all such points are vary variable. More Letters of Charles Darwin — Volume 2 The most interesting point in Hildebrand's experiments is the difference in the effects of illegitimate fertilisation with a flower's own pollen, and with that from a distinct plant of the same form. The Different Forms of Flowers on Plants of the Same Species It is not known why a certain amount of differentiation is necessary or favourable for the chemical affinity or union of two substances, any more than for the fertilisation or union of two organisms. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Thus, while working upon the 'Variations of Animals and Plants,' in 1860-61, he made out the fertilisation of Orchids, and thought himself idle for giving so much time to them. Life and Letters of Charles Darwin — Volume 1 The aphorism, Nature abhors close fertilisation,' and the demonstration of the principle, belong to our age and to Mr. Darwin. Life and Letters of Charles Darwin — Volume 2 I have long wished some one to observe the fertilisation of Scaevola, and you must permit me to tell you what I have observed. More Letters of Charles Darwin — Volume 2 This confirms my suspicion that some of the few capsules produced by the foregoing seventeen short-styled plants were the product of accidental legitimate fertilisation. The Different Forms of Flowers on Plants of the Same Species Juglans regia. anemophilous plants. fertilisation of Plantago. excretion of nectar. secretion of nectar to defend the plant. anemophilous and entomophilous plants. dioecious plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Some of the adaptations displayed by Climbing Plants are as beautiful as those of Orchids for ensuring cross- fertilisation. Life and Letters of Charles Darwin — Volume 1 Here is given an account of the fertilisation of Platanthera Hookeri. Life and Letters of Charles Darwin — Volume 2 By the way, can you lend me the January number of the "London Journal of Botany" for an article on insect-agency in fertilisation? More Letters of Charles Darwin — Volume 2 Whether these three capsules were the product of accidental legitimate fertilisation, owing to the branches of the plants of the two forms interlocking, I will not pretend to decide. The Different Forms of Flowers on Plants of the Same Species Corydalis lutea. spontaneously self-fertilised flowers. various mechanical structure to check self-fertilisation. early separation of the sexes. on Aristolochia. fertilisation of the Gramineae. wide dissemination of seeds. Effects of Cross and Self Fertilisation in the Vegetable Kingdom With plants having separated sexes, and with those in which, though hermaphrodites, the pollen does not spontaneously fall on the stigma, some aid is necessary for their fertilisation. The Origin of Species by means of Natural Selection, 6th Edition Not to the applause which followed it:— "They are wonderful creatures, these Orchids, and I sometimes think with a glow of pleasure, when I remember making out some little point in their method of fertilisation." Life and Letters of Charles Darwin — Volume 2 I presume you do not want seeds of this plant, as I have plenty from artificial fertilisation. More Letters of Charles Darwin — Volume 2 I allude to this fact because botanists in speaking of the fertilisation of various flowers, often refer to the wind or to insects as if the alternative were indifferent. The Different Forms of Flowers on Plants of the Same Species Mirabilis, dwarfed plants raised by using too few pollen-grains. number of grains necessary for fertilisation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Every hybridizer knows how unfavourable exposure to wet is to the fertilisation of a flower, yet what a multitude of flowers have their anthers and stigmas fully exposed to the weather! The Origin of Species by means of Natural Selection, 6th Edition I am extremely much pleased to hear that you have been looking at the manner of fertilisation of your native Orchids, and still more pleased to hear that you have been experimenting on Linum. Life and Letters of Charles Darwin — Volume 2 Farewell.—I wish I could compel you to go on working at fertilisation instead of so insignificant a subject as the commerce of the country! More Letters of Charles Darwin — Volume 2 Thus the stigmas of both forms will receive indifferently the pollen of both forms; but we know that the pollen alone of the opposite form causes fertilisation. The Different Forms of Flowers on Plants of the Same Species Muller, Hermann, fertilisation of flowers by insects. on Digitalis purpurea. Effects of Cross and Self Fertilisation in the Vegetable Kingdom There are essential differences in the manner in which fertilisation occurs. Darwin and Modern Science The flowers of the Papilionaceae attracted his attention early, and were the subject of his first paper on fertilisation. Life and Letters of Charles Darwin — Volume 2 The following letter refers to a series of excellent observations on the fertilisation of Leguminosae, made by Lord Farrer in the autumn of 1869, in ignorance of Delpino's work on the subject. More Letters of Charles Darwin — Volume 2 In the case of Cephalanthera grandiflora I have shown that precocious and partial self-fertilisation, with subsequent full fertilisation, is the regular course of events. The Different Forms of Flowers on Plants of the Same Species Lamium album. on anemophilous plants. fertilisation of Plantago. secretion of nectar. instinct of bees sucking nectar. bees frequenting flowers of the same species. cause of it. powers of vision and discrimination of bees. Effects of Cross and Self Fertilisation in the Vegetable Kingdom This may be effected in four different ways; there are two legitimate and two illegitimate types of fertilisation. Darwin and Modern Science How could the wind, which is the agent of fertilisation, with Plantago, fertilise "reciprocally dimorphic" flowers like Primula? Life and Letters of Charles Darwin — Volume 2 This is at least the most plausible explanation I can offer for the different results in my experiments on the fertilisation of apparently similar morphologically constructed flowers; others may, however, occur to you. More Letters of Charles Darwin — Volume 2 In their manner of fertilisation these plants offer a more remarkable case than can be found in any other plant or animal. The Different Forms of Flowers on Plants of the Same Species Moreover, in this case, a very small quantity of pollen would have been sufficient for fertilisation, instead of millions of grains being produced. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The fact that legitimate pollen effects fertilisation, even if illegitimate pollen reaches the stigma a short time previously, also points to this conclusion. Darwin and Modern Science But fertilisation is more sure and effective if the pollen comes from a different individual—if there is "cross fertilisation." The Story of Evolution I have been looking at the fertilisation of wheat, and I think possibly you might find something curious. More Letters of Charles Darwin — Volume 2 Consequently the flowers are capable of spontaneous self- fertilisation of a legitimate nature and yield a full complement of seed, or even more than the number produced by ordinary flowers legitimately fertilised. The Different Forms of Flowers on Plants of the Same Species Since the appearance of my book on Orchids, many excellent works on the fertilisation of flowers, such as those by Hildebrand, Delpino, Axell and Hermann Muller, and numerous shorter papers, have been published. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The observations on Linaria and the investigations of the results of legitimate and illegitimate fertilisation in heterostyled plants were apparently the beginning of a long series of experiments. Darwin and Modern Science The analogy between haemolysis and fertilisation throws, possibly, some light on a curious observation. Darwin and Modern Science Since I have had an opportunity of perusing your work on orchid fertilisation, my attention has been particularly directed to the curiously constructed floral organs of Acropera. More Letters of Charles Darwin — Volume 2 The flowers in this case as in the last are capable of spontaneous legitimate fertilisation, and are rather more productive than ordinary flowers legitimately fertilised. The Different Forms of Flowers on Plants of the Same Species The fertilisation of the flowers with their own pollen was superfluous, as this convolvulus is highly self-fertile; but I acted in this manner to make the experiments correspond in all respects. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Publication of "The Effects of Cross and Self fertilisation". Darwin and Modern Science It is obvious that there could only be a biology of flowers after it had been demonstrated that the formation of seeds and fruit in the flower is dependent on pollination and subsequent fertilisation. Darwin and Modern Science In regard to the mere question of fertilisation, then, I am perfectly satisfied, but there are other points which require further elucidation. More Letters of Charles Darwin — Volume 2 Illegitimate fertilisation, which is an abnormal process, is likewise an exciting cause; and with illegitimately descended long- styled plants of P. Sinensis, I have observed the first appearance and subsequent stages of this variation. The Different Forms of Flowers on Plants of the Same Species The flowers of the common Foxglove are proterandrous; that is, the pollen is mature and mostly shed before the stigma of the same flower is ready for fertilisation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom It is for this reason that the detailed investigation of fertilisation phenomena immediately followed researches into the nucleus. Darwin and Modern Science In the latter position, if the insect visited another flower, the pollinium would exactly hit the sticky stigmatic surface and thus effect fertilisation. Darwin and Modern Science Bolbophyllum is remarkable for the closure of the stigmatic cavity which comes on after the flower has been open a little while, instead of after fertilisation, as in other genera. More Letters of Charles Darwin — Volume 2 The males and females would also have to be equalised in number, or produced in some fitting proportion for the effectual fertilisation of the females. The Different Forms of Flowers on Plants of the Same Species The structure of the flowers of this plant, and their manner of fertilisation, have been described by H. Muller 'Befruchtung' etc. page 243. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Every sexual differentiation in organisms, which occurred in the course of phylogenetic development, was followed by fertilisation and therefore by the creation of a diploid or double-chromosome product. Darwin and Modern Science Even if the pollen of the same species reaches the stigma rather later than that of another species, the latter does not effect fertilisation. Darwin and Modern Science A difference in the size of the pollen-grains would be conclusive evidence; but in some cases experiments by fertilisation can alone decide the point. More Letters of Charles Darwin — Volume 2 Conversely the pistils in the flowers which open last sometimes abort; as when they are ready for fertilisation all the pollen has been shed. The Different Forms of Flowers on Plants of the Same Species Mr. Meehan says, that in the United States bees bore through the corolla for the nectar, and adds that their "fertilisation is carried on by night-moths." Effects of Cross and Self Fertilisation in the Vegetable Kingdom The whole Order is relatively primitive, as shown most strikingly in its cryptogamic mode of fertilisation, by means of spermatozoids, which it shares with the maidenhair tree alone, among recent seed-plants. Darwin and Modern Science Self-fertilisation is for the most part relatively and not absolutely injurious and always better than no fertilisation. Darwin and Modern Science In other Seed-plants the sperms are mere passengers, carried all the way by the pollen-tube; this fact has alone rendered the Angiospermous method of fertilisation through a stigma possible. Darwin and Modern Science According to H. Muller, there are only two forms in Germany, neither of which show any special adaptation for insect fertilisation, and both appear to be hermaphrodites. The Different Forms of Flowers on Plants of the Same Species Their fertility even increased in the later generations, as if they were becoming habituated to illegitimate fertilisation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The pollen-tube method ultimately prevailed, becoming a constant "morphological character," for no other reason than because, under the new conditions, it provided a more perfect mechanism for the accomplishment of the act of fertilisation. Darwin and Modern Science Those who concerned themselves with flowers endeavoured to investigate their development and structure or the most minute phenomena connected with fertilisation and the formation of the embryo. Darwin and Modern Science The further development of floral biology by Darwin is in the first place closely connected with the book on the fertilisation of Orchids. Darwin and Modern Science The collecting hairs on the pistil, which play so important a part in the fertilisation of the perfect flowers, are here quite absent. The Different Forms of Flowers on Plants of the Same Species In the following experiment any doubt arising from illegitimate fertilisation was completely eliminated. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Possibly in no other field of Biology has our ability to control life-phenomena by outside conditions been proved to such an extent as in the domain of fertilisation. Darwin and Modern Science Thus his original interest in the fertilisation of flowers was evolutionary. Darwin and Modern Science But in the case of flowers there is not only the question of adaptation to fertilisation to be considered. Darwin and Modern Science Delpino believes that cleistogamic flowers have been developed in order to ensure the production of seeds under climatic or other conditions which tend to prevent the fertilisation of the perfect flowers. The Different Forms of Flowers on Plants of the Same Species Wilder, Mr., fertilisation of flowers with their own pollen. Effects of Cross and Self Fertilisation in the Vegetable Kingdom If we put unfertilised eggs of a sea-urchin into sea-water which contains a trace of saponin we notice that, after a few minutes, all the eggs form the typical membrane of fertilisation. Darwin and Modern Science As is shown by what we have said about Catasetum, other problems in addition to those concerned with fertilisation are dealt with in the Orchid book. Darwin and Modern Science This inference is corroborated by observations on the fertilisation of the sea-urchin egg with ox blood. Darwin and Modern Science For the full and legitimate fertilisation of these plants pollen from the one form must be applied to the stigma of another. The Different Forms of Flowers on Plants of the Same Species The fertility—measured by the number or weight of the seeds produced by an equal number of plants—noticed under different conditions of fertilisation may be quoted in illustration. Darwin and Modern Science If this view is correct, it would be necessary to ascribe the fertilisation of the egg to the same process. Darwin and Modern Science For a long time it seemed as if an exception to this rule existed in the case of the fertilisation of the yucca blossoms by a little moth, Pronuba yuccasella. Darwin and Modern Science There was further, as we may suppose, a gain in certainty of fertilisation. Darwin and Modern Science The facts of Artificial Parthenogenesis, as the chemical fertilisation of the egg is called, have, perhaps, some bearing on the problem of evolution. Darwin and Modern Science |
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