There are many cases where the pistil of a flower necessarily comes in contact with its own pollen, yet fertilization does not take place, however improbable this may appear.
All too soon after fertilization the now useless corolla slides along to the tip of the pistil, where it swings a while before dropping to earth.
The stamens radiate, that self-fertilization need not take place except as a last extremity.
At this time, the anthers being closed, self-fertilization is impossible.
Self-fertilization may be an evil, but failure to produce seed at all is surely the greatest one.
After fertilization the corolla turns yellow to let visitors know the mutual benefit association has gone out of business.
On the slight downward movement of the column in the ladies' tresses, then, as well as on the bee's ministrations, the fertilization of the flower absolutely depends.
As the fertilization of the germ-cell in the archegonium cannot take place except under water, perhaps the fact is accounted for that ferns are found chiefly in moist places.
Keeping shade trees in a vigorous condition by proper watering and fertilization helps reduce their susceptibility to weevil attack.
In shade and ornamental trees, pruning of infected twigs, burning of leaves, and fertilization will reduce the disease impact.
These shades are most distinct on the most vigorous males, and disappear with the warty excrescences after the fertilization of the eggs.
The egg of the fish develops only after fertilization (amphimixis).
If this be so, there is a good reason why bees should be specially fond of blue, and why blue flowers should be specially adapted for fertilization by their aid.
It is on the prothallus, however, that the sexual organs are produced, and after fertilization the plant as we know it arises.
In passing, it may be pointed out that the term Cryptogam is a name which was originally given to the flowerless plants by Linnaeus to indicate that the plan of fertilization was hidden.
Now and again in certain species it is seen that the megaspores develop to such an extent within the sporangium that fertilization takes place, and even an embryo or young plant may be formed.
Probably the tendency of the world to become drier has had something to do with the decline, seeing that in all cases the fertilization is carried out under water.
After the fertilizationis completed the first happening is the formation of a cell-wall round the ovum.
Fertilization then takes place, and the final outcome is the young plant.
With Ferns, as is the case with nearly all the Cryptogams, the fertilization takes place under water; the moisture may be the outcome of heavy rain or even dew.
The manner of fertilization may be briefly outlined, although the observation of this is beyond the ordinary student.
These are borne straight on the leaves, and are produced without anything in the way of fertilization having taken place.
Fertilization of the ovum, as this event is scientifically termed, has as its main purpose the uniting of the nucleus of a male germinal cell with the nucleus of the female germinal cell.
Unless some arrangement was made to prevent it, the act of fertilization would cause the number of chromosomes in the fertilized ovum to be double the number characteristic of the species.
Of its own accord the ovum can move after fertilization no better than before; it is never capable of moving itself.
In man, for example, the addition of twenty-four chromosomes from the spermatozoon to an ovum that already contained twenty-four chromosomes of its own would mean that after fertilization the ovum contained forty-eight.
More commonly their genesis depends upon the ripening of two eggs at about the same time and the fertilization of both by two different spermatozoa.
In our every-day way of speaking, fertilization means conception; it is the instant in which a living being begins its existence.
Before the significance of fertilization was understood, it was perhaps not unreasonable to believe that life began with quickening or about the time the fetal heart-sounds could be heard.
After fertilization there is a period of eight to ten days before oviposition.
In botany Conrad Sprengel, who belongs to the eighteenth century, had shown the work effected by insects in the fertilizationof plants.
It is supposed that the little insects insure fertilization by carrying the pollen from the male flowers near the opening of the fig down to the female flowers, and also accelerate ripening the fruit by puncturing it.
I think fertilization with barn-yard litter beneficial on upland orchard, but would not advise its use on rich bottom.
I believe that cross-fertilization is beneficial to an orchard in making fruit more plentiful, larger, smoother, better color and quality.
Professor Darwin says self-fertilization is abhorrent to nature, and the same rule that applies to small fruits is equally applicable to apples.
I fertilize my orchard by mowing the clover, and think it beneficial to young trees, and would advise the use of clover fertilization on all soils.
The subject of cross-fertilization of flowers was in Darwin's mind, as shown by his note-book in 1837.
The same is true of the little water-fleas, or Daphnids; while in some kinds of rotifers fertilization is said never to occur.
This process of fusion of germinal cells is called fertilization (see Fig.
The ovum before fertilization is a simple spherical cell, without any large amount of nutritive material in the form of food-yolk (A.
Fertilization takes place; and the fertilized ova develop into little hydras, which produce, by budding, new colonies.
Where, as in the case of aphids and daphnids, fertilization occasionally takes place, it would seem that lowered temperature and diminished food-supply are the determining conditions.
F] It is not, however, necessary in all cases that fertilization of the ovum should take place.
The cells in which drones are developed are somewhat smaller than those for ordinary workers; but what may be the nature of the stimulus that prompts the queen to withhold fertilization we at present do not know.
The presence or absence of fertilization in this case determines the sex.
An hour or two after fertilization the egg divides into two cells (fig.
The act of fertilization is the union of two cells (fig.
Chance combinations at fertilization give the three classes of individuals of the second generation.
Since self-fertilization is the normal process in this bean the purity of the germ plasm already existed when Johannsen began to experiment.
It has since been pointed out by Jennings and by Pearl that a race that reproduces by self-fertilization as does this bean, automatically becomes pure in all of the factors that make up its germ plasm.
Simple as the process of fertilization appears to us today, its discovery swept aside a vast amount of mystical speculation concerning the rôle of the male and of the female in the act of procreation.
Defn: Fertilization of two ova, at the same menstruation, by two different acts of coition.
Cross fertilization, fertilization by pollen from some other blossom.
Defn: The process of fertilization in plants by an indirect or circuitous method; -- opposed to orthogamy.
Defn: The fertilization of a flower by pollen from the same flower and without outer aid; autogamy.
All the Spermatophyta are heterosporous; fertilization of the egg cell is either through a pollen tube emitted by the microspore or (in a few gymnosperms) by spermatozoids.
Defn: The process or result of cross fertilization between different kinds of animals, or different varieties of plants.
Defn: Direct fertilization in plants, as when the pollen fertilizing the ovules comes from the stamens of the same blossom; -- opposed to heterogamy.
Defn: One of the arms of the male of most kinds of cephalopods, which is specially modified in various ways to effect the fertilization of the eggs.
Defn: Fertilization of flowers by pollen from other flowers on the same plant.
Defn: The production of two or more embryos in one seed, due either to the existence and fertilization of more than one embryonic sac or to the origination of embryos outside of the embryonic sac.
The beginning of this period is precise and definite--it is the completion of the fertilization of the ovum, in which the life of the individual has its start.
These began in 1875 and following years with a careful examination of the behaviour of the germinal vesicle in the maturation and fertilization of the ovum.
Giard suggests that in some cases of apparently normal fertilizationone of the pronuclei may degenerate, the resultant embryo being the product of one pronucleus only.
The florist prevents fertilization in the same kind and compels fertilization of a different kind.
The former is found, of course, only in the higher animals, where fertilization is voluntary.
So also in case of hermaphrodite animals, where the fertilization is involuntary; many aquatic species are found together in the same locality, and the water is filled with sperm-cells of many different species.
Even in plants, Darwin has shown that cross-fertilization has better effect than self-fertilization, this last being of course the closest possible breeding.
Then comes cross-fertilizing hermaphroditism; and Nature takes much pains and uses many ingenious devices to prevent self-fertilization and insure cross-fertilization.
In hermaphroditic plants in which there may be either self-fertilization or else cross-fertilization with other individuals of the same species, the latter produces better results in number and vigor of offspring.
When the spermatozoon enters the egg of the sea urchin it calls forth the formation of a membrane--the fertilization membrane.
Lillie assumes that this agglutinating substance contained in egg sea water is required to bring about fertilization and he therefore calls it "fertilizin.
The idea that fertilizationand membrane formation cause an increase in the permeability of the egg was later accepted and elaborated by R.
Hertwig had defined fertilization as consisting in the fusion of two nuclei, the egg nucleus and the sperm nucleus.
They can in no way be distinguished from the frogs produced by fertilization with a spermatozoon.
The spermatozoon enters the egg through the so-called fertilization cone, i.
If an egg with A is fertilized by a pollen with a (or vice versa), after fertilization the chromosome constitution of the fertilized egg is Aa.
It seems that thefertilization of the egg by sperm is rendered possible by two facts; first that where fertilization takes place outside the body egg and sperm are shed simultaneously by the two sexes.
Thus cross-fertilization is brought about by the bees which come for the nectar of Salvia.
The insects serve the flowers by carrying the fertilizing pollen from one flower to another, and thus promoting cross-fertilization among separate individual plants of the same species.
In the first cell (a) the ovum is shown in process of fertilization by the entering spermatozoon or male sexual element.
The process of sexual fertilization consists in the union of the male and female sex cells and an equal blending of the chromatin contained in each (Fig.
More commonly the arrangements are such that it takes place only after some opportunity for cross fertilizationhas been afforded.
An essentially similar process of fertilization has been discovered in the preceding and the following families of Pteridophytes; but it is mostly subterranean and very difficult to observe.
There must be some essential advantage in cross fertilization or cross breeding.
Fertilization in Mosses is by the analogues of stamens and pistils, which are hidden in the axils of leaves, or in the cluster of leaves at the end of the stem.
But close fertilization is inevitable in what are called Cleistogamous Flowers, that is, in those which are fertilized in the flower-bud, while still unopened.
Cross fertilization depends upon the transportation of pollen; and the two principal agents of conveyance are winds and insects.
Moreover, there are two arrangements for cross fertilization common to hermaphrodite flowers in various different families of plants, which have received special names, Dichogamy and Heterogony.
The most remarkable are in some way connected with fertilization (Sect.
Some of the adaptations which favor or ensure cross fertilization are peculiar to the particular kind of blossom.
In Nature, even with hermaphrodite plants, there is a vast amount of cross-fertilization among various individuals of the same species.
The superabundance of the pollen of pine-trees above referred to, and in oak-trees, is correlated with chancefertilization under the winds.
This Conclusion inferred from the Provisions and Arrangements in Nature to secure Cross-Fertilization of Individuals.
Who can suppose that such a costly process as this, and that all the exquisite arrangements for cross-fertilization in hermaphrodite plants, do not subserve some most important purpose?
The conveyance of pollen from one flower to another in cross-fertilization is effected naturally by the wind, or by the agency of insects and other creatures.
When, through the introduction of the male plant from Japan, itsfertilization was rendered possible, ripe berries, before unknown, became common ornaments of the shrub.
Self-fertilization occurs when the pollen of a given flower affects the egg-cell of the same individual flower.
Hence, the successful grower makes an effort through disease and insect control and proper fertilization and cultivation to keep his trees strong.
In order to develop a good nut there must be two chestnut trees within a reasonable distance of each other so that cross fertilization may take place.
In later years the orchards were not cultivated but nitrogen fertilization was substituted.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "fertilization" in a variety of sentences. We hope that you will now be able to make sentences using this word. Other words: conjugation; enrichment; impregnation; insemination
