self-pollination

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self-pollination

the transfer of pollen from the anthers to the stigma of the same flower or of another flower on the same plant

Self-Pollination

 

the transfer of pollen from the stamen of a flower to the stigma of the same flower (autogamy) or to the stigma of another flower of the same plant (geitonogamy). According to their capacity for self-pollination, plants are distinguished as those that are self-fertile and those that are self-sterile. Self-fertile plants, which include oats, peas, and barley, produce normal seeds through self-pollination. Self-pollination generally occurs in the flower bud, whereas “alien” pollen, which may play a subsequent role in fertilization, usually falls on the stigma of an already opened flower. Self-pollination occurs rarely in wild plants; it occurs in cultivated plants considerably more often. However, even in self-fertile plants, self-pollination apparently leads to gradual degeneration of varieties, and periodic intravarietal cross-pollination is conducted to increase viability.

Self-sterile plants that have been self-pollinated either do not produce seeds or produce underdeveloped seeds from which stunted plants develop. Self-sterility may be explained by self-incompatibility, that is, the inability of male and female sex cells descended from a single flower to merge and form an embryo. In cross-pollinators, self-incompatibility is controlled by special genes that inhibit growth of the pollen tubule on its own stigma or along the column of the pistil or, finally, inhibit the merging of sex cells and development of the embryo. Fundamental to these processes is the apparent capacity of the plants to elaborate substances similar to antibodies that inhibit the development of pollen on their own stigma. The manifestation of genes of incompatibility is strongly influenced by external conditions, which may partially or completely suppress their effects. The degree of self-incompatibility is usually not identical in different individuals of the same variety or species. Nor is it the same during the different periods of flowering, thereby making it possible to overcome self-incompatibility in selection work. I. V. Michurin used a number of artificial methods in his experiments.

In many plants, self-pollination occurs at the end of the flowering period, serving as a “reserve” phenomenon in the event that normal cross-pollination has not occurred. To ensure self-fertilization, plants have elaborated special adaptations—for example, changes in the position of the flower and the turning of the stigmas toward the stamens or of the stamens toward the stigmas.

REFERENCES

Darwin, C. Deistvie perekrestnogo opyleniia i samoopyleniia ν rastitel’nom mire. Moscow-Leningrad, 1939.
Lobashov, M. E. Genetika, 2nd ed. Leningrad, 1967.
Pervukhina, N. V. Problemy morfologii i biologii tsvetka. Leningrad, 1970.
Kugler, H. Blütenökologie, 2nd ed. Jena, 1970.

V.N. VEKHOV

self-pollination

[¦self ‚päl·ə¦nā·shən]
(botany)
Transfer of pollen from the anther to the stigma of the same flower or of another flower on the same plant.
References in periodicals archive ?
There is a tendency for obtaining larger fruits from flowers self-pollinated after stigma excision and two self-pollinations.
The strategy could also be interest for the determination of stability and distinctness of inbred rice lines, as well as other non-hybrid plant varieties, but it couldn't effectively discriminate self-pollinated off-types from those true hybrid individuals.
The second one is that there is a comprehensive separation of self-incompatibility among progeny from the same self-pollinated self-compatible chrysanthemum cultivar.
Self-pollinated plants are usually genetically homozygous with both alleles of a given gene being identical (i.e., either AA or aa, but not Aa).
Depending on whether plants are self-pollinated or crosspollinated, and how many independently inherited characteristics distinguish the parents, the offspring may closely resemble the parents or be very different.
In particular, flowers pollinated with outcross pollen produced seeds with significantly higher germination frequency and seedling mass than flowers pollinated with self pollen, whereas seed set was higher in fruit from self-pollinated flowers (Fig.
The seeds were extracted from the cones and counted, and at least 100 self-pollinated, and 100 open-pollinated seeds from every tree were X-rayed and classified as live (filled) or aborted (empty).
Bumblebee pollinated Cherry flowers yielded higher fruit weight (8.5 g/fruit) followed by manually and self-pollinated flowers (6.2, 1.9 g/fruit), respectively.
The F1 plants were self-pollinated to produce the F2 seeds and backcrossed with MX169 to obtain the backcross generation (BC1), that were used for gentic inheritance analysis; A set of T.
60 taxa, which are supposedly mostly self-pollinated since the filaments often elongate after the anthers mature thus contacting the stigma.
According to Baker & Baker (1983) starchy pollen grains are generally considered to be characteristics of species that are self-pollinated, wind pollinated, pollinated by Lepidoptera or by birds, while lipidic pollen grains are characteristics that have species of bee-pollination and flypollination.
In each generation, resistant plants were identified and self-pollinated. Analyses for oleic acid concentration were conducted on seed harvested from [F.sub.3] to [F.sub.6] plants by gas chromatography.