self-pollination


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
Related to self-pollination: cross-pollination

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 ?
After spontaneous self-pollination, fruit set was significantly lower than that of all other treatments (p<0.05), and pollination by A.
[SCI.sub.f] was calculated by dividing the mean number of seeds per fruit in the self-pollination treatment by the number of seeds in the artificial cross-pollination treatment.
Although a large amount of pollen is released onto the stigma, in self-pollination, the fruit set is low compared to buzz pollination.
An alternative hypothesis is that resource limitation, or changes in resource allocation, of clipped plants decreases their ability to benefit from a lack of self-pollination. In this scenario, the same proportional amount of self pollen is deposited on the flowers of clipped and control plants, and there are no differences in the foraging of pollinators.
The flowers' morphophysiological development evidenced that the probability of self-pollination in the two short stamens is limited, since they release pollen grains under the stigma during the entire anthesis period.
During May 1998, once a flower opened, it was randomly assigned to one of the following treatments: (1) Automatic self-pollination: bagged flowers with no further manipulation,(2) Forced self-pollination: flowers manually self-pollinated, (3) Cross-pollination: pollen from ten plants was applied to previously emasculated flowers, the average distance of pollen source was approximately 50 m and none of the 31 plants (block) were included and (4) Open-pollination (control): mature flowers left open and bagged at the end of the day.
Honey-bee-mediated cross-versus self-pollination of "Sharpblue" blueberry increases fruit size and hastens ripening.
The majority of outcrossing angiosperms have bisexual flowers, a condition from which self-pollination can evolve directly through the modification of self-incompatibility or other floral traits that prevent self-pollination.
Here, selfed means self-pollination was applied, and paired means paired without reciprocal cross.
A similar situation was reported in Iris versicolor from Kent Island, New Brunswick, where facultative self-pollination was promoted by wind that forced reflexed stigmas to brush against petals of the same flowers where pollen had settled (Zink & Wheelwright, 1997).
The scientists later collected seeds and genetically characterized them to determine whether they were the result of self-pollination. The tests also revealed the handedness of the pollen-donating parents.
(c) Self-pollination (SP): buds about to open next day were quantified and enclosed in a pollination bag; the following day the unopened buds were discarded and the open flowers were self-pollinated to evaluate self-compatibility.