Direct pollination (Autopolinizaci³n)
What is the direct pollination? Concept and definition
The direct pollination is the type of pollination in which the pollen grain arrives by its own means at the stigma of the flower, without the intervention of agents external pollenizers such as insects, birds or animal.
Autonomy is the word with which we can summarize what implies the direct pollination, also well-known as autopolinizaci³n or self-fertilization.
The pollination is the transport of pollen from a plant to another one and, exactly, the direct pollination happens when the pollen grain arrives by its own means, without no external help, to the stigma of a flower, originating of the stamen, without almost wasting nothing or very little of pollen, since the transfer of the same is very short.
The pollen grain arrives by its own means at the stigma of the flower.
Autogamia & Geitonogamia
Autogamia is denominated when the autopolinizaci³n or autofertilizaci³n takes place in flowers hermaphrodites (stamen and pistils in the same flower).
Autogamia & alogamia. As much autogamia as alogamia are terms used in Biology to describe two types of reproduction of the feminine plants that are different in the origin of the masculine sperm cells and that participates in the fertilization. If the sperm cells come from the same individual - it plants, it is spoken of autogamia. If the sperm cells come from individuals - you plant different, it is spoken of alogamia.
Characteristics of the species aut³gamas
In the species aut³gamas, the flowers frequently are small, with inconspicuous floral pieces, produce little amount of pollen and they do not present fragrance nor nectar.
Examples of species aut³gamas
The pioneering weeds, plants and the island species, that need that the isolate individuals fructify and produce seeds.
Types of pollination aut³gama
The pollination aut³gama can be forced or facultative. Autogamia forced occurs when the seeds of the plant aut³gama only come from the autopolinizaci³n and self-fertilization. On the other hand, autogamia facultative occurs when the seeds of the plant aut³gama, in addition to the autopolinizaci³n, can have their origin by alogamia (to the being fertilized by another individual). In other words, the facultative species aut³gamas are preponderantly aut³gamas but they have the capacity to produce seeds by pollination with other individuals nonbecome related. In other words, autogamia in these species coexists with alogamia in an adaptive balance.
Geitonogamia is denominated when the autopolinizaci³n or autofertilizaci³n takes place between flowers different from same individio - it plants.
Genetically, geitonogamia is equivalent to autogamia.
Examples of geitonogamia
The geitonog¡mica pollination is common in species with massive flowering, as lapacho (Tabebuia heptaphylla), ibir¡-pit¡ (Peltophorum dubium) and the drunk wood (speciosa Ceiba).
Advantages and disadvantages of the direct pollination
In spite of the little complexity of the process, when being realised the direct pollination takes place a reduction of the genetic diversity, since normally it brings about a limitation in the variety. In addition, the stem of the plant can turns affected in its size. In spite of this, it runs with a geographic advantage: it allows that the plants obtain an extension by outside their geographic rank and the descendants in places where, perhaps, the pollenizers underwent a reduction. All this obtains it by its own means.
In synthesis, we summarized one of the processes that can happen within the pollination: the direct pollination, that one that acts of independent way, without dependency of the agents pollenizers.