Cross Pollination vs. Self-Pollination

Pollen is transferred to the female reproductive organs of seed plants resulting in fertilization and reproduction in a process called pollination. There are two types of pollination, cross-pollination and self-pollination. In cross-pollination the reproduction is called allogamy, and in self-pollination it is autogamy or geitonogamy.

In cross pollination, pollen is transferred from plant to plant by an insect or by the wind, both called pollinators. Specifically, from the pollen grains of the anther to the stigma of a flower of a different plant of the same species.

However, during self-pollination the plant's stamen shed pollen onto its own stigma during the process. The pollen grains are transferred from the anther to the stigma of the same flower.

There are differences in the plants using the two types of pollination. For cross-pollination they are brightly colored petals, with nectar and scent, and long stamens and pistils. For self-pollination it includes much smaller flowers.

The two types of pollination can be found in many different plants. Cross-pollination occurs by insects for several plants such as apples, grapes, plums, pears, raspberries, strawberries, daffodils, tulips, and others. It also occurs by wind for different grasses, catkins, dandelions, maples tress, and a few others. It can occur in either perfect or imperfect flowers. Most flowering plants use cross-pollination.

Self-pollination may be seen in some legumes, such as peanuts, as well as orchids, peas, sunflowers, wheat, oats, potatoes, peaches, and several more. It can occur only in perfect flowers. In addition, peas, sunflowers, and orchids only use self-pollination if cross-pollination is not successful.

The results of the pollination methods have differences as well. Cross-pollination results in more variety of the species, allowing for a more diverse appearance of the different plants and flowers. The genetic information of the plants are combined, but it must rely on the pollinators such as insects and the wind moving the pollen from plant to plant. If it does not take place, the pollination will not occur.

In self-pollination the results allow for more uniform progeny, and permits the plants to be less resistant to disease. In addition, since the plants do not need to use energy to attract pollinators, they can spread beyond areas where cross-pollination pollinators are found.

Another big difference between the two are the number of pollen grains being spread. In cross-pollination there are a very large number, but in self-pollination there is a very small number of pollen grains.

In summary, cross-pollination is the transfer of pollen to different plants, occurs in open flowers, depends on pollinators, a variety of traits produced, adapts to the changing environment, and helps in the development of new species.

On the other hand, self-pollination is the transfer of pollen within the same plant, occurs in open and closed flowers, does not need pollinators, not much variety, more difficulty in adapting to a new environment, and does not help in the development of a new species.