Ristiinpölytys

Ristiinpölytys refers to the transfer of pollen from the anther of one flower to the stigma of another flower. This process is crucial for the sexual reproduction of many flowering plants, leading to the production of seeds and fruits. There are two main types of cross-pollination: geitonogamy and xenogamy. Geitonogamy occurs when pollen is transferred between different flowers on the same plant. While genetically similar to self-pollination, it is often considered a form of cross-pollination because the transfer is between distinct flowers. Xenogamy, on the other hand, involves the transfer of pollen between flowers of different plants of the same species. This type of cross-pollination promotes genetic diversity within a population, which can enhance a species' ability to adapt to changing environmental conditions and resist diseases.

Various agents facilitate cross-pollination. Wind is a significant pollinator for many plants, carrying light pollen grains over long distances. Insects, such as bees, butterflies, and moths, are also vital, attracted to flowers by their color, scent, and nectar. Birds, bats, and even water can act as pollinators in specific ecosystems. For cross-pollination to be successful, several factors must align, including the timing of flower opening, the compatibility of pollen and stigma, and the presence of effective pollinators. Plants have evolved diverse strategies to encourage cross-pollination, such as producing attractive floral displays, scents, and rewards, as well as developing mechanisms to prevent self-pollination.