(self fertilization, endogamy) Fusion of female and male gametes derived from genetically similar sources, usually the same individual. This mechanism restricts genetic variability of the population but can stabilize selected traits and ensures that isolated individuals have the opportunity to reproduce. Autogamy may be found in species where cross pollination cannot be assured, as in pioneer populations (many weeds are autogamic) or where insect vectors may be rare (as in the tundra ecosystems). Autogamy is thought to be derived from allogamy by the overcoming of self-incompatibility systems. Total autogamy is rare in the plant kingdom except in species showing * cleistogamy. In most cases autogamy is facultative and may be triggered by adverse climatic conditions, such as high humidity or intense cold, or by failure to achieve cross fertilization. See also homogamy. |
