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Vesmír č. 10
Vesmír č. 10
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2. 10. 2017
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Tyčinky, pestíky a evoluce

Anthers, pistils and evolution (The evolution of reproduction systems in angiosperms) by Helena Štorchová.

The reproduction systems in flowering plants are very diverse, most likely owing to sessile life way of plants. Without the possibility to move, search for the partner to reproduce becomes difficult. Insect transfers pollen from one plant individual to another, which led to co-evolution of both flowering plants and their pollinators. The prevailing reproduction system in angiosperms is a hermaphroditism. The presence of both male and female organs in the same flower may results in self-crossing and increased risk inbreeding. Thus, plants evolvedseveral mechanisms to avoid self-pollination. One of them is pollen self-incompatibility, which causes suppression of pollen germination on the stigma of the same genotype. After loss of selfincompatibility, some species developed a specific reproduction system called gynodioecy. It is characteristic by a co-occurrence of females and hermaphrodites in the same population. Females produce outbred progeny, whereas hermaphrodites ensure reproduction if the partner plants are not accessible. Dioecy, the reproduction system with females and males, widespread in animals, also occurs in plants, but with much lower frequency.