Botany and Plant Science

Dioecious plants have male and female flowers on different individuals, which physically prevents both autogamy (self-pollination within a flower) and geitonogamy (pollination between flowers on the same plant).

Outbreeding devices are strategies plants use to encourage cross-pollination. These include unisexual flowers, monoecious conditions, and physiological mechanisms like self-incompatibility.

Outbreeding devices include dichogamy (asynchrony of maturation), herkogamy (spatial separation), and self-incompatibility, all of which reduce self-pollination.

Plants provide various rewards to pollinators, including nectar, pollen, and safe sites for egg-laying, as seen in the symbiotic relationships of Yucca and Amorphophallus.

Pollination by water is relatively rare in angiosperms, occurring in about 30 genera, mostly monocots. Examples include Vallisneria, Hydrilla, and Zostera.

Wind-pollinated plants require light, non-sticky pollen, well-exposed stamens, and feathery stigmas to maximize the chances of capturing pollen from the air.

Cleistogamous flowers are closed, forcing self-pollination. This process is known as autogamy.

Viola, Oxalis, and Commelina are classic examples of plants that produce both chasmogamous (open) and cleistogamous (closed) flowers.

Geitonogamy involves the transfer of pollen to the stigma of another flower on the same plant. Because the pollen comes from the same plant, it is genetically similar to autogamy, even though it requires a pollinator.

The transfer of pollen from the anther to the stigma of another flower on the same plant is the definition of geitonogamy.

A mature angiosperm embryo sac contains 8 nuclei but only 7 cells, because the two polar nuclei reside in a single large central cell.

The filiform apparatus consists of cellular thickenings at the micropylar end of the synergids, which guide the pollen tube into the embryo sac.