Hydrophily

Hydrophilicity (also Hydrogamie ) refers to the pollination of flowers by water as a transport medium for the pollen, or the adaptation of plants to this type of pollination. Hydrophilicity is a rare form of pollination and only occurs in some aquatic plants. Pollination can be done below the water surface ( Hyphydrophilie ) or directly on or above the water surface ( Ephydrophilie ).

Features

The following characteristics are common in water- pollinated plants:

• The flowers are inconspicuous.
• The flowers are unisexual ( Diklinie: monoecious, dioecious ).
• Frequently air tissue occur.
• The - mostly thin - pollen wall is not wetted with the buoyant pollen grains.
• The pollen grains are filiform or pollen tube germinates early.
• The scar has an increased surface area.
• Per flower, there are only one or a few ovules.

Hyphydrophilie

In hyphydrophilen plant pollination below the water surface takes place. The anthers open in the water. In some species, the pollen grains are filiform, which provides the location of scars, such as when ordinary eelgrass ( Zostera marina). The whole species of seagrasses ( Zostera ), the pollen grains are about 0.5 mm long and have no exine. At the Grand Naiad ( Najas marina) germinates from the pollen already in the anthers into a tube. The flowers are small, inconspicuous and unisexual. The female flower usually has only one ovule. Also Ceratophyllum is pollinated under water, as are some types of Callitriche.

Ephydrophilie

At ephydrophilen plant pollination takes place at or above the water surface. This form of pollination occurs approximately at the frog bite plants. In the genera Vallisneria and Elodea, the male flowers detach from the plant and drive because of their air tissue ( aerenchyma ) at the water surface. In Elodea nutallii the blossoms open on the surface, the anthers release the buoyant pollen in tetrads on the water surface. The female flowers are lifted by a stretching of the hypanthium surface of the water system and work their three sepals. The scars protrude between the sepals into the water. The sepals are water-repellent, thus the water surface lower here. Pollentetraden that come close to the female flowers are therefore attracted and thus arrive at the scars.

In Lagarosiphon, sham Waterweed, the pollen sticks to the anthers. These are horizontally protruding from the blossom that drives like a boat in the wind. If it comes close to a female flower (which is built like Elodea ), the shuttle and the pollen -covered anthers tends stripes on the scar.

Documents

• Peter Leins: flower and fruit. Morphology, evolution, phylogeny, function, ecology. E. Content Free Trial, Stuttgart 2000, pp. 207, 214-218. ISBN 3-510-65194-4

• Pollination