Meteorochory

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The nuts of the " dandelion " are paragliders

The meteorochory is a form of the propagation strategy of plants with the wind. It is a sub-form of the anemochory , which is one of the most original forms of spread of plants. The plants are called wind flyer or seeds flyer .

Construction principles of the diaspores

The construction principle of the diaspores that are spread out meteorochore can be divided into four subspecies:

It is typical for meteorochore plants that the diaspores reduce their specific weight through air-filled cavities and / or increase their air resistance through various surface designs such as wings, flying hairs or parachutes.

Trichometeorochory: hair fruit, umbrella fruit

In the dandelion genus Leontodon the pappus sits at the end of the fruit, in the dandelion genus Taraxacum on a beak (stem) and they are therefore "beaked"
  • Tuft-like hair formations that are located at the tip of the diaspores are particularly common in the composite plants (such as arnica or elephant ) and valerian plants . The head of hair, called pappus , acts like a parachute by generating a cushion of air that prevents the diaspores from sinking too quickly to the ground. These diaspores are therefore also known as umbrella fliers . Many pioneering plants, such as fireweed, use this mode of action to scatter their seeds for miles. The pappus either sits directly at the tip of the diaspores (as with dandelion (Leontodon) ) or the diaspores are beaked and the pappus sits on a stem that hangs from the diaspore (as with dandelion (Taraxacum) )
  • Feather-tailed fliers such as the heron-beaked species or the cow bells follow a different principle of action. They increase air resistance by transforming the stylus of the diaspores into a long feather tail as the fruit ripens.
  • On the other hand, hair fliers , as diaspores are called, whose seeds are covered with a hair, are rarer . The best-known example is the dandelion or the poplar and cotton seeds or sycamore seeds .

Pterometeorochory: wing fruit / wing seed

Alsomitra macrocarpa as an example of a winged seed

Wing fliers are based on the principles of lift .

  • Screw planes , also rotary planes , mostly work like a rotor blade according to the principle of autorotation . The seed has a core, in which the center of mass lies, and a light wing. After a short dive, it turns into a spiral and helical movement. It rotates on its own axis and also screws itself down in a large spiral. With some maples this is a double wing made of two fruits, with others as well as with conifers , linden and ash with one leaf and the hornbeam ; here is a special, overgrown leaf of the wings.
  • Glider : Another principle is a staggering-soaring way of flight - similar to a butterfly - with flat wings, multi-fingered in birch plants such as birch , roundish in elms (for an example, see the illustration in field elm ). The Zanonia has particularly good sliding properties . The seed has thin wings on both sides that give it the appearance of a small dragon . If it is brought out of its stable flight position by a collision or wind, it swings briefly and then finds its way back into the optimal flight position. He therefore became the model for the construction of aircraft ( Etrich Taube ).

literature

  • Angelika Lüttig & Juliane Kasten: Rose hip & Co - flowers, fruits and spread of European plants. Fauna Verlag, Nottuln 2003, ISBN 3-935980-90-6 .

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