Dissemination

Dissemination [ Botany ]
Synonym: Seed dispersal

Dictionary of botanic terminology - index of names


	In biology the dispersal or dissemination is the natural process of dispersing of plant fruit and seeds and of the offspring of non-mobile organisms over a wide area.

Plants reproduce in a very different way than animals, they produce new plants by making seeds. Seeds usually move away from the parent plant in some way and grow in new places sometimes a long way from the parents.
Fruit disseminate together at the time it or its seed(s) are dispersed from the plant, or just prior to germination on the plant.
The Dissemination is important because if the seeds are not dispersed, many germinating seedlings will grow very close to the parent plant. This results in competition between every one of the seedlings as well as with the parent plant. The competition is for light, space, water and nutrients. All of these are important for plants to be able to grow. The mechanism by which this is done is called dispersal.

There are six common means of dispersal:

• Anemochory: Dispersal by wind.
• Autochory: Dispersal by physical expulsion, often explosively.
• Endozoochory: Dispersal through animal ingestion and excretion.
• Epizoochory: Dispersal by attachment to fur or feathers.
• Hydrochory: Dispersal by water.
• Myrmecochory: Dispersal by ants.

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Holdfast roots [ Botany ]
Dictionary of botanic terminology - index of names

Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.

Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans), develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994