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Epilobium hirsutum seed head dispersing seeds. In spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant. [1] Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vectors, such as the wind, and living vectors such as birds.
Epilobium hirsutum — Seed head. In the broadest sense, dispersal occurs when the fitness benefits of moving outweigh the costs. There are a number of benefits to dispersal such as locating new resources, escaping unfavorable conditions, avoiding competing with siblings, and avoiding breeding with closely related individuals which could lead to inbreeding depression.
In the simplest case, these objects are just finitely many points in the plane (called seeds, sites, or generators). For each seed there is a corresponding region, called a Voronoi cell, consisting of all points of the plane closer to that seed than to any other. The Voronoi diagram of a set of points is dual to that set's Delaunay triangulation.
Seeds generated by apomixis are a means of asexual reproduction, involving the formation and dispersal of seeds that do not originate from the fertilization of the embryos. Hawkweeds ( Hieracium ), dandelions ( Taraxacum ), some species of Citrus and Kentucky blue grass ( Poa pratensis ) all use this form of asexual reproduction.
In leptosporangiate ferns, the fern catapults its spores 1-2 cm so they can be picked up by a second dispersal vector, often the wind. [4]Autochory is the dispersal of diaspores, which are dispersal units consisting of seeds or spores, using only the energy provided by the diaspore or the parent plant. [5]
Some seeds (e.g., pine) have a wing that aids in wind dispersal. The dustlike seeds of orchids are carried efficiently by the wind. Some seeds (e.g. milkweed, poplar) have hairs that aid in wind dispersal. [28] Other seeds are enclosed in fruit structures that aid wind dispersal in similar ways: Dandelion achenes have hairs. Maple samaras have ...
Mistletoe use a sticky seed for dispersal. The seed sticks to nearby animals and birds and then comes into direct contact with the host. [5] Arceuthobium seeds have a similarly sticky seed as the mistletoe but they do not rely on animals and birds, they mainly disperse by fruit explosiveness. Once the seed makes contact with the host, rainwater ...
The main difference between spores and seeds as dispersal units is that spores are unicellular, the first cell of a gametophyte, while seeds contain within them a developing embryo (the multicellular sporophyte of the next generation), produced by the fusion of the male gamete of the pollen tube with the female gamete formed by the ...