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The spores are dispersed through a catapult-like system, flinging the spores out briefly at up to 10m/s. This is caused by the gradual build up of a high negative pressure (200-300 atmospheres) within annulus cells from water loss. [1] As these cells lose water, they shrink, and are designed to inwardly bend on the outer face of the annulus.
Dispersal is also used to describe the movement of propagules such as seeds and spores. Technically, dispersal is defined as any movement that has the potential to lead to gene flow. [1] The act of dispersal involves three phases: departure, transfer, and settlement. There are different fitness costs and benefits associated with each of these ...
The bryophytes consist of about 20,000 plant species. [5] [6] Bryophytes produce enclosed reproductive structures (gametangia and sporangia), but they do not produce flowers or seeds. They reproduce sexually by spores and asexually by fragmentation or the production of gemmae. [7]
Explosive dehiscence is a ballistic form of dispersal that flings seeds or spores far from the parent plant. This rapid plant movement can achieve limited dispersal without the assistance of animals.
A diaspore of seed plus elaiosome is a common adaptation to seed dispersal by ants (myrmecochory). This is most notable in Australian and South African sclerophyll plant communities. [1] Typically, ants carry the diaspore to their nest, where they may eat the elaiosome and discard the seed, and the seed may subsequently germinate.
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]
At that time, the elaters uncoil to extend out from the spore and will catch air currents. The fact that they are extended only when conditions are dry means that successful spore dispersal is more likely. The mature strobili of a horsetail (Equisetum arvense). A cross section through a horsetail strobilus, showing spores with elaters.
Hornwort spores are relatively large for bryophytes, measuring between 30 and 80 μm in diameter or more. The spores are polar, usually with a distinctive Y-shaped tri-radiate ridge on the proximal surface, and with a distal surface ornamented with bumps or spines.