Basidiospore

Basidiospores are generally characterized by an attachment peg (called a hilar appendage) on its surface. This is where the spore was attached to the basidium. The hilar appendage is quite prominent in some basidiospores, but less evident in others. An apical germ pore may also be present. The surface of the spore can be fairly smooth, or it can be ornamented. There are several factors that can influence the size of a basidiospore. One study found that among polypores, variations in spore size could be accounted for by nutritional modes, host trees, rot type and basidiocarp (fruiting body) size. Parasitic polypores produced larger spores than saprotrophic ones, and species that preferred deciduous trees generally produced larger spores than those colonizing conifers. Additionally, species with larger basidiocarps likewise produced larger spores. However, this correlation was only weakly found among agarics in another study. However, total basidiospore volume per basidium, is strongly correlated with basidium volume among all basidiomycetes. Shape Many basidiospores have an asymmetric shape due to their development on the basidium. Plages are quite variable between different basidiomycetes. Rather than simply a flat area above hilar appendix, some fungi have a dimple. This is called a suprahilar depression. These variations may happen because of structural differences in the gills or pores of different species, as they need different volumes of water, to disperse the spore. These characteristics can be useful in distinguishing between Lactarius species. == Development ==

Basidiospores develop from basidia, reproductive structures found on the gills, spines, tubes or surfaces (depending on species) of basidiomycetes. In smaller fungi, like basidiomycete yeasts, rusts or smuts, basidiospores are generated by single cells, or germinating spores. == Dispersal ==

Basidiospores can be dispersed actively (through a fungus's own mechanisms) or passively (through reliance on another organism or abiotic factor). Actively dispersed basidiospores are also called ballistospores. They are discharged through water being condensed near the base (basidium facing) part of the spore, called the apiculus. This droplet, called Buller's drop, grows and in rapid sequence, fuses with the meniscus of water around the top of the spore. This causes the centre of gravity to shift dramatically, causing the spore to break off of the sterigma. Basidiospores excrete sugars like glucose and fructose, as well as mannitol near their apiculus to create a focal point on its surface to condense water from the atmosphere. To overcome still air, some fungi create their own draft, by evaporating water which causes differences in air temperature beneath the hymenium. Basidiospores can be categorised by whether they have characteristics that optimise dispersal or survival. Memnospores tend to be large, spherical, thick-walled and require specific environmental stimuli to germinate, which optimizes survival. Xenospores, tend to be small, thin-walled, oblong and ornamented, which optimizes dispersal. == Germination ==

A large percent of basidiospores released by their parent do not make it to a suitable habitat and eventually die. == Ecology and environment ==

One cubic meter of air in temperate climates typically contains 1,000-10,000 fungal spores, a majority of which are basidiospores. == References ==