Also found in: Wikipedia.
Related to appressorium: haustoria, tyloses


n. pl. ap·pres·so·ri·a (-sôr′ē-ə)
The flattened tip of a hypha in various species of parasitic fungi, from which a filament emerges that penetrates the host's tissues.

[New Latin appressōrium, from Latin appressus, past participle of apprimere, to press down; see appressed.]


n, pl -ria (-rɪə)
(Botany) botany a flattened hypha of a parasitic fungus that penetrates the host tissues
[from New Latin, from Latin appressus; see appressed]
References in periodicals archive ?
During germination, the spore produces specialized infectious structures called appressorium that infect aerial tissues.
Hyphae also can grow from one vessel member to another through perforated end walls as well as directly through secondary wall material by using an appressorium.
The proteins identified as exclusive to the conidia were involved in protective processes, appressorium formation, and the degradation of the host cuticle and exclusive proteins to mycelia were involved in biosynthetic and energy-generating metabolic processes, such as UTPglucose-1-phosphate uridylyltransferase and heatshock protein 70.
On the basis of above findings, it may be speculated that the directly penetrating spores through appressorium enables spore penetration and once the penetration occurs the spore firmly attached with the cuticle and cannot be removed by allogrooming.
The disease cycle begins with conidia contacting and adhering to the integument of the host (Figure 1), followed by germination, appressorium production (Figure 2a) or without appressorium formation (Figure 2b), penetration (Figure 3a,b), development in the hemocoel with the dimorphic (yeast-like forms) stage represented by the formation of short, thick and septated hyphal bodies, mostly with one or more septation (Figure 3a), to mycelial exteriorisation (Figure 4a,b) and as shown (Figure 6 a,b) on pupae mycelial exteriorisation and conidiogenesis on the carcass.
Effect of chemical substances associated with the surfaces of plant leaves on appressorium formation by Colletotrichum acutatum.
Some hyphae were also seen forming what appear to be an appressorium.
Occasionally a germ tube or immature appressorium is observed which suggests that f urther study is warranted.
This structure, called an appressorium, then produces the probes that penetrate the plant tissue.