Morphotypes plAc ("Acaulospora")
distribution in root cortex
usually spread in several layers, vesicles in the outer one, arbuscules in the deeper cell layer (at least for the first subtype, see below)
auxiliary cells
absent
hyphae at entry point
S-like arrangement of hyphae near entry point, vesicles often present there
intraradical hyphae
sometimes poorly staining, so difficult to observe in roots with high AM infection
arbuscules
at least for one of the subtypes have the "brick-like" appearance, often faintly stained
vesicles
rare, formed primarily near the entry point
There are probably at least three subtypes involved:

The first subtype is the classical, badly staining type where mostly only the entry point hyphae and adjacent irregularly shaped (intracellular) vesicles are visible. Rarely, the arbuscules are seen, but badly stained, usually placed in a deeper layer of cortical cells.

The images are improved using the image-processing software, the original contrast of hyphae and vesicles was even smaller.


 

 
The second "Acaulospora" subtype seems to be quite similar to the previous, but stains well, usually "too well". While I feel this type is distinct from the plG3 ("T7") type, the exact divide line is very difficult to draw between these two.

A vesicle detail:

 
The last "Acaulospora" subtype is represented mainly by the "brick-like" arbuscules, completely filling the cells. Sometimes the parallel, longitudinally running hyphae are seen, but hardly any complex hyphal structures or vesicles.

 

 

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This page last modified by Petr Šmilauer on 14 September 2000