Arashiran Two flexible hyaline inner walls gw1 and gw2 can be seen in all spores IF scgobiculata separate when each spore is broken. A layer that thickens initially by formation of pale yellow to acaulospoar sublayers or laminae with ovoid concave depressions on the surface. Arbuscular mycorrhizal fungi in Hawaiian sand dunes: Note the last photo in the sequence below, in which the tip of a corn root is filled with many coiled hyphae. Layer 2 plastic, 0. Acaulospora scrobiculata Then proceed back to the spore wall.

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This orb is difficult to see except in older spores where contents have cleared with fusion of lipid globules in the spore lumen, mostly because it is wide enough to span most of the diameter of the spore and so edges of the orb are seen only with a limited range of spore orientations. Spain reports orbs of A. The photo above was provided courtesy of Joyce Spain from her publication. MYCORRHIZAE Arbuscules often stain lightly in trypan blue, but sometimes stain more darkly; intensity of staining appears to vary with many factors that have yet to be resolved possibly age of the mycorrhizae and of the host root.

Infection units are patchy because they often do not overlap and appear merged. Vesicles often form most abundantly near entry points and range from spherical to oblong to irregularly shaped. Note the last photo in the sequence below, in which the tip of a corn root is filled with many coiled hyphae. The fungus and host respond dynamically to structural and physiological changes in root regions, and this accounts for the wide range of morphological structure and pattern in the same root system.

Arbuscules in cortical cells of corn root All structures of mycorrhiza in corn NOTES Inner wall structure often is very difficult to define clearly for several reasons: 1 ornamentations on L2 of the spore wall cause considerable light-scattering which reduces the ability to resolve hyaline flexible walls within the spore and 2 L3 of the spore wall and iw1 can produce numerous folds that make it almost impossible to define inner wall structure clearly.

The trick is to focus first on the second germinal wall gw2 as a positional reference; its easy to start with because the wall consistently separates readily from the rest of the spore and has a beaded surface if examined at least within 30 days of mounting.

Then proceed back to the spore wall. If there are many folds, ignore that spore and move to another one. When it was not detected, the spores were classified as being a separate usually undefined species.

It should be remembered that the granules on L1 of gw2 are not permanently fixed in place unless spores have been stored for more than 60 days in formalin or some other preservative and can disperse upon crushing of the spore and disappear. They also appear to dissolve or lose refractivity in PVLG-based mountants after days varying with condition of spores and fungal species.



Spore wall composed of three layers swl Layer 2 laminate, yellowish white 3A2 to pale yellow 3A3 , 3. Layer 3 flexible, hyaline, 0. Germination wall 1 consists of two, flexible, hyaline layers gw1l1 and 2 , tightly adherent to each other in moderately crushed spores, but usually separating in vigorously crushed spores; each layer ca. Germination wall 2 contains two layers gw2l1 and 2.







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