Limits...
Determining the fibrillar orientation of bast fibres with polarized light microscopy: the modified Herzog test (red plate test) explained.

Haugan E, Holst B - J Microsc (2013)

Bottom Line: The test has the reputation for never producing false results, but also for occasionally not working.However, so far, no proper justification has been provided in the literature that the 'no false results' assumption is really correct and it has also not been clear up till now, why the method sometimes does not work.We also provide an explanation for why the Herzog test sometimes does not work: According to our model, the Herzog test will not work if none of the three distinct layers in the secondary cell wall is significantly thicker than the others.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Technology, University of Bergen, Bergen, Norway.

Show MeSH
(A) The total retardation as a function of the sample orientation angle α for a sample with positive elongation. The expected observable colours are also shown, from the Michel–Levy birefringence chart (Fig. 5). Note the blue and yellow hues for α close to . (B) Wavefront ellipses of the compensator and sample, vertical line represents the analyser axis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4263192&req=5

fig06: (A) The total retardation as a function of the sample orientation angle α for a sample with positive elongation. The expected observable colours are also shown, from the Michel–Levy birefringence chart (Fig. 5). Note the blue and yellow hues for α close to . (B) Wavefront ellipses of the compensator and sample, vertical line represents the analyser axis.

Mentions: In the case where the slow axes of the specimen and compensator are not exactly parallel or perpendicular (i.e. for all other angles than and , partially subtractive or additive compensation occurs. This effect is shown in Figure 6 for the case of a specimen with a positive SE. Observe that when the sample is rotated a few degrees away from and , a blue or yellow shift is observed.


Determining the fibrillar orientation of bast fibres with polarized light microscopy: the modified Herzog test (red plate test) explained.

Haugan E, Holst B - J Microsc (2013)

(A) The total retardation as a function of the sample orientation angle α for a sample with positive elongation. The expected observable colours are also shown, from the Michel–Levy birefringence chart (Fig. 5). Note the blue and yellow hues for α close to . (B) Wavefront ellipses of the compensator and sample, vertical line represents the analyser axis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263192&req=5

fig06: (A) The total retardation as a function of the sample orientation angle α for a sample with positive elongation. The expected observable colours are also shown, from the Michel–Levy birefringence chart (Fig. 5). Note the blue and yellow hues for α close to . (B) Wavefront ellipses of the compensator and sample, vertical line represents the analyser axis.
Mentions: In the case where the slow axes of the specimen and compensator are not exactly parallel or perpendicular (i.e. for all other angles than and , partially subtractive or additive compensation occurs. This effect is shown in Figure 6 for the case of a specimen with a positive SE. Observe that when the sample is rotated a few degrees away from and , a blue or yellow shift is observed.

Bottom Line: The test has the reputation for never producing false results, but also for occasionally not working.However, so far, no proper justification has been provided in the literature that the 'no false results' assumption is really correct and it has also not been clear up till now, why the method sometimes does not work.We also provide an explanation for why the Herzog test sometimes does not work: According to our model, the Herzog test will not work if none of the three distinct layers in the secondary cell wall is significantly thicker than the others.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Technology, University of Bergen, Bergen, Norway.

Show MeSH