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United States Department of Agriculture

Agricultural Research Service

Title: Microscopic Confirmation of Cotton Fiber Maturity Measurements

Author
item Goynes, Wilton

Submitted to: Microscopy Society of America Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 26, 2005
Publication Date: N/A

Interpretive Summary: Development of simple, accurate, economical methods for determining fiber maturity has been an ongoing quest because fiber properties such as strength, reactivity and processability depend on fiber secondary wall thickness or maturity. This work compares results of maturity measurements by nine processes currently being used or that are in development in order to determine which methods best characterize the sample maturity. To correlate with maturity measurements, the samples were evaluated by a differential dyeing procedure to visually show gross maturity differences, and cross sections of the dyed fibers were observed to relate differences found in the measured data. Maturity comparisons within each system were somewhat consistent, however, some systems failed to recognize extremely immature samples as well as others. Samples were dyed and sectioned both directly from the bale and after combing. Dyeing and microscopic observations indicated that differences between measured numerical maturity data could be due to 1) sampling, 2) choice of measuring bale or cleaned samples, 3) method of cleaning, or 4) consistent selection of area along length of fiber to be measured. The work is being continued using a broader set of samples with additional measured data.

Technical Abstract: Cotton fiber maturity values have been inconsistent among various methods of mass measurements. These measurements are difficult because cotton is a natural product and all harvested fibers do not reached maximum wall thickness simultaneously. No single method seems to provide definitive measurements. This work compares results of maturity measurements by nine processes currently being used or that are in development, in order to determine which methods best characterize the sample maturity. The samples were evaluated by a differential dyeing procedure to visually show gross maturity differences, and by cross sections of the dyed fibers using light microscopy to relate differences found in the measured data. Neps in all samples were examined using scanning electron microscopy. Two Fibermax varieties grown in three geographical areas were examined. Both bale samples and hand-combed samples were dyed and sectioned. Obvious differences in sample maturity became evident by dyeing, These differences were not obvious in all instrumental methods. One problem in comparing data from the various measuring systems is that they do not all report maturity in the same values. Maturity comparisons within each system were somewhat consistent, however, some systems failed to recognize extremely immature samples as well as other systems did. Dyeing and microscopic observations indicated that differences between measured values from different instruments could be due to 1) sampling, 2) choice of measuring bale or cleaned samples, 3) method of cleaning, or 4) consistent selection of area along length of fiber to be measured.

Last Modified: 9/10/2014
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