Microscopy of the Pericarp and the Testa of Different Genotypes of Sorghum1
- Mary E. Blakely,
- L. W. Rooney,
- R. D. Sullins and
- F. R. Miller2
Scanning electron and light microscopy were used to determine the location and structure of the pigment containing tissues in kernels of six sorghum [Sorghum bicolor (L.) Moench] genotypes. The genotypes included kernels with white pericarp with and without a testa, red pericarp with and without a testa, and a brown pericarp (genetically red) with a testa and dominant spreader (S-) gene. The sixth sorghum genotype had a partial testa. The polyphenollc pigments were located m the epicarp and endocarp of sorghums with a red pericarp (R-Y-). Sorghums with dominant B1-B2- genes had a pigmented testa.
The testa did not always appear as a noncellular band. The testa was often composed of two overlapping layers, which were usually different colors. In some kernels, the testa appeared as blocky subunlts, while in other kernels the testa was a single, structuxeless layer. Thickness of the testa was measured around the kernel at eight locations. The thickest region of the testa occurred directly under the style and the thinnest areas on the sides of the kernel. We found no differences in thickness among the different genotypes with a testa. Greater differences in testa thickness appeared within a given kernel than between kernels of the different sorghum genotypes with B1-B2- genes. Kernels with a dominant S- and B1-B2- had brown pigments in the epicarp and endocarp.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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