Photos of teosinte glume architecture1
-- Jane Dorweiler and John Doebley

In our recent paper on Teosinte glume architecture1 (tga1) (Dorweiler et al., Science 262:233-235, 1993), the reproduction of Figures 1, 3, 4 and 5 was not what we hoped because the printer reduced some figures more than desirable and printed others from polaroids sent for the reviewers rather than from the originals. These figures are reproduced here to more clearly show the effects of tga1 on ear and glume morphology.

Figure 1. Ear of pure teosinte (left) composed of eight cupulate-fruitcases and an ear of teosinte homozygous for the maize allele at tga1 (right). The rachids of teosinte (R) are fully developed, forming a deep invagination in which the kernels are housed. The glume (G) seals the opening of the invagination so that the kernel is completely hidden and protected. The rachids of teosinte with maize allele at tga1 are less developed, forming only a short, shallow invagination that does not fully encase the kernel. Scale in mm.

Figure 3. Scanning electron micrographs of single fruitcases of teosinte (A) and of teosinte homozygous for the maize allele at tga1 (B), both collected just prior to pollination. The maize allele makes the rachid (R) shorter and narrower, exposing more of the outer glume (G). In teosinte, the glume arches into the cupule, while the maize allele causes the glume to be oriented directly upward at this stage. Bar represents 0.5 mm.

Figure 4. Scanning electron micrographs of the surface of the outer glume of the ear of teosinte (A, B, C) and of teosinte homozygous for the maize allele at tga1 (D, E, F). Glume surfaces just prior to pollination (A, D), and approximately two (B, E) and five (C, F) weeks post-pollination are shown. In teosinte, the short cells (c) are arranged in distinct rows (A) and the glume epidermis forms a smooth regular surface as it matures (B, C). The maize allele at tga1 appears to alter both the arrangement of short cells and the formation of a smooth regular surface at maturity (F). Stomata (s) are visible before pollination in teosinte but are obscured as the glume matures (B, C). With the maize allele at tga1, the stomata remain visible even in the mature glume (F). Bar represents 50 microns.

Figure 5. Mature ears (without kernels) of maize line W22 homozygous for the maize (A, C) and teosinte alleles (B, D) at tga1. With the maize allele (A), the relatively small outer glumes are not visible, being obscured by the red pigmented bracts (paleas and lemmas). With the teosinte allele (B), the paleas and lemmas are obscured by the enlarged, unpigmented outer glumes. Longitudinal cross-sections show that W22 with the maize allele at tga1 has outer glumes (G) that are thin and perpendicular to the axis of the ear (C), while those of W22 with the teosinte allele at tga1 are thicker and curved upward (D). The black bar in B represents 1 cm and applies to both A and B; the black bar in D represents 5 mm and applies to both C and D


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