Protein Body Size and Distribution and Protein Matrix Morphology in Various Endosperm Mutants of Zea mays L.
- P. S. Baenziger and
- D. V. Glover
Maize (Zea mays, L.) protein body size and distribution and matrix morphology were studied to determine their relationship with endosperm lysine content and kernel density and vitreousness. Thirteen near-isogenic (Bc 6) endosperm mutant genotypes, their double mutants with opaque-2, and the normal Oh43 inbred were studied. Two endosperm mutants, sugary-2 (su2) and waxy (wx), and their double mutant with o2 each near-isogenlc (Bc 6) inbreds B37, C103, and W64A and their normal and opaque-2 counterparts were also studied. Mature kernels of these genotypes were thin sectioned, destarched, and studied using interference-contrast light microscopy.
Protein bodies were observed and measured in amylose. extender (ae), dull (du), floury-1 (fl1), soft starch (h), su2 and wx endosperm of Oh43 and in the normal counterpart. Protein body size was significantly different among genotypes and decreased going into the center of the kernel from the aleurone layer.
No protein bodies were visible in o2, floury-2 (fl2), sugary-1 (su1), shrunken-1 (shl) , shrunken-2 (sh2), brittle-1 (btl), and brittle-2 (bt2). The endosperm mutants with high lysine levels had no visible protein bodies while the mutants with intermediate lysine levels had fewer and generally smaller protein bodies than did the mutants with the lower lysine levels.
Opaque.2 and the double mutants with o2 did not have visible protein bodies and the matrix was generally thinner than in the single mutants. Sugary-2 opaque.2 had a thicker, more extensive matrix than observed in o2 endosperm.
Protein bodies were visible in the su2 and wx isogenic conversions of Oh43, B37, C103, and W64A and their normal counterparts. Differences among inbreds, genotypes, and the interaction of inbred Χ genotypes were highly significant. No protein bodies were visible in o2 and the double mutants with o2. The data suggest that protein matrix may be involved in the expression of kernel density and vitreousness. The matrix of vitreous su2o2 kernels resembled the matrix of vitreous sue kernels and not that of o2 kernels.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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