Grain development in normal and high lysine barley

During the period from pollination to day 33, seeds from the Risø high lysine mutants No. 56,86 and 1508 and their respective mother lines were compared by means of light and electron microscopy as well as SDS‐polyacrylamid gel electrophoresis. All mutants had a lower dry matter content per cell owing to reduced seed growth rates. The number of endosperm cells was the same in all lines. In the mother lines cell size doubled between day 15 and 33, whereas in Mutants 56 and 1508 cell growth stopped after 21 days. In Mutant 86 the growth was more similar to the mother line. A reduced starch deposition could account for the smaller grains of the mutants. In Mutant 56 and Mutant 1508, the reduced starch deposition was partly due to a reduction in the size of the large starch granules, as well as an almost complete lack of small starch granules. In Mutant 86, fewer large starch granules were found. Mutant 56 had a reduced amount of B‐hordeins, whereas, in Mutant 1508, B‐ and C‐hordeins were almost absent. In Mutant 86 a delayed onset of the hordein synthesis was revealed. There was a correlation between the amount of hordein present and the content of protein bodies per cell. The altered protein body morphology in the mutants could be explained by assuming the presence of prolamin in two of the protein body components described.