Protein and Carbohydrate Accumulation in Normal and High-Lysine Barley in Spike Culture

Spikes of barley cv. Bomi and high-lysine mutants Riso 1508 and Riso 56 were cultured on liquid media at varying N and sucrose levels. Bomi accumulated N in response to increasing N levels in the medium and a higher level was reached than in spikes of intact plants. The distribution of N in salt-soluble, hordein, and non-protein N fractions appeared to be normal. Endosperm dry weight and starch were lower than in intact plants and declined at higher N levels. A linear relationship was observed between starch content and the concentration of sucrose in the endosperm water. Uptake of culture medium by the spikes was affected by both N and sucrose concentration. The mutants had lower dry weights and starch contents, and higher sucrose contents than Bomi. At high N levels, the mutants accumulated less hordein, and more non-protein N than Bomi.