Abstract
brittle culms (bcs) are mutants of grasses such as rice, barley and maize whose plant bodies are easily broken and expected to have defects in the cell wall formation. The brittle phenotype of rice bc5 mutant exclusively appears in the developed nodes. In the present study, cell walls of bc5 nodes were analyzed. Decreased accumulation of lignin in the sclerenchyma tissues was observed in bc5 nodes stained with Safranin O and phloroglucinol-HCl. Amounts of cellulose and hemicellulose were reduced 47% and 35%, respectively, compared with those in the wild-type plants. The sugar composition and linkage analyses of the hemicellulose indicated that the accumulation of glucuronosylarabinoxylan is perturbed in bc5 nodes. These results indicate that BC5 regulates the accumulation of cellulose, glucuronosylarabinoxylan and lignin thereby affecting the deposition of secondary cell wall in sclerenchyma tissue of nodes.
