Abstract
Silicon (Si) is a beneficial element for plant. Several benefits of Si have been reported, such as enhancement of pest and pathogen resistance, drought and heavy metal tolerance, and improvement of agricultural crop quality and yield, in a wide variety of plant species. Plant species differ greatly in silicon accumulation, ranging from 0.1% to 10% in shoot dry weight. Rice (Oryza sativa) is a typical Si-accumulating plant and is able to accumulate Si to >10% of the shoot dry weight. In the shoot, it is known that Si exists as a polymerized form in motor cells or beneath the cuticle layer. On the other hand, it is suggested that there are silicon-containing high molecular weight compounds in cell wall. Therefore, our objective is to investigate the relationship between Si and cell wall matrix, especially its sugar composition. Sugar composition of cell wall fractions isolated from rice grown in hydroponics with or without 1.5 mM silicic acid were analyzed by gas-liquid chromatography. As a result, in the pectic fraction, amounts of some sugars were different between two Si conditions. Based on these results, the interaction between Si and cell wall matrix will be discussed.
