Abstract
Stems of higher plants offer support to the aerial portion of the plant body and serve as conduits for the translocation of nutrients and water. Using gene-specific oligonucleotide microarray system, we identified a set of genes that play important roles in specific aspects of cell wall construction in basal of the inflorescence stem of Arabidopsis. Some of the genes are involved in cellulose deposition or lignification in secondary cell wall. The expression of these genes sharply decreased when the inflorescence stem are placed horizontally. The results suggest that the weight carried by the upper part of the stem may be a signal for the induction of cell wall rigidification in basal of the stem. We have also examined expression profiles of promoter::GUS fusion constructs for each of the genes expressed highly in basal of the stem. The roles of the genes in contributing to the wall rigidification is discussed.
