Abstract
Our previous work suggests that leaf gibberellin (GA) is required for tissue-reunion of cortex in the cucumber and tomato cut hypocotyls, but molecular mechanisms are still unclear. In this study, morphological and gene expression analyses during tissue-reunion were performed using the Arabidopsis cut flowering stem. The lowest internode of stem was cut transversely and reunion process was analyzed. Cell division was initially observed in 3 days and tissue-reunion almost completed in14 days. In contrast to the case of cucumber, normal reunion was observed in ga3ox1/ga3ox2 or Paclobutrazol treated-plants. The microarray analysis during reunion process was performed. A number of genes involved in cell division, cell wall-modification, phyohormone-synthesis and signal transduction were determined to be up-regulated. The ACC synthase gene was significantly up-regulated at 1 day and ethylene signaling-deficient mutant showed lower efficiency in the tissue-reunion. The gene expression analysis of XTH showed that cell wall-modification occurred during reunion process.
