Abstract
Redox status in apoplast appears to affect cell wall metabolism and hence cell growth in plants. To examine this possibility, we examined effects of two antioxidants, ascorbic acid (AsA) and glutathione (GSH) on cell elongation in epicotyl segments of azuki bean under light and/or dark conditions. We found that neither AsA nor GSH stimulated cell elongation in darkness. However GSH strongly stimulated it under the light unlike AsA. GSH mimicked auxin effects because it alone stimulated cell elongation with no IAA application. Externally applied GSH increased the intercellular level of GSH in the segments. However, BSO, the specific inhibitor of GSH synthesis, did not inhibit cell elongation of epicotyl segments. These results suggested that GSH might stimulate cell elongation of stem segments by changing redox status in apoplast or by modifying some process linking to the transport of GSH to symplast.
