Abstract
The light irradiation strongly inhibits growth of mesocotyl in dark-grown maize seedlings. We previously reported that white-light illumination caused a decrease in the contents of water and reduced form glutathione (GSH) in maize mesocotyls, suggesting their possible roles in the growth inhibition by light. In the present study, we examined effects of humidity and the GSH synthesis inhibitor BSO on the growth and GSH levels in maize mesocotyls. Under high humidity conditions in closed chambers, BSO (200 μM) caused a 25-33% growth inhibition and 37-45% decrease in GSH levels in 4-day-old mesocotyls. However, under these conditions, light caused very little growth inhibition in the presence or absence of BSO. These results suggested that water rather than GSH contents has a critical role in the growth inhibition of mesocotyls by light. GSH level might be changed as a result of water loss or concomitant cell damage by light.
