SOUTH AFRICAN JOURNAL OF BOTANY, vol.75, no.1, pp.34-42, 2009 (SCI-Expanded)
Water shortages and soil water losses due to environmental change and land use change are challenges to maize production. An experiment was conducted to investigate the physiological responses of the maize (Zea mays L.) cultivars Doge, Vero and Luce to drought conditions. Drought stress was imposed on the plants 12 days after sowing by withholding irrigation for 12 days and then rewatering for 6 days. Growth of all cultivars was retarded under drought stress conditions and regained speed during the recovery stage. RWC decreased in all cultivars by drought and reached the control values during the recovery period. Fresh and dry biomass of the cultivars significantly decreased in all cultivars. Drought affected the minimum fluorescence (F-o) of all cultivars, but a significant effect was only found in Doge. Drought also caused decreases in F-M, F-V/F-M, F-V'/F-M', phi(PSII) and q(L); and an increase of non-photochemical quenching (NPQ), but those returned to control values during the recovery stage in all three cultivars. Chlorophyll (chl) a, chl b, total chl (a+b) and carotenoid contents of all maize cultivars were significantly reduced under drought, but a recovery was observed following rewatering. Anthocyanin and proline contents increased in all cultivars. Although Doge was affected from drought more than the other cultivars, it could probably withstand drought with better upregulating its protective mechanisms. As a result of that Doge was classified as less drought tolerant, but others as tolerant. (C) 2008 SAAB. Published by Elsevier B.V. All rights reserved.