Differential Responses of Electrolyte Leakage and Pigment Compositions in Maize and Sorghum After Exposure to and Recovery from Pre-and Post-Flowering Dehydration

Drought stress is often the most limiting factor to maize and sorghum production in the semi-arid areas.This study evaluates the response of electrolyte leakage,chlorophyll,carotenoid and anthocyanin contents in maize(cv.Melkassa-2 and sorghum cv.Macia)after exposure to and recovery from pre-and post-flowering dehydration in plants grown in a controlled environment growth chamber under constant environmental conditions(12/12 h day/night,28-32/17℃ day/night temperature,60-80%RH and PPFD of 1200-1400μmol m-2 s-1),at the Department of Botany,University of Cape Town,South Africa.It was revealed that dehydration induced increases in electrolyte leakage was observed in both species during both pre-and post-flowering stages.Electrolyte leakage was however,higher during post-than pre-flowering dehydration in both species.Dehydration during both pre-and post-flowering stages caused a decrease in chlorophyll and carotenoid contents in both maize and sorghum.Chlorophyll and carotenoid contents of both pre-and post-flowering dehydrated sorghum was markedly higher than that of maize throughout the duration of the dehydration period.As opposed to chlorophyll and carotenoid contents,anthocyanin contents increased during pre-and post-flowering dehydration in both species.Differences were however,observed between both species in the response of anthocyanin content to pre-and post-flowering dehydration.Full recovery of chlorophyll,carotenoid and anthocyanin contents were observed in those plants rehydrated during pre-flowering stages.There was however,no recovery in both species during post-flowering rehydration.This study should help understand some adaptive mechanisms developed by maize and sorghum during the dehydration and rehydration periods and contribute to identify useful traits for breeding programs.