Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Morphological and physiological response of sorghum (Sorghum bicolor L. Moench) to different pattern of drought

Auteur : Alhassan Lansah Abdulai

Université de soutenance : Universitat zu Bonn

Grade : Master of Science 2005

Résumé
Drought is a major stress affecting rainfed sorghum production systems. An experiment was setup in a green house to evaluate the morphological and physiological responses of sorghum to different drought patterns. Two - week old seedlings of “ICSV 111 IN” were transplanted into 9 L pots filled with loamy sand (11.3 kg) or si lt loam (10.8 kg) and grown for one month. Pots were subjected either to constant drought (70% of field capacity (CD)) or to progressive drought (slow drying - out close to permanent wilting point (PD)). Growths, biomass accumulation, assimilate partitioni ng , xylem ABA content , gas exchange, and plant water relations were determined. Drought effects were more pronounced on loamy sand than on silt loam. Soil moisture content, rather than soil water potential triggered drought responses. Constant drought and Progressive drought conditions reduced growth and biomass accumulation, as well as all the gas exchange components, in both loamy sand and silt loam. Assimilate partitioning did not change under constant drought conditions , but was shifted in favor of roots under progressive drought conditions . Xylem ABA content increased (more pronounced on loamy sand than silt loam) under progressive drought conditions, but was not affected by constant drought conditions. The genotype adjusted and adapted to constant drought conditions but employed survival mechanisms under progressive drought conditions .

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