Effect of mycorrhizal colonisation on drought stress effects and phosphorus uptake from dry soil in two cowpea cultivars and Sorghum bicolor

Abstract

To investigate the influence of mycorrhizal colonisation on drought-stress effects, two cultivars of Vigna unguiculata (cowpea) were cultivated either with or without mycorrhizal infection. Drought stress was induced by lowering soil water content. After a drought stress period of approximately three weeks, drought stressed plants were harvested or rewatered and maintained under optimal water supply for three more weeks. Control plants were well supplied with water at all time. In an additional experiment, the ability of mycorrhizal roots and hyphae to supply plants with phosphorus from dry soil was investigated in a split-root experiment. In the first experiment showed, that mycorrhizal infection did not affect plant water uptake from dry soil. However mycorrhizal infection enhanced the ability of plants to recover from drought stress, probably mediated by a better phosphorus (P) nutrition. The P uptake from dry soil was distinctively enhanced in mycorrhizal roots compared to nonmycorrhizal roots in the split-root experiment.