Resumption of water uptake by sorghum after water stress

Exposure of roots to dry soil may reduce their ability to absorb water when the soil is rewet. We sought to quantify the effects of the duration of exposure to dry soil and the availability of water in deeper soil layers on resumption of water uptake by roots of Sorghum bicolor (L.) Moench following rewetting of the soil. Plants were grown in a greenhouse in pots, half of which were fitted with a water-filled reservoir below the pot bottom. Soil was allowed to dry for either 26 or 39 d before rewetting. Reservoir roots were excised at rewatering to limit uptake to roots previously exposed to soil drying. Time courses of plant transpiration and leaf water potential prior to and after rewatering were measured [...]