Phosphorus uptake from soil by Lolium perenne during and after severe drought.
Mature Lolium perenne plants grown in pots of P deficient soil were subjected to gradually increasing drought, and uptake of P was determined during and after the drought. Relatively mild drought (soil matric potentials -0.6 to -0.8 MPa) stopped P uptake, probably because P in the drying soil became unavailable. After drought, the rates of uptake of P and of applied 32P from rewetted soil were reduced, although some recovery in rate of P uptake occurred 2 and 3 weeks after rewetting. Reduction in 32P uptake following drought was approx. the same whether the plants were mycorrhizal or not. Control of the reduced uptake was located in the root.