Simulated drought with Polyethylene-Glycol (PEG) decreases above-ground performance and increases nodulation in the legume Medicago lupulina

We investigated drought growth responses in <i>Medicago lupulina</i> using PEG to simulate drought stress. We grew <i>Medicago lupulina</i> plants inoculated with <i>Sinorhizobium meliloti</i> in Magenta boxes under randomly assigned treatments: a control, PEG applied to the bottom (PEG added to the bottom-watering container), or PEG applied from the top (PEG poured over the growth media). PEG treatments significantly reduced above-ground growth but unexpectedly increased nodulation. Our results suggest that while PEG effectively simulates drought stress on above-ground growth parameters, it may not accurately simulate drought effects on rhizobial symbiosis.