Cerium oxide nanoparticles improve cotton salt tolerance by enabling better ability to maintain cytosolic K+/Na+ ratio.

PNC enhanced leaf K+ retention and Na+ exclusion, but not vacuolar Na+ sequestration to enable better maintained cytosolic K+/Na+ homeostasis and thus to improve cotton salt tolerance. Our results add more knowledge for better understanding the complexity of plant-nanoceria interaction in terms of nano-enabled plant stress tolerance.