Abstract
BackgroundSalinity is a worldwide factor limiting the agricultural production. Cotton is an important cash crop; however, its yield and product quality are negatively affected by salinity. Using nanomaterials such as cerium oxide nanoparticles (nanoceria) to improve plant tolerance to stresses, e.g. salinity, is an emerged approach in agricultural production. Nevertheless, to date, our knowledge about the role of nanoceria in cotton salt response and the behind mechanisms is still rare. ResultsWe found that PNC (poly acrylic acid coated nanoceria) helped to improve cotton plant tolerance to salinity, showing the better phenotypic performance, the higher chlorophyll content and biomass, and the better photosynthetic performance in PNC treated cotton plants than the control group. Under salinity stress, in consistent to the results of the enhanced antioxidant enzyme activities, PNC treated cotton plants showed significant lower MDA content and ROS level than the control group, both in the first and second true leaf. Further experiments showed that under salinity stress, PNC treated cotton plants had significant higher cytosolic K+ and lower cytosolic Na+ fluorescent intensity in both the first and second true leaf than the control group. This is further confirmed by the leaf ion content analysis, showed that PNC treated cotton plants maintained significant higher leaf K+ and lower leaf Na+ content, and thus the higher K+/Na+ ratio than the control plants under salinity. Whereas no significant increase of vacuolar Na+ intensity was observed in PNC treated plants than the control under salinity, suggesting that PNC enhanced leaf K+ retention and leaf Na+ exclusion, but not leaf vacuolar Na+ sequestration are the main mechanisms behind the PNC improved cotton salt tolerance. qPCR results showed that under salinity stress, the modulation of HKT1 but not SOS1 refers more to the PNC improved cotton leaf Na+ exclusion than the control. ConclusionsNanoceria enhanced leaf K+ retention and Na+ exclusion, but not vacuolar Na+ sequestration are the main mechanisms behind the nanoceria improved 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.
In Vitro and In Vivo Antioxidant Activity of the New Magnetic-Cerium Oxide Nanoconjugates
