Reactive oxygen species (ROS) modulate nitrogen signaling using temporal transcriptome analysis in foxtail millet.

Reactive oxygen species (ROS) is a chemically reactive chemical substance containing oxygen and a natural by-product of normal oxygen metabolism. Excessive ROS affect the growth process of crops, which will lead to the decrease of yield. Nitrogen, as a critical nutrient element in plants and plays a vital role in plant growth and crop production. Nitrate is the primary nitrogen source available to plants in agricultural soil and various natural environments. However, the molecular mechanism of ROS-nitrate crosstalk is still unclear. In this study, we used the foxtail millet (Setaria italica L.) as the material to figure it out. Here, we show that excessive NaCl inhibits nitrate-promoted plant growth and nitrogen use efficiency (NUE). NaCl induces ROS accumulation in roots, and ROS inhibits nitrate-induced gene expression in a short time. Surprisingly, low concentration ROS slight promotes and high concentration of ROS inhibits foxtail millet growth under long-term H2O2 treatment. These results may open a new perspective for further exploration of ROS-nitrate signaling pathway in plants.

Colorimetric Detection of Iodine Ion Based on Its Inhibition Effect on Peroxidase-Like Activity of Platinum Nanoparticles / 分析化学

As an important inorganic element, iodine not only plays an important role in human growth and metabolism, but also has an irreplaceable role in the chemical engineering, medicine, food and other fields.Thus the detection of iodine ion is of important significance.In this work, colorimetric recognition and sensing of iodine ion with high sensitivity was proposed based on target induced shielding of the peroxidase-like activity of bare platinum nanoparticles ( PtNPs ).This assay exhibited simplicity and cost-effectiveness.The recognition of iodine ion by bare PtNPs could be fulfilled in a few seconds and the assay could be accomplished within 10 min.The detection range for iodine ion was 20 nmol/L-5.0 μmol/L and the detection limit was 8 nmol/L ( S/N = 3 ).Furthermore, the new assay system did not require surface modification of nanoparticles, nor complex organic synthesis.This assay was successfully applied to detection of iodine concentration in real salt and water samples, exhibiting promising application prospects.