Molecular Hydrogen Increases Quantitative and Qualitative Traits of Rice Grain in Field Trials.

How to use environmentally friendly technology to enhance rice field and grain quality is a challenge for the scientific community. Here, we showed that the application of molecular hydrogen in the form of hydrogen nanobubble water could increase the length, width, and thickness of brown/rough rice and white rice, as well as 1000-grain weight, compared to the irrigation with ditch water. The above results were well matched with the transcriptional profiles of representative genes related to high yield, including up-regulation of () for cellular proliferation, () for grain width, () for grain length and width, () for grain width and weight, and down-regulation of negatively correlated gene () for grain length. Meanwhile, although total starch content in white rice is not altered by HNW, the content of amylose was decreased by 31.6%, which was parallel to the changes in the transcripts of the amylose metabolism genes. In particular, cadmium accumulation in white rice was significantly reduced, reaching 52% of the control group. This phenomenon was correlated well with the differential expression of transporter genes responsible for Cd entering plants, including down-regulated (), ( and ), and (), and for decreasing Cd accumulation in grain, including down-regulated (). This study clearly showed that the application of molecular hydrogen might be used as an effective approach to increase field and grain quality of rice.