Magnesium Hydride-Mediated Sustainable Hydrogen Supply Prolongs the Vase Life of Cut Carnation Flowers via Hydrogen Sulfide

Magnesium hydride (MgH(2)) is a promising solid-state hydrogen source with high storage capacity (7.6 wt%). Although it is recently established that MgH(2) has potential applications in medicine because it sustainably supplies hydrogen gas (H(2)), the biological functions of MgH(2) in plants have not been observed yet. Also, the slow reaction kinetics restricts its practical applications. In this report, MgH(2) (98% purity; 0.5–25 μm size) was firstly used as a hydrogen generation source for postharvest preservation of flowers. Compared with the direct hydrolysis of MgH(2) in water, the efficiency of hydrogen production from MgH(2) hydrolysis could be greatly improved when the citrate buffer solution is introduced. These results were further confirmed in the flower vase experiment by showing higher efficiency in increasing the production and the residence time of H(2) in solution, compared with hydrogen-rich water. Mimicking the response of hydrogen-rich water and sodium hydrosulfide (a hydrogen sulfide donor), subsequent experiments discovered that MgH(2)-citrate buffer solution not only stimulated hydrogen sulfide (H(2)S) synthesis but also significantly prolonged the vase life of cut carnation flowers. Meanwhile, redox homeostasis was reestablished, and the increased transcripts of representative senescence-associated genes, including DcbGal and DcGST1, were partly abolished. By contrast, the discussed responses were obviously blocked by the inhibition of endogenous H(2)S with hypotaurine, an H(2)S scavenger. These results clearly revealed that MgH(2)-supplying H(2) could prolong the vase life of cut carnation flowers via H(2)S signaling, and our results, therefore, open a new window for the possible application of hydrogen-releasing materials in agriculture.