Cadmium (Cd) is a non-redox heavy metal which is difficult to degradation, therefore Cd is one of the major environmental pollutants, resulting in serious toxic problems to all living organisms including human and various plant species. To alleviate Cd-caused health problems in humans, exploring the Cd-induced toxicity in plants is very important, including antioxidative response, Cd transport and uptake, lipid peroxation, photosynthesis, the metabolism of nitrogen (N) and sulfur (S). 

Nitric oxide (NO) and hydrogen sulfide (H₂S) are important gaseous molecules, serving as important secondary messengers in plant response to various biotic and abiotic stresses. However, the interaction between NO and H₂S in plant stress response was largely unclear. 

Dr. SHI Haitao, under the supervision of Prof. CHAN Zhulong from Wuhan Botanical Garden, examined changes of endogenous NO and H₂S after cadmium treatment in bermudagrass, and the effects of exogenous applications of NO donors (SNP and GSNO), and investigated a donor of H₂S (sodium hydrosulfide, NaHS) and a sulphur-containing compound (sodium sulfide, Na₂S) to dissect the in vivo roles of NO and H₂S in response to cadmium stress, including plant growth, cell damage and reactive oxygen species (ROS) accumulation.  

Moreover, combined treatments of donors, inhibitors and scavengers of NO and H₂S under cadmium stress conditions were performed to assign the interaction of NO and H₂S in bermudagrass response to cadmium stress. Interestingly, combined treatments with inhibitors and scavengers of NO and H₂S under cadmium stress condition showed that NO signal could be blocked by both NO and H₂S inhibitors and scavengers, while H₂S signal was specifically blocked by H₂S inhibitors and scavengers, indicating that NO-activated H₂S was essential for cadmium stress response. These results provided the basic mechanisms and the overall effects of NO and H₂S that modulating Cd stress response in bermudagrass. Taken together, they assigned the protective roles of endogenous and exogenous NO and H₂S in bermudagrass response to cadmium stress, and speculated that NO-activated H₂S might be essential for cadmium stress response in bermudagrass. 

Relevant results have been published in Plant Physiology and Biochemistry (doi: 10.1016/j.plaphy.2013.11.001) entitled “Nitric oxide-activated hydrogen sulfide is essential for cadmium stress response in bermudagrass (Cynodon dactylon (L). Pers.)”.