Physiological Functions of Nitric Oxide in Sedum Alfredii Hance under Complex Heavy Metals Stress

Heavy metals contamination is a major environmental issue, and phytoremediation is a promising, environmentally friendly alternative to conventional cleanup techniques for heavy metal contaminated sites. This paper is intended to explore the physiological functions of nitric oxide (NO) in the signaling pathways as well as defense responses in Sedum Alfredii Hance, a new zinc (Zn) promising hyperaccumulating plant species for the phytoremediation exposured to Cd/Zn/Pb complex contaminations. The induced NO and free radicals (O₂ ^ldr, H₂O₂, ldrOH and malondialdehyde) were quantitatively determined and the functions of NO, reactive oxygen species (ROS) and sacylic acid (SA) in the regulation of the redox signaling against oxidative stress were also discussed. The hypothetical mode of NO effecting plant defense responses was proposed. The results indicated that NO as the versatile and powerful effector of redox-regulated signaling, can acts synergistically with ROS to defend the plant against oxidative attack caused by Cd/Zn/Pb complex contaminations by activating elaborate defenses.