Soil salinity is a major abiotic stress that limits plant growth and agriculture productivity.To cope with salt stress,plants have evolved complex salt-responsive signaling and metabolic processes at the cellular,organ,and whole-plant levels.Halophytes are known for their ability to adapt to living in salinity environments by undergoing a series of adaptive changes.These plants provide viable organisms for studying the mechanisms of how plants respond and acclimate to high salt concentrations.Suaeda are typical euhalophytes,which are important halophyte resources and widely distributed throughout the world.More than twenty species of Suaeda have been reported for their ability to survive high salt conditions.Several different organs(seed,root,stem,leaf and aerial part) were used to examine the physiological and biochemical responses of halophyte Suaeda to NaCl stress.Previous studies have provided invaluable information toward understanding the complex salt-tolerance mechanisms in plants,which include leaf succulence,ion compartmentalization,osmotic modulation and antioxidant activity.The deleterious effects of salt stress are commonly thought to result from low water potential and ion toxicity.Therefore,plant survival under salt stress depends on its ability to cope with water stress and ion toxicity.Although much effort has been invested on the salt tolerance mechanisms in Suaeda,the understanding of the underlying mechanisms is far from complete.Previous studies have focused on the aerial part and overlooked the underground part of the plants.The studies have focused on evaluating a part of biological indicator or physiological changes without comprehensive analysis of physiological processes under salt stress.Most of the studies have focused on the neutral salt effect on Suaeda,only a few attempts have been undertaken to study the effect of alkaline conditions.It has become necessary to carry out further research for a better understanding of the complex molecular interactions in plants,which are complementary to the traditional physiological studies that are limited in the number of biological indicators or phenotypes.Future research needs to focus on questions related to regulation and control of the signaling and metabolic networks underlying the response to salt stress in Suaeda.In the initial stages of salt stress,the change of environmental conditions is sensed by the plant and activates a network of signaling pathways.In later phases,the signal transduction pathways activated in the first phase trigger the changes of different proteins and compounds to allow a new state of homeostasis.Systems biology research will open new avenues for further studies on the mechanisms of salt tolerance in plants because it enables us to recognize the networks of signal transduction pathways,metabolite profiles and unique metabolic pathways responding to stress conditions.Systems biology approaches allow not only to analyze the topology of the biochemical and signaling networks involved in the stress responses,but also to capture the dynamics of the responses.The power of the systems biology approaches is the ability to determine the responses at a number of different levels,including transcripts,proteins or metabolites.Combination of transcriptomics,proteomics and metabolomics will provide us with a holistic view of how plants respond to abiotic and biotic stress and enable us to develop advanced strategies to enhance the tolerance of different plants and crops to the stress conditions.