A Review on Plant Responses to Salt Stress and Their Mechanisms of Salt Resistance

Abstract

Nowadays, crop insufficiency resulting from soil salinization is threatening the world. On the basis that soil salinization has become a worldwide problem, studying the mechanisms of plant salt tolerance is of great theoretical and practical significance to improve crop yield, to cultivate new salt-tolerant varieties, and to make full use of saline land. Based on previous studies, this paper reviews the damage of salt stress to plants, including suppression of photosynthesis, disturbance of ion homeostasis, and membrane peroxidation. We have also summarized the physiological mechanisms of salt tolerance, including reactive oxygen species (ROS) scavenging and osmotic adjustment. Four main stress-related signaling pathways, salt overly sensitive (SOS) pathway, calcium-dependent protein kinase (CDPK) pathway, mitogen-activated protein kinase (MAPKs) pathway, and abscisic acid (ABA) pathway, are included. We have also enumerated some salt stress-responsive genes that correspond to physiological mechanisms. In the end, we have outlined the present approaches and techniques to improve salt tolerance of plants. All in all, we reviewed those aspects above, in the hope of providing valuable background knowledge for the future cultivation of agricultural and forestry plants.

Spermidine Modify Antioxidant Activity in Cucumber Exposed to Salinity Stress

“…The negative and statistically significant correlation confirmed the hypothesis that polyamine spermidine was at least partially able to alleviate the deleterious effect of NaCl stress in cucumber leaves. This result is consistent with the findings of studies on Bermuda grass [47], calendula [48], rice [46], tomato [56], pepper seedlings [57], and cucumber roots [40,43]. The effect of exogenous Spd was more pronounced in the salinity-sensitive cucumber variety than in the salinity-tolerant cucumber roots [43].…”

“…Soil salinity has become one of the most important environmental issues of the 21st century. Salinity impairs plants' growth and development, causing water stress and an excessive uptake of ions such as sodium, chloride, and nutritional imbalance [11,40]. Salt stress has been widely reported to induce PA accumulation [23,26,41].…”

Soil Salinity, a Serious Environmental Issue and Plant Responses: A Metabolomics Perspective

“…However, a significant gap exists in metabolomics research concerning the spatial resolution of the in vivo state of metabolites due to the dynamic nature of the metabolic networks involved [165,167]. This systems biology approach was used in the exploration of salinity tolerance adaptive mechanisms in the legume Medicago truncatula, where transcriptional analysis identified the expression of many genes related to stress signalling, and metabolite profiling was employed to explore the different genotype-related responses to stress at the molecular level [168][169][170][171][172][173][174][175]. This global approach contributes to gaining significant insights into the complexity of stress-adaptive mechanisms, as well as aid in the identification of potential targets for crop improvement.…”

Comparative Transcriptome Profiling Provides Insights into Plant Salt Tolerance in Watermelon (Citrullus lanatus)

“…Excessive accumulation of Na + and Cl − is the main cause of salt damage, resulting in a lack of Ca 2+ and K + and other important ions. The content of Na + in plants increased with the increase of Na + concentration in soil [ 6 ]. Under the action of a chemical gradient, the decrease of membrane potential caused by high concentration of Na + can promote the absorption of Cl − .…”