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Melatonin (MT) is a growth regulator and antioxidant that can resist peroxidation damage on plants caused by environmental stresses. In this study, the alleviation effects of melatonin on alfalfa under salt stress were investigated in terms of photosynthesis, antioxidant enzymes, and osmoregulation. The alfalfa seedlings were cultured in 200 mM NaCl Hoagland solution. Five levels of MT (0, 0.1, 0.2, 0.3, and 0.4 mM) were applied as a foliar spray. Generally, the foliar spray of MT increased root length, root surface area, height, leaf length and width, aerial and root biomass, SPAD readings, the content of proline and soluble protein, and the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Malonaldehyde (MDA) content was decreased by MT foliar spray. The beneficial effects of MT on alfalfa under salt stress were dosage-dependent, and excessive MT levels inhibited alfalfa growth. The alleviating effects of MT on salt stress were more pronounced at 0.3 mM MT. This study suggested that exogenous MT foliar spray at appropriate levels can ameliorate the adverse effects of salt stress on alfalfa seedlings. [ABSTRACT FROM AUTHOR]

Sorghum ("Jitian 3") is a salt-tolerant seed cultivar used regularly in marginal lands, such as those with saline soils. Herein, we examined the potential of employing gibberellic acid (GA3) as an inducer of sorghum development during salt stress. Thus far, there have been no reports on the signaling network involved in the GA3-mediated regulation of sorghum development. In this study, we demonstrated that the stimulating properties of 50 mg/L GA3 on sorghum development was far superior to other GA3 concentrations under a 150 mM NaCl salinity condition. Furthermore, using methylated RNA immunoprecipitation sequencing (MeRIP-seq), we established an m6A methylation (m6A-M) profile in sorghum following exposure to 50 mg/L GA3. Overall, 23,363 m6A peaks and 16,200 m6A genes were screened among the GA3-treated and control leaves. These identified peaks were shown to be primarily enriched in the coding, as were the 3′- and 5′-untranslated regions. In addition, we employed m6A and transcript expression cross-analysis to identify 70 genes with differential transcript expression and simultaneous m6A-M. Intriguingly, the principal gene, LOC8066282, which is associated with LOC8084853, was shown to be intricately linked to the phosphatidylinositol signaling, which in turn regulates sorghum development and response to salt stress. This investigation presents a novel RNA m6A-M profile in sorghum, which may facilitate new insights into the underlying signaling behind salt stress resistance. This work will also benefit future investigations on foreign GA3 administration of sorghum. [ABSTRACT FROM AUTHOR]

Salinity one of environmental factor that limits the growth and productivity of crops. This research was done to investigate whether GA3 (0, 144.3, 288.7 and 577.5 μM) and nitrogen fertilizer (0, 90 and 135 kg N ha−1) could mitigate the negative impacts of NaCl (0, 100, and 200 mM NaCl) on emergence percentage, seedling growth and some biochemical parameters. The results showed that high salinity level decreased emergence percentage, seedling growth, relative water content, chlorophyll content (SPAD reading), catalase (CAT) and peroxide (POD), but increased soluble protein content, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content. The SOD activity was decreased by nitrogen. However, the other measurements were increased by nitrogen. The interactive impact between nitrogen and salinity was significant in most parameters except EP, CAT and POD. The seedling length, dry weight, fresh weight, emergence percentage, POD, soluble protein and chlorophyll content were significantly affected by the interaction between GA3 and salinity. The GA3 and nitrogen application was successful mitigating the adverse effects of salinity. The level of 144.3 and 288.7 μm GA3 and the rate of 90 and 135 kg N ha−1 were most effective on many of the attributes studied. Our study suggested that GA3 and nitrogen could efficiently protect early seedlings growth from salinity damage. [ABSTRACT FROM AUTHOR]

Salinity limits germination and plant growth and development in 45 million ha worldwide. Techniques to overcome this problem are needed. This project investigated the effects of jasmonic acid (JA) (0, 5, and 10 mM JA) and humic acid (HA) (0, 3, and 6 g HA kg−1 soil) on growth and physiological parameters of forage sorghum (Sorghum bicolor L. Moench) under different NaCl salinity levels (0, 100, and 200 mM NaCl, with an equivalent electrical conductivity (EC) of 0.12 dSm−1 as control treatment, 3.22, and 5.78 dSm−1, respectively). NaCl salinity reduced emergence percentage, emergence rate, salt tolerance index and seedling vigor index, all seedling growth parameters, ascorbate peroxidase (APX) activity, chlorophyll a, b and total chlorophyll content. Proline content and soluble protein content were increased with salinity. At the 200 mM salinity level, seeds treated with 10 mM JA had a positive effect on emergence percentage, emergence rate, shoot length, total fresh weight, salt tolerance index, seedling vigor index, chlorophyll a and total chlorophyll content. At 200 mM NaCl salinity level, seeds treated with 6 g HA kg−1 soil had increased root length, total dry weight, salt tolerance index, seedling vigor index, shoot length, protein content, APX, chlorophyll b, and total chlorophyll in seedlings. The application of 5 mM JA combined with 6 g HA kg−1 soil was most effective in minimizing salinity stress. Our study suggested that the appropriate combined application of HA and JA could efficiently protect early seedlings from salt stress damage and alleviate abiotic stress. [ABSTRACT FROM AUTHOR]

Salinity is a growing problem worldwide, and techniques are needed to mitigate this problem. This study was conducted to determine if biochar (BC) can alleviate the adverse impacts of salinity stress on sorghum (Sorghum bicolor L.) seedling growth. Sorghum variety Kambal was sown in salinized soils at levels of 1.2, 3.1, and 7.3 dS m−1. The saline soils were treated with four BC rates of 0, 2, 4, and 8% (w/w). The test was a factorial design arranged as a completely randomized design with three replications. Seedling emergence percentage; root and shoot length; root and shoot dry weight; relative water content (RWC); and the activity of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) were affected by the interaction between salinity and BC. At the 7.3 dS m−1 salinity level, 2% BC increased seedling emergence percentage by 25.0% (P =.012). At the 7.3 dS m−1 salinity level, 4% BC level increased root and shoot length (P =.009) and RWC by 46.0, 28.0, and 19.8% respectively. At the 7.3 dS m−1 salinity level, 8% biochar decreased CAT by 50.6%. At the high salinity level, 4% BC decreased POD and SOD by 24.9 and 23.4%, respectively. Biochar amendment proved to be more useful to alleviate the effects of salinity on the seedling growth stage. These findings suggest that using BC in suitable amounts could mitigate the adverse effects of salinity, but excess BC application may have negative influences on seedling growth. [ABSTRACT FROM AUTHOR]

Salinity is a major abiotic stress limiting crop growth and reducing grain yield. In recent years, little progress was made in salt‐tolerant cultivation techniques. Therefore, a controlled experiment was conducted to study the effects of nitrogen management (NM) on growth, antioxidant ability, and yield performance of salt‐tolerant rice (Oryza sativa L.) under salinity stress. Three salinity levels (0‰ as control; 0.75‰, 4.3 dS m−1; and 1.5‰, 7.7 dS m−1) and four levels of NM (tillering fertilizer/panicle initiation fertilizer = 7:3, 6:4, 5:5, and 4:6) were arranged in this study. Under salinity stress, plant height, tiller number, fresh weight, grain yield, panicle, spikelets per panicle, grain weight, and soluble sugar content in stem were significantly decreased. In contrast, antioxidant parameters of superoxide dismutase, peroxidase, and catalase were significantly increased. Grain filling percentage and sucrose content were slightly changed. Compared to the control, grain yield was reduced by 45.6%, 34.8%, 60.4%, and 46.7% at the ratio of 7:3, 6:4, 5:5, and 4:6 NM at 0.75‰ salinity level, and 73.5%, 59.7%, 74.8%, and 61.7% at 1.5‰ salinity level, respectively. The highest yield was generated by 6:4 NM at both the 0.75‰ and 1.5‰ salinity level, and the lowest by 4:6 and 5:5. However, NM could obviously alleviate the inhibition effects of salinity stress and improve antioxidant ability of rice. Among them, 6:4 NM performed the best alleviation effects, followed by 7:3 and 5:5 NM. This study suggests that the appropriate NM can effectively alleviate salinity stress and increase grain yield. [ABSTRACT FROM AUTHOR]

• Salt stress adversely affected the photosynthesis and biochemical traits of forage sorghum. • Jasmonic acid and humic acid in regulating stress responses, plant growth and development. • Jasmonic acid and humic acid may be used as a tool to mitigate salinity-induced photosynthesis and biochemical parameters injury in forage sorghum Soil salinity, whether natural or induced, is one of the most serious environmental stresses limiting crop production in the world. In this study, the impacts of foliar application of jasmonic acid and soil amendment with humic acid on growth parameters, forage yield, chlorophyll content, and physiological characteristics of forage sorghum were studied to mitigate salinity in combination with different concentrations under greenhouse conditions. The plants were subjected to salinity at 0.26 (S0), 2.3 (S1), and 4.7 dS m−1 (S2), different rates of humic acid at 0, 373.21, and 746.42 kg HA ha−1, were designed as HA0, HA1, and HA3 respectively, and jasmonic acid at 0 (JA0), 5 (JA1) and 10 mM (JA2) as a foliar application. Salinity stress had detrimental effects on all the parameters and they were gradually reduced with increased salinity. Applications of humic acid and jasmonic acid mitigated the inhibitory effects of salt stress on these variables at all salinity levels. The rate of HA1 increased fresh weight, chlorophyll a and b , transpiration rate, relative humidity, stomatal conductance to CO 2 and stomatal conductance by 14.2%, 45.6%, 41.8%, 50.2%, 11.2%, 32.1% and 18.5% respectively, under S2. In addition, jasmonic acid at JA1 treatment increased plant height, elongation percentage, fresh and dry weight, chlorophyll a and b , relative humidity, and stomatal conductance to CO 2 under S2. Interaction between JA2 and HA1 improved all the traits except plant height, elongation percentage, and leaf area, suggesting that JA and HA can reduce the negative effects of salinity on the sorghum. In conclusion, jasmonic acid and humic acid treatments improved the forage sorghum performance under salinity conditions through anthesis stages, better photosynthetic and growth parameters, which reduced the impacts of salinity, and resulted in better plant growth and biomass production, and help the plant to improved salt tolerance. [ABSTRACT FROM AUTHOR]

Castor bean (Ricinus communis L.), a promising bioenergy crop, is readily planted in marginal lands like saline soils. A controlled experiment was conducted to explore the possibility of using gibberellic acid (GA3) as a promoter for caster bean grown under NaCl conditions and to try to determine the most appropriate concentration of GA3 for seedling growth. The seeds of salt-tolerant cultivar Zibi 5 were firstly soaked with 0, 200, 250, and 300 µM GA3 for 12 h and then cultured with 1/2 Hoagland solution containing 0, 50, and 100 mM NaCl in pots filled with sand. Plant height, stem diameter, leaf area, dry mater of each organ, activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), soluble protein, and proline content in the leaves were examined. Plant height and stem diameter, SOD, and POD activity was significantly highest in the treatment of 250 µM GA3 under salt concentration of 50 mM NaCl among all the testing days; protein content was highest when GA3 concentration was 250 µM under 100 mM NaCl treatment. This indicated that caster bean seed soaking with 250 µM GA3 could be the most suitable concentration for promoting seedling growth of caster bean, improving their stress resistance. [ABSTRACT FROM AUTHOR]

Because of inadequate water resources and poor irrigation facilities, salinity and drought stresses often co-occur in rice production in saline lands. Nevertheless, little information is available on the agro-physiological traits and grain yield of rice when subjected to combined salinity × drought stress. We evaluated the individual and interactive influences of salinity and drought on rice yield and agro-physiological characteristics using two rice cultivars, Nanjing 9108 (salinity-tolerant rice) and Wuyunjing 30 (salinity-susceptible rice). This experiment was conducted under non-salinity (NS) and salinity (S) conditions and three drought levels from jointing to heading (CC, control condition; MD, moderate drought; SD, severe drought). Individual salinity and drought treatments and their combination shortened the total growth duration by 3–4 days and 4–6 days in Nanjing 9108 and Wuyunjing 30, respectively. Both salinity and drought treatments reduced (P < 0.01 or P < 0.05) rice yield by 12.9%−40.9% and 28.1%−35.0% across the two cultivars, respectively, and the combined salinity × drought treatment resulted in a more pronounced yield loss of 53.1%−113.3%. A greater reduction in grain yield caused by the combined salinity × drought stress was detected in Wuyunjing 30 than in Nanjing 9108. The poor grain yield performance of rice under combined salinity × drought stress was mainly attributable to the following: (1) yield components, panicle length, and single panicle weight were lower than they were under an individual stress; (2) combined stress caused greater reductions in shoot biomass, leaf area index (LAI), and nonstructural carbohydrate (NSC) content in the stem at heading and maturity, although harvest index and NSC remobilization reserve were increased; (3) each stress and especially combined stress increased Na+/K+ ratio in the leaf, while reducing leaf photosynthetic rate and SPAD values after heading, and total accumulation of nitrogen (N), phosphorus (P), and potassium (K). Our results suggested that the combined salinity × drought stress was more damaging than either stress alone, and resulted in a greater yield penalty of rice. In terms of grain yield, salinity-susceptible rice was more responsive to the combined stress than salinity-tolerant rice. • The effects of combined salinity × drought stress on rice yield and NPK uptake were evaluated. • The combined salinity × drought stress reduced rice yield more than either stress alone. • Salinity-susceptible rice was more responsive to the combined salinity × drought stress. [ABSTRACT FROM AUTHOR]