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Salinity is one of the major constraints to crop production. Rice is a main staple food and is highly sensitive to salinity. This study aimed to elucidate the effects of salt stress on physiological and agronomic traits of rice genotypes with contrasting salt tolerance. Six contrasting rice genotypes (DJWJ, JFX, NSIC, HKN, XD2H and HHZ), including three salt-tolerant and three salt-sensitive rice genotypes, were grown under two different salt concentrations (0 and 100 mmol L−1 NaCl solution). The results showed that growth, physiological and yield-related traits of both salt-sensitive and salt-tolerant rice were significantly affected by salt stress. In general, plant height, tiller number, dry weight and relative growth rate showed 15.7%, 11.2%, 25.2% and 24.6% more reduction in salt-sensitive rice than in salt-tolerant rice, respectively. On the contrary, antioxidant enzyme activity (superoxide dismutase, peroxidase, catalase), osmotic adjustment substances (proline, soluble protein, malondialdehyde (MDA)) and Na+ content were significantly increased under salt stress, and the increase was far higher in salt-tolerant rice except for MDA. Furthermore, grain yield and yield components significantly decreased under salt stress. Overall, the salt-sensitive rice genotypes showed a 15.3% greater reduction in grain yield, 5.1% reduction in spikelets per panicle, 7.4% reduction in grain-filling percentage and 6.1% reduction in grain weight compared to salt-tolerant genotypes under salt stress. However, a modest gap showed a decline in panicles (22.2% vs. 22.8%) and total spikelets (45.4% vs. 42.1%) between salt-sensitive and salt-tolerant rice under salinity conditions. This study revealed that the yield advantage of salt-tolerant rice was partially caused by more biomass accumulation, growth rate, strong antioxidant capacity and osmotic adjustment ability under salt stress, which contributed to more spikelets per panicle, high grain-filling percentage and grain weight. The results of this study could be helpful in understanding the physiological mechanism of contrasting rice genotypes' responses to salt stress and to the breeding of salt-tolerant rice. [ABSTRACT FROM AUTHOR]

Salinity stress is one of the major constraints to plant growth and crop production. Optimum fertilizer management is essential for promoting crop growth and productivity in saline soils. A field experiment was conducted to study the effects of nitrogen and phosphate combination on sesbania pea (Sesbania cannabina (Retz.) Poir.) growth and associated physiology in saline soils. Three N rates (N1: 240 kg⋅ha-1, N2: 360 kg⋅ha-1, N3: 480 kg⋅ha-1) and two P rates (P1: 120 kg⋅ha-1, P2:180 kg⋅ha-1) were arranged in this study using a RCBD with 3 replicates. The application of N and P fertilizers significantly improved plant growth and associated physiological traits of sesbania pea. Plant height (P=0.0001), fresh biomass weight (P=0.0006), dry biomass weight (P=0.0006), relative growth rate (RGR) (P=0.005), chlorophyll (P=0.002), peroxidase (POD) (P=0.0003), catalase (CAT) (P=0.0001), superoxide dismutase (SOD) (P=0.0001) and soluble protein (P=0.0053) were significantly increased, and the maximum values were consistently produced under N2P2 combination at each growth stage. On the contrary, malondialdehyde (MDA) was prominently decreased by N and P fertilizer application (P=0.0029), and the lowest values were all produced under N2P2 combination. The highest values of plant height, fresh biomass weight and dry biomass weight were recorded on the 163rd day after seeding (DAS). The highest RGR and MDA content were determined on the 141st DAS. The highest chlorophyll content, CAT and SOD activity, and soluble protein content were recorded on the 110th DAS, and the highest POD activity was at 47 DAS. This study suggested that the optimum N and P fertilizer combination was N2P2 (360 kg⋅hm-2 N + 180 kg⋅hm-2 P), which was superior in promoting growth and biomass yield with enhanced antioxidant capacity of sesbania pea in saline soils. [ABSTRACT FROM AUTHOR]

Germination is a very sensitive stage for the harmful effect of salinity stress. Plants respond differently to different types of salt. Gibberellic acid (GA3) is the most important hormone to mitigate salt stress. A controlled germination study was conducted to evaluate the impact of different salts (0, 150 mM NaCl, and 150 mM Na2SO4) and different GA3 concentrations (0, 50, 100, 250, and 300 mg L-1) on the germination of the two most used Sudanese sorghum (Sorghum bicolor [L.] Moench) varieties Wadahmed and Tabat. The studied parameters were seed water uptake after 8 h imbibition, germination percentage, germination rate, shoot and root length, shoot and root fresh weight, shoot and root dry weight, and seed vigor index. Results showed that Na2SO4 reduced germination percentage, germination rate, shoot length, root length, root fresh weight, shoot dry weight, root dry weight, and seed vigor index by 17.0%, 50.0%, 86.99%, 89.03%, 76.8%, 54.5%, 66.6%, and 89.7%, respectively, when compared with the non-saline treatment. The maximum values for seed water uptake, germination percentage, germination rate, shoot length, and seed vigor index were achieved at 100 mg L-1 GA3. The Na2SO4 salt had a more harmful effect than NaCl. The 100 mg L-1 GA3 concentration can be recommended to improve seed water uptake, germination parameters, and seedling growth under salt stress in the two Sudanese sorghum varieties (Wadahmed and Tabat). 'Wadahmed' was more tolerant to salinity stress than 'Tabat' at the germination stage. [ABSTRACT FROM AUTHOR]