Attempts to cultivate sugar beet (Beta vulgaris spp. vulgaris) in the sub-tropical saline soils are ongoing because of its excellent tolerance to salinity. However, the intrinsic adaptive physiology has not been discovered yet in the sub-tropical climatic conditions. In this study, we investigated morpho-physiological attributes, biochemical responses, and yield of sugar beet under a gradient of salinity in the soil-pot culture system to evaluate its adaptive mechanisms. Results exhibited that low and high salinity displayed a differential impact on growth, photosynthesis, and yield. Low to moderate salt stress (75 and 100 mM NaCl) showed no inhibition on growth and photosynthetic attributes. Accordingly, low salinity displayed simulative effect on chlorophyll and antioxidant enzymes activity which contributed to maintaining a balanced H 2 O 2 accumulation and lipid peroxidation. Furthermore, relative water and proline content showed no alteration in low salinity. These factors contributed to improving the yield (tuber weight). On the contrary, 250 mM salinity showed a mostly inhibitory role on growth, photosynthesis, and yield. Collectively, our findings provide insights into the mild-moderate salt adaptation strategy in the soil culture test attributed to increased water content, elevation of photosynthetic pigment, better photosynthesis, and better management of oxidative stress. Therefore, cultivation of sugar beet in moderately saline-affected soils will ensure efficient utilization of lands.

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Copper (Cu) pollution of agricultural land is a major threat to crop production.Exogenous chemical treatment is an easily accessible and rapid approach to remediate metal toxicity, including Cu toxicity in plants.• We compared the effects of ascobin (ASC; ascorbic acid:citric acid at 2:1) and glutathione (GSH) in mitigation of Cu toxicity in rice.• Plants subjected to Cu stress displayed growth inhibition and biomass reduction, which were connected to reduced levels of chlorophylls, RWC, total phenolic compounds, carotenoids and Mg 2+ . Increased accumulation of ROS and malondialdehyde indicated oxidative stress in Cu-stressed plants. However, application of ASC or GSH minimized the inhibitory effects of Cu stress on rice plants by restricting Cu 2+ uptake and improving mineral balance, chlorophyll content and RWC. Both ASC and GSH pretreatments reduced levels of ROS and malondialdehyde and improved activities of antioxidant enzymes, suggesting their roles in alleviating oxidative damage. A comparison on the effects of ASC and GSH under Cu stress revealed that ASC was more effective in restricting Cu 2+ accumulation (69.5% by ASC and 57.1% by GSH), Ca 2+ and Mg 2+ homeostasis, protection of photosynthetic pigments and activation of antioxidant defence mechanisms [catalase (110.4%), ascorbate peroxidase (76.5%) and guaiacol peroxidase (39.0%) by ASC, and catalase (58.9%) and ascorbate peroxidase (59.9%) by GSH] in rice than GSH, eventually resulting in better protection of ASCpretreated plants against Cu stress. • In conclusion, although ASC and GSH differed in induction of stress protective mechanisms, both were effective in improving rice performance in response to Cu phytotoxicity.

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