Soil salinization is a worldwide problem affecting agriculture and the environment. Utilizing saline land by screening and cultivating salt-tolerant crops is an economical and ecological solution. Leaf beet (Beta vulgaris var. cicla) is an important vegetable resource and has certain salt tolerance, but what concentration it can tolerate still remains to be verified. Hence, this work explored the adaptability of leaf beet to salt stress. A soil culture experiment was conducted. By adding NaCl to the soil, the concentrations of 0% (S₀), 0.3% (S₃), 0.5% (S₅) and 0.7% (S₇) NaCl salinity were set to analyze the changes of leaf beet growth (plant height, leaf number and biomass); leaf morphology (leaf area, shape, leaf mass per area (LMA) and tissue density); and leaf physiology (chlorophyll content, leaf relative water content (LRWC), water content at saturation (WCS), water saturation deficit (WSD) and succulence). The results showed that 0.3% NaCl salinity increased LMA and decreased biomass, while the rest were almost the same as the control (S₀). Under 0.5% and 0.7% NaCl salinity, LRWC decreased significantly, while WCS and WSD increased significantly. Under such salt stress, the leaf beet adapted by reducing plant height, delaying the engendering of new leaves, decreasing leaf area, changing leaf shape, maintaining high chlorophyll content, and increasing LMA, tissue density and succulence. With these strategies, the leaf beets survived under salt stress up to 0.7% NaCl salinity with a certain biomass, providing a meaningful exploration for the multi-purpose planting and application of leaf beets on saline soils.

• Reduced nitrogen supply caused a rapid production of H₂O₂ in lettuce leaves. • H₂O₂ addition effectively increased the accumulation of phenolic compounds. • Gene expressions of key enzymes involved in phenolic biosynthesis were upregulated by H₂O₂ addition. • H₂O₂ regulated the antioxidant enhancement of lettuce under low nitrogen condition.

• The maximum enhancement of growth performances was found in lettuce elicited with 10 mmol/L H₂O₂. • H₂O₂ elicitation increased minerals, phenolic compounds, and antioxidant quality of lettuce. • H₂O₂ elicitation increased chlorophyll content and photosynthetic efficiency of lettuce. • The impacts of H₂O₂ elicitation on growth and quality varied among two genotypes of lettuce.

Magnesium (Mg) plays an important role in numerous physiological and biochemical processes in plants. However, Mg deficiency is common worldwide, especially in greenhouse vegetable systems, due to the overuse or misuse of fertilizers. This study investigated the effects of different Mg application strategies in alleviating Mg deficiency of tomatoes in PE-film covered greenhouse. Six field treatments were used: conventional fertilization practice (C), conventional fertilization + soil warming (CW), conventional fertilization + Mg applied to soil (C + MgS), conventional fertilization + Mg applied as foliar application (C + MgF), conventional fertilization + Mg applied to soil and foliar application (C + MgSF), and conventional fertilization + Mg applied to soil and foliar application with soil warming (C + MgSFW). Foliar spray of Mg fertilizer (C + MgF, C + MgSF, and C + MgSFW) increased the total Mg uptake and Mg content of functional leaves in both winter-spring and autumn-winter seasons. Soil warming treatments (CW and C + MgSFW) were also beneficial for Mg uptake and chlorophyll biosynthesis compared with no-warming treatments (C and C + MgSF), especially in autumn-winter season. Additionally, Mg fertilizer application and soil warming increased tomato yields; the C + MgSFW treatment had the highest increase in yields compared with the C treatment. Therefore, foliar Mg fertilizer application combined with soil warming, while considering seasonal variation, is feasible for reducing Mg deficiency in tomatoes under PE-film covered greenhouse vegetable systems.