The paper reports the effects of selenium (Se) supply on growth and some physiological traits of wheat (Triticum aestivum L. cv Shijiazhuang NO. 8) seedlings exposed to drought stress. The growth and physiological responses of seedlings were different depending on the Se concentration. The higher (3.0 mg Se kg(-1)) and lower amount used (0.5 mg Se kg(-1)) did not significantly affect on biomass accumulation. Treatments with 1.0 and 2.0 mg Se kg(-1) promoted biomass accumulation of wheat seedlings. Treatments at 1.0, 2.0, and 3.0 mg Se kg(-1) significantly increased root activity, proline content, peroxidase (POD), and catalase (CAT) activities, carotenoids (Car) content, chlorophyll content, and reduced malondialdehyde (MDA) content of wheat seedlings. Lower Se treatment did not significantly effect on chlorophyll content and MDA content, although it also increased some antioxidant index (proline and Car content, POD and CAT activities) in wheat seedlings. These results suggest that optimal Se supply is favorable for growth of wheat seedlings during drought condition.

Dose-dependent effects of selenium on growth and physiological trait of wheat seedlings (Triticum aestivum L. cv Han NO.7086) exposed to cold stress are reported. Responses of seedlings were different depending on the Se concentration. The treatments with 0.5 and 1.0 mg Se kg(-1) significantly increased biomass and chlorophyll content of seedlings. However, the treatments at 2.0 and 3.0 mg Se kg(-1) only induced an evident increase in chlorophyll content and did not promote biomass accumulation of seedlings. Antioxidant compounds content (anthocyanins, flavonoids, and phenolic compounds) and antioxidant enzymes' activities (peroxidase and catalase) increased by different Se treatments, while only the treatment with 1.0 mg Se kg(-1) induced a significant reduce in malondialdehyde content and the rate of superoxide radical production of wheat seedlings. The results of this study demonstrated that Se supply could increase antioxidant capacity of seedlings, and optimal Se supply reduced production of free radicals, membrane lipid peroxidation, and promoted biomass accumulation.

Inspired by its unique porous structure, high value-added functional hydrogels combined with metal nanoparticles can lead to applications in different areas, including environmental catalysis. For this purpose, controlling the metal nanoparticle size is paramount. Herein, the porous lignocellulose hydrogel (LCG) with different lignin contents served as the matrix for in situ-synthesizing silver–lignin nanoparticles (Ag-L NPs), with lignin in the LCG as the reducing and capping agent of Ag-L NPs and the lignin content to control the size of Ag-L NPs. The well-dispersed lignin in the LCG network ensures immobilization and dispersion of Ag-L NPs. The particle size of Ag-L NPs is tailored by adjusting the lignin content (0.5, 6.5, 11.6, and 18.4%) of the LCG: the higher the lignin content, the smaller the Ag-L NPs. The smallest Ag-L NPs obtained were of 9.5 nm. The as-prepared Ag-L NPs/LCG composite samples showed outstanding catalytic reduction capability, with superior stability/reusability when applied for the catalytic reduction of 4-nitrophenol. Moreover, the Ag-L NPs/LCG composites exhibited high antibacterial activity, thus contributing to long-term storage stability.

The paper reports the effects of selenium (Se) supply on growth and antioxidant traits of wheat (Triticum aestivum L. cv Han NO.7086) seedlings exposed to enhanced ultraviolet-B (UV-B) stress. Antioxidant responses of seedlings were different depending on the Se concentration. Compared with the control, the lower amount used (0.5 mg Se kg(-1) soil) had no significant effect on biomass accumulation. The treatments with 1.0, 2.0, and 3.0 mg Se kg(-1) promoted biomass accumulation of wheat seedlings, and the increased amount in biomass was the most at 1.0 mg Se kg(-1) treatment. Se treatments with 1.0, 2.0, and 3.0 mg kg(-1) also significantly increased activities of peroxidase (POD) and superoxide dismutase (SOD) and reduced the rate of superoxide radical (O (2) (-) ) production and malondialdehyde (MDA) content of wheat seedlings. In addition, anthocyanins and phenolic compounds content in wheat seedlings evidently increased by the treatments with 1.0 and 2.0 mg Se kg(-1). The lower Se treatment had no significant effect on MDA content, although it increased activities of antioxidant enzymes (POD, SOD, and catalase activities) and reduced the rate of O (2) (-) production in wheat seedlings. These results suggest that optimal Se supply is favorable for the growth of wheat seedlings and that optimal Se supply can reduce oxidative stress of seedlings under enhanced UV-B radiation.

Enhanced ultraviolet-B (UV-B) irradiation is one of the most important abiotic stresses that could influence the growth and physiological traits of plants. In this work, we reported the effects of silicon on the growth and physiological characteristics of wheat seedlings (Triticum aestivum L. cv Hengmai5229) subject to UV-B stress. Treatments with silicon significantly increased total biomass and chlorophyll (a + b) content, and reduced malondialdehyde (MDA) content and the rate of superoxide radical (O(2) (-) ) production in wheat seedlings subjected to UV-B stress. Silicon treatments also induced an increased in soluble sugar, anthocyanins, and flavonoid content. Leaf silicon concentration increased with the increasing of silicon supply to soil. Positive correlations were found in leaf silicon concentration with total biomass, chlorophyll (a + b), proline, and soluble protein content, respectively. MDA content and the rate of O(2)(-) production were negatively correlated with leaf silicon concentration in seedlings. The results demonstrated that silicon alleviated the damage caused by UV-B on wheat seedlings to some extent by the increase in antioxidant compounds content and leaf silicon concentration.

The paper evaluated the effects of Se application time and rate on physiological traits, grain Se content, and yield of winter wheat by field experiment. Se application significantly increased grain Se content and yield, and the increased amount treated with 20 and 30 mg Se L(-1) was the highest. At blooming-filling stage, Se application significantly increased grain Se content, but did not affect yield. Chlorophyll content was increased by Se application, and the increased amount at heading-blooming stage was higher than that in wheat leaves at the other stages. At four development stages, Se treatments (except for 10 mg Se L(-1) at jointing-heading stage) significantly decreased the rate of superoxide (O(2) (-)) radical production. At heading-blooming (except for 50 mg Se L(-1)) and blooming-filling stages, hydrogen peroxide (H(2)O(2)) content was significantly decreased by Se treatments. The rate of O(2) (-) production and H(2)O(2) content at 20 and 30 mg Se L(-1) was the lowest. Se treatments (except for 10 mg Se L(-1) at regreening-jointing and blooming-filling stages) also induced an evident decrease in malondialdehyde content. Proline content induced by Se treatments at jointing-heading and heading-blooming stages was higher than that in wheat leaves at regreening-jointing and blooming-filling stages. At four development stages, Se treatments all significantly increased glutathione peroxidase activity, and the treatments with 20 and 30 mg Se L(-1) also evidently increased reduced glutathione content. These results suggested that Se application at different development stages increased antioxidant capacity of wheat, reduced oxidant stress to some extent, and the effects of Se treatments was the best if Se concentration ranged between 20 and 30 mg Se L(-1). In addition, Se application time was more beneficial for Se accumulation and yield in wheat grain at heading-blooming stage.

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