Silicon-Mediated Regulation of Sodium Distribution in Barley Plants

Salinity is one of the largest problems in the world today. Silicon (Si)-mediated increase in plant tolerance to saline environment has been well documented, while the underlying mechanisms remain unclear. Monosilicic acid, polysilicic acid, and sodium (Na) were analyzed in the apoplast and symplast of roots, stems and leaves of salt-stressed barley plants in dynamics. Sodium moved predominantly via apoplastic pathway. The dynamics of Na in apoplast represented a parabolic curve. Soluble Si in nutrient solution increased the total Na in the roots but restricted the Na root-to-shoot transport via apoplastic pathway and reduced Na accumulation in stems and leaves. Plant exposure to high concentration of Na resulted in increased polysilicic acids in the root symplast and stem apoplast and symplast. These increases are attributable to Si redistribution within plant with its accumulation in stressed tissue. Probably, Si moves in the form of polysilicic acid. Under optimum or low stress growth conditions, Si mainly accumulated in the roots and leaves. Under higher stress, this Si can be redistributed to a mostly stress-affected place.

Impact of Foliar Application of Various Forms of Silicon on the Chemical Composition of Sugar Beet Plants

The effect of marine calcite, a mixture of ortho- and polysilicic acid as well as orthosilicic acid applied as a foliar spray on the chemical composition of sugar beet leaves in the critical phase of nutrient supply (beginning of July) but also leaves and roots during harvest time in 2015–2016, was studied. The content of silicon in the leaves ranged from 1.24 to 2.36 g kg−1 d.m. at the beginning of July, 3.85–5.34 g kg−1 d.m. during harvest and 2.91–4.20 g kg−1 d.m. in the roots. The foliar application of silicon caused a significant increase in the content of magnesium and calcium in leaves (in July) as compared to the control. The sugar beet consumes approx. 75 kg Si ha−1, which is almost 3.5 times more than P and 20% more than Mg thus proving its importance for its species. About 70% of the silicon taken up by sugar beet is stored in roots and 30% in leaves. The pure sugar yield is most favorably influenced by two- and threefold foliar application of the product containing silicon in the form of orthosilicic acid stabilized with choline, and a threefold mixture of ortho- and polysilicic acid. The increase in the pure sugar yield is not the result of a change in the chemical composition of sugar beet plants, but their more efficient functioning after foliar application of silicon under stress conditions caused by water shortage.

Treatment of Oil-Contaminated Water by Modified Polysilicate Aluminum Ferric Sulfate

In this experiment, a variety of inorganic materials were simply compounded with Polysilicate Aluminum Ferric Sulfate (PSAFS) to treat emulsified oil-contaminated water. Manganese sulfate (MnSO4), magnesium sulfate (MgSO4), and zinc sulfate (ZnSO4) were selected as the materials to modify PSAFS in order to obtain a coagulant with good flocculation performance. During the preparation of modified PSAFS, metal manganese, magnesium, and zinc were introduced for modification, and four factors were used to optimize the best proportion of modifiers and PSAFS. The results showed that the order of demulsification and oil-removal ability is as follows: Mn-PSAFS (Mn-modified PSAFS) > Zn-PSAFS (Zn-modified PSAFS) > Mg-PSAFS (Mg-modified PSAFS) > PSAFS. Modified PSAFS was characterized by infrared spectroscopy (IR) and a Scanning Electron Microscope (SEM). In the range of 604 cm−1 to 1200 cm−1, due to the complexation reaction between metal ions and polysilicic acid, the absorption peaks of the modified PSAFS and PSAFS were significantly different. SEM results revealed that the particles of the spatial network structure were fibrous and arranged more closely (0.5 mm × 50.0 mm) than others. This study provided that the modified PSAFS had good potential application in treating emulsified oily wastewater in the future.

Characterization and application of a novel inorganic polymer coagulant: polytianium-silicate-chloride

A novel inorganic polymer coagulant, polytitanium-silicate-chloride, was synthesized by two approaches: (1) hydroxylation of a mixture of TiCl4 and fresh polysilicic acid; (2) hydroxylated polytitanium chloride combined with polysilicic acid was aged for 2 h.