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Rice has been shown to respond positively to Si fertilizer in terms of growth and productivity. The objective of this study was to evaluate the effect of a series of Si application rates on grain yield, Si concentration, and the expression of the OsLsi6 gene among three Thai rice varieties. The varieties CNT1, PTT1, and KDML105 were grown in a pot experiment under six levels of Si (0, 100, 150, 200, 250, and 300 kg Si/ha). Grain yield was the highest at 300 kg Si/ha, being increased by 35%, 53%, and 69% in CNT1, PTT1, and KDML105, respectively, compared with the plants grown without added Si. For Si concentrations in rice plants, rising Si fertilizer application up to 150 kg/ha significantly increased the Si concentration in straw, flag leaf, and husk in all varieties. The Si concentration in all tissues was higher under high Si (300 kg Si/ha). Applying Si fertilizer also increased the expression level of OsLsi6 in both CNT1 and PTT1 varieties. The highest expression level of OsLsi6 was associated with 300 kg Si/ha, being increased by 548% in CNT1 and 326% in PTT1 compared with untreated plants. These results indicate that Si application is an effective way to improve rice yield as well as Si concentration, and that the effect is related to the higher expression of the OsLsi6 gene. [ABSTRACT FROM AUTHOR]

Rice has been shown to respond positively to Si fertilizer in terms of growth and productivity. The objective of this study was to evaluate the effect of a series of Si application rates on grain yield, Si concentration, and the expression of the OsLsi6 gene among three Thai rice varieties. The varieties CNT1, PTT1, and KDML105 were grown in a pot experiment under six levels of Si (0, 100, 150, 200, 250, and 300 kg Si/ha). Grain yield was the highest at 300 kg Si/ha, being increased by 35%, 53%, and 69% in CNT1, PTT1, and KDML105, respectively, compared with the plants grown without added Si. For Si concentrations in rice plants, rising Si fertilizer application up to 150 kg/ha significantly increased the Si concentration in straw, flag leaf, and husk in all varieties. The Si concentration in all tissues was higher under high Si (300 kg Si/ha). Applying Si fertilizer also increased the expression level of OsLsi6 in both CNT1 and PTT1 varieties. The highest expression level of OsLsi6 was associated with 300 kg Si/ha, being increased by 548% in CNT1 and 326% in PTT1 compared with untreated plants. These results indicate that Si application is an effective way to improve rice yield as well as Si concentration, and that the effect is related to the higher expression of the OsLsi6 gene.

In this study, a pot experiment was designed to elucidate the effect of varying dosages of silicon (Si) fertilizer application in Si-deficient and enriched paddy soils on rice phytolith and carbon (C) bio-sequestration within phytoliths (PhytOC). The maximum Si fertilizer dosage treatment (XG3) in the Si-deficit paddy soil resulted in an increase in the rice phytolith content by 100.77% in the stem, 29.46% in the sheath and 36.84% in the leaf compared to treatment without Si fertilizer treatment (CK). However, the maximum Si fertilizer dosage treatment (WG3) in the Si -enriched soil increased the rice phytolith content by only 32.83% in the stem, 27.01% in the sheath and 32.06% in the leaf. Overall, Si fertilizer application significantly (p < 0.05) increased the content of the rice phytoliths in the stem, leaf and sheath in both the Si-deficient and enriched paddy soils, and the statistical results showed a positive correlation between the amount of Si fertilizer applied and the rice phytolith content, with correlation coefficients of 0.998 (p < 0.01) in the Si-deficient soil and 0.952 (p < 0.05) in the Si-enriched soil. In addition, the existence of phytoliths in the stem, leaf, and sheath of rice and its content in the Si-enriched soil were markedly higher than that in the Si-deficient soil. Therefore, Si fertilizer application helped to improve the phytolith content of the rice plant. [ABSTRACT FROM AUTHOR]

Silicon has been found to enhance the plants' tolerance to heavy metal stress. In a field study, the effect of different types of Si-rich soil amendments (slag, ground slag, and diatomaceous earth) and fertilizers (activated slag, ground activated slag, and commercial Si fertilizer) on the distribution of soluble and insoluble forms of Cd in the rice plant organs grown on long-term cultivated paddy soil contaminated with Cd (central part of Hunan Province, China) was investigated. The soluble Si and Cd were tested in the apoplast and symplast of the roots, stems, and leaves of rice at a tillering stage. The Si-rich materials increased rice biomass by up to 15.5% and reduced the total leaf Cd by 8.5 to 21.9%. Commercial Si fertilizer was the most effective. Three main locations of the most active Si-Cd interactions were distinguished in the soil-plant system: soil, where monosilicic acid affords adsorption and fixation of the bioavailable Cd and root apoplast and apoplast above roots, where monosilicic acid can precipitate Cd. The transport of Cd to stems and leaves and the mobility of Cd in the soil depend on the content of monosilicic acid in the system. [ABSTRACT FROM AUTHOR]

Silicon (Si) was shown to be able to reduce arsenic (As) uptake by rice in hydroponic culture or in low As soils using high Si application rates. However, the effect of Si application on As uptake of rice grown in As-contaminated soils using Si fertilizer recommendation rate has not been investigated. In this study, the effect of Si application using Si fertilizer recommendation rate on As release and phytotoxicity in soils with different properties and contents of As was examined. The results show that the concentrations of As in soil solutions increased after Si applications due to competitive adsorption between As and Si on soil solids and the Si concentrations in soil solutions were also elevated to beneficial levels for rice growth. The rice seedlings accumulated more As and its growth was inhibited by Si application in As contaminated/spiked soils. The results indicate that there is an initial aggravation in As toxicity before the beneficial effects of Si fertilizing to rice were revealed when Si application based on fertilizer recommendation rate to As-contaminated paddy soils. Therefore, for As-contaminated paddy soils with high levels of As, the application of Si fertilizer could result in increasing As phytotoxicity and uptake by rice. [ABSTRACT FROM AUTHOR]