Does silicon exist in association with organic compounds in rice plant?

Abstract

Silicon-organic compounds in the cell walls of rice seedlings grown in solutions with different levels of CaCl₂ and with or without silicon were investigated by IR and UV absorption spectroscopy. Levels of the lignin-carbohydrate complexes (LCC) in cell walls decreased by silicon deficiency. A bathochromic effect, namely, shifting of the absorption maximum to a longer wavelength, a hyper-chromic effect, evident as an increase in the maximum absorbance in the absorption spectrum, and an absorbance band at 940 cm^-1 in the IR spectrum, suggesting the combination between an aromatic ring and Si-O, were observed in the LCC from the cell walls supplied with silicon, while only a hyperchromic effect was observed when calcium was supplied. Thus, in the cell walls of rice plants, evidence was provided for the possible presence of silicon combined with some organic compounds.

Key Words:

• bathochromic effect
• lignin-carbohydrate complexes
• IR absorption spectra
• silicon.