Ameliorative effects of phosphate and silicate on aluminum toxicity in barley and rice plants

Abstract

The effects of phosphate (3–150 µM P) and silicate (0–2000 µM Si) supplied with aluminum (0–100 µM Al) in the culture solution, on root elongation of barley and rice, were studied. The soluble Al concentration in the culture solution decreased markedly as the phosphate supply increased, but decreased only slightly as the silicate supply increased. The root length of barley and rice decreased with the increase in Al concentration, and this inhibition was alleviated by the supply of phosphate or silicate. Pre-treatment of the rice seedlings with silicate (2000 µM Si) for one day before Al (50 µM) treatment for 2 days, increased root elongation and root length to be comparable to that of the control seedlings without Al and silicate. Silicate may prevent Al ions from entering into root tissues by decreasing the concentration of Al monomer ions in culture solution or by inducing some morphological changes of the roots.