2011 Volume 60 Issue 12 Pages 497-503
We present 28Mg imaging analysis in rice roots to study Mg uptake activity along the position of the root. The Mg uptake activity of 1mm root tip was relatively higher than those of the other parts. When the root was treated with aluminum, the Mg uptake activity was increased approximately twofold, suggesting that the increase of Mg uptake activity in root is one of the mechanisms of Al tolerance in a rice plant. The treatment with uncouplers (carbonyl cyanide m-chlorophenyl hydrazone and 2,4-dinitrophenol) and ATPase inhibitor (orthovanadate) showed the uniform decrease of Mg uptake activity in the root. On the other hand, the Mg uptake activity in the root tip was drastically reduced by hexaaminecobalt(III), an analog of hydrated Mg2+. The results suggest that hydrated Mg2+ is the dominant chemical form in Mg uptake in the root tip.