File:X 2.jpg

(A) RT-PCR ofSTAR1, STAR2, and actin (internal standard) transcripts in the roots and shoots of wild-type rice treated with or without aluminum. (B) and(C) Time-dependent(B) and aluminum concentration- and pH-dependent(C) expression ofSTAR1andSTAR2in rice roots. One-week-old seedlings of rice (cv Koshihikari) were treated with 50mM Al, pH 4.5, for different time periods(B)or treated with various concentrations of Al at pH 4.5 or with different pHs (4.5 and 5.6) in the absence of Al for 6 h(C). The root tips (0 to 10 mm from tip) were harvested. (D) Response to different metals. Five-day-old seedlings were exposed to a 0.5 mM CaCl2solution at pH 5.6 or to a 0.5 mM CaCl2solution, pH 4.5, containing 50mMAl,30mM Cd, or 10mM La for 6 h at 258C. Entire roots were harvested. Expression levels ofSTAR1,STAR2,andActinas an internal control were determined by quantitative RT-PCR. Relative value toSTAR1orSTAR2expression levels in plants without Al treatment was shown, and values are means6SDof biological replicates (n=3)in(B) to(D).