Abstract
A tobacco cell line tolerant to ionic A1 (AIT) was selected at a frequency of 10-6 to 10-7 by plating the wild-type cells on agar medium containing 2.5 mm AICI3 and 0.1 mM phosphate at pH 4.0. Another cell line which is able to grow with insoluble Al-phosphate as a sole source of phosphate (IPU) was also selected by subculturing the wild-type cells for more than 10 passages in suspension culture in the presence of 2 mM phosphate and 4 mM A1C13 at pH 5.0. The IPU cell line also tolerated ionic A1 but the AIT line showed poor growth with insoluble Al-phosphate as a sole source of phosphate. Both cell lines excreted citrate into the media. The rate of citrate excretion by the IPU cell line, on a fresh weight basis, was higher than that by the AIT and wild-type cell lines.