Abstract
To investigate the mechanism of Ni tolerance in common plants, we selected cell lines of tobacco (Nicotiana tabacum L.cv.BY-2 ) tolerant to 700μM NiCl2 (NIT cells). The NIT cells exhibited slight tolerance to excess of Cu and Al, and high tolerance to excess of Ni especially. Contents of Ni, Fe and Mg in NIT cells increased obviously under Ni treatment. Organic acids levels were constitutively high in NIT cells. Histidine level was 3 to 5 fold higher in the NIT cells with 700μM NiCl2 than in the wild-type cells without Ni. Complexation with organic acids or histidine has been identified as an important mechanism for detoxifying Ni. We have also found the NIT specific proteins secreted to medium constitutively. To determine the localization of Ni, isolation of protoplasts and vacuoles from NIT cells is undergoing.
