缺磷对烟草悬浮细胞交替呼吸途径的影响及其与活性氧积累的关系

Effect of Phosphorus Deficiency on Alternative Respiratory Pathway and Its Relation with O_2^- Accumulation in Suspension-cultured Tobacco Cells

用两个耐低磷能力差异显著的烟草悬浮细胞系,研究了缺磷胁迫对交替呼吸途径的影响及其与活性氧积累的关系。牛津细胞耐缺磷胁迫能力明显高于K326。缺磷降低了K326交替途径的容量及实际运行量,但对牛津的影响不大。无论在缺磷还是正常磷水平下,牛津细胞交替途径容量和实际运行量都比K326高。用分离的线粒体进一步证实了上述结果。缺磷胁迫可以提高AOX的蛋白表达量,但品种间差异不明显。缺磷胁迫下K326细胞中的超氧阴离子积累量远高于牛津细胞。由此认为交替途径可能在细胞耐低磷中起作用。

Effects of phosphorus deficiency on alternative respiratory pathway and its relation with O2- production were investigated in two lines of suspension-cultured tobacco cells which have different tolerances to P deficiency. Oxford cells were shown to be much more tolerant than K326 (Fig. 1). There were no apparent differences in inorganic and total phosphorous content between the two cell lines (Fig.2). The capacity and activity of alternative respiratory pathway were decreased by P deficiency in K326 cells but were little influenced in Oxford cells. Under either P-deficient or sufficient condition, the capacity and activity of alternative respiratory pathway were always higher in Oxford than in K326. When mitochondria were isolated and used for the same study, similar results were obtained as described above (Fig.3 and Fig.4). The expression of AOX at protein level was induced by P deficiency in both lines to similar extents (Fig.5). O2- content in K326 cells was significantly higher under P deficiency but little affected in Oxford (Fig.6). It is suggested that alternative respiratory pathway may be associated with tolerance of tobacco cells to P deficiency and may play a role in scavenging reactive oxygen species.