Physiological characteristics of inbred line maize seedling root under phosphorus stress

Pot sand culture was set up for two inbred line maize with different phosphorus (P) efficiencies to investigate root physiological characteristics at seedling stage under P stress. When subject to low-P treatment, roots of low-P efficiency line 04065 have a significantly higher acid phosphatase (APase) activity during 4～8 leaf-stage and a lower P content than those of high-P efficiency line 04419. This indicates that root APase activity can be a suitable criterion for evaluating P efficiency of different maize inbred lines. With prolonged exposure to low-P stress (up to 6～8 leaf-stage), other physiological characteristics of maize roots, including root APase, root activity, MDA content, total root length and dry matter accumulation,except for root/shoot ratio, are significantly different between the two inbred lines. As such, tolerance of different maize genotypes to low-P stress is related to multiple physiological processes.