Abstract:

【Objective】 The relationship between root morphology and its spatial distribution in the soil and nitrogen acquisition efficiency was studied. The visualization of root architecture was attempted by using root functional-structural model. 【Method】 A field experiment was conducted with two maize inbred lines, N-efficient 478 and N-inefficient Wu312. The lengths of embryonic and different whorls of node roots harvested at different developmental stages were scanned, and used as parameters to simulate root architecture based on the modified root functional-structural model. 【Result】 478 had a longer root lengths of embryonic and node roots, better root spatial distribution in the soil than that of Wu312. The roots of 478 had larger growth rate and higher branching density than those of Wu312 in terms of simulation. The root length of the embryonic roots and the early initiated three whorls of nodal roots, which represented a small portion of total root length, declined rapidly after reaching their highest values before silking. The shoot-born roots from the higher nodes initiated predominantly, which was synchronized closely with shoot development and demand for nutrients, reached their maximal lengths at 93 d after sowing and then declined. 【Conclusion】 The differences in root length and its spatial distribution in the soil play an important role in nitrogen acquisition efficiency between maize genotypes. The root architectures of both maize inbred lines at different developmental stages could be visualized by using root functional-structural model.

Key words: maize (Zea mays L.), N-efficiency, root architecture, root spatial distribution in the soil, visualization of root architecture