Abstract:

A pot experiment with twenty-three open-pollinated Liriodendron chinense families from Liping of Guizhou at two nitrogen levels was conducted to investigate family variation and inheritance of nitrogen absorption and utilization efficiency related to nitrogen supply. The growth response of different families to nitrogen supply was found to be significant. Nitrogen efficiency of the families varied from 17.5% to 98.8%. The families were classified into two types according to the nitrogen efficiency, namely a stable type with high nitrogen efficiency and a sensitive type with low nitrogen efficiency. There existed significant family variation for nitrogen absorption and utilization efficiency among various organs and total plants at different nitrogen levels, besides leaf nitrogen utilization efficiency at low nitrogen level. The variation was under moderate or strong genetic control with family heritabilities ranged from 0.511 5 to 0.963 0. Stable type of families with high nitrogen efficiency exhibited greater biomass accumulation, more and larger leaves, more developed lateral and fibrous roots under low nitrogen level, because of high nitrogen and phosphorus absorption efficiency. However, the families had lower leaf nitrogen utilization efficiency.

Key words: Liriodendron chinense, family, nitrogen nutrition, absorption efficiency, utilization efficiency