RESUMEN
A pot experiment was conducted in a greenhouse on one-year-old clonal seedlings of Cunninghamia lanceolata. Five treatments were designed including control, conventional fertilization and three exponential fertilization treatments, with N application rates of 0, 0.5, 0.5, 1.0 and 2.0 g·seedling-1, with N applied at 20 times at 10-day interval. The height, ground diameter, biomass, chlorophyll fluorescence and N absorption were measured after 210 days of N application. The results showed that fertilization significantly promoted the seedling height, ground diameter and biomass with the optimal values of 59.0 cm, 6.0 mm, 52.99 g·seedling-1, in exponential fertilization treatment of 1.0 g N·seedling-1. Chlorophyll fluorescence in exponential fertilization treatments was significantly higher than that in conventional fertilization. The photochemical quenching, PS2 electron transport rate and photochemical efficiency of PS2 in exponential fertilization treatments increased first and then decreased, with the optimal values of 0.89, 35.79 and 0.71 in 1.0 g N·seedling-1 treatment. N contents in different organs of C. lanceolata clonal seedlings were in the order of leaf > root > stem. Compared with the CK, the N contents in root, stem and leaf increased by 39.6%, 16.6% and 41.1% in the conventional fertilization treatment, and by 22.6%-81.4%, 27.3%-152.6% and 73.6%-135.5% in exponential fertilization treatments. N contents in root, stem and leaf in the exponential fertilization treatments of 1.0 and 2.0 g N·seedling-1 were significantly higher than those in the conventional fertilization treatment. P and K contents were not significantly different among the different organs. Considering the characteristics of seedling growth, chlorophyll fluorescence, the contents of N, P and K, the exponential fertilization treatment of 1.0g N· seedling-1 was the best in cultivating C. lanceolata clonal seedlings in this experiment.