Effects of shading and nitrogen addition on growth and physiological characteristics of Cyclobalanopsis glauca seedlings

In order to explore the suitable light and nitrogen levels and their interaction effects for the growth of Cyclobalanopsis glauca seedlings, improve the utilization rate of nitrogen fertilizer, one-year-old C. glauca seedlings were taken as the research object and a two-factor pot experiment was set up with four light levels and four nitrogen levels. The results showed that under the same light intensity, the seedling height, ground diameter, leaf area, activity of SOD, NR and GS of C. glauca seedlings increased first and then decreased with the increase of nitrogen. MDA content decreased first and then increased. Under the same nitrogen level, the seedling height, ground diameter, leaf area, activity of SOD, NR and GS of C. glauca seedlings increased first and then decreased with the decrease of light intensity. MDA content decreased first and then increased. There was a significant interaction between different light and nitrogen levels(P < 0.05). Through the principal component analysis and evaluation of each index of C. glauca seedlings, it is concluded that the maximum principal component comprehensive value of C. glauca seedlings is the treatment of 50% light intensity, 1.2 g/plant of nitrogen(L₃N₂). Under the condition, the growth of C. glauca seedlings was the best, and the growth in seedling height and ground diameter are 31.1 cm and 1.78 mm respectively.