Abstract:

The responses of the growth and the allocation of photosynthetic products in Chinese fir seedlings to N, P fertilizer and NP compound fertilizer under the N-deficiency and P-deficiency conditions in the soil were studied in this paper. The main results were as follows: (1) Under the N and P stress, N fertilizer accelerated the growth of two-year-old seedlings in some degree and the accumulation of photosynthetic products moved from roots to leaves. This showed that the N stress had been relaxed gradually. The use of P fertilizer, which caused the movement of photosynthetic products from roots to stem and leaves, indicated that the increase of P fertilizer could alleviate and sometimes could eliminate the P deficiency of one-year-old seedlings. By contraries, the P fertilizer caused the movement of photosynthetic products accumulation in 2-year-old seedlings from stem to roots. It showed that the P stress had not been eliminated essentially in 2-year-old seedlings with the increase of P concentration in soil and 2-year-old seedlings needed more N than 1-year-old seedlings. Hence, it was very important to use the balance NP compound fertilizer properly on seedlings at different growth stages. (2)Under the N-adequate and P-deficient situation in soil, the application of NP compound fertilizer caused the movement of photosynthetic products accumulation in 2-year-old seedlings from roots to stem (the rate of moved accumulation was 0.50%～3.13%) and leaves (the rate of moved accumulation was 7.21%～11.76%),and also revealed the elimination of P deficiency.

Key words: Chinese fir, Seedlings, Nutrient characteristics, Allocation of photosynthetic products