Abstract: To understand the effects of stumping on the contents and stoichiometry of carbon (C), nitrogen (N), and phosphorus (P) in different organs of Pinus yunnanensis seedlings, and the correlations and allometric relationships among C, N and P, the contents of C, N, P and the ratios of C∶N, C∶P and N∶P in seven organs (taproot, lateral root, stem, lateral branch, mother plant needle, sprout branch, sprout needle) of P. yunnanensis seedlings with different stumping heights (CK, 5, 10 and 15 cm) were analyzed. The results showed that N, P, C∶N, C∶P, N∶P had significant differences among stumping heights, organs, stumping heights×organs, except that C content showed no response to stumping height. With the increases of stumping height, N, P, C∶N, C∶P, N∶P showed a trend of first increase and then decrease, while C∶N and C∶P showed an opposite trend. The variation coefficients of contents and ratios of elements in each organ fluctuated slightly under different stumping heights, indicating that stumping had little effect on C, N, P contents and their stoichiometric stability. The correlations between C and N and between C and P changed among different stumping heights, while the correlations between C and N and between C and P were weakened with increasing stumping height. Stumping did not affect the allometric growth relationship between them, with the accumulation rate of C being lower than that of N and P, and the growth of seedlings being mainly regulated by N. In summary, stumping changed nutrient content, and then changed the balance of C, N and P in plants. The performance of P. yunnanensis seedlings was mainly regulated by N. With increasing stumping height, the utilization of N and P in seedlings decreased first and then increased, at the same time the degree of N limitation decreased first and then increased.

Key words: C∶N∶P, stoichiometry, nutrient limitation, allometric growth.