Stoichiometric characteristics and allometric analysis of nitrogen, phosphorus and potassium in different organs of Pinus yunnanensis

In order to explore the relationship of nitrogen (N), phosphorus (P), potassium (K) stoichiometry and its anisotropic growth analysis among different organs of Pinus yunnanensis seed seedlings, and to understand the allocation of each element among its different organs for growth and development, two-year old (2018-2020) P. yunnanensis seedlings grown in the seed of P. yunnanensis seed garden in Maidu, Yunnan Province, were used as experimental objects, and the whole plant and different organs' N, P, K content and stoichiometric ratio were analyzed and combined with correlation and anisotropic growth analysis. Analyzing the N, P, K contents and stoichiometric ratios of the whole plant and different organs, and combining correlation and anisotropic growth analyses to explore the growth relationship between different organs of P. yunnanensis seedling, in order to provide a theoretical basis for the efficient cultivation of P. yunnanensis. The results showed that the average contents of N, P and K among different organs were stem > root > leaf in descending order, and the N∶P of each organ was root > stem > leaf, the N∶K was root > stem > leaf, and the K∶P was leaf > root > stem. the N∶P ratio was significantly less than 14, which indicated that the growth of P. yunnanensis seedling was greatly affected by the limitation of N. The K contents of different organs showed the relationship of isochronous growth, and the accumulation rate of the N and P contents of root was smaller than that of leaf, which indicated that the growth of P. yunnanensis seedlings was greatly influenced by the limitation of N. The K contents of organs showed the relationship of isochronous growth, and the N and P contents of root accumulated less than the accumulation rate of leaf, which indicated the accumulation rate of leaf. The accumulation rate of N and P elements in roots was smaller than that in leaves, indicating that N and P elements were preferentially allocated to leaves when P. yunnanensis seedlings were biennial. The results of this study deepen the understanding of the growth mechanism of P. yunnanensis seedlings and provide a theoretical basis for practical application, which can help to realize more efficient and sustainable cultivation and propagation of more excellent P. yunnanensis seedlings.