Responses of Nitrogen, Phosphorus and Potassium Contents and Stoichiometric Characteristics of Fraxinus malacophylla Seedlings to Shading

Purpose  To compare the contents of nitrogen (N), phosphorus (P) and potassium (K) and stoichiometric characteristics of white lance pole (Fraxinus malacophylla) seedlings under different shade conditions in response to shading, providing a scientific management basis for understory planting of F. malacophylla seedlings.

Methods One-year old F. malacophylla potted seedlings were used as materials, and four shading treatments (full light, 25% shading, 50% shading and 75% shading) were set up for three months, and then the height and diameter of F. malacophylla seedlings were measured, biomass of each organ, and N, P, and K contents of each organ were determined, and the stoichiometric characteristics of N, P, and K were analyzed.

Results Under 50% shading treatment, N content in leaves, P content in stems and leaves, and K content in roots and leaves were highest; under 75% shading treatment, N content in roots and stems was highest, and P use efficiency was highest in F. malacophylla seedlings. The N, P, and K partitioning ratios in leaves of F. malacophylla seedlings all reached maximum values under the 75% shading treatment. With the increase of shading, N, P and K accumulation in all organs of F. malacophylla seedlings tended to increase and then decrease, and reaching a maximum value at 50% shading.

Conclusion Under the conditions of this study, both full light and excessive shade affect the growth of F. malacophylla seedlings, while the growth of F. malacophylla seedlings and the accumulation of N, P, K and biomass in each organ of F. malacophylla seedlings can be promoted under 50% shading treatment. It can be seen that F. malacophylla seedlings have a certain degree of shading tolerance and are suitable for growth under 50% shading.