Nitrogen supply forms alter adaptive properties of Moso bamboo seedlings in low phosphorus conditions

Abstract

Aims Soil phosphorus loss often occurs in subtropical areas, resulting in extremely low phosphorus levels in forest land, thus affecting soil fertility and hindering normal plant growth. Further research is needed to understand plant preference for different nitrogen sources and to select appropriate nitrogen sources to improve fertilizer use efficiency. The relationship between soil nutrient dynamics and seedling physiology was studied, and the effects of different nitrogen fertilizers on the growth of Phyllostachys edulis seedlings under low phosphorus conditions were evaluated. Methods Under four different forms of nitrogen supply (NO₃⁻-N; NH₄⁺-N; NO₃⁻-N + NH₄⁺-N; Org-N) and two phosphorus treatment conditions (deficient, 5.0 mg·kg^− 1; sufficient, 20 mg·kg^− 1). Results Low phosphorus can alter the nutrient environment of some substrates and inhibit the growth of bamboo seedlings, but it improves the efficiency of plant phosphorus utilization; Low phosphorus has a strong inhibitory effect on bamboo, and under low phosphorus conditions, the proportion of amino acid components in bamboo is imbalanced. But it will enhance its adaptability to low phosphorus stress by coordinating the root to shoot ratio, changing the root morphology, improving the efficiency of nitrogen transport and metabolism in roots, stems, and leaves, enhancing the efficiency of leaf electron transfer, and redistributing nutrient resources. In addition, supplying NH₄⁺-N fertilizer under low phosphorus conditions can increase the root to shoot ratio of bamboo, promote the absorption of phosphorus and metal ions by roots, improve nitrogen transport and metabolic efficiency, enhance leaf light utilization capacity, and alleviate the inhibitory effect of bamboo under low phosphorus stress. However, supplying NO₃⁻-N + NH₄⁺-N fertilizer under suitable phosphorus conditions is more conducive to improving the photosynthetic capacity, nitrogen transport and metabolic efficiency of bamboo seedlings, resulting in a significant increase in their total biomass. Therefore, in the actual production and cultivation of bamboo seedlings, attention should be paid to the supply form of nitrogen fertilizer. Conclusions Single ammonium nitrogen fertilizer was more suitable for planting bamboo seedlings in natural forest land with seriously low phosphorus, while mixed inorganic nitrogen fertilizer was more suitable for planting bamboo seedlings in soil with reasonable phosphorus fertilizer. It provides theoretical basis for the cultivation and nutrient management practice of bamboo industry.