Balancing the nutrient needs: Optimizing growth in Malus sieversii seedlings through tailored nitrogen and phosphorus effects

The impact of nitrogen (N) and phosphorus (P) on the physiological and biochemical processes crucial for tree seedling growth is substantial. Although the study of plant hydraulic traits in response to N and P is growing, comprehensive research on their combined effects remains limited. Malus sieversii, a key ancestral species of modern apples and a dominant species in Xinjiang's Tianshan wild fruit forest, is witnessing a decline due to climate change, pests and diseases, compounded by challenges in seedling regeneration. Addressing this, a four-year study was conducted to determine the optimal fertilization method for it. The experiment explored varying levels of N (N10, N20, N40) and P (P2, P4, P8), and their combined effects (N20Px: N20P2, N20P4, N20P8; NxP4: N10P4, N20P4, N40P4), assessing their impact on gas exchange, hydraulic traits, and the interplay among functional traits in Tianshan Mountains' M. sieversii seedlings. Our study revealed that all nitrogen treatments enhanced g..., Select sun-oriented, fully expanded leaves. Gas exchange parameters, including net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and intercellular CO2 concentration (Ci), were measured using a Li-Cor 6400 portable photosynthesis system under a photosynthetic photon flux density of 1500 μmol m-2 s-1 between 9:00-13:00 BST. The leaf chamber used was a 2×3 cm unit with a red and blue light source. CO2 concentration was set to 400 ppm with a high flow rate of 500 μmol s-1 to minimize stabilization time for Pn and Gs measurements. Predawn water potential (ΨPd) and the midday water potential (ΨM) were measured at predawn (5:00–7:00) and midday (13:00–14:00) using a pressure chamber (Model 3500, PMS Instrument Company, Albany, USA). The evening before measurements, select and mark healthy, north-south oriented branches with colored tape. The next day, measure the water potential of the marked branches. Place the cut branches in the pressure chamber, open the co..., , # Balancing the nutrient needs: Optimizing growth in Malus sieversii seedlings through tailored nitrogen and phosphorus effects [https://doi.org/10.5061/dryad.brv15dvj0](https://doi.org/10.5061/dryad.brv15dvj0) All data in this dataset were obtained from field measurements in the field through in situ experiments. The hydraulic trait and gas exchange data for the NxP4 addition were not included in this study. The notation \"n/a or null\" is used in the dataset to indicate the portions where data is missing. ## Description of the data and file structure The nutrient addition patterns that emerged from the data are specifically described as follows： | Treatments | N (g m-2 yr-1) | P (g m-2 yr-1) | Nutrient Description | | :--------- | :------------- | :------------- | :------------------- | | CK | 0 | 0 | Control group | | N10 | 10 | 0 | Low N addition | | N20 | 20 | 0 | Medi...氮（N）和磷（P）对林木幼苗生长至关重要的生理生化过程影响显著。尽管针对植物水力性状响应氮磷的研究日益增多，但关于二者联合效应的综合研究仍较为匮乏。新疆野苹果（Malus sieversii）是现代苹果的核心祖先种，同时也是新疆天山野果林的优势物种，当前其种群因气候变化、病虫害正面临衰退，且幼苗更新面临诸多挑战。为此，本研究开展了为期四年的定位试验，旨在确定该物种的最优施肥方案。本试验设置了不同施氮水平（N10、N20、N40）与施磷水平（P2、P4、P8），以及二者的联合处理（N20Px：N20P2、N20P4、N20P8；NxP4：N10P4、N20P4、N40P4），并评估了这些处理对天山新疆野苹果幼苗气体交换参数、水力性状及功能性状间相互关系的影响。研究发现，所有施氮处理均提升了…… 选取向阳、完全展开的叶片。于英国夏令时9:00-13:00，在光合有效辐射通量密度为1500 μmol·m⁻²·s⁻¹的条件下，使用Li-Cor 6400型便携式光合测定系统测定气体交换参数，包括净光合速率（Pn）、气孔导度（Gs）、蒸腾速率（Tr）及胞间CO₂浓度（Ci）。试验采用2×3 cm的红蓝光源叶室，将CO₂浓度设定为400 ppm，以500 μmol·s⁻¹的高流速进行测定，以缩短净光合速率与气孔导度的稳定时间。 分别于黎明前（5:00-7:00）与正午（13:00-14:00），使用压力室（美国奥尔巴尼PMS仪器公司3500型）测定黎明前水势（ΨPd）与正午水势（ΨM）。测定前一晚，选取并标记健康的南北向枝条，次日对标记枝条的水势进行测定。将剪下的枝条放入压力室，开启…… # 平衡养分需求：通过定制化氮磷调控优化新疆野苹果（Malus sieversii）幼苗生长 https://doi.org/10.5061/dryad.brv15dvj0 本数据集所有数据均通过原位野外试验的实地测量获取。 本研究未纳入NxP4添加处理的水力性状与气体交换数据。数据集中使用"n/a或null"标记数据缺失的部分。 ## 数据与文件结构说明 本数据集中的养分添加处理模式具体描述如下： | 处理组 | 施氮量（g·m⁻²·yr⁻¹） | 施磷量（g·m⁻²·yr⁻¹） | 养分处理说明 | | :----- | :------------------- | :------------------- | :----------- | | CK | 0 | 0 | 对照组 | | N10 | 10 | 0 | 低氮添加 | | N20 | 20 | 0 | 中等...