Tian Jinyuan, Zhang Hongxia, Wang Anzhi, Wu Jiabing, Rosner Sabine, Zhu Kai, Cai Rongrong, Yuan Fenghui
CAS Key Laboratory of Forest Ecology and Silviculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.
Front Plant Sci. 2025 Apr 14;16:1574468. doi: 10.3389/fpls.2025.1574468. eCollection 2025.
Climate change profoundly impacts the physiological processes and adaptation strategies of plants. However, the physiological mechanisms of coniferous species responding and adapting to combined drought and nitrogen (N) addition remain unclear. Here, based on 2-year multi-level N addition and drought experiments, we investigated the responses of carbon assimilation (net photosynthetic rate , stomatal conductance and intrinsic water use efficiency WUE) and carbon reserves (non-structural carbohydrates, NSC) of 7-year-old Korean pine () saplings. Our results showed that: (1) Drought decreased and , while N addition increased and decreased . N addition decreased and WUE but increased in plants under drought conditions, indicating that N addition under drought stress will maintain gas exchange by increasing stomatal opening, but failed to mitigate the reduction of . (2) Both drought (moderate and severe) and N addition reduced leaf NSC concentrations. Under moderate drought stress, however, N addition led to an increase in leaf NSC concentrations. (3) The interconversion between leaf starch and soluble sugars slowed the decrease in carbon assimilation caused by drought. saplings adopted a conservative strategy of increasing leaf mass per area (LMA) to adapt to reduced water use efficiency. The study highlights the coordinated relationship between carbon assimilation and carbon reserves of Korean pine saplings under combined drought and N addition, which improves our understanding of the diverse carbon dynamics of different species under climate change.
气候变化对植物的生理过程和适应策略产生深远影响。然而，针叶树种对干旱和氮添加复合胁迫的响应及适应的生理机制仍不清楚。在此，基于为期两年的多层次氮添加和干旱实验，我们研究了7年生红松幼树的碳同化（净光合速率、气孔导度和内在水分利用效率）和碳储备（非结构性碳水化合物，NSC）的响应。我们的结果表明：（1）干旱降低了净光合速率和气孔导度，而氮添加增加了净光合速率并降低了气孔导度。在干旱条件下，氮添加降低了内在水分利用效率但增加了净光合速率，这表明干旱胁迫下的氮添加将通过增加气孔开度来维持气体交换，但未能减轻净光合速率的降低。（2）干旱（中度和重度）和氮添加均降低了叶片NSC浓度。然而，在中度干旱胁迫下，氮添加导致叶片NSC浓度增加。（3）叶片淀粉和可溶性糖之间的相互转化减缓了干旱引起的碳同化下降。红松幼树采取了增加单位叶面积质量（LMA）的保守策略来适应水分利用效率的降低。该研究突出了干旱和氮添加复合胁迫下红松幼树碳同化与碳储备之间的协调关系，这增进了我们对气候变化下不同物种多样碳动态的理解。
