Li Junyu, Liao Yongmei, Wei Wanrong, Xu Xiaoqin, He Jundong, Zhao Tingting
College of Geography and Geomatics, Xuchang University, Xuchang 461000, China.
Key Laboratory of Southwest China Wildlife Resources Conservation, Ministry of Education, Nanchong 637009, China.
Plants (Basel). 2025 Apr 21;14(8):1261. doi: 10.3390/plants14081261.
Human activities have increased the imbalance in atmospheric N and P deposition, which changes soil nutrient availability and subsequently affects the structure and function of terrestrial ecosystems. Dioecious plants are important parts of terrestrial ecosystems and are characterized by sex-related differences in their response to the external environment and always exhibit a skewed sex ratio, which makes them more vulnerable to climate change and increases their risk of extinction. However, little attention has been paid to the effects of unbalanced N and P deposition on these plants, especially on their defense traits. In this study, we used dioecious to investigate the influence of gradient N and P deposition on the correlation between growth and defense traits. The results showed that although the different rates of N and P deposition enhanced biomass accumulation in both sexes to varying degrees, the most substantial biomass increment was noted under a lower-nitrogen and higher-phosphorus (LNHP) treatment regimen, with females showing an approximately 112% increase and males a 47% increase in total biomass. In response to varying levels of simulated N and P deposition, males and females adopt distinct strategies for biomass allocation. Although declines in root biomass were observed in both sexes as nutrient availability increased, the decrement was more marked in males; under the LNHP treatment, it dropped by about 11%, while under a high-nitrogen and high-phosphorus (HNHP) treatment, the decrease was about 35%. Conversely, females demonstrated a heightened propensity to allocate biomass towards leaf development. Furthermore, with increasing N and P deposition, there was a general reduction in the concentrations of physical and chemical defense substances within the leaves of both sexes. Nonetheless, the correlations between defense substances, nutrient element content, non-structural carbohydrate (NSC) content, and dry biomass were more pronounced in males, suggesting a greater sensitivity to defense substance responses in males than in females. Overall, these results indicate that there is sexual dimorphism in the accumulation of chemical substances in male and female under unbalanced N and P deposition and they provide a technical and theoretical basis for predicting the population dynamics of dioecious plants, maintaining the stability of poplar populations, and constructing high-productivity poplar plantations globally in the future.
人类活动加剧了大气中氮和磷沉降的失衡，这改变了土壤养分有效性，进而影响陆地生态系统的结构和功能。雌雄异株植物是陆地生态系统的重要组成部分，其特点是对外部环境的反应存在性别差异，且性别比例往往失衡，这使得它们更容易受到气候变化的影响，增加了灭绝风险。然而，人们很少关注氮磷沉降失衡对这些植物的影响，尤其是对其防御性状的影响。在本研究中，我们利用雌雄异株植物来探究梯度氮磷沉降对生长与防御性状之间相关性的影响。结果表明，尽管不同的氮磷沉降速率在不同程度上促进了两性生物量的积累，但在低氮高磷（LNHP）处理方案下生物量增加最为显著，雌性总生物量增加了约112%，雄性增加了47%。针对不同水平的模拟氮磷沉降，雄性和雌性采取了不同的生物量分配策略。尽管随着养分有效性的增加，两性的根生物量均有所下降，但雄性的下降更为明显；在LNHP处理下，根生物量下降了约11%，而在高氮高磷（HNHP）处理下，下降了约35%。相反，雌性表现出更高的生物量向叶片发育分配的倾向。此外，随着氮磷沉降的增加，两性叶片中物理和化学防御物质的浓度总体上有所降低。然而，防御物质、营养元素含量、非结构性碳水化合物（NSC）含量与干生物量之间的相关性在雄性中更为显著，这表明雄性对防御物质反应的敏感性高于雌性。总体而言，这些结果表明，在氮磷沉降失衡的情况下，雌雄异株植物在化学物质积累方面存在性别差异，为未来预测雌雄异株植物种群动态、维持杨树种群稳定性以及在全球范围内构建高产杨树人工林提供了技术和理论依据。
