State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Resources and Environment, University of Chinese Academy of Sciences, the Chinese Academy of Sciences, Beijing, China.
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
Sci Total Environ. 2024 Apr 1;919:170920. doi: 10.1016/j.scitotenv.2024.170920. Epub 2024 Feb 12.
Variation in biomass elemental composition of grassland plants may have important implications for ecosystem functioning in response to global change. However, relevant studies have mostly focused on variation of nitrogen (N) and phosphorus (P) concentrations in plant leaves, while few studies have evaluated other elements and plant organs of grassland species. Here, we examined the effects of N addition on multi-element concentrations, and analyzed their patterns across different organs (leaf, stem, root and seed) of five plant species in a steppe community of the Inner Mongolian grassland. Our results showed that seeds exhibited the most stable elemental composition with N addition, and that manganese (Mn) and iron (Fe) concentrations were substantially more variable than macro-elements in response to N addition. In particular, we identified a set of significant negative relationships between elemental concentrations and their corresponding CVs (coefficients of variation) for all plant organs as a whole and for each individual organ. We further found that changes in soil pH and the availability of soil nutrients contributed mostly to variation in the biomass elemental composition of major plants in this community. These findings are important for accurately assessing the effects of N deposition on the biochemical cycling of nutrient elements in grassland ecosystems, and provide critical clues for developing effective approaches to adaptively managing grassland resources as well as mitigating the impact of global change on the dryland ecosystems in the Mongolia Plateau.
草原植物生物量元素组成的变化可能对生态系统功能对全球变化的响应有重要意义。然而，相关研究主要集中在植物叶片氮（N）和磷（P）浓度的变化上，而很少有研究评估草原物种的其他元素和植物器官。在这里，我们研究了氮添加对五种草原植物物种叶片、茎、根和种子等不同器官中多元素浓度的影响，并分析了它们在不同器官中的变化模式。我们的结果表明，种子对氮添加表现出最稳定的元素组成，锰（Mn）和铁（Fe）浓度比宏量元素对氮添加的变化更为显著。特别是，我们发现所有植物器官和每个单独器官的元素浓度与其相应的变异系数（CV）之间存在一组显著的负相关关系。我们进一步发现，土壤 pH 值的变化和土壤养分的有效性主要导致了该群落中主要植物生物量元素组成的变化。这些发现对于准确评估氮沉降对草原生态系统养分元素生物化学循环的影响非常重要，并为开发有效方法来适应管理草原资源以及减轻全球变化对蒙古高原旱地生态系统的影响提供了关键线索。
