关键词: 叶片性状网络, 季节动态, 黑沙蒿, 性状变异

Abstract: Aims Clarifying the network characteristics of plant traits is one of the research hotspots in functional ecology. However, the understanding of plant trait networks and their driving factors at the seasonal scale is still limited. Methods We used a Li-6400 portable photosynthetic instrument to regularly measured the light response and carbon dioxide response curves of Artemisia ordosica during the growing season (May-September), and leaf structural and biochemical indicators as well, to explore the correlation and trait network characteristics among 25 leaf traits. Important findings There are significant correlation between leaf traits at the seasonal scale, and the closest coupling relationship between traits occurs between photosynthetic physiological traits, with a total of 67 pairs of physiological trait combinations showing significant correlation. The edge density, diameter, average path length, and modularity of the plant trait network (PTN) are 0.58, 3, 1.51, and 0.08, respectively. The betweenness of leaf tissue density (LTD), leaf nitrogen content per unit area (Narea), and transpiration rate (E) is relatively high, making it a "bridge" in PTN. PTN does not have an absolute central trait, and physiological traits as a whole exhibit high degree, eigenvector centrality, and clustering coefficient, indicating that the trait network is jointly dominated by physiological traits. Further analysis indicates that the 25 leaf traits at the seasonal scale can be compressed into two major trait dimensions: one is regulated by air temperature and soil moisture, and the other is regulated by photosynthetic effective radiation. The research results emphasize that when evaluating the potential response of different trait functional groups to climate fluctuations, it is necessary to distinguish the degree and effect of environmental factors on different traits. If the seasonal response of plant traits to the environment is included in a unified paradigm, it will wrongly evaluate the adaptability of plant traits.

Key words: leaf trait network, seasonal dynamics, Artemisia ordosica, trait variation