Understanding the relationships and dynamics of environmental variables, leaf traits, and photosynthetic parameters in determining gross ecosystem productivity (GEP) is fundamental to assessing the carbon (C) cycle. However, existing knowledge in this area, especially concerning desert ecosystems, remains entirely inadequate. In this study, we used near-continuous eddy covariance, foliar, and photosynthetic data acquired from an -dominated shrubland over a seven-year period (2013–2019). The study proceeded to assess: (i) the influence of environmental variables on GEP as a function of leaf phenology, (ii) the role of foliar traits and photosynthetic parameters in regulating GEP, and (iii) resource use strategies adopted by in response to adverse environmental conditions. Analysis of controlling factors indicated that various environmental and photo-physiological factors influenced GEP to different extents, depending on leaf phenology. During the leaf-expanding phase, GEP was largely controlled by maximum carboxylation rate (). With leaf expansion, the leaf dark respiration rate (), stomatal conductance (), and light compensation point (LCP) played pivotal roles in an upregulation of GEP. However, during the leaf-coloring phase, GEP was limited by the maximum electron transport rate (). Our findings accentuate 's conservative strategy in nitrogen resource investment, which influences the shrubland's role as a C sink. These insights emphasize the importance of considering both climatic and plant physiological controls, especially as it pertains to photosynthesis, when seeking to understand broader C dynamics in desert ecosystems.

中文翻译：

---

沙漠灌木丛中生态系统规模的碳动态：揭示叶子功能和生理特性与环境之间复杂的相互作用


了解环境变量、叶片性状和光合参数在确定总生态系统生产力 (GEP) 方面的关系和动态是评估碳 (C) 循环的基础。然而，这一领域的现有知识，特别是关于沙漠生态系统的知识，仍然完全不足。在这项研究中，我们使用了七年期间（2013-2019）从 主导灌木丛中获取的近连续涡度协方差、叶面和光合作用数据。该研究继续评估：(i) 环境变量对 GEP 的影响（作为叶片物候的函数），(ii) 叶性状和光合参数在调节 GEP 中的作用，以及 (iii) 采取的资源利用策略不利的环境条件。控制因素分析表明，各种环境和光生理因素对GEP有不同程度的影响，具体取决于叶片物候。在叶片展开阶段，GEP 主要受最大羧化速率控制 ()。随着叶片扩张，叶片暗呼吸速率 ()、气孔导度 () 和光补偿点 (LCP) 在 GEP 上调中发挥关键作用。然而，在叶子着色阶段，GEP 受到最大电子传输速率的限制 ()。我们的研究结果强调了氮资源投资的保守策略，这影响了灌木丛作为碳汇的作用。这些见解强调了在寻求了解沙漠生态系统中更广泛的碳动态时考虑气候和植物生理控制的重要性，特别是与光合作用有关的控制。