Abstract We develop a hierarchical approach to modeling organism acclimation to changing availability of and requirements for substitutable and interdependent resources. Substitutable resources are resources that fill the same metabolic or stoichiometric need of the organism. Interdependent resources are resources whose acquisition or expenditure are tightly linked (e.g., light, CO2, and water in photosynthesis and associated transpiration). We illustrate the approach by simulating the development of vegetation with four substitutable sources of N that differ only in the cost of their uptake and assimilation. As the vegetation develops, it uses the least expensive N source first then uses progressively more expensive N sources as the less expensive sources are depleted. Transition among N sources is based on the marginal yield of N per unit effort expended, including effort expended to acquire C to cover the progressively higher uptake costs. We illustrate the approach to interdependent resources by simulating the expenditure of effort to acquire light energy, CO2, and water to drive photosynthesis in vegetation acclimated to different conditions of soil water, atmospheric vapor pressure deficit, CO2 concentration, and light levels. The approach is an improvement on the resource optimization used in the earlier Multiple Element Limitation (MEL) model.

中文翻译：

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一种可替代和相互依赖的资源优化建模方法

摘要 我们开发了一种分层方法来模拟生物体适应可替代和相互依赖资源的不断变化的可用性和需求。可替代资源是满足生物体相同代谢或化学计量需要的资源。相互依赖的资源是其获取或支出密切相关的资源（例如光合作用和相关蒸腾作用中的光、二氧化碳和水）。我们通过模拟具有四种可替代 N 源的植被发育来说明该方法，这些 N 源仅在其吸收和同化成本方面有所不同。随着植被的发展，它首先使用最便宜的氮源，然后随着较便宜的源耗尽而逐渐使用更昂贵的氮源。N 源之间的转换基于每单位努力所花费的 N 的边际产量，包括为获得 C 以支付逐渐提高的吸收成本所花费的努力。我们通过模拟获取光能、CO2 和水以驱动适应土壤水、大气蒸汽压差、CO2 浓度和光照水平的不同条件的植被中的光合作用的努力来说明相互依赖资源的方法。该方法是对早期多元素限制 (MEL) 模型中使用的资源优化的改进。和水以驱动植被中的光合作用，以适应土壤水分、大气蒸气压不足、二氧化碳浓度和光照水平的不同条件。该方法是对早期多元素限制 (MEL) 模型中使用的资源优化的改进。和水以驱动植被中的光合作用，以适应土壤水分、大气蒸气压不足、二氧化碳浓度和光照水平的不同条件。该方法是对早期多元素限制 (MEL) 模型中使用的资源优化的改进。