Daufresne Tanguy, Hedin Lars O
Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
Proc Natl Acad Sci U S A. 2005 Jun 28;102(26):9212-7. doi: 10.1073/pnas.0406427102. Epub 2005 Jun 17.
We present a model of plant-nutrient interactions that extends classical resource competition theory to environments in which essential nutrients (resources) are recycled between plant and soil pools and dissolved nutrients are lost through plant-available (i.e., inorganic forms) or plant-unavailable (i.e., complex organic forms) pathways. Losses by dissolved organic pathways can alter ratios of nutrients that are recycled and supplied within the plant-soil system, thereby influencing competition and coexistence among plant species. In special cases, our extended model does not differ from classical models, but in more realistic cases our model introduces new dynamical behavior that influences competitive outcomes. At equilibrium, coexistence still depends on nutrient supply and consumption, but nutrient supply includes recycling and is highly sensitive to whether a species promotes more organic losses of the nutrient that limits its own growth than of nutrients that limit its competitors. Because recycling operates with a time delay compared with consumption, recycling-mediated effects on competition can, under certain conditions, lead to sustained population oscillations. Our findings have implications for how we understand nutrient competition, nutrient cycles, and plant evolutionary strategies.
我们提出了一个植物 - 养分相互作用模型，该模型将经典资源竞争理论扩展到这样的环境中：在这些环境中，必需养分（资源）在植物和土壤库之间循环，溶解态养分通过植物可利用（即无机形式）或植物不可利用（即复杂有机形式）的途径流失。通过溶解有机途径的流失会改变在植物 - 土壤系统中循环和供应的养分比例，从而影响植物物种之间的竞争和共存。在特殊情况下，我们的扩展模型与经典模型没有差异，但在更现实的情况下，我们的模型引入了影响竞争结果的新动态行为。在平衡状态下，共存仍然取决于养分供应和消耗，但养分供应包括循环，并且对一个物种促进限制其自身生长的养分的有机流失是否多于限制其竞争者生长的养分的有机流失高度敏感。由于与消耗相比，循环以时间延迟的方式运行，在某些条件下，循环介导的竞争效应可能导致种群持续振荡。我们的研究结果对于我们如何理解养分竞争、养分循环和植物进化策略具有启示意义。
