Ecophysiology of Carnivorous Plants Worldwide 1980-2011

Identification of trade-offs among physiological and morphological traits and their use in cost-benefit models and ecological or evolutionary optimization arguments have been hallmarks of ecological analysis for at least 50 years. Carnivorous plants are model systems for studying a wide range of ecophysiological and ecological processes and the application of a cost-benefit model for the evolution of carnivory by plants has provided many novel insights into trait-based cost-benefit models. Central to the cost-benefit model for the evolution of botanical carnivory is the relationship between nutrients and photosynthesis; of primary interest is how carnivorous plants efficiently obtain scarce nutrients that are supplied primarily in organic form as prey, digest and mineralize them so that they can be readily used, and allocate them to immediate versus future needs. Most carnivorous plants are terrestrial - they are rooted in sandy or peaty wetland soils - and most studies of cost-benefit trade-offs in carnivorous plants are based on terrestrial carnivorous plants. However more than 10% of carnivorous plants are unrooted aquatic plants. By examining data published between 1980 and 2011, we ask whether the cost-benefit model applies equally well to aquatic carnivorous plants and what general insights into trade-off models are gained by this comparison. Nutrient limitation is more pronounced in terrestrial carnivorous plants, which also have much lower growth rates and much higher ratio of dark respiration to photosynthetic rates than aquatic carnivorous plants. Phylogenetic constraints on ecophysiological trade-offs among carnivorous plants remain unexplored. Despite differences in detail, the general cost-benefit framework continues to be of great utility in understanding the evolutionary ecology of carnivorous plants. We provide a research agenda that if implemented would further our understanding of ecophysiological trade-offs in carnivorous plants and also would provide broader insights into similarities and differences between aquatic and terrestrial plants of all types.

生理与形态性状间权衡关系的识别，及其在成本效益模型、生态学或进化优化论证中的应用，已是至少50年来生态学分析的标志性研究范式。食虫植物是研究多种生态生理过程与生态学过程的模式系统，而针对植物食虫性演化的成本效益模型应用，也为基于性状的成本效益模型研究提供了诸多新颖见解。植物食虫性演化的成本效益模型，其核心在于养分与光合作用之间的关联；研究的核心关切在于，食虫植物如何高效获取主要以猎物有机形式存在的稀缺养分，对其进行消化与矿化以实现高效利用，并将养分分配至当前或未来生长需求。多数食虫植物为陆生类型，扎根于沙质或泥炭质湿地土壤中；现有关于食虫植物成本效益权衡的研究，也大多基于陆生食虫植物。然而，超过10%的食虫植物为无根水生植物。本研究通过梳理1980年至2011年间发表的相关数据，旨在探讨成本效益模型是否同样适用于水生食虫植物，以及该对比分析能为权衡模型研究带来哪些普适性见解。陆生食虫植物的养分限制更为显著，其生长速率远低于水生食虫植物，而暗呼吸与光合速率的比值则远高于后者。食虫植物生态生理权衡关系所受的系统发育约束，仍有待探索。尽管细节上存在差异，但通用的成本效益框架仍在解析食虫植物演化生态学方面具有极高的应用价值。本研究提出了一套研究议程，若得以实施，将有助于深化我们对食虫植物生态生理权衡关系的认知，同时也能为各类水生与陆生植物间的异同点提供更普适性的见解。