Plant economics run on carbon and nutrients instead of money. Leaf strategies aboveground span an economic spectrum from “live fast and die young” to “slow and steady,” but the economy defined by root strategies belowground remains unclear. Here, we take a holistic view of the belowground economy and show that root-mycorrhizal collaboration can short circuit a one-dimensional economic spectrum, providing an entire space of economic possibilities. Root trait data from 1810 species across the globe confirm a classical fast-slow “conservation” gradient but show that most variation is explained by an orthogonal “collaboration” gradient, ranging from “do-it-yourself” resource uptake to “outsourcing” of resource uptake to mycorrhizal fungi. This broadened “root economics space” provides a solid foundation for predictive understanding of belowground responses to changing environmental conditions.

植物经济学依靠的是碳和养分而不是金钱。地上的叶子战略涵盖了从“快活早逝”到“缓慢而稳定”的经济范围，但地下根战略所定义的经济仍不清楚。在这里，我们对地下经济进行了全面的观察，并表明根菌根协作可以缩短一维经济范围，提供整个经济可能性的空间。来自全球 1810 个物种的根性状数据证实了经典的快慢“保护”梯度，但表明大多数变异是由正交“协作”梯度解释的，范围从“自己动手”资源吸收到“外包”资源菌根真菌的资源吸收。这种扩大的“根经济学空间”为预测了解地下对不断变化的环境条件的反应提供了坚实的基础。