Metabolic scaling theory predicts that plant productivity and biomass are both size-dependent. However, this theory has not yet been tested in plant roots. In this study, we tested how metabolic scaling occurs in plants using a comprehensive plant root dataset made up of 1016 observations from natural habitats. We generated metabolic scaling exponents by log-transformation of root productivity versus biomass. Results showed that the metabolic scaling exponents of fine root (< 2 mm in diameter) productivity versus biomass were close to 1.0 for all ecosystem types and functional groups. Scaling exponents decreased in coarse roots (> 2 mm in diameter). We found isometric metabolic scaling in fine roots, a metabolically active organ similar to seedlings or saplings. Our findings also indicate a shift in metabolic scaling during plant development. Overall, our study supports the absence of any unified single constant scaling exponent for metabolism-biomass relationships in terrestrial plants, especially for forests with woody species.

中文翻译：

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测试植物根系中的异度缩放比例关系

代谢缩放理论预测植物的生产力和生物量均与大小有关。但是，该理论尚未在植物根部得到检验。在这项研究中，我们使用由来自自然栖息地的1016个观测值组成的综合植物根数据集，测试了植物中代谢缩放的发生方式。我们通过根生产力对生物量的对数转换来生成代谢比例指数。结果表明，对于所有生态系统类型和功能组，细根（直径<2 mm）生产力与生物量的代谢缩放指数均接近1.0。粗根（直径> 2 mm）的缩放指数减小。我们在细根中发现了等距代谢结垢，细根是一种类似于幼苗或树苗的代谢活跃器官。我们的发现还表明在植物发育过程中代谢水垢的变化。