Earlier start of the growing season (SGS) and delayed end of the growing season (EGS) affect plant carbon uptake. However, the effects of phenological changes on carbon allocation to different plant organs remain unclear. Here, we examined the effects and potential mechanisms of phenological changes on carbon allocation to different organs over the northern hemisphere (> 30° N). We found the earlier SGS facilitated allocating carbon to roots in warm areas, and delayed EGS benefited allocating carbon to roots in dry areas. Moreover, the effects of SGS and EGS on carbon accumulation in different organs significantly enhanced over time. Path analyses indicated that phenological changes contributed to root–stem ratio mainly by regulating the growing season length. Our findings further highlight that phenological changes alter plants' investment strategies in carbon allocation for above‐ and below‐ground parts, and considering this role is critical for accurately estimating the carbon budget in terrestrial ecosystems.

中文翻译：

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植物物候的变化显著影响植物不同器官的碳分配


生长季节提前开始 （SGS） 和生长季节延迟结束 （EGS） 会影响植物的碳吸收。然而，物候变化对不同植物器官碳分配的影响仍不清楚。在这里，我们研究了物候变化对北半球 （x3E 30° N） 不同器官碳分配的影响和潜在机制。我们发现，较早的 SGS 有助于将碳分配给温暖地区的根系，而延迟的 EGS 有利于将碳分配给干燥地区的根系。此外，SGS 和 EGS 对不同器官碳积累的影响随着时间的推移而显著增强。路径分析表明，物候变化主要通过调节生长季长度对根茎比做出贡献。我们的研究结果进一步强调，物候变化改变了植物在地上和地下部分碳分配的投资策略，考虑这一作用对于准确估计陆地生态系统中的碳收支至关重要。